Sedimentary Geology 208 (2008) 79–87

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Sedimentary Geology

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Facies analysis of Lofer cycles (Upper Triassic), in the Argolis Peninsula (Greece)

F. Pomoni-Papaioannou ⁎Department of Geology & Geoenvironment, University of Athens, Panepistimiopolis, 157 84 Athens, Greece

⁎ Fax: +30 2107274187.E-mail address: fpomoni@geol.uoa.gr.

0037-0738/$ – see front matter © 2008 Elsevier B.V. Aldoi:10.1016/j.sedgeo.2008.04.005

A B S T R A C T

A R T I C L E I N F O

Article history:

The Upper Triassic carbona Received 11 October 2007Received in revised form 28 March 2008Accepted 6 April 2008

Keywords:Upper TriassicCyclic carbonatesPaleosolsEarly diagenesisAllocyclicity

te sediments of Argolis Peninsula are part of the Upper Triassic–Lower Jurassicextensive and thick neritic carbonate formations (Pantokrator facies) that formed at the passive Pelagonianmargin and are considered as Dachstein-type platform carbonates. Facies analysis of the Upper Triassic“Lofer-type” lagoonal–peritidal cycles in the Dhidimi area, proved that cycles, although mostly incomplete,were regressive shallowing-upward. The ideal elementary cyclothems are meter-scale in thickness and beginwith a subtidal bed (Member C), represented by a peloidal dolostone with megalodonts (wackestone orpackstone), being followed by a stromatolitic intertidal dolomitic mudstone and/or fenestral intertidaldolomitic mudstone (Member B) that is overlain by dolocrete (terrestrial stromatolites or pisoidic dolomite)or a supratidal “soil conglomerate” in red micritic matrix (Member A). Lofer-cycle boundaries are defined atthe erosional surfaces and accordingly the Lofer cyclothems are unconformity-bounded units. Due tocommon post-depositional truncation of the subtidal and intertidal facies, the supratidal members prevail,being developed, in places, directly upon subaerial exposure surfaces (erosionally reduced cyclothems).Peritidal layers are characterized by a well-expressed lamination, sheet cracks, tepee structures, fenestralpores and karst dissolution cavities.The studied lagoonal–peritidal cycles are considered to have been deposited in a tidal-flat setting (innerplatform), repeatedly exposed under subaerial conditions, in the context of a broader tropical rimmedplatform. Although the studied area was tectonically active due to rift-activity and the autocyclic processesshould also be taken in consideration, the great lateral correlatability of cycles, the facies shifting and thewidespread erosion that resulted in superposition of supratidal-pedogenic facies directly upon subtidalmembers (subaerial erosional unconformity), indicating a sea-level drop, reflect allocyclic control via high-frequency eustatic sea-level oscillation (orbital forcing).Sediment deposition occurred during low-stand system tract (LST), that probably continued also in thetransgressive system tract (TST) and reflects an overall sea-level fall. Under these conditions dissolution andcement precipitation episodes, as well development of paleosols and karsts, were triggered, during arelatively less arid interval.

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1. Introduction

Lofer cycles of the Alpine Triassic have been well studied in theDachstein Limestone of the Northern Calcareous Alps (Sander, 1936;Schwarzacher, 1948, 1954, 2005; Fischer, 1964,1975; Zankl, 1967, 1969;Piller, 1976; Wurm, 1982; Schwarzacher and Haas, 1986; Haas, 1991,1994, 2004; Satterley, 1994; Satterley and Brandner, 1995; Enos andSamankassou, 1998; Haas et al., 2007). Due to the regularity ofbedding, the Dachstein Limestone (Upper Norian to Rhaethic) playedan important role in the attempt to interpret the origin of sedimentarycycles. Indeed, Wilson (1975) used the term “lofer cyclothem” for allcyclothems regardless their age.

Sander (1936), who was the first to describe the rhythmicsedimentation of the Dachstein Limestone, introduced the term

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“Lofer facies” due to its excellent exposure in the Austrian LofererSteinberge, near Lofer. Subsequently, Schwarzacher (1948) and Fischer(1964) confirmed Sander's conclusions and added new data. Schwar-zacher (1948) pointed out a higher order organization of the basiccycles that he attributed to temporal processes. Later, Schwarzacher(1954) suggested that the 100 ka and 20 ka Milankovitch climaticvariation, due to changes in the earth's orbit, may have been theultimate cause of the cyclic regularity of stratification.

The modern genetic characterization and facies associationinterpretation of Lofer cycles were performed by Fischer (1964) inhis fundamental work on the Dachstein Limestone of the NorthernCalacareous Alps. According to him, the Lofer cyclothem typicallyconsists in ascending order of: (1) a disconformity at the base (d); (2) abasal argillaceous member, commonly restricted to solution ordesiccation cavities in the underlying rock, corresponding to supra-tidal facies (reworked paleosol, member A); (3) an intertidal memberwith algal mats (member B: loferites); and (4) a subtidal massive

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limestone member with a varied biota (member C). Fischer (1964)argued that the cycles represented progressive change from lagoonalto peritidal depositional conditions that were attributable to rhythmicvariations in the rate of tectonic subsidence.

Investigating cores from deep boreholes in the Bakony Mountains(Transdanubian Central Range), Haas (1982, 1991, 1994) revealed anadditional intertidal facies below the disconformity (BV). This wasconsidered the regressive portion of the cycle and thereby modifiedthe basic pattern of the Lofer cycles to a symmetrical, ideal cycle(transgression–regression cycles). The cycle-boundaries were definedat the erosional surfaces (d: disconformity, according to Fischerterminology) and accordingly the Lofer cyclothems are unconformity-bounded units (Schwarzacher, 1948; Fischer, 1964; Haas, 1982, 1991).Fischer's facies organization was later modified by Satterley (1996a)who considered that a complete Lofer cyclothem begins with ashallow subtidal wackestone–packstone (Fischer's Member C) over-lain by an intertidal and possibly supratidal mudstone (Fischer'sMember B) and finally by a supratidal “soil conglomerate” (Fischer'sMember A).

The cyclic pattern of ancient cyclic carbonate sequences is, in mostcases thought to be controlled by eustatic sea-level oscillations:allocyclic model (Fischer, 1964, 1975, 1991; Haas, 1982, 1991, 1994,2004; Schwarzacher, 2005). Such cyclicity, however, may also resultfrom the progradation of tidal flats: autocyclic model (Zankl, 1967;Satterley and Brandner, 1995; Satterley, 1996b; Enos and Samankas-sou, 1998). The differentiation between these two models is a difficulttask especially in tectonically active areas where orbitally controlledcyclicity is not reliably recorded (Strasser, 1991).

The deposition of Lofer cycles is known to be controlled by low-amplitude sea-level variations (Goldhammer et al., 1990; Haas, 1994)and accumulation takes place at relatively high long-term sedimen-tation rates of 100–200 m/m.y. (Garrison and Fischer, 1969).Numerous authors have ascribed Lofer cyclicity to orbitally forcedeustatic oscillations, that were considered to have produced a cyclestacking pattern with an average of five individual fifth-order cyclespackaged into fourth-order megacycles (Schwarzacher, 1954;Fischer, 1964, 1975; Haas, 1982, 2004). Fischer (1964, 1975)suggested that Lofer cycles were deposited under control of fifth-

Fig. 1. (A) Regional geological setting of Dhidimi area, in SE Argolis Peninsula (modified by PhJurassic, 2: Asklipion unit, deep water facies, Triassic–Jurassic, 3: Ophiolites, 4 and 5: Cretacecarbonate facies, 8: Flysch, 9: Neo-volcanism, 10: Recent formations. (B)Geographical locati

order glacio-eustatic sea-level oscillations (corresponding to 21 ka or41 ka orbital cycles).

Recently, however, the allocyclicity model has been challenged,especially in areas subject to differential subsidence of fault-boundedblocks and rift-activity. As an alternative to orbital forcing, Gold-hammer et al. (1990) suggested that successions formed of Lofer cyclesprobably resulted from the non-rhythmic sum of subsidence pulses,sedimentation, autocyclicity, and sea-level variation. Under the above-mentioned conditions, multiple sedimentary cycles (autocycles) and atectonic overprint might be detectable in successions of Lofer cycles.Platform-edge strike-slip faulting may form either deepening-upwardLofer cycles (Cisne, 1986) or shallowing-upward cycles (Fischer, 1986).

The Dachstein-type loferitic facies were among the first to berecognized as ancient counterparts of modern peritidal carbonatedeposits, such as those of the Arabian Gulf, Florida, the Bahamas andShark Bay. Although Fischer (1964, 1975) described the Lofer cycles ofthe Dachstein as essentially deepening-upward regressive–transgres-sive couplets, a regressive, shallowing-upward pattern has beensupported by many authors (Haas, 1982, 1994; Goldhammer et al.,1990). Lofer-cycle boundaries, marking a relative deepening upwardtendency, are defined by the subtidal facies, as well as by the transitionof the microbial (stromatolitic) or fenestral loferite to homogeneousloferite (Satterley, 1996a,b).

Apart from the Northern Calcareous Alps, Dachstein-type platformcarbonates have been recognized in Central and Inner WesternCarpathians, in the Transdanubian Range, in the NW part of thePannonian Basin, in Southern Alps, in Dinarides, and in Hellenides.Analogous formations have been described in the Wettersteinkalk ofBleiberg-Kreuth, in Austria (Bechstadt, 1975). In Hellenides, “loferitic”facies have been studied in Late Triassic carbonates of the island Hydra(Richter and Fuchtbauer, 1981) and in the region Pigadakia of thePeloponnese (Kalpakis and Lekkas, 1982). Distinctive cyclothems havebeen described, as well, by Pomoni-Papaioannou et al. (1986) in theUpper Triassic sequence of Mountain Olympus (Formation AghiosDionysios), exhibiting strong similarities with the ideal Lofercyclothems of the Northern Calcareous Alps. The Upper Triassicloferites of the Pelagonian have been correlated with those of theTransdanubian Range inHungary (Haas and Skourtsis-Coroneou,1995).

otiades, 2006 after Baumgartner, 1985). 1: Basal sequence, carbonate platform, Triassic–ous shallow water carbonate facies, 6 and 7: Cretaceous shallow water and deep wateron of the area studied.

Fig. 3. Dolostones and dolomitic limestones with Megalodonts in growth position.

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Spectacular Lofer-cyclic Dachstein-type carbonate sequences,punctuated by paleosol horizons, found on the SE Argolis Peninsulaare the focus of this paper. A detailed facies analysis has beenperformed with the aim of determining the origin of the carbonatecyclothems and assessing the relationship between the peritidalformations and the paleosols. Thin sections have been studied indetail in order to reveal the structural and textural characteristics ofthe studied material.

2. Geological setting

The Argolis Peninsula belongs to the Pelagonian zone (Aubouinet al., 1970; Celet and Ferriere, 1978; Robertson et al., 1991). DuringTriassic–Early Jurassic times, a carbonate platform developed in theeastern portion of the External Hellenides that corresponded to thepassive Pelagonian margin.

The Dachstein-type platform carbonates found on the ArgolisPeninsula are a part of the extensive and thick Upper Triassic–LowerJurassic carbonate series (Pantokrator facies) that represents the firststage in the evolution of the Triassic–Late Jurassic passive Pelagonianmargin (Haas and Skourtsis-Coroneou, 1995). The Pantokrator faciesextends over an area of 1000 km, covering the greatest part of theArgolis Peninsula (Fig.1). The Trapezona, Koni and Dhidimi heights arebuilt up of this facies (Photiades, 1995).

According to Gaitanakis and Photiades (1991, 1993) and Gaitanakiset al. (2005), the stratigraphic basement of the Pantokrator lime-stones, consists of hemipelagic limestones of Anisian age, developeddirectly upon Lower Triassic volcanic tuffs. On the other hand,Dercourt (1964) and Vrielynck (1978a,b, 1982) described the strati-graphic base of the Pantokrator Formation as consisting principally ofdolomitized stromatolitic limestones with Middle Triassic Dasyclada-cean algae (Diplopora annulata).

Fig. 2. Cross section in Dhidimi area (SE Argolis Peninsula).

The Triassic–Early Jurassic carbonate formations of the Pelagonianzone are overlain by olistrostromes, overthrusted from a stack oftectonic units, including ophiolites, pillow-lavas cherts, tectonicmélanges of serpentinites, Paleozoic, (Middle-) Upper Jurassic–Upper Cretaceous carbonates, and Maastrichtian–Paleogene flysch( Aubouin et al., 1970; Jacobshagen et al., 1976; Vrielynck, 1978a,b,1982; Baumgartner, 1985; Photiades, 1986, 1987, 2006; Clift andRobertson, 1989; Bortolotti et al., 2002, 2003; Gaitanakis andPhotiades, 1991; Gaitanakis et al., 2005).

The Dhidimi height, is composed entirely of the PantokratorFormation (Norian) forming an anticline of WSW–ENE direction.The studied stratigraphic section on Dhidimi height is made up of acarbonate succession of ca. 70 m thick (Fig. 2). It is composed ofwell-bedded dolomites and dolomitized limestones of cycliclagoonal–peritidal facies that are punctuated by subaerial exposuresurfaces and paleosol horizons (Pomoni-Papaioannou and Pho-tiades, 2007).

Shallow subtidal carbonates are characterized by Megalodonts ingrowth position that usually occur at the base of cyclothems (Fig. 3).Peritidal facies, which are rare, are represented by stromatoliticdolostones (dolomitic microbial stromatolites) that are characterizedby wavy-wrinkled laminations and loferites recording subaerialexposure (tepee structures, bird's eyes, desiccation cracks and karstcavities) (Fig. 4).

Fig. 4. Loferitic dolostone with tepee structures and bird's eyes.

Fig. 7. Grainstone with benthic foraminifera and calcareous algae.

Fig. 5. Flat erosional discontinuity surface between dolomitic limestones withMegalodonts (top) and loferites (base).

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In the studied section paleosol horizons are represented by laminardolocretes and loferitic breccias (supratidal soil conglomerates).Laminar dolocretes and soil breccia lie directly upon the subtidalfacies, or even directly upon a subaerial erosional unconformity.

The discontinuity surface between the loferites or dolocretes andthe overlying subtidal facies is a flat erosional surface (Fig. 5). Incontrast, the surface between the unaltered loferites or the subtidalfacies and the overlying breccias or pedogenic facies is an unevensurface.

3. Facies analysis — interpretation

Cyclothems, observed in the Dhidimi stratigraphic section, aremostly incomplete and show a regressive shallowing-upward trend.Lofer-cycle boundaries are defined at the erosional surfaces andaccordingly the Lofer cyclothems are unconformity-bounded units.

Ideal elementary cyclothems, sensu D'Argenio (1974) and Strasser(1991), are meter-scale in thickness and involve a subtidal bed(Member C) represented by peloidal dolostones and dolomitic

Fig. 6. Packstone with fragments of Megalodonts, calcareous algae and benthicforaminifera (subtidal facies). Megalodont molds have been filled by dog-teeth cementand the remaining space by poekilitic cement. Note a circumgranular desiccation cracksurrounding a Megalodont bioclast.

limestones with Megalodonts and calcareous algae (wackestones,packstones) (Fig. 6) or by packstones/grainstones with benthicforaminifera (Aulotortinae) and/or calcareous algae (Figs. 7 and 8). Itis followed by loferitic dolostones represented by dolomitic stroma-tolite mudstone (Figs. 9, and 10) and/or fenestral dolomitic mudstoneof tidal-flat facies (Member B) (Fig. 11). Member B is overlain bydolocretes (terrestrial stromatolites (Fig. 12) or pisoidic dolomite) orsupratidal “soil conglomerate” in red fine-grained matrix (Member A)(Fig. 13). Laminar dolocretes are characterized by interconnectingelongated cavities showing geopetal filling (Fig. 14).

The facies observed correspond, respectively, to Phase C and thecombined Phases B and A of Fischer's cycle. The above faciesalternation defines a series of lagoonal–peritidal cyclothems that arealways capped by a subaerial exposure surface, marked by loferitesand commonly by paleosols and soil conglomerates. Althoughmost ofthe cyclothems are regressive, some of them appear to be symmetric.In the latter case, the subtidal dolostones are embedded withinunderlying and overlying loferites (ABCBV). Thus, the cyclothemsusually lie either above the top of the previous ones or above paleosol.Paleokarst dissolution cavities commonly occur near the tops of thecyclothems.

The microbial-laminated intertidal dolomitic mudstones corre-spond to loferites of tidal-flat facies (intertidal-supratidal, Member B)and consist of low-relief and planar stromatolites with rare bioclasts.They are characterized by a well-developed lamination, desiccationcracks and bird's eyes containing internal vadose sediment at the baseand spar filling in the residual space (geopetal structures) (Fig. 13).

Fig. 8. Grainstone with benthic foraminifera (Aulotortinae).

Fig. 11. In-situ brecciated stromatolites containing elongate cavities with geopetalfilling.

Fig. 9. Undulate discontinuity surface between stromatolites (base) and dolocretes(top).

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Thrombolitic structures composed of dark, clotted micrite withpeloids are common. The deposition of the studied lagoonal–peritidalsuccession occurred during a time interval characterized by high-frequency and relatively long-lasting exposures of the inner platform.Under these circumstances repeated episodes of dissolution and earlylithification (cementation) took place, as well as development ofpaleosols.

Microbial stromatolites and loferites are deeply modified bypedogenic processes, leading to the formation of dolocretes. Due totruncation of the subtidal and peritidal facies, subaerial exposurefeatures are directly superimposed by subtidal facies, preventing theestimation of the original thickness of the cyclothems. In that case, theterm “erosionally reduced cyclothem” can also be applied.

Supratidal weathering led to formation of incipient paleokarstfeatures, i.e., biomolds filled with cement and/or internal sedimentand interconnected large shrinkage and/or dissolution cavities, linedby dog-teeth cement and filled with poekilitic cement, commonlyoverprinting the underlying subtidal bed (Fig. 15). Microkarst is oftenfilled with reworked intraclasts. Dolocretes (terrestrial stromatolites)correspond to biogenic laminar calcretes sensu Wright et al. (1988)and are composed of alternate bands of micrite (dark) and sparrycalcite (white) with irregular boundaries (Fig. 16). The bandedstructure of the dolocretes (zebra-like laminar dolocretes) is con-sidered a result of an alternation of periods of colonization ofendolithic organisms in a subaerial environment (cyanobacteria,fungi, lichens) and periods of cementation following the decay of

Fig. 10. Microbial carbonates (calcified cyanobacteria).

these organisms (Jimenez de Cisneros et al., 1993). Klappa (1979) firstproposed this model for lichen stromatolites.

Laminar dolocretes show a dendroid micrite morphology and arecharacterized by irregular micritic coatings with protuberancesforming bridges in-between grains and meniscus cement (Fig. 17).Cylindrical subparallel cavities and numerous corroded surfaces,suggesting several exposure stages, are common (Fig. 18). Bituminousrhizolite-like structures (Fig. 19), alveolar-septal textures filled byblocky and/or drusy cement, septarian concretions with crystallaria-like cracks and elongated calcified root structures occur, in places(Fig. 20). In-situ brecciation marks subaerial exposure intervals(Fig. 21).

4. Depositional environment

All known examples of Lofer-type facies (Austrian and Italian Alps)correspond to tidal-flat systems developed on wide inner platformswith well-studied reefs on platform margins (e.g., Zankl, 1969; Wurm,1982; Satterley, 1994). Reefs similar to those known from the AustrianAlps were also reported from the Argolis Peninsula. Matarangas et al.

Fig. 12. Dendroid micrite morphologies (microbial?) and irregular micritic coatingsforming bridges in-between grains.

Fig. 15. Cavities ligned by dog-teeth cement.Fig. 13. In-situ brecciated pedogenic facies.

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(1995) studied a Carnian reef facies and Senowbari-Darian et al. (1996)described Norian–Rhaetian reefs consisting of corallinacean lime-stones. In addition, Senowbari-Darian et al. (1997) reported LateTriassic reefs with Sphinctozoan sponges, on the isle of Hydra.

The Lofer-type cycles of Argolis are lagoonal–peritidal cyclesconsidered to have been developed on the wide inner platform of abroad rimmed carbonate platform, as a result of lateral faciesmigration, due to small-scale sea-level fluctuations.

The biological association in the subtidal member, which isdominated by molluscs, calcareous algae, and benthic foraminifera(chlorozoan–chloralgal association, Carannante et al.,1988), supports atropical carbonate platform model. In that context, microbial dolo-mites are considered to have been precipitated into hypersalineenvironment, most likely through evaporative synsedimentary dolo-mitization, possibly involving bacteria andorganicmatter degradation.

5. Climatic indicators

The occurrence of calcretes in the geological record is widelyconsidered as a significant climatic indicator related to semi-arid orarid conditions, whereas karst facies, related to wet periods, developin variable climates. That means that karst and calcrete diageneticenvironments are not mutually exclusive (Esteban and Klappa, 1983).Jimenez de Cisneros et al. (1993), however, suggested that coexistenceand overlapping of different stages of karst and calcrete point tochanges of climatic conditions, following the general relations karst-wetter climate and calcrete-drier climate.

Fig. 14. Laminar dolocrete with interconnecting elongated cavities (geopetal filling).

In agreement with that aspect, it is herein proposed that thecoexistence of karst and paleosol horizons suggest a relatively less aridinterval. This is in accordance with Chandler et al. (1992), whoconsidered that the Late Triassic and Early Jurassic were relatively lessarid than surrounding time periods. In the Transdanubian Range(Hungary) the latest Carnian to Late Norian is semi-arid and the latestNorian to Rhaetian is semi-humid. The calcretes–dolocretes are typicalin the more arid, whereas the incipient karstification for the morehumid periods and there is a thick transitional interval, where bothoccur (Haas, pers. communication).

6. Discussion

A major challenge in the interpretation of carbonate cyclothemssuccession is the distinction between autocyclic (aperiodic, randomdeposition, free oscillations) and allocyclic processes. Although faciesanalysis has proved crucial in distinguishing autocyclic and allocyclicprocesses, “stochastic” (autocyclicity) versus “deterministic” processes(allocyclicity) are hardly differentiated.

An autocyclic process is defined as a change in the status of asedimentary system without the intervention of external forcing(Ginsburg, 1971; Pratt and James, 1986), whereas an allocyclic processis considered to be forced by changes in the Earth's orbital parameters(Goldhammer et al., 1987). In that sense, autocyclic processes arecompletely internal to the sedimentary system including lateralmigration of inter- to supratidal mudbanks and subtidal areas. In the

Fig. 16. Zebra-like laminated dolocrete with alveolar-septal structure and meniscuscement.

Fig. 19. Bituminous rhizolite-like structures.Fig. 17. Dolocrete crusts showing micritic coatings with protuberances.

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case of allocyclic processes, the resulting environmental changes(eustatic and climatic changes produced by Milankovitch insolationcycles) are registered in carbonate platforms contributing to theprocess of recognizing astronomical signals in peritidal deposits(Fischer, 1964, 1975). The possibility of faithfully recording orbitallycontrolled cyclicity, however, is minimal for most environments(Satterley, 1996a,b), especially in tectonically active areas (passivemargins, throughout initiation and rift stages, Ben-Avraham et al.,1979; Rankey et al., 1994).

Taking into consideration that the Argolis Peninsula was atectonically active area during the Late Triassic–Early Jurassic due torift-activity (extensional zone), the autocyclic facies migrationprocesses most probably have contributed to the cyclicity of theformations. In fact, during the Late Triassic glacio-eustacy they mayhave been subordinate because this period corresponds to a hot,nonglacial interval of the Earth's climatic history (Frakes et al., 1992).According to Satterley (1996a,b), the probable lack of an ice cap in theTriassic questions the applicability of glacio-eustacy for the explana-tion of the Lofer cyclicity. During that period, composite fourth- andfifth-order eustacy was probably of low-amplitude, which wasprimarily caused by climatic fluctuations via expansion/contractionof seawater.

Conversely, the great lateral correlatability of cycles and thewidespread erosion and pedogenesis that resulted in the super-position of supratidal-pedogenic facies directly upon subtidal mem-bers (erosional unconformity) indicating sea-level drop, reflectallocyclicity (Haas, 2004). Accordingly, the Upper Triassic cycles in

Fig. 18. Numerous corroded surfaces suggesting several exposure stages.

the Argolis Peninsula that can be considered a variant of the Lofercycles, although incomplete, should rather be regarded as a record oforbitally forced eustatic high-frequency sea-level oscillations. Conse-quently, the cyclothems record orbitally forced environmentalchanges (eustatic and climatic changes produced by Milankovitchinsolation cycles).

The studied cyclic lagoonal–peritidal succession indicates thatsediment deposition occurred during low-stand system tract (LST),that probably continued also in the transgressive system tract (TST)and reflects an overall sea-level fall that reduced accommodationspace provided by the interaction between sea-level and subsidence(Bera, 2007). Under these conditions dissolution and cementprecipitation episodes, as well development of paleosols and karsts,were triggered.

7. Conclusions

The Upper Triassic carbonate sediments of the Dhidimi area, in theArgolis Peninsula, are considered Dachstein-type platform carbonatesformed on the passive Pelagonian margin. The studied lagoonal–peritidal cycles are considered to have been deposited in a tidal-flatsetting (inner platform), repeatedly exposed under subaerial condi-tions, in the context of a broader tropical rimmed platform.

Facies analysis has proved that the cyclothems studied, althoughmostly incomplete, reflect a regressive shallowing-upward trend. Thecyclothems are meter-scale in thickness and beginwith a subtidal bed(Member C) represented by a peloidal dolostone with megalodonts

Fig. 20. Elongated calcified root structures and septarian concretion with crystallaria-like cracks.

Fig. 21. In-situ brecciated dolocrete with meniscus cement.

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(wackestone or packstone), being followed by a microbial-laminated(stromatolitic) intertidal dolomite and/or fenestral dolomitic mud-stone of tidal-flat origin (Member B) that is overlain by dolocretes(terrestrial stromatolites or pisoidic dolomite) or a supratidal “soilconglomerate” in red fine-grained matrix (Member A). Peritidal layersare characterized by a well-expressed lamination, sheet cracks, tepeestructures, fenestral cavities and karst dissolution cavities.

Due to truncation of the subtidal and intertidal facies, thesupratidal members prevail, being developed in places directly uponsubaerial exposure surfaces (erosional reduced cyclothems). Althoughthe investigated area was tectonically active, due to rift-activity andthe autocyclic processes should have contributed to the cyclicity, thegreat lateral correlatability of cycles, the facies shifting and thewidespread erosion, resulting in the superposition of supratidal-pedogenic facies directly upon subtidal members (subaerial erosionalunconformity) indicating sea-level drop, mainly reflect allocyclicprocesses related to eustatic high-frequency sea-level oscillations(eustatic and climatic changes produced by Milankovitch insolationcycles, 4th and 5th order).

Sediment deposition occurred during low-stand system tract (LST),that probably continued also in the transgressive system tract (TST)and reflects an overall sea-level fall that reduced accommodationspace provided by the interaction between sea-level and subsidence.Under these conditions dissolution and cement precipitation epi-sodes, as well development of paleosols and karsts, were triggered,during a relatively less arid interval.

Acknowledgements

I am highly indebted to Dr Paul Pearson for his substantial remarksand to Dr Janos Haas for his valuable contribution to the evaluation ofthe mns through his constructive review. I also address my gratitudeto Dr Brian Jones for his significant suggestions. I would like to thankDr Adonis Photiades (Institute of Geology andMineral Exploration) forthe profound geological knowledge which he gladly offered me.

References

Aubouin, J., Bonneau, M., Celet, P., Charvet, J., Clement, B., Degardin, J.M., Dercourt, J.,Ferriere, J., Fleury, J.J., Guernet, C., Maillot, H., Mania, J.H., Mansy, J.L., Terry, J.,Thiebault, P., Tsoflias, P., Verrieux, J.J., 1970. Contribution a la geologie desHellenides: le Gavrovo, le Pinde et la zone ophiolitique subpelagonienne. Ann.Soc. Geol. Nord 90, 277–306.

Baumgartner, P.O., 1985. Jurassic sedimentary evolution and nappe emplacement in theArgolis Peninsula (Peloponnesus, Greece). Mem. Soc. Helv. Sci. Nat. 99, 1–111.

Bechstadt, T., 1975. Zyklische Sedimentation im erzfuhrenden Wettersteinkalk vonBleiberg — Kreuth (Kartnen, Osterreich). N. Jb. Geol. Palaont. Abh. 149, 73–95.

Ben-Avraham, Z., Almagar, G., Garfunkel, Z., 1979. Sediments and structure of the Gulf ofElat (Agaba) — Northern Red Sea. Sediment. Geol. 23, 239–267.

Bera, F., 2007. Sedimentation in shallow to deep water carbonate environments across asequence boundary: effects of a fall in sea-level on the evolution of a carbonatesystem (Ladinian-Carnian, eastern Lombardy, Italy). Sedimentology 54, 721–735.

Bortolotti, V., Carras, N., Chiari, M., Fazzuoli, M., Marcucci, M., Photiades, A., Principi, G.,2002. New geological observations and biostratigraphic data on the ArgolisPeninsula: palaeogeographic and geodynamic implications. Ofioliti 27 (1), 43–46.

Bortolotti, V., Carras, N., Chiari, M., Fazzuoli, M., Marcucci, M., Photiades, A., Principi, G.,2003. . The Argolis Peninsula in the palaeogeographic and geodynamic frame of theHellenides. Ofioliti 28/2, 79–94.

Carannante, G., Esteban, M., Milliman, J.D., Simone, L., 1988. Carbonate lithofacies aspaleolatitude indicators: problems and indicators. Sediment. Geol. 60, 333–346.

Celet, P., Ferriere, J., 1978. Les Hellenides internes: le Pelagonien. Ecl. Geol. Helv. 71 (3),467–495.

Chandler, M.A., Rind, D., Ruedy, R., 1992. Pangaean climate during the Early Jurassic:GCM simulations and the sedimentary record of paleoclimate. Geol. Soc. Am. Bull.104, 543–559.

Cisne, J.L., 1986. Earthquakes recorded stratigraphically on carbonate platforms. Nature323, 320–322.

Clift, P.D., Robertson, A.H.F., 1989. Evidence of a late Mesozoic ocean basin andsubduction/accretion in southern Greek Neo-Tethys. Geology 17, 559–563.

D' Argenio, B., 1974. Le piattaforme carbonatiche periadriatiche : una rassegna diproblemi nel quadro geodinamico mesozoico dell'area mediterranea. Mem. Soc.Geol. Ital. 13 (2), 1–28.

Dercourt, J., 1964. Contribution a l'etude geologique d’un secteur du Peloponneseseptentrional. Ann. Géol. Pays Hell. 15 , 1–417.

Enos, P., Samankassou, E., 1998. Lofer cyclothems revisited (late Triassic, Northern Alps,Austria). Facies 38, 207–228.

Esteban, M., Klappa, C.F., 1983. Subaerial exposure environment. In: Scholle, P.A.,Bebout, D.G., Moore, C.H. (Eds.), Carbonate Depositional Environments. Am. Assoc.Pet. Geol. Mem., 33, pp. 1–54.

Fischer, A.G., 1964. The Lofer cyclothems of the Alpine Triassic. In: Merriam, D.F. (Ed.),Symposium on Cyclic Sedimentation. Kansas Geol. Surv., Bull., vol. 169, pp.107–146.

Fischer, A.G., 1975. Tidal deposits, Dachstein Limestone, of the North-Alpine Triassic. In:Ginsburg, R.N. (Ed.), Tidal Deposits: A Casebook of Recent Examples and FossilCounterparts. Springer-Verlag, Berlin, pp. 234–242.

Fischer, A.G., 1986. Stratigraphic record of earthquake incidence. Nature 324, 492.Fischer, A.G., 1991. Orbital cyclicity inMesozoic strata. In: Einsele, G., Ricken,W., Seilacher,

A. (Eds.), Cycles and Events in Stratigraphy. Springer-Verlag, Berlin, pp. 48–62.Frakes, L.A., Francis, J.E., Syktus, J.I., 1992. ClimateModes of the Phanerozoic; The History

of the Earth's Climate over the last 600 Million Years. Cambridge University Press.274 pp.

Gaitanakis, P., Photiades, A., 1991. Geological structure of SW Argolis (Peloponnesus,Greece). Geol. Soc. Greece Bull. 25 (1), 319–338.

Gaitanakis, P., Photiades, A., 1993. New data on the geology of Southern Argolis(Peloponnesus, Greece). Geol. Soc. Greece Bull. 28 (1), 247–267.

Gaitanakis, P., Photiades, A., Tsaila-Monopolis, S., Tsapralis, V., 2005. Geological map ofGreece “Spetses sheet” 1:50.000, I.G.M.E., Athens, Greece.

Garrison, R.E., Fischer, A.G., 1969. Deep water limestones and radiolarites of the AlpineJurassic. In: Friedman, G.M. (Ed.), Depositional Environments in Carbonate Rocks.Society of Economic Paleontologists and Mineralogists Special Publication, vol. 14,pp. 20–56.

Ginsburg, R.N., 1971. Landward movement of carbonate mud: newmodel for regressivecycles in carbonates (abstract). AAPG Bull. 55, 340.

Goldhammer, R.K., Dunn, P.A., Hardie, L.A., 1987. High frequency glacio-eustatic sea leveloscillations with Milankovitch characteristics recorded in Middle Triassic platformcarbonatesin Northern Italy. Am. J. Sci. 287, 853–892.

Goldhammer, R.K., Dunn, P.A., Hardie, L.A.,1990. Depositional cycles, composite sea-levelchanges, cycle stacking patterns and the hierarchyof stratigraphic forcing: examplesfrom Alpine Triassic platform carbonates. Geol. Soc. Am. Bull. 102, 535–562.

Haas, J., 1982. Facies analysis of the cyclic Dachstein Limestone Formation (UpperTriassic) in the Bakony Mountains, Hungary. Facies 6, 75–84.

Haas, J., 1991. A basic model for lofer cycles. In: Einsele, G., Ricken, W., Seilacher, A.(Eds.), Cycles and Events in Stratigraphy. Springer-Verlag, Berlin, pp. 722–732.

Haas, J., 1994. Lofer cycles of the Upper Triassic Dachstein platform in the TransdanubianMid-Mountains (Hungary). Int. Assoc. Sedimentol., Spec. Publ. 19, 303–322.

Haas, J., 2004. Characteristics of peritidal facies and evidences for subaerial exposures inDachstein-type cyclic platform carbonates in the Transdanubian range, Hungary.Facies 50, 263–286.

Haas, J., Skourtsis-Coroneou, V., 1995. The Upper Triassic platform sequences in theTransdanubian range and the Pelagonian Zone s.l.: a correlation. Proc. XV CongressCarpatho-Balcan Geol. Assoc., Geol. Soc. Greece Bull., Sp. Publ., vol. 4, pp. 195–200.

Haas, J., Lobitzer, H., Monostori, M., 2007. Characteristics of the Lofer cyclicity in the typelocality of the Dachstein Limestone (Dachstein Plateau, Austria). Facies 53, 113–126.

Jimenez de Cisneros, C., Molina, J.M., Nieto, L.M., Ruiz-Ortiz, P.A., Vera, J.A., 1993.Calcretes from a palaeosinkhole in Jurassic palaeokarst (Subbetic, southern Spain).Sediment. Geol. 87, 13–24.

Jacobshagen, V., Risch, H., Roeder, D., 1976. Die eohellenische Phase, Definition undInterpretation. Z. Dtsch. Geol. Ges. 127, 133–145.

Kalpakis, G., Lekkas, S., 1982. Facies Loferitiques de la region Pigadakia, Peloponnese.Ann. Geol. Pays Hellen. 31, 73–88.

Klappa, C.F., 1979. Lichen stromatolites: criterion for subaerial exposure and a mechanismfor the formation of laminar calcretes (caliche). J. Sediment. Petrol. 49, 387–400.

Matarangas, D., Marcopoulou-Diacandoni, A., Vartis-Matarangas, M., 1995. Carnian reeffacies from Pantokrator limestones of Argolis Peninsula (NE Mavrovouni),Peloponnese. Proc. XV Congress Carpatho-Balcan Geol. Assoc. Geol. Soc. GreeceBull., Spec. Publ., vol. 4 (1), pp. 218–225. Athens.

87F. Pomoni-Papaioannou / Sedimentary Geology 208 (2008) 79–87

Photiades, A., 1986. Contribution a l'tude geologique et metallogenique des unitesOphiolitiques de l'rgolide septentrionale (Greece). Ph.D. Thesis, Univ. Besancon,France.

Photiades, A., 1987. Emplacement and nature of the ophiolite units in Northern Argolis(Peloponnesus). Proc. Symp.Ophiolites andoceanic Lithosphere,Nicosia, Cyprus, p. 75.

Photiades, A., 1995. Geological Map of Greece scale 1:25.000 “Epidavros AngelokastronSheet”. Inst. Geol. Mineral Explor., Athens, Greece.

Photiades, A. (2006). Geological study of the quarry plain area in Dhidhima of Argolis.Institute of Geology and Mineral Exploration. Intern. Rep. (in greek).

Piller, W., 1976. Facies und Lithostratigraphie des gebankten Dachsteinkalkes (Ober-trias) am Nordrand des Toten gebirges (S. Grunau/Almtal, Oberosterreich). Mitt.Ges. Geol. Bergbaustud Oster 23, 133–152.

Pomoni-Papaioannou, F., Photiades, A., 2007. Stacked loferite cycles and paleosoils(Upper Triassic, Argolis Peninsula, Greece). Proc. 25th IAS Meeting, Patras, Greece,p. 141.

Pomoni-Papaioannou, F., Trifonova, E., Tsaila-Monopolis, S., Katsiavrias, N.,1986. Lofer TypeCyclothems is a Late Triassic Dolomite Sequence on the Eastern part of Olympus.Institute Geology Mineral Exploration, Geol. & Geoph. Studies, pp. 403–417.

Pratt, R.B., James, N.P., 1986. The St George Group (Lower Ordovician) of westernNewfoundland: tidal flat island model for carbonate sedimentation in shallowepeiric seas. Sedimentology 33, 313–343.

Rankey, E.C., Walker, K.R., Srinivasan, K., 1994. Gradual establishment of lapetan“passive” margin sedimentation: stratigraphic consequences of Cambrian episodictectonism and eustacy, Southern Appalachians. J. Sediment. Res. B64, 298–310.

Richter, D.R., Fuchtbauer, H., 1981. Merkmale und Genese von Breccien und ihreBedeutung im Mesozoikum von Hydra (Griechenland). Z. Dtsch. Geol. Ges. 132,451–501.

Robertson, A.H.F., Clift, P.D., Degnan, P.J., Jones, G., 1991. Palaeogeographic andpalaeotectonic evolution of the Eastern Mediterranean Neotethys. Palaeogeogr.palaeoclimatol. palaeoecol. 87, 289–343.

Sander, B., 1936. Beitrage zur Kenntniss der Anlagerungsgefuege. Miner. Petr. Mitt 48,27–139.

Satterley, A.K., 1994. Sedimentology of the Upper Triassic Reef complex of theHochkönig Massif (Northern Calcareous Alps, Austria). Facies 30, 119–150.

Satterley, A.K., 1996a. Cyclic carbonate sedimentation in the Upper Triassic DachsteinLimestone, Austria: the role of patterns of sediment supply and tectonics in aplatform-reef-basin system. Journ. Sed. Res. 66 (2), 307–323.

Satterley, A.K., 1996b. The interpretation of cyclic succession of the Middle and UpperTriassic of the Northern and Southern Alps. Earth Sci. Rev. 40, 181–207.

Satterley, A.K., Brandner, R., 1995. The genesis of Lofer cycles of the DachsteinLimestone, Northern Calcareous Alps, Austria. Geol. Rundsch. 84, 287–292.

Schwarzacher, W., 1948. Uber die sedimentare rhythmic des Dachstein Kalkes von Lofer.Geol Bundesanst Verh. 10–12, 176–188.

Schwarzacher, W., 1954. Uber die Grossrhytmic des Dachdtein Kalkes von Lofer.Tschermaks Mineral. Petrogr. Mitt. 4, 44–54.

Schwarzacher, W., 2005. The stratification and cyclicity of the Dachstein Limestone inLofer, Leogang and Steinernes Meer (Northern Calcareous Alps, Austria). Sediment.Geol. 181 (1–2), 93–106.

Schwarzacher,W., Haas, J., 1986. Comparative statistical analysis of some Hungarian andAustrian Upper Triassic peritidal carbonate sequences. Acta Geol. Hung. 29,175–196.

Senowbari-Daryan, B., Matarangas, D., Vartis-Matarangas, M., 1996. Norian–RhaetianReefs in Argolis Peninsula, Greece. Facies 34, 77–82.

Senowbari-Daryan, B., Matarangas, D., Vartis-Matarangas, M., 1997. Cinnabaria minimaSENOWBARI_DARYAN, a sphinctozoid sponge from the Late Triassic reef limestonesof Hydra, Greece. Revue Paleobiol. 16 (1), 1–6.

Strasser, A., 1991. Lagoonal–peritidal sequences in carbonate environments: autocyclicand allocyclic processes. In: Einsele, G., Ricken, W., Seilacher, A. (Eds.), Cycles andEvents in Stratigraphy. Springer-Verlag, Berlin, pp. 709–721.

Vrielynck, B., 1978a. Donees nouvelles sur les zones internes du Peloponnese (Greece).Ph.D.Thesis, Univ. Lille, France.

Vrielynck, B., 1978b. Donnees nouvelles sur les zones internes du Peloponnese: LesMassifs a l'st de la Plaine d'Argos (Greece). Ann. Geol. Pays Hell. 29, 440–462.

Vrielynck, B., 1982. Evolution paleogeographique et structurale de la presqu'ile d'rgolide(Greece). Rev. Geol. Dyn. Geogr. Phys. 23, 277–288.

Wilson, J.L., 1975. Carbonate Facies in Geologic History. (Springer), Berlin. 471 pp.Wright, V.P., Platt, N.H., Wimbledon, W.A., 1988. Biogenic laminar calcretes: evidence of

calcified root-mat horizons in paleosols. Sedimentology 35, 603–620.Wurm, D., 1982. Mikrofazies, Paläontologie und Palökologie der Dachsteinriffkalke

(Nor) des Gosaukammes, Österreich. Facies 6, 203–296.Zankl, H., 1967. Die karbonatsedimente der OberTrias in den nordlichen Kalkalpen. Geol.

Rundsch. 56, 128–139.Zankl, H., 1969. Der Hohe Göll — Aufbau und Lebensbild eines Dachsteinkalk-Riffes in

der Obertrias der nördlichen Kalkalpen. Abh. Senckenb. Naturforsch. Ges. 519,1–123.