olaru geotectonic context · 2019. 2. 17. · acta palaeontologica romaniae v. 6 (2008), p 253-277....

ACTA PALAEONTOLOGICA ROMANIAE V. 6 (2008), P 253-277.

1 “Al. I. Cuza” University of Iaşi, Department of Geology, Bd. Carol I, no. 20A, 700505, Iasi, Romania, e-mail: [email protected]

GEOTECTONIC CONTEXT AND PALYNOLOGICAL ARGUMENTS FOR CAMBRIAN / ORDOVICIAN BOUNDARY IN THE METAMORPHITES OF TULGHEŞ GROUP FROM

EAST CARPATHIANS, ROMANIA

Leonard OLARU1

Abstract: Establishing the stratigraphical boundaries within the metamorphic formations is difficult to achieve due to the complexity of the geological and tectonic factors, which contributed to the spatial definition of these formations. During our study, we focused our investigations on the upper formations of Tulgheş Group from East Carpathians, also known as Arşiţa Rea Formation (Tg. 4) from Bălan area. The present metamorphic formations of Tulgheş Group initially had a sedimentary feature, subsequently being affected by tectonic factors and by metamorphism. In spite of this, they preserve the arguments of the sedimentary stage, represented by the content with acritarch and chitinozoan assemblages. The tectonic and structural changes of these initially sedimentary formations are mainly the result of the collision between East-European Craton (EEC) and the rigid Central European Platform. As a result of this collision, there was a repeated overthrust of these formations from Tulgheş Group, E-W oriented, over the stable and calcareous platform of Rebra Group (Munteanu, Tatu, 2003). All these formations were initially affected by the Caledonian metamorphism and subsequently by the Varistic one. Besides the overthrusting and the metamorphism phenomena, there was a lithological, structural and palynological mixture of all the affected formations. The initial organic elements, the acritarchs and the chitinozoans, due to their constitution, survived the metamorphic and tectonic phenomena, which affected these formations, and nowadays it represents the only important arguments for the biostratigraphical study and the regional correlation. The stratigraphical boundary for Cambrian/Ordovician is difficult to be established due to the lack of the faunistic remains (trilobites, graptolites, conodonts), or because of the mixture between the existent acritarch and chitinozoan assemblages. In spite of all, the presence of some marker-elements for a stratigraphical boundary, such as Coryphidium bohemicum, Acanthodiacrodium angustum, Conochitina symmetrica, Conochitina raymondii, Lagenochitina esthonica, Desmochitina bulla, allowed us to establish that the Cambrian/Ordovician boundary is included within Arşiţa Rea Formation (Tg. 4), considered to be Arenigian age (Lower Ordovician). This boundary was also established by correlating the classical regions from Peri-Gondwanaland, Central and Western Europe, Baltic region, Laurentia and East-European Platform, using the comparison with the marker-assemblages of trilobites, graptolites and conodonts. With this correlation, there was established also the amalgamation feature of the acritarch and chitinozoan assemblages, also using the common coexistence of the Gondwanian, Laurential, Baltic, Central and East-European elements. Key words: Palynology, Geotectonic context, Cambrian / Ordovician boundary, Metamorphites, Tulgheş Group, East Carpathians, Romania

Introduction The problem of the stratigraphical limits

represents one of the main conclusions of each study in the geological research. Thus, the correct delimitation of the studied formations is a first guarantee for the best results every stratigraphical investigation. In order to have properly outlined stratigraphical limits, the studies should impose solid arguments to justify these conclusions.

In approaching the problems of the stratigraphical limits, firstly, there is necessary a thorough and analytical study of the biostratigraphy and lithology of the under-study geological formation. Secondly, there is necessary a certain knowledge of a proper work methodology and of the work resources. On this basis, there is also necessary the existence of a comparison and correlation possibility of the obtained data to other studies and conclusions from classical regions. Not at least, for the metamorphites, the geotectonical context of their settlement has a major importance in establishing a proper geological and stratigraphical limit. At last, using multiple investigation methods for stratigraphical limits

represents an important safety factor for the resulted conclusions.

Concerning the approached subject in the present study, on Cambrian - Ordovician boundary within metamorphites from East Carpathians, we focused on the upper formation of Tulgheş Group (Tg.4), also called Arşiţa Rea Formation.

Choosing this as an example is due to the fact that, generally, the lithological formations of this group have a larger spreading nappes within East Carpathians (Vodă, Balintoni, 1996), being present along all Central - East Carpathian nappes: Bucovinic Nappe, Subbucovinic Nappe and Infrabucovinic Nappe (Vodă, 2000). Thus, the formations of Tulgheş Group, from the entire East Carpathian range, are the best studied, being compared and correlated with other orogenic and platform regions.

Investigation methods To approach the Cambrian - Ordovician

boundary within Tulgheş Group, we chose the method of palynological investigations, with arguments from acritarch and chitinozoan

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assemblages, the only markers of the organic world, preserved in the aquatic basin where the primary sediments deposited, and which, subsequently, were tectonized and metamorphosed, representing today the formations of Tulgheş Group. The other arguments of the biostratigraphical investigation, using the sedimentary rocks equivalent in age, but unmetamorphosed and tectonically not disordered, such as conodonts, graptolites, and trilobites, or other macroorganic rests are totally lacking within these metamorphic formations.

During our investigations we were always related and compared to the results and the conclusions of geochronological, lithological, structural, and geotectonical studies on the same formations, which helped us a lot in having a real interpretation of our results (Balintoni, 1997; Balintoni et al., 1983; Bercia et al., 1976; Kräutner, 1987, 1997; Kräutner, Bindea, 2002; Munteanu, Tatu, 2001, 2003; Mureşan, 2000; Săndulescu, 1976, 1980a, 1980b, 1984; Zincenco, 1995). For verification and for the safety our interpretations we had permanently made biostratigraphical correlations with the platform regions, with sedimentary rocks, tectonically not disordered and unmetamorphosed, where continuous lithological successions were able to be tracked, within drillings approached in complex stratigraphical studies. Thus, there were created parallel acritarch, chitinozoan, conodont, graptolite, and trilobite biozones. Therefore, in these regions not only biostratigraphical conclusions came out, but also palaeoecological, palaeoenvironmental, palaeogeographical and palaeotectonical, too.

The chances and the advantage of using acritarch and chitinozoan assemblages in the biostratigraphical study and in approaching the stratigraphical limits in metamorphic formations are represented by the fact that these cellulose or chitinous palynomorphs fossilized themselves within the primary sedimentary rocks, deposited in the pre-metamorphic oceanic basins. Subsequently, these sediments, including the comprised organic elements, were metamorphically transformed and affected by the successive orogenic and geotectonic phases, therefore nowadays these palynomorphs represent organic evidence of an initial, oceanic, primitive organic life from the pre-metamorphical stage of the present day metamorphites. Thus, all metamorphic rocks which include microorganic rests initially were sedimentary rocks, and those having no organic rests come from former magmatic

rocks. Both types of rocks suffered deep transformations during the different metamorphic and geotectonic phases. Therefore, parametamorphites and orthometamorphites came out, which form the present assemblage of metamorphic rocks from the Mesozoic - Crystalline of East Carpathians.

Lithological content and geotectonic

context of Tulgheş Group Tulgheş Group includes a series of

lithostratigraphical successions, named lithological formations or lithozones (Vodă, Balintoni, 1996; Balintoni, 1997), recognized within the entire spreading area of East Carpathians.

Considering other opinions (Munteanu, Tatu, 2003), Tulgheş Group does not include a succession of lithostratigraphical terms, but discontinuous parts of an insular arch. The complicated problems appear at the lower and the upper parts of this group, where the limits of the succession or of the compounding elements are much affected by the geotectonic phases (Vodă, 2000; Olaru et al., 2003-2004; Munteanu, Tatu, 2003) (Figure 4). As we mentioned, Tulgheş Group has the largest spreading in East Carpathians, starting with Maramureş Mountains, go on with Bistriţa Mountains, Giurgeu and Ciuc Mountains, with its last emergence in Perşani Mountains, respectively Gârbovei Massif (Balintoni, 1997; Vodă, 2000).

Tulgheş Group presents a varied lithology, prevailing quartzitic - feldspar rocks, besides black and white quartzites (Balintoni, 1997; Vodă, 2000). The carbonatic rocks are weakly represented, occurring mainly at the lower part of Tulgheş Group; in the rest – as rare intercalations, same as the metabasites. At the lower and the median parts of Tulgheş Group (Tg.2 and Tg.3) it stands out the abundance of manganese in the quartzitic - graphitous rocks and of metallic sulphures in volcanic - sedimentary rocks. These types of rocks, besides feldspar quartzites lead to the hypothesis that Tulgheş Group formed in a nearby insular arch basin (Balintoni, 1997). Also, the presence of metarhyolites in the median formation (Tg.3) from Bistriţa Mountains shows they occur in a volcanic arch tectonic environment (Munteanu et al., 1999). On the other hand, the basic rocks represent intercalations at the basis of the lithostratigraphical succession of the acid metavolcanites (metarhyolites) formation (Tg.3) from Bistriţa Mountains,

GEOTECTONIC CONTEXT AND PALYNOLOGICAL ARGUMENTS FOR CAMBRIAN / ORDOVICIAN BOUNDARY IN THE METAMORPHITES OF TULGHEŞ GROUP FROM EAST

CARPATHIANS, ROMANIA

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Figure 1. Lithostratigraphical succession of the Tulghes Group on Bucovinic Nappe from Bistritei and Bucovinei Mountains (Lucina – Pojorata – Brosteni Region after Kräutner et al. 1988).

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from Crucea – Broşteni - Borca region and from the phyllitous, quartzitic formation (Tg.4) from the regions of Fundu Moldovei, Broşteni, Bălan and Sândominic. These intercalations have intermediary characteristics between oceanic ground basalts and insular arch basalts, a compatible interpretation with the sedimentation hypothesis of Tulgheş Group in a back-arch basin, with oceanic crust (Vodă, 2000). The content of organic rests, acritarchs and chitinozoans of the metamorphites from Tulgheş Group shows they have an initially sedimentary origin, thus, they are paramorphites.

Lithologically, Tulgheş Group or Tulgheş Lithogroup (Balintoni, 1997) includes a succession of four formations (Vodă, Balintoni, 1996; Vodă, 2000), or lithozones (Balintoni, 1997). Considering other authors (Munteanu, Tatu, 2003), Tulgheş Group consists in four discontinuous parts of an insular arch. In order to ease the explanation, these formations are noted as Tg.1 - Tg.4 (Vodă, 2000). These formations are best represented in Bucovinic Nappe, from Broşteni region (Vodă, 1986), in stratigraphical order (Figure 1), as it follows:

1. Căboaia Formation (Lithozone) (Tg.1) is mainly terrigenous, non-graphitous, occurring on restrained areas southward Zugreni, in the basement of Bucovinic Nappe and on the upper stream of Vaser, in Maramureş, in the basement of Subbucovinic Nappe.

2. Holdiţa Formation (Lithozone) (Tg.2) is quartzitic, graphitous, occurring on the entire spreading area of East Carpathians, both in the basement of Bucovinic, and Subbucovinic Nappes. The presence of graphite confers a black color, therefore easy to recognized, with as a guiding mark lithological position by the presence of black quartzites, and as a palynostratigraphical guiding mark for the “explosion” of many genders and species of Lower Cambrian acritarchs. This formation also includes premetamorphic mineralizations of Fe-Mn and barite.

3. Leşu Ursului Formation (Lithozone) (Tg.3) is well represented in the area of East Carpathians, being characterized by an acid volcanogenous - sedimentary sequence (metarhyolites) with important accumulations of stratiform metallic sulphures.

4. Arşiţa Rea Formation (Lithozone) (Tg.4) is phyllitous, quartzitic and has a reduced spreading, although has a large thickness (2,000 m). This formation occurs only in Bucovinic Nappe and in the digitations from its front, Bălan and Sândominic (Figure 2a, 2b). The best representation occurs in Broşteni region, open in the right flank of Neagra Broştenilor Brook (Arşiţa Rea) and northward,

in the left flank of Puzdra Brook (Vodă, 1986, 2000). Considering the lithological limit, it is interesting the normal position of this formation over the acid vulcanite formation (Tg.3). Arşiţa Rea Formation (Tg.4) starts with a terrigenous sequence of thin black quartzites, followed by blackish schists and quartzites in plates, graded and with microconglomerations at the base of the lithological banks (Figure 3). Thin layers of tuffogenous, basic, greenish schists, grey phyllites, crystalline limestones and quartzitic - feldspar rocks with chlorite occur as intercalations (Vodă, 1986; 2000). Other authors even encourage the idea of a mixture between Tg.3 and Tg.4 formations, subsequently metamorphosed into green schist facies, possibly representing fragments of the oceanic crust (Bercia et al., 1976). This mixture of the rocks from Tg.4 formation is also confirmed by the amalgamation of different age palynomorph assemblages (acritarchs and chitinozoans). This formation ends the lithostratigraphical succession of Tulgheş Group in East Carpathians.

The geotectonic context the sediments of Tulgheş Group deposited may be observed on the normal succession of constitutive deposits, considering the characteristics of the acid and basic volcanic products and the products of the associated metallogenesis.

The lithological succession of Tulgheş Group is monotonous, terrigenous, represented by sericitic-chloritous schists, often with graphite, black and white quartzites, metagraywacke and rare intercalations of carbonatic rocks and products of an acid and basic volcanism (Figure 1, 3). The large thickness of the deposited sediments shows a powerful subsidence, the rich pyroclastic material deposited in this sedimentary basin significantly influenced the composition of different lithological sequences, as well as the basinal sedimentation conditions. After ending the volcanic processes, the sedimentation continued in the same conditions, with prevailing black, terrigenous, graphitous deposits, rich in organic rests. This situation also may be observed in Arşiţa Rea Formation (Tg.4). It is possible the sedimentary basin should have a smaller depth, and a greater mobility (Vodă, 2000), also to be observed in Arşiţa Rea Formation (Tg.4), where it is situated the shift between graded quartzites to fine schists, and then to thicker metagraywacke sequences. If we consider the manganese abundance in quartzitic - graphitous Holdiţa Formation (Tg.2), as well as the metallic sulphures from volcanic-sedimentary Leşu Ursului Formation (Tg.3), besides the prevailing types of rocks, the



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Figure 2a Geological column of the Upper Formation (Tg. 4) Tughes Group from the Balan Formation (after Kräutner & Bindea, 1995).

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Figure 2b Geological column of the Upper Formation (Tg. 4) Tulghes Group from the Sândominic Formation (after Kräutner & Bindea, 1995).



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Figure 3. Lithostratigraphical column of the Tulghes Group on Bucovinical Nappe from Brosteni (1:20 000) after Voda (1986, 2000)

1. feldspar greenish quartzites; 2. graphitous black quartzites; 3. crystalline limestones; 4. metagraywackes; 5. basic – tuffs green schists; 6. white quartzites; 7. sulfure mineralizations; 8. acid metavolcanites (rhyolites); 9. white quartzites and microconglomerates; 10. sericite – chlorite ± graphite schists with albite porphyroblasts.

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feldspar quartzites and the quartzous rocks, it comes out the hypothesis that Tulgheş Group formed in a nearby volcanic arch basin (Balintoni, 1997). Vodă (2000) stands for a similar conclusion, mentioning that the metarhyolites from volcanic-sedimentary formation (Tg.3) shows a depositing in a volcanic arch tectonic environment. According to a quite similar hypothesis, other authors (Munteanu et al., 1999, 2000; Munteanu, Tatu, 2001, 2003) assert that Tulgheş Group includes discontinuous parts of an insular volcanic arch. The fact that, in the phyllitous - quartzitic formation (Tg.4) from the regions of Fundu Moldovei, Broşteni, Bălan and Sândominic, the basic rocks have intermediary characteristics, between oceanic ground basalts and insular arch basalts, the basic there is possible the sediments of Tulgheş Group to had deposited in a back-arch basin with oceanic crust (Vodă, 2000).

Tulgheş Group is polymetamorphic, as well as other lithological groups from East Carpathians. The first metamorphism took place in Early Caledonian, being proved by the K-Ar oldest ages (Kräutner et al., 1976), representing 470 M.a. Subsequently, the second Varistic regional type metamorphism is known by the proof of some earlier K-Ar ages, of 360-310 M.a. (Kräutner, in: Săndulescu, 1989; fide Vodă, 2000). This second metamorphism is characterized by a high thermal gradient and low pressure. One of the recent hypothesis (Munteanu, Tatu, 2003) endorsing that the structure of the crystalline from East Carpathians is a mixture of compounding parts from Gondwanaland (Avalonia) and from the East - European Craton (EEC), and that these were affected by a single metamorphism (Caledonian), and the second metamorphism (Varistic) affected only the Varistic lithological successions. This hypothesis was previously put by Balintoni (1997), Kräutner (1997) and subsequently retaken by Kräutner, Bindea (2002).

The age of Tulgheş Group is approached by two methods, radiometric and palynological. The Pb-Pb radiometric method gave the most realistic age data (545-470Ma), equivalent to the palynological data corresponding to Lower Cambrian - Lower Ordovician (Arenigian). These values are also mentioned in the most recent Geological Time Scale (Gradstein, Ogg, 1996). References over the age of the different formations from Tulgheş Group appeared in numerous studies of many authors: Iliescu, Mureşan, 1972; Iliescu, Kräutner, 1975; Iliescu et al., 1983; Olaru, Oniceanu, 1984, 1985; Olaru, Gunia, 1988; Olaru, Horaicu, 1989; Olaru, 1991,

1994, 1997, 2001, 2002, 2005; Olaru, Apostoae, 1994-1995, 2003; Olaru, Apostoae, Apostoae, 2003-2004; Olaru,Lazăr, 2005; Vaida, 1999; Horaicu, 2000; Mureşan, 2000.

Geotectonic and palynological aspects

at Cambrian - Ordovician boundary and of Arşiţa Rea Formation (Tg.4) of Tulgheş Group

From the beginning, we remind that the spatial position of this boundary should be, considering some data known until now, between Leşu Ursului (Tg.3) and Arşiţa Rea (Tg.4) lithological formations of Tulgheş Group. As we mentioned before, there are some hypothesis (Munteanu, Tatu, 2003), according to some older opinions (Bercia et al., 1976; Kräutner, 1987), which consider that the lithological formations of Tulgheş Group do not represent stratigraphical sequences, but correspond to different complex discontinuous parts of an insular arch. As a result, Leşu Ursului Formation (Tg.3) represents a part of the volcanic arch, and Arşiţa Rea Formation (Tg.4) would represent the accretion wedge as a result of the collision between Central - European Plate (CEP) with East - European Craton (EEC). Therefore, it is confirmed the lithological mixture of Arşiţa Rea Formation (Tg.4), including prevailing sericitous - chloritous schists (Bălan Nappe), or sericitous-graphitous phyllites (Sândominic Nappe), with intercalations of quartzites, microconglomerates, green schists, metabasites, rhyolitic metavolcanites (Figure 2a, 2b). It is possible this tectonic amalgamation process to be included together with the sediments of Tg.3 and Tg.4 formations, therefore the impossibility of outlining the limit between these formations. The weak consolidation of the initial sediments and their rough collision contact with East - European Craton (EEC) represented the cause of the westward overthrust of the upper part of the latest, namely the deposits of Bretila Group, over the deposits of Rebra and Tulgheş Groups from the sedimentation basin (Figure 4). The depositional finalization of the sequences from Tulgheş Group took place in Upper Ordovician, and then in Silurian these were affected by a Caledonian metamorphism, corresponding to the PT conditions, equivalent to the zone of garnets facies (Zincenco, 1995 fide Munteanu, Tatu, 2003). Thus, the sediments of the accretion wedge, meaning of Arşiţa Rea Formation (Tg.4), were intense folded in a nape system, lithologically mixed and overthrusting the sediments of Leşu Ursului Formation (Tg.3), represented by more competent volcanic masses. As we mentioned



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before, there is possible that, in this collision and ovethrust process, a lithological amalgamation would also had place between the two contact formations (Figure 4). The phenomena of tectonic distention started subsequently, in Silurian, after the depositional ending of Arşiţa Rea Formation (Tg.4) and continued until the end of Palaeozoic. Moreover, the second Varistic-type

metamorphism, in green schists facies, would had affected not only the Varistic successions (Balintoni et al., 1983; Balintoni, 1997), deposited on a continental crust, such as Repedea, Rusaia, Cimpoiasa Groups (Kräutner, 1997; Kräutner, Bindea, 2002). In fact, the implication of low pressure metamorphism in the collisional event is very improbable (Kräutner et al., 1975).

Figure 4. Tentative reconstruction of the Paleozoic amalgamation of the Crystalline - Mesozoic Zone. No scale implied. Rb – the Rebra Group; Ptr – the Pietrosu Bistritei porphyroids; Tg (Tg.1 – Tg. 4) – the Tulghes Group and its four formations; Br – the Bretila Group; Rb – Tg – the Rebra – Tulghes terrane. A - drift of the Rebra – Tulghes terrane toward EEC. B and C – colision of the Rebra – Tulghes terrane with EEC and thrusting of the Bretila terrane; onset of the pre-alpine thrustings. D – pre-alpine nappe stack is established and sedimentation is active in the Rodna rifting basin. E – the Rodna basin is closed and the thrusting of the Infrabucovinian Nappes in the Rodna Mountains has ceased. (after Munteanu, Tatu, 2003).

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If we analyze the microfloristic content of Arşiţa Rea Formation (Tg.4), we find out a notable palynomorph mixture (acritarchs and chitinozoans), of different ages, Cambrian and Ordovician, also typical for other regions of Upper Cambrian and Lower Ordovician (Olaru, 1991, 2001, 2005; Olaru, Apostoae, 2004; Olaru, Apostoae, Apostoae, 2004; Olaru, Lazăr, 2005).

All these studies were made on the constitutive rocks of Arşiţa Rea Formation (Tg.4) from Bălan area, Bălan and Sândominic Nappes. This lithological and, implicitly, palynological mixture was previously mentioned in other studies (Codarcea - Dessila et al., 1964; Kräutner, 1997; Kräutner, Bindea, 2002). These authors considered the existence of Arşiţa Rea Formation (Tg.4) as the result of the frequent collision irregularities along the Crystalline - Mesozoic area that generated its varied and complex lithological composition, or even of the mixture between Tg.3 and Tg.4 formations, subsequently metamorphosed (Bercia et al., 1976).

Due to the collisional effect and to the rocks metamorphism, except the microfossils – such as acritarchs and chitinozoans, which resisted these phenomena –, there is no other organic or macrofaunistic rest in these formations. Although there are lithological similitudes, between Arşiţa Rea Formation (Tg.4) and formations from Avalonia and Baltica, just the presence of the organic microfosil rests above mentioned and their mixture create difficulties of comparing and correlating with Acado-Baltic (Avalonian) interval. In spite of all these difficulties, there were possible biostratigraphical correlations, both with Peri-Gondwanaland (Avalonian) space, and with the Baltic one (Olaru, 2001, 2005; Olaru, Apostoae, 2004; Olaru, Apostoae, Apostoae, 2003-2004; Olaru, Lazăr, 2005).

Acritarch assemblages An important argument for discussing the

Cambrian - Ordovician boundary was represented by the establishing of a complex acritarch assemblage (Table 1) from Arşiţa Rea Formation (Tg.4), Bălan area, Bălan and Sândominic Nappes (Olaru, Lazăr, 2005 – in press). Palynologically there were studied Arama Oltului Member from Bălan Nappe and Başca and Pârâul Crucii Members from Sândominic nappe (Table 1). Considering this assemblage, there were made correlations with regions such as Gondwanaland, Avalonia,

Laurentian Shield, Baltic Shield, East - European Platform, Siberian Platform, and Sinian Shield (Olaru, Apostoae, 2004; Olaru, Apostoae, Apostoae, 2003-2004; Olaru, 2005).

Within the acritarch assemblage, there were separated several subassemblages which characterize more age intervals, between Upper Cambrian and Lower Ordovician (Arenigian). These show the palynological mixture from the members of Arşiţa Rea (Tg.4) Formation, proved by the lithological mixture of this formation, due to the overthrusting on the members of Leşu Ursului Formation (Tg.3), considering the collisional context they formed.

The Upper Cambrian acritarch

assemblage This assemblage is typical for Upper

Cambrian and disappearing at its end (Table 1). We found it incorporated within Arşiţa Rea Formation (Tg.4), of younger age. It seems that the typical Upper Cambrian rocks were involved and incorporated within this Tg.4 formation during the geotectonic collision and overthrusting events, because in the present lithological succession of Tulgheş Group there is no Upper Cambrian Formation. This formation has the following structure:

Acanthodiacrodium snookense, Veryhachium dumontii, Leiofusa stoumonensis, Orthosphaeridium extensum, Pirea orbicularis, Ooidium cf. clavigerum, Cristallinium cf. randomense, Trichosphaeridium annolovaense.

Among the determined taxa, we remind as zone taxa Acanthodiacrodium sp. and Orthosphaeridium extensum, typical for RA5 zone, equivalent to the trilobite zone with Peltura precursor and Peltura minor from Random Isle, Newfoundland, Canada (Parsons, Anderson, 2000).

From RA6 zone, corresponding to the trilobite zone with Peltura scarabeoides, we determined only Acanthodiacrodium snookense, which was moving up from the previous zone, and Calyxiella izhoriensis is missing from our samples.

From RA7 zone, equivalent to the lower part of Acerocare zone, probably a subzone of the previous one with Peltura scarabeoides, we determined Poikilofusa squama, and the second typical species, Ladogiella rotundiformis, is missing in our samples. This subzone was recognized also in Newfoundland and in Scandinavia.



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Table 1. Range chart showing of stratigraphic distribution of acritarch assemblage in the Upper Formation (Tg.4) of the Tulgheş Group, Balan Zone (East Carpathians).

TAXONOMIC UNITS ANALYSED SAMPLES CHRONOSTRATIGRAPHIE

1 2 3 4 5 6 7 8 9 10 11 12 1 3 4 5 6 9 10 11 Cb.3 Trem. Aren.

Acantodiacrodium angustum (Dow.) Comb. ● ● ● ● ● ● ●

Leiosphaeridia sp. A. ● ● ● ● ● ● ● ●

Baltisphaeridium crinitum Martin ●

Acantodiacrodium snookense Parsons & Anderson

● ● ●

Acantodiacrodium golubii Fensome et al. ● ● ● ●

Leiosphaeridia sp. B. ● ● ● ● ● ● ● ●

Veryhachium dumontii Vang. ● ● ● ● ● ●

Baltisphaeridium aciculare (Tim.) ●

Lunulidia lunula (Eis.) Eis. ● ● ● ●

Leiofusa stoumonensis Vang. ● ● ● ●

Acanthodiacrodium lanatum (Tim.) Martin ● ●

Orthosphaeridium extensum

Parsons & Anderson ●

Saharidia cf. fragilis (Dow.) Combaz. ● ● ●

Polygonum minimum (Tim.) Volkova ●

Impulviculus bibulbulus Parsons & Anderson ●

Tasmanites sp. ● ● ●

Elenia armilata (Vanderflit) Volkova ● ●

Polygonum sexradiatum (Tim.) Volkova ●

Vulcanisphaera tuberculata (Downie) Eis. ●

Cristallinium cambriense (Slavikova) Vanguestaine ● ●

Buediingisphaeridium tremadocum Rasul ● ●

Izhoria angulata Golub et Volkova ●

Cymatiogalea gorkae Rauscher ●

Acanthodiacrodium sp. ● ● Pirea orbicularis Volkova ● ● ●

Dactylofusa squama (Deunff) Martin ● ●

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Baltisphaeridium setaceum (Tim.) ●

Arbusculidium ornatum (Deunff) Martin ●

Cristallinium pilosum Golub. et Volkova ●

Vulcanisphaera capillata Jardiné ●

Dactylofusa velifera Cocchio ● ● ●

Poikilofusa squama (Deunff) Martin ● ● ●

● ● Stelliferidium cf. stelligerum (Gorka) Deunff et al.

Timofeevia estonica Volkova ● ●

Cristallinium cf. randomense Martin Fensom et al., Ribb. & Vang.

●

Ooidium cf. rossicum Timofeev ●

Ooidium timofeevii Loeblich ●

Leiofusa sp. ● ● ● ●

Trachydiacrodium coarctatum Tim. ●

Ooidium cf. clavigerum Parsons & Anderson ● ●

Trichosphaeridium annovaelense Tim. ●

Lophodiacrodium valdaicum (Tim.) Defl. et Defl.-Rigaud. ●

For RA8 zone, from Newfoundland, we

determined Ooidium cf. clavigerum, and Striatotheca randomnensis is missing from our samples. This zone might be equated to the median zone with Acerocare (Parsons, Anderson, 2000).

For RA9 zone, equivalent to the upper part with Acerocare, we determined Ooidium rossicum, and Nellia acifera is missing from our samples.

As we notice from the above mentioned data, there is possible a correlation between our separated assemblages and the biostratigraphical zones from West of Avalonia (Newfoundland region, Canada), where there is an obvious correlation with the trilobite biozones; the analyzed deposits that offered these faunistic assemblages are not tectonized or metamorphosed.

Upper Cambrian - Tremadocian

acritarch assemblage This transitional assemblage is also rich

(Table 1), being represented by the following species:

Leiosphaeridia sp., Baltisphaeridium crinitum, Acanthodiacrodium golubii, Acanthodiacrodium lanatum, Saharidia cf. fragillis, Polygonum minimum, Impulviculus bibulbulus, Vulcanisphaera tuberculata, Cristallinium cambriense, Izhoria angulata, Cymatiosphaera gorkae, Arbusculidium cf. destombesii, Cristallinium pilosum, Poikilofusa squama, Ooidium cf. rossicum, Ooidium timofeevii, Leiofusa sp., Lophodiacrodium valdaicum, Cymatiogalea cf. cuvillierii, Cymatiogalea velifera.

Tremadocian acritarch assemblage Within the established complex

assemblage, there is a subassemblage, representative only for Tremadocian (Table 1), where we mention: Acanthodiacrodium angustum, Baltisphaeridium aciculare, Lunulidia lunula, Elenia armillata, Polygonum sexradiatum, Buedingiisphaeridium temadocum, Dactylofusa squama, Dactylofusa velifera, Baltisphaeridium setaceum, Vulcanisphaera cf. briatnnica, Stelliferidium cf. stelligerum, Vulcanisphaera cf. capillata.



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The taxa of this assemblage and part of the previous one (Upper Cambrian-Tremadocian) are represented in the UK4B and OT1, OT2 and OT3 “acritarch complexes”, from East - European Platform, respectively Baltic province (Volkova, 1995) and Moscow Syneclise (Volkova, 1999). These assemblages are equivalent in the mentioned regions with the zones with conodonts, graptolites and trilobites.

Therefore, for the UK4B acritarch assemblage (“acritarch complex”), equivalent to the zone with Peltura scarabeoides and Acerocare and that of the conodonts Protoconodontus and Cordylodus andresi, we found in our samples species such as: Cristallinium cambriense, Cristallinium pilosum, Ooidium rossicum, Elenia armillata. This assemblage represents the Upper Cambrian - Tremadocian boundary zone.

The typical OT1 assemblages (Tremadocian from Estonia) starts with acritarchs from Diacromorphita family (Lower Tremadocian), being equivalent to the trilobite zone with Acerocare, to the conodont zone with Cordylodus proavus and Cordylodus intermedius, as well as to the graptolite zone with Rhabdinipora flabelliforme.

Also, in the Moscow Syneclise area, the Upper Cambrian - Tremadocian boundary is marked by the UK4B-1 “acritarch complex”, from the basis of OT1 assemblage with Cordylodus andresi. For equivalence with OT1 assemblage, we determined the assemblage with Acanthodiacrodium angustum, Izhoria angulata, Cristallinium pilosum, Ooidium rossicum, Ooidium timofeevii.

The second Lower Tremadocian assemblage, OT2, from Baltic region (Estonia) is represented by the species we determined, among them we mention: Vulcanisphaera cf. britannica, Baltisphaeridium setaceum, Lunulidia lunula, Baltisphaeridium aciculare, Elenia armillata, Dactylofusa squama, Saharidia cf. fragillis, Acanthodiacrodium angustum.

For this assemblage the equivalents are the conodont zones with Cordylodus lindstroemi and Cordylodus rotundatus – Cordylodus angulatus.

A third acritarch assemblage, OT3, from Upper Tremadocian, Estonia, is probably equivalent with the graptolite zone with Clonograptus – Didymograptus deltifer pristinus.

From our acritarch assemblage, we mention the characteristic Upper Tremadocian species: Acanthodiacrodium angustum, Baltisphaeridium aciculare, Baltisphaeridium setaceum, Leiosphaeridia sp.

Arenigian acritarch assemblage Some species from our acritarch

assemblage pass the Tremadocian - Arenigian boundary, continuing their evolution besides typical Arenigian taxa (Table 1). Among them, we mention: Acanthodiacrodium angustum, Acanthodiacrodium lanatum, Acanthodiacrodium sp., Dactylofusa squama, Poikilofusa squama, Leiofusa sp., Leiosphaeridia sp.

An interesting case is represented by the species of Coryphidium bohemicum Vavrdova, with whom Arenigian starts in the Prague Basin, also being identified in Klabava Formation (Vavrdova, 1965). This species marks the entire Lower Arenigian-Upper Arenigian interval from the Peri-Gondwanaland region. Determining this species was difficult in the analyzed formations, but several exemplars were found in Sândominic Formation, Pârâul Crucii Member, defining the Arenigian age of this formation. Coryphidium bohemicum represents a constitutive element of the “messaoudensis - trifidum” acritarch assemblage from Prague region (Fatka et al., 2000), and from other locations from Bohemia, Germany, Walles, England, Spain, assemblage which includes besides acritarchs, chitinozoans and graptolites. This assemblage marks the Tremadocian - Arenigian interval in cold water marine environment, around Gondwanaland (Avalonia), and among others includes species of Conochitina symmetrica (from chitinozoans), typical for Lower Arenigian, which we also determined in the analyzed samples in numerous exemplars.

From the successive presentation of the acritarch assemblages, separated from the analyzed samples and correlated with the classical zone from regions of Newfoundland, East - European Platform and Prague Basin, where there were established equivalences with the typical zone with conodonts, graptolites and trilobites, we are able to establish the Lower Ordovician (Arenigian) age to Arşiţa Rea Formation (Tg.4) from Bălan area, where it was analyzed. The Cambrian - Ordovician boundary stands within this formation, being included in the transition interval for the palynological Upper Cambrian - Tremdocian and Tremadocian - Arenigian elements. Due to the lithological and microfloristic mixture, this limit cannot be outlined on a lithological guide mark, representing a stratigraphical limit.

Chronostratigraphically, Tremadocian is considered the lower stage of Lower

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Ordovician, with a radiometric age of 495 - 485 M.a., while Arenigian, representing the upper stage of Lower Ordovician, is about 485 - 470 M.a. (Zincenco, 1995; Gradstein, Ogg, 1996).

Chitinozoan assemblage Besides acritarchs, chitinozoans are

present in all yielded and analyzed samples from Arşiţa Rea Formation (Tg.4), from Bălan area, Bălan and Sândominic Nappes. The chitinozoan assemblage comes from the same analyzed samples as the acritarchs (Olaru, Apostoae, 2004; Olaru, Apostoae, Apostoae, 2003-2004). Chitinozoans were found in Northern Gondwanaland, Baltica and Laurentia, where they form characteristic zones, being used for stratigraphical biozonations at large distances.

Chitinozoans came out form Tremadocian, in Northern Gondwanaland, with the species of Lagenochitina destombesi, which characterize a typical biozone for this age, equivalent to the graptolite zone with Rhabdinipora flabelliforme (Paris, 1992). In our analyzed samples, this species is missing, but we established a Tremadocian acritarch assemblage, which is equivalent with the graptolite zone with Rhabdinipora flabelliforme.

In Bălan region, where the chitinozoan assemblages come from, Arenigian starts with Conochitina symmetrica, as in Northern Gondwanaland and Laurentia (Achab, 1986; Paris, 1992). We found this species in all the samples coming from phyllites, black quartzites and sericitous - chloritous schists from the lithological members Arama Oltului, Pârâul Crucii and Başca, Bălan and Sândominic Nappes, Arşita Rea Formation (Tg.4), Tulgheş Group (Olaru, Apostoae, 2004; Olaru, Apostoae, Apostoae, 2003-2004). This species is characteristic for the biozone with the same title also from Prague Basin, being present in the “messaoudensis – trifidum” acritarch assemblages, which also includes the acritarch species of Coryphidium bohemicum, as well as other acritarch species determined by us (Olaru, Apostoae, Apostoae, 2003-2004; Olaru, Lazăr, 2005 – in press). Therefore, we are able to appreciate that the lower boundary of Arenigian in East Carpathians is marked by this chitinozoan species, which stands beside the typical acritarchs, previously mentioned, included in the “messaoudensis – trifidum” acritarch assemblage, equivalent in Prague Basin with the graptolite biozone with Tetragraptus approximatus,(Kraft, Mergl,1979;Fatka et al.,2000) and it coexists with the Clonograptus zone at the lower part of Klabava Formation, Prague Basin (Paris,Mergl,1984).

As in the case of acritarchs, Conochitina symmetrica was found in all analyzed samples from the Arenigian stratigraphical interval, which also indicates a lithological and microfloristic amalgamation of Arşiţa Rea Formation (Tg.4), as a effect of the collisional geotectonical event it was submitted. Also in this case, this fact makes impossible the outlining of the Cambrian - Arenigian boundary at a lithological guide mark, the limit being included within Arşiţa Rea Formation (Tg.4), with a characteristic of stratigraphical limit.

In Baltic region, the species of Conochitina symmetrica is lacking, considered as the result of a lithological hiatus, or of some unfavorable palaeogeographical and palaeoclimatic conditions (Paris, 1992).

Beside Conochitina symmetrica, in the analyzed samples, we also determine Lagenochitina esthonica and Conochitina raymondii which form together a characteristic Lower Arenigian biozone in Laurentia, and which, considering the spatial condition, is right above the Conochitina symmetrica zone (Paris, 1992). The Conochitina symmetrica zone is equivalent in Baltica with the conodont zone with Prionodus proteus, and in Northern Gondwanaland with the graptolite zone with Tetragraptus approximatus. In exchange, the Lagenochitina esthonica / Conochitina raymondii zone, which ends the upper boundary of Lower Arenigian, is equivalent with the conodont zone with Prionodus elegans in Baltica and the graptolite zone with Didymograptus deflexus in Northern Gondwanaland and China (Paris, 1992).

This limit species are also mentioned in the low latitude deposits from Laurentian Shiled, at the lower part of Levis Formation from Quebec (Achab, 1980; 1986) and in Nambeet Formation from Canning Basin, Australia (Achab, Millepied, 1980), as well as the south of the Sinian Palaeoplate (China) in Dawan Formation (Geng, 1984).

From these exemplifications, there stands out that the lower and the upper Arenigian boundaries are very well outlined all over the globe, especially in the sedimentary formations where it is possible a biozonation and a very good correlation on large distances. Although in the analyzed metamorphic formations we found many of the characteristic species, of stratigraphical limit, from different classical zone, the correlation, the biozonation and especially the establishing of the stratigraphical limits in these metamorphic formations might be realized with some difficulties, due to the geotectonic amalgamation of the initial sediments and its subsequent metamorphic transformation. In



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the analyzed metamorphic formations from East Carpathians, the zone characteristic species, such as Conochitina symmetrica, Lagenochitina esthonica, Conochitina raymondii, are associated with other chitinozoan species, typical for Arenigian from different regions on the globe:

Lagenochitina cf. combazi – Arenigian, Australia, Québec, Terra Nova

Lagenochitina brevicollis – Arenigian, Montagne Noire, France

Conochitina decipiens – Arenigian, Sahara, Quebec, Terra Nova

Clavachitina decipiens – Arenigian, Sahara, Quebec, Terra Nova

Conochitina brevis – Arenigian, Sahara, Russian Platform, Quebec

Euconochitina brevis – Arenigian, Montagne Noire, France

Euconochitina parvicola – Arenigian, Montagne Noire, France

Conochitina kryos – Arenigian, Spitzbergen Archipelago, Quebec

Fustichitina grandicula – Lower Arenigian, Quebec, Levis Formation (holotype)

Rhabdochitina magna – Ordovician, Baltica; Lower Arenigian, Quebec

Clathrochitina oblonga – Arenigian, Sahara, Quebec, SW Europe, Bohemia, Baltica, Terra Nova

A special importance belongs to Desmochitina bulla, which we separated in the analyzed samples, yielded from black quartzites and grey sericitous - chloritous phyllites from Pârâul Crucii Member, Sândominic Nappe (Olaru, Apostoae, 2004; Olaru, Apostoae, Apostoae, 2003-2004). The yielded phyllites have thin intercalations of black quartzites and they periodically repet in Pârâul Crucii Member (Figure 2b). The cause of this repeated lithological succession is also the effect of the lithological amalgamation of the initial sediments, in the collisional geotectonic context; as a result Arşiţa Rea Formation (Tg.4) took the place of an accretion wedge. Desmochitina bulla is typical for the upper boundary of Arenigian for a normal lithological succession. It was described in this position in Klabava Formation from Prague Basin (Paris, Mergl, 1984), in Gondwanaland and Baltic regions (Paris, 1981; 1996), and it was mentioned in Tadla Basin from Morocco, Sahara (Soufiane, Achab, 1993), in other localities from Bohemia, in Baltic region and Russia (Achab, 1982; 1991).

The presence of this typical species at the upper boundary of Arenigian in our analyzed samples, besides characteristic species for the lower boundary and for the entire Arenigian

interval, leads us to the conclusion that, also considering the new palynological arguments, the lower Arenigian stratigraphical boundary, as well as the upper limit of the same stage, cannot be outlined at the levels of a lithological guide mark, these being included inside the lithological succession of the Arenigian Arşiţa Rea Formation (Tg.4) (495-470 M.a.) (Zincenco, 1995; Gradstein, Ogg, 1996; Mureşan, 2000). As a matter of fact, the Cambrian - Ordovician boundary stands evident as a stratigraphical limit, considering the successive presence of several acritarch and chitinozoan palynological assemblages, of different ages, which are amalgamated within Arşiţa Rea Formation (Tg.4), with no possibility of its precise outlining at a lithological guide mark level.

Conclusions As a result of this study, the following

conclusions could be synthesized: The geological and stratigraphical limits in

the metamorphic formations of East Carpathians depend very much of the geotectonic context which affected the respectively geological formations and of the stratigraphical arguments, typical for each formation.

In the case of Arşiţa Rea Formation (Tg.4) from Bălan area of Tulgheş Group, the geotectonic context it formed, place it in an accretion wedge position, in the collision process between East-European Craton (EEC) and Central European Shield, on its edges East Carpathians formed.

The accretion wedge position of the analyzed formation had an effect its lithological and microfloristic (palynological) amalgamation.

Due to the collisional geotectonic context and to the metamorphic transformation of the initial sedimentary deposits, in the lithological composition of this formation there are preserved only the acritarch and chitinozoan assemblages, as the only proves of the initial sediments, missing the micro and macrofaunistic remains.

These microfloristic assemblages contain typical and zonal species which could be correlated to other classical regions on the globe from Central and Western Europe, Gondwanaland, Baltica, Laurentia, East - European Platform, where they could be equated to parallel zones with conodonts, graptolites and trilobites.

Based on these acritarch and conodont assemblages we defined the stratigraphical limit between Cambrian - Ordovician, but which as a result of the microfloristic mixture

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cannot be precisely positioned in space, at the level of some lithological guide marks, but it is included in Arşiţa Rea Formation (Tg.4), of Arenigian age, in the transition zones for the palynological assemblages.

Thus the lower and the upper Arenigian boundaries may be defined.

The radiometric age of Arşiţa Rea Formaition (Tg.4) is 495-470 M.a.

References Achab, A. (1980) Chitinozoaires d’Arenig

inférieur de la Formation de Levis, Quebec, Canada. Revue Paleobotanical and Palynological, 31:219 – 239.

Achab, A. (1982) Chitinozoaires de l’Arenig supérieur (zone D) de la Formation de Lévis, Quebec, Canada. Canadian Journal of Earth Sciences, 19: 1295 – 1307.

Achab, A. (1986) Assemblages de chitinozoaires dans l’Ordovicien inférieur de l’Est du Canada. Canadian Journal of Earth Sciences, 23: 682 – 695.

Achab, A. (1991) Biogeography of Ordovician Chitinozoa. In: Barnes, C. R. & Williams, S. h. (Eds.): Advances in Ordovician Geology: 135 – 142, Papers Geological Survey, Canada, 90-9;135 – 142.

Achab, A., Millepied, P. (1980) Conochitina symmetrica Tougourdeau et de Jekhowsky a guide fossil to the Lower Ordovician. Fifth International Palynological Conference, Cambridge, England, Abstract: 3.

Balintoni, I. (1997) Geotectonica terenurilor metamorfice din Romania. Editura Carpatica, Cluj – Napoca, 176 p.

Balintoni, I., Gheuca, I., Vodă, Al. (1983) Alpine and Hercynian Overthrust Nappes in the Central and Southern part of the East Carpathian Cristalline – Mesozoic Zone. Anuarul Institutului de Geologie si Geofizica al Romaniei, Bucuresti, LX, 15 – 22.

Bercia, I., Kräutner, H. G, Muresan, M. (1976) Pre-Mesozoic Metamorphites of the East Carpathians. Anuarul Insitutului de Geologie si Geofizica Bucharest, 50, 37– 70.

Codarcea – Dessila, M., Bercia, I., Kräutner, H., Muresan, M. (1964) Structural and stratigraphic research of the Bistrita Metamorphic Mts. (Barnarel - Holdita region). Dari de Seama ale Sedintelor Comitetului de Stat Geologie, Bucharest, 50/2, 3-23. (in romanian).

Fatka, O., Molyneux, S., Samuelson. J., Servais, T. (2000) Integrated biostratigraphy (acritarchs,

chitinozoans, grapatolites) of the Tremadoc/ Arenig boundary interval in European Peri-Gondwana. 10th International Palynological Congress, Nanjing, China, Abstracts : 40.

Geng, Liangyu (1984) Chitinozoa from the Fenhsiang, Huanghuayuan and Dawan Formations of Huanghuachang, Yichang, Hubei; Stratigraphy and palaeontology of systemic boundaries in China. Ordovician - Silurian Boundary. Nanjing Institute of Geology and Palaeontology, Academia Sinica, Anhui Science and Technology Publishing House, 509 – 516.

Gradstein, F. M., Ogg, J. G. (1996) Geological Time Scale for the Phanerozoic, Episodes, 1996, Saga Petroleum, 19, 1, 2, 3-4.

Horaicu, C. ((1999) Studiul geologic, petrografic si metalogenetic al bazinului inferior al Vaserului. Corelari si datari pe baza asociatiilor palinologice in formatiunile metamorfice din masivul cristalin al Maramuresului. Teza de doctorat, Universitatea “Al. I. Cuza” Iasi (manuscris).

Horaicu, C. (2000) Datari si corelari pe baza asociatiilor palinologice in formatiunile metamorfice din bazinul inferior al vaii Vaserului, masivul cristalin al Maramuresului si Carpatii Orientali. Editura Sedcom Libris, 130 p.

Iliescu, V., Muresan, M. (1972) Asupra prezentei Cambrianului inferior in Carpatii Orientali - seria epimetamorfica de Tulghes. Dari de Seama ale Sedintelor Institutului de Geologie si Geofizica a Romaniei, Bucuresti, LVIII, 4, 23 - 38.

Iliescu V., Kräutner, H. G. (1975) Contribution à la connaisance du contenu en microflore et de l’âge des formations metamorphiques des Monts Rodnei et des Monts Bistritei. Dari de Seama ale Sedintelor Instituttului de Geologie si Geofizica a Romaniei, Bucuresti, LXI, 11-25.

Iliescu, V., Kräutner, H. G., Kräutner, F., Hann, H. (1983) New palynological proofs on the Cambrian age of the Tulghes Group (East Carpathians) Anuarul Institutului



269

Geologic al Romaniei, Bucharest, 59, 7- 17.

Kraft, J., Mergl, M. (1979) New graptolite fauna from Klabava Formation of Bohemia. Věstnyk Ǔstrědy Ǔstavu Geologiczny, 54(5):291- 295.

Kräutner, H. G. (1987) The metamorphic Paleozoic of the Romanian Carpathians In: Flugel, H. W., Sassi, F. P., Grecula (Eds.). Pre-Variscan and Variscan events in the Alpine – Mediteranian mountain belts. Mineralia slovaca - monography, Alfa Publishing, Bratislava, 329 – 350.

Kräutner, H., G. (1997) Alpine and pre-Alpine terranes in the Romanian Carpathians and Apuseni Mts. Annales Géologiques des Pays Helléniques, Athens, 37, 330 – 400.

Kräutner, H., G., Sassi, F., P., Zirpoli, G., Zulian, T. (1975) The pressure characters of the pre-Alpine metamorphisms in East Carpathians (Romania). Neues Jahrbuch Mineral Abhandlungen Sttutgart, 125/3, 278- 296.

Kräutner, H., G., Kräutner, FL., Tanasescu, A., Neacsu, V. (1976) Interprétation des âges radiométriques pour les roches métamorphiques régénérees. Anuarul Institutulul de Geologie si Geofizica a Romaniei, Bucuresti, L, 167- 229.

Kräutner, H., G., Bindea, G. (2002) Structural units in the pre-Alpine basement of the Eastern Carpathians. Geologica Carpathica, 53, Spl. Issue, 143-176.

Munteanu, M., Rosu, E., Vodă, A. (1999) Caledonian metavolcanics from the Eastern Carpathians: geochemistry and tectonic setting. Romanian J. Tectonics Regional Geology, Bucharest, 77, 70- 71.

Munteanu, M., Dumitrascu, C., Tatu, M. (2000) Tulghes Group: Depositional sequence or collisional stacking?. Anuarul Institutului Geologic al Romaniei, Bucharest, 72, p. 55.

Munteanu, M., Tatu, M. (2001) The East - Carpathian metamorphic terranes (Romania): evolution from Gondwana to the East European Platform. Gondwana Research, 4, pp. 712.

Munteanu, M., Tatu, M. (2003) The East - Carpathian Crystalline - Mesozoic Zone (Romania): Paleozoic Amalgamation of Gondwana - and East European Craton- derived Terranes. Gondwana Research, 6, 2, 185-196

Muresan, M. (2000) Age des épimétamorphites du Grupe de Tulghes

(Carpates Orientales). Romanian Journal of Mineral Deposits, 79, Suppl, 66- 68.

Olaru, L. (1991) Stratigraphical evolution of the palynological assemblages from the crystalline formations of the Romanian East Carpathians and the correlation with other areas from Europe. Evolution and Adaptation, Cluj-Napoca, 4, 77 – 87.

Olaru, L. (1994) Biostratigraphical value of Acritarch assemblages of the metamorphic formations of the East Carpathians of Romania. CIMP Symposium on Palynologie, Palaeoenvironment and Stratigraphy, Sheffield,England,Abstract, 29.

Olaru, L. (1997) Sur la corrélation des différentes zones des formations metamorphiques de la Roumanie, par les associations des acritarches. XVéme Symposium, APLF Lyon, Volume des Résumes, 46.

Olaru, L. (2000) Palynostratigraphical correlation of Cambrian Formations from the East Carpathians of Romania. Xth International Palynological Congress, Nanjing, China, Abstracts, 126-127.

Olaru, L. (2001) Using acritarch assemblages to correlate Upper Proterozoic and Lower Paleozoic metamorphic sequences in Romania. Proceedings of the IX International Palynological Congress, Houston, Texas, USA, 1996, AASP, Foundation, 115- 127.

Olaru, L. (2002) New palynological and palynostratigraphical data about black quartzites and graphite schists of the Tulghes Group. Acta Palaeotologica Romaniae, Iasi, III, 299- 308.

Olaru, L. (2005) Some problems of biostratigraphy and palynological correlation of Upper Formation (Tg. 4) from Tulghes Group, East Carpathians (Romania). Acta Palaeontologica Romaniae, Bucuresti, V, 351- 366.

Olaru, L., Oniceanu, M. (1985) Sur la présence de quelques associations d’acritarches du Protérozoïque supérieur et du Paléozoïque inférieur dans les Carpates Orientales de Roumanie. Science Géologique Bulletin, Strasbourg, 38, 1, 131- 136.

Olaru, L., Gunia, T. (1988) Palynological correlation between the Cambrian Formations in the Sudetic Mountains (Poland) and the East Carpathians (Romania). Analele stiintifice ale

L. OLARU

270

Universitatii”Al. I. Cuza”Iasi, II b, Geologie-Geografie, XXXIV, 23-30.

Olaru, L., Horaicu, C. (1989) Palynological studies on the metamorphic formations of the Tulghes Group in the East Carpathians of Romania. Analele stiintifice ale Universitatii “Al. I. Cuza” Iasi, Stiinte Naturale, b, Geologie-Geografie, XXXV.

Olaru, L., Apostoae, L. (1994-1995) La présence de quelques acritarches dans le Groupe de Tulghes (Tg. 3, la zone Balan, Carpates Orientales). Analele stiintifice ale Universitatii “Al. I. Cuza” Iasi, Geologie, 40-41, 277-282.

Olaru, L., Apostoae, L. (2003) Arenigian chitinozoans from the Tulghes Group, Upper Formation (Tg. 4) from Balan Zone (Eastern Carpathians Romania). Acta Palaeontologica Romaniae, Cluj-Napoca, IV, 299-314

Olaru, L., Apostoae, L., Apostoae, L. (2003-2004) Contributions à l’étude palynologique de la formation supérieur (Tg. 4) de la region de Balan, (Carpates Orientales, Roumanie). Analele stiintifice ale Universitatii “Al. I. Cuza” Iasi, Geologie, XLIX – L, 133-159.

Olaru, L., Lazar, A. (2005) New data on typical acritarch assemblage from the Upper Formation (Tg. 4) from Tulghes Group, Balan area, Eastern Carpathians (Romania). Analele stiintifice ale Universitatii « Al. I. Cuza” Iasi, Geologie, 51, (in press).

Paris, F., (1981) Les chitinozoaires dans le Paléozoïque de sud- oust de l’Europe (Cadre géologique - Etude systématique-Biostratigraphie). Mémoire de la Societé Géologique et Miniére de Bretagne, 26, 1-496.

Paris, F. (1992) Application of chitinozoans in long-distance Ordovician correlations. Global Perspectives on Ordovician Geology. In: Webby, B. D., Laurie, J. R. (Eds.), Balkema, A. A. / Rotterdam / Brookfield.

Paris, F. (1996) Chitinozoan biostratigraphy and palaeoecology. In: Jansonius, J. & Mc Gregor, D. C. (Eds.), Palynology: principles and applications. AASP Foundation, 2, 531- 552.

Paris, L., Mergl, M. (1984) Arenigian chitinozoans from Klabava Formation, Bohemia. Review Palaeobotany and Palynology, 43:33-35.

Parsons, G. M., Anderson, M. M. (2000) Acritarch microfloral succession from the Late Cambrian and Ordovician (Early Tremadoc) of Random Island,

Eastern Newfoundland and its comparison to coeval microfloras particularly those of the East European Platform. AASP, Contribution Series, no.38,Dallas Texas, p. 129.

Sandulescu, M. (1976) La correlation structurale du tronçon Oriental avec celui Meridional des Carpates Orientales Roumaines. Dari de Seama ale Sedintelor Institutului de Geologie si Geofizica, Bucuresti, LXIII/5, 177- 194.

Sandulescu, M. (1980 a) Analyse géotectonique des chaines alpines situees autour de la Mèr Noire occidentale. Anuarul Institutului de Geologie si Geofizica, Bucuresti, LVI, 5- 54.

Sandulescu, M. (1980 b) Sur certaines problèmes de la correlation des Carpates Orientales roumaines avec les Carpates ucraïniennes. Dari de Seama ale Sedintelor Institutului de Geologie si Geofizica, Bucuresti, LXV/5, 163 - 180.

Sandulescu, M. (1984) Geotectonica Romaniei. Editura Stiintifica, Bucuresti, 336p.

Soufiane, A., Achab, A. (1993) Quelques assemblages de chitinozoaires de l’Ordovicien de Maroc, Bassin de Tadla. GEOBIOS, 26, 5 : 535-553.

Vaida, M. (1999) Datarea si corelarea pe baza asociatiilor palinologice a formatiunilor cristalofiliene si mineralizatiilor associate din partea sudica a masivului cristalin al Carpatilor Orientali si partea estica a Carpatilor Meridionali. Teza de doctorat, Universitatea”Al. I. Cuza’Iasi.

Vavrdova, M. (1999) Ordovician acritarchs from Central Bohemia. Vestnic Ǔstredniho Ǔstavu Geologickeho, 40: 351- 357.

Vodă, Al. (1986) Central East Carpathians Formations in the Brosteni-Borca Region. Dari de Seama ale Sedintelor Institutului de Geologie si Geofizica a Romaniei, Bucuresti, 70- 71/5, 269-275.

Vodă, Al. (2000) Sinteza zonei cristalino-mezozoice a Carpatilor Orientali. Date regionale, geologie si metalogeneza regionala. Tema V/15, 1997, S. C. “Prospecţiuni” S. A., Bucuresti, 18 p.

Vodă, A., Balintoni, I. (1996) Corelari litostratigrafice in cristalinul Carpatilor Orientali. Studia Universitatis “Babes- Bolyai”,Cluj-Napoca, Geologie,XXXIX /1-2,61-66.

Volkova, N. A. (1995) Akritarhi pogranicinâh otlojenii Kembria-Ordovika, Baltiiskoi fitoplanktonoi provintii. Stratigrafia.



271

Gheologhiceskaia Korreliatia, 3, 4, 31- 43.

Volkova, N. A. (1999) Acritarchs from Upper Beds of the Upper Cambrian – Lower Tremadocian of the Moscow Syneclise. Stratigraphy and Geological Correlation, 7/5, 452 – 464.

Zincenco, D. (1995) Chronostratigraphic Scale of the pre- Permian metamorphites and granitoids from Romanian Carpathians. Carpathian - Balkan Geological Association, XVth Congress. Spl. Published, Geological Society, Greece, Athens, 4/2, 647- 652.

EXPLANATION OF PLATES

PLATE I 1. Leiosphaeridia sp. A (2 specimens) 2. Acanthodiacrodium angustum (Downie) Combaz 3. Acanthodiacrodium angustum (Downie) Combaz 4. Arbusculidium cf. destombesii Deunff 5. Dactylofusa squama (Deunff) Martin 6. Dactylofusa velifera Cocchio 7. Lunulidia lunula Eisenack 8. Dactylofusa squama (Deunff) Martin 9. Lunulidia lunula Eisenack 10. Cymatiogalea cf. cuvillieri (Deunff) Martin 11. Baltisphaeridium setaceum (Timofeev) Martin 12. Baltisphaeridium aciculare (Timofeev) Martin 13. Acanthodiacrodium lanatum (Timofeev) Martin 14. Pirea orbicularis Volkova 15. Pirea cf. orbicularis Volkova 16. Pirea sp. 17. Dactylofusa cf. squama (Deunff) Martin 18. Poikilofusa squama (Deunff) Martin 19. Dactylofusa squama (Deunff) Martin All figures increased by 1000 X

PLATE II 1. Orthosphaeridium extensum Parsons & Anderson 2. Leiofusa stoumonensis Vanguestaine 3. Veryhachium cf. dumontii Vanguestaine 4. Acanthodiacrodium angustum (Downie) Combaz 5. Leiosphaeridia sp. A 6. Cymatiosphaera deunffi Jardiné et al. 7. Ooidium cf. clavigerum Parsons & Anderson 8. Saharidia cf. fragilis (Downie) Combaz 9. Dactylofusa velifera Cocchio 10. Leiosphaeridia sp. A 11. Veryhachium dumontii Vanguestaine 12. Leiospharidia sp. B (3 specimens) 13. Cristallinium cf. cambriense Slaviková 14. Acanthodiacrodium golubii Fensome et al. 15. Vulcanisphaera cf. britannica Rasul 16. Coryphidium aff. bohemicum Vavrdová 17. Veryhachium dumontii Vanguestaine 18. Baltisphaeridium crinitum Martin 19. Buedingiisphaeridium tremadocum Rasul 20. Acanthosphaeridium angustum (Downie) Combaz 21. Lunulidia lunula (Eisenack) Eisenack All figures increased by 1000 X

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PLATE III 1. Lagenochitina esthonica Eisenack (39 x 23 µm); sample no. 1, black quartzites, Şindrila de Sus Brook, Pârâul

Crucii Member, Sândominic Formation. 2. Lagenochitina esthonica Eisenack (39 x 26 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul

Crucii Member, Sândominic Formation. 3. Lagenochitina esthonica Eisenack (36 x 23 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul Crucii

Member, Sândominic Formation. 4. Lagenochitina esthonica Eisenack (38 x 26 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul

Crucii Member, Sândominic Formation. 5. Lagenochitina esthonica Eisenack (43 x 23 µm); sample no. 5, grey phyllites, Pârâul Scurt Brook, Pârâul

Crucii Member, Sândominic Formation. 6. Lagenochitina esthonica Eisenack (38 x 24 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul

Crucii Member, Sândominic Formation. 7. Lagenochitina esthonica Eisenack (37 x 24 µm); sample no. 4, black quartzites, Babaşa Brook, Pârâul



Crucii Member, Sândominic Formation. 10. Lagenochitina esthonica Eisenack (38 x 23 µm); sample no. 9, black graphitous phyllites with intercalations

of black quartzites, Pârâul Crucii Member, Sândominic Formation. 11. Lagenochitina esthonica Eisenack (39 x 24 µm); sample no. 5, grey phyllites, Pârâul Scurt Brook, Pârâul

Crucii Member, Sândominic Formation. 12. Lagenochitina esthonica Eisenack (43 x 27 µm); sample no. 5, grey phyllites, Pârâul Scurt Brook, Pârâul

Crucii Member, Sândominic Formation. 13. Lagenochitina esthonica Eisenack (35 x 21 µm); sample no. 9, black graphitous phyllites with intercalations

of black quartzites, Pârâul Crucii Member, Sândominic Formation. 14. Lagenochitina esthonica Eisenack (47 x 28 µm); sample no. 4, black quartzites, Babaşa Brook, Pârâul Crucii

Member, Sândominic Formation. 15. Desmochitina bulla Taug. & Jekh. (20 x 15 µm); sample no. 1, black quartzites, Şindrila de Sus Brook,

Pârâul Crucii Member, Sândominic Formation. 16. Desmochitina bulla Taug. & Jekh. (22 x 18 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul Crucii

Member, Sândominic Formation. 17. Desmochitina bulla Taug. & Jekh. (17 x 12 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul Crucii

Member, Sândominic Formation. 18. Desmochitina bulla Taug. & Jekh. (17 x 13 µm); sample no. 6, grey sericitous-graphitous phyllites, Şipoş

Valley, Başca Member, Sândomonic Formation. 19. Desmochitina bulla Taug. & Jekh. (15 x 10 µm); sample no. 9, black graphitous phyllites with intercalations of

black quartzites, Pârâul Crucii Member, Sândominic Formation. 20. Conochitina symmetrica Taug. & Jekh. (46 x 31 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul

Crucii Member, Sândominic Formation. 21. Conochitina symmetrica Taug. & Jekh. (47 x 32 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul

Crucii Member, Sândominic Formation. 22. Conochitina symmetrica Taug. & Jekh. (45 x 30 µm); sample no. 4, black quartzites, Babaşa Brook, Pârâul

Crucii Member, Sândominic Formation. 23. Conochitina symmetrica Taug. & Jekh. (47 x 33 µm); sample no. 5, grey phyllites, Pârâul Scurt Brook, Pârâul

Crucii Member, Sândominic Formation. 24. Conochitina symmetrica Taug. & Jekh. (52 x 35 µm); sample no. 6, grey sericitous-graphitous phyllites,

Şipoş Valley, Başca Member, Sândomonic Formation. Without dimensions scale PLATE IV 1. Conochitina symmetrica Taug. & Jekh. (47 x 33 µm); sample no. 9, black graphitous phyllites with

intercalations of black quartzites, Pârâul Crucii Member, Sândominic Formation. 2. Conochitina symmetrica Taug. & Jekh. (46 x 30 µm); sample no. 9, black graphitous phyllites with

intercalations of black quartzites, Pârâul Crucii Member, Sândominic Formation. 3. Conochitina symmetrica Taug. & Jekh. (46 x 34 µm); sample no. 9, black graphitous phyllites with

intercalations of black quartzites, Pârâul Crucii Member, Sândominic Formation. 4. Fustichitina grandicula Achab (77 x 20 µm); sample no. 1, black quartzites, Şindrila de Sus Brook, Pârâul

Crucii Member, Sândominic Formation. 5. Fustichitina grandicula Achab (76 x 19 µm); sample no. 1, black quartzites, Şindrila de Sus Brook, Pârâul

Crucii Member, Sândominic Formation. 6. Rhabdochitina magna Eisenack (87 x 18 µm); sample no. 1, black quartzites, Şindrila de Sus Brook, Pârâul

Crucii Member, Sândominic Formation.



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7. Rhabdochitina magna Eisenack (101 x 16 µm); sample no. 9, black graphitous phyllites with intercalations of black quartzites, Pârâul Crucii Member, Sândominic Formation.

8. Clavachitina decipiens Taug. & Jekh. (54 x 30 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul Crucii Member, Sândominic Formation.

9. Clavachitina decipiens Taug. & Jekh. (53 x 31 µm); sample no. 1, black quartzites, Şindrila de Sus Brook, Pârâul Crucii Member, Sândominic Formation.

10. Conochitina decipiens Taug. & Jekh. (49 x 23 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul Crucii Member, Sândominic Formation.




14. Clavachitina decipiens Taug. & Jekh. (52 x 30 µm); sample no. 4, black quartzites, Babaşa Brook, Pârâul Crucii Member, Sândominic Formation.

15. Clavachitina decipiens Taug. & Jekh. (54 x 33 µm); sample no. 9, black graphitous phyllites with intercalations of black quartzites, Pârâul Crucii Member, Sândominic Formation.

16. Conochitina decipiens Taug & Jekh. (46 x 23 µm); sample no. 1, black quartzites, Şindrila de Sus Brook, Pârâul Crucii Member, Sândominic Formation.

17. Lagenochitina cf. combazi Finger (29 x 18 µm); sample no. 1, black quartzites, Şindrila de Sus Brook, Pârâul Crucii Member, Sândominic Formation.

18. Lagenochitina cf. combazi Finger (19 x 11 µm); sample no. 5, grey phyllites, Pârâul Scurt Brook, Pârâul Crucii Member, Sândominic Formation.

19. Lagenochitina cf. combazi Finger (18 x 10 µm); sample no. 9, black graphitous phyllites with intercalations of black quartzites, Pârâul Crucii Member, Sândominic Formation.

20. Euconochitina brevis conica (Taug. & Jekh.) (40 x 20 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul Crucii Member, Sândominic Formation.

21. Euconochitina brevis conica (Taug. & Jekh.) (40 x 20 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul Crucii Member, Sândominic Formation.

22. Euconochitina parvicola (Taug.) (23 x 19 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul Crucii Member, Sândominic Formation.

23. Conochitina raymondii Achab (57 x 17 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul Crucii Member, Sândominic Formation.

24. Conochitina raymondii Achab (55 x 19 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul Crucii Member, Sândominic Formation.

25. Conochitina raymondii Achab (38 x 20 µm); sample no. 4, black quartzites, Babaşa Brook, Pârâul Crucii Member, Sândominic Formation.

26. Conochitina raymondii Achab (46 x 21 µm); sample no. 6, grey sericitous-graphitous phyllites, Şipoş Valley, Başca Member, Sândomonic Formation.

27. Conochitina raymondii Achab (37 x 20 µm); sample no. 9, black graphitous phyllites with intercalations of black quartzites, Pârâul Crucii Member, Sândominic Formation.

28. Conochitina kryos Bockelie (72 x 25 µm); sample no. 9, black graphitous phyllites with intercalations of black quartzites, Pârâul Crucii Member, Sândominic Formation.

29. Lagenochitina brevicollis (Taug. & Jekh.) (43 x 28 µm); sample no. 3, grey phyllites, Fagul Înalt Brook, Pârâul Crucii Member, Sândominic Formation.

30. Lagenochitina brevicollis (Taug. & Jekh.) (42 x 31 µm); sample no. 5, grey phyllites, Pârâul Scurt Brook, Pârâul Crucii Member, Sândominic Formation.

31. Conochitina brevis Taug. & Jekh. (37 x 25 µm); sample no. 9, black graphitous phyllites with intercalations of black quartzites, Pârâul Crucii Member, Sândominic Formation.

32. Clathrochitina oblonga Ben. & Taug. (46 x 30 µm); sample no. 9, black graphitous phyllites with intercalations of black quartzites, Pârâul Crucii Member, Sândominic Formation.

33. Lagenochitina brevicollis (Taug. & Jekh.) (43 x 24 µm); sample no. 9, black graphitous phyllites with intercalations of black quartzites, Pârâul Crucii Member, Sândominic Formation.

34. Lagenochitina cf. combazi Finger (23 x 18 µm); sample no. 6, grey sericitous-graphitous phyllites, Şipoş Valley, Başca Member, Sândomonic Formation.

35. Lagenochitina cf. combazi Finger (30 x 23 µm); sample no. 5, grey phyllites, Pârâul Scurt Brook, Pârâul Crucii Member, Sândominic Formation.

Without dimensions scale

L. OLARU PLATE I

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L. OLARU PLATE II

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L. OLARU PLATE III

276

L. OLARU PLATE IV

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olaru geotectonic context · 2019. 2. 17. · acta palaeontologica romaniae v. 6 (2008), p 253-277....

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