grain-size analysis of the neogene red clay formation in the pannonian basin

ORIGINAL PAPER

Grain-size analysis of the Neogene red clay formationin the Pannonian Basin

Janos Kovacs

Received: 11 April 2006 / Accepted: 4 August 2006 / Published online: 13 December 2006� Springer-Verlag 2006

Abstract The red clay is a significant deposit under-

lying the Pleistocene loess-paleosols sequence in the

Pannonian Basin. The sedimentary processes involved

and the origin of the materials remain controversial. In

order to determine the depositional processes of the

Pliocene red clay formation we studied many red clay

sections in Hungary. Here, we present results of grain-

size analyses of the red clay from representative sites.

In particular their grain-size distribution is compared

with that of typical Pleistocene eolian loess-paleosols,

as well as lacustrine and fluvial sediments. It appears

from the sedimentological data that the majority of the

red clay is of a wind-blown origin. The red clay might

be transported by weak westerly winds and has been

modified by post-depositional alteration.

Keywords Sedimentology � Neogene � Red clay �Pannonian Basin � Grain size

Introduction

Over the past decade abundant information about var-

ious aspects of the loess was obtained, but little attention

has been paid to the red clay in the Pannonian Basin. Full

investigation of the formation is needed, particularly

regarding its geographic distribution, stratigraphy,

chronology and paleoclimate reconstruction. At the first

stage of this investigation, it is critical to determine the

manner of deposition of the red clay deposits.

Different views on the formation, properties and

distribution of red clays in the Pannonian Basin have

been published by several authors. Early scientists

described the red clay as a variety of loess, sediment

formed by the deposition of wind-blown silt (Loczy

1886; Treitz 1904; Sumeghy 1944). At that time other

researcher e.g. Szabo and Molnar (1866) and Balle-

negger (1917) agreed that the red clay formed by the

weathering of volcanic material. After the 1950s dif-

ferent ideas have developed about the distribution of

red clay. Many geologists draw parallels between red

clays and bauxites (Vadasz 1956; Vendl 1957; Bardossy

and Aleva 1990).

In the last decade investigations have focused on

geology, mineralogy and pedology (Fekete et al. 1997;

Nemeth et al. 1999; Fekete 2002; Foldvari and Kovacs-

Palffy 2002; Viczian 2002a, b; Berenyi-Uveges et al.

2003; Koloszar and Marsi 2005). Complex investigation

including geology, geomorphology, mineralogy and

geochemistry was carried out only a few authors like

Schweitzer and Szo}or (1997) and Kovacs (2003). None

of these recent investigations discussed the deposi-

tional process of the red clay.

The most remarkable progress made on the red clay

research worldwide is that sedimentology, geochemis-

try, geomorphology and field survey all demonstrate a

wind-blown origin for the red clay (Ding et al. 1998;

Sun et al. 2002, 2004; Lu et al. 2001; Yang and Ding

2004; Kovacs 2006), like the overlying Pleistocene and

Holocene loess. However, the stratigraphy of the

whole Pliocene is still far from being understood,

mainly because of the efficient coverage of the terrain

by the terrestrial alluvial fan systems.

Important key formations in the stratigraphy are

the red (silty) clays. Litho-, bio-, chemo- and

J. Kovacs (&)Department of Geology, University of Pecs,Ifjusag u. 6, Pecs, Baranya 7624, Hungarye-mail: [email protected]

123

Int J Earth Sci (Geol Rundsch) (2008) 97:171–178

DOI 10.1007/s00531-006-0150-2

magnetostratigraphic data show that they formed in

different periods (Schweitzer and Szo}or 1997; Kovacs

2003). The youngest one the red paleosol (or reddish

clay) is of Early Pleistocene age. The older one (red

clay) was formed probably in the Zanclean–Piacenzian

(4.6–3.2 Ma) under a warm, humid subtropical mon-

soon-like climatic conditions (Kretzoi 1987; Pecsi 1985;

Schweitzer and Szo}or 1997; Kovacs 2003).

Geological setting

The investigated sections selected for this study are

located mainly on the foothills of Hungarian moun-

tains (Fig. 1). These sections are of Pliocene and Early

Pleistocene age. From the studied areas we present

here a sequence (case study) which is similar to the

others.

Atkar site

Atkar (sand pit) lies on the southern remnants of the

Matra pediment. The sand pit deepens 20–25 m into

the surface. The exposure shows the Upper Miocene–

Lower Pliocene sequence where we can easily study

the landscape evolution through geological times

(Fig. 2). It consists of mainly three types of sediments

from upper to the lower: loess–paleosol sequence, a red

clay sequence and sand.

The bottom of the sand bed is made up of 5–10 m

thick grayish-yellow, mica-rich, cross-bedded sand. The

lower part of the sand bed bears different fossils (ani-

mals, plants), sometimes between sandstone benches.

There are particularly numerous brown colored

gastropod internal clasts in this stratum. Many bone

fragments can be found like teeth, jaws, costae from

Hipparion sp., Mastodon sp. and Rhinoceros sp. (Fa-

bian et al. 2004a, b). The cross-bedded sand is overlain

by 2–4 m thick red clay horizon. The red clay (5YR 4/6)

has prismatic structure with slickenside, stress surfaces

and black and yellowish mottles. The lower part of the

red clay strata bears lots of large CaCO3 nodules. It is

covered by a 2–3 m thick loamy loess and recent soil.

The age of the recovered fossils is 6 Ma, but

unfortunately they are only facies indicators and not

persistent stratigraphic markers (Kovacs 2003).

Materials and methods

Red clay samples from the Pannonian Basin were

collected during the field observations. Many expo-

sures and outcrops were investigated in the basin. A

total of 50 samples were taken from the northern part,

from the southwestern and western part of Hungary.

All samples were kept in polythene bags and trans-

ferred to the laboratory for granulometric analyses.

The analyses were carried out at the university’s sedi-

ment lab. The grain-size distribution of all samples was

measured by laser diffraction (Fritsch Analysette 22)

methods according to the approach described by

Konert and Vandenberghe (1997). Laser particle sizers

can identify particle fractions with a higher resolution

than the sieve or pipette method. This instrument has

measurement ranges of 0.3–300 lm, thus giving 63

channels, in that order. After processing the samples

Fig. 1 Schematic mapshowing the sampling sites ofred clay sediments inHungary. Gray areas aremountains and hills. 1 Atkarsite; 2 Hatvan site; 3 Visontasite; 4 Mogyorod site; 5Szuliman site; 6 Cserdi site; 7Pecs-Postavolgy site; 8Beremend site; 9 Csarnotasite; 10 Bataszek and Batasite; 11 Szekszard site; 12 Pakssite; 13 Voros-to site; 14Csipkerek site

172 Int J Earth Sci (Geol Rundsch) (2008) 97:171–178

123

with (10 ml, 30%) H2O2 and (10 ml, 10%) HCl to re-

move organic matter and carbonate, respectively,

10 ml of 0.05 N (NaPO3)6 was added to the sample,

which was then ultrasonicated for about 15 min. Next

the sample was transferred to the laser grain-size

analyzer.

Laser diffraction method enables the more accurate

calculation of the moment values of mean, mean

square deviation (MSD), skewness and kurtosis. We

use the sedimentological and statistical methods of Lu

et al. (2001) to present the eolian origin of the red clay.

Results

Grain-size distribution curves

The granulometric results are presented in Table 1.

The grain-size distribution curves demonstrate a pre-

dominantly bimodal character (Fig. 3). The >63 lm

(4F) fraction is almost insignificant in all the sedi-

ments except the fluvial sediments. The fine fraction is

clay-sized or very fine silt, while the coarser fraction is

medium to coarse silt and fine sand in fluvial sedi-

ments. However, the samples from the red clay, loess–

paleosol and fluvial sediments can be distinguished

rather easily from each other: the fine fraction is well

represented in the paleosol, lacustrine sediments and

a bit less in the red clay sediments, but progressively

less evident in the loess and fluvial sediments. The

grain-size distribution of the red clay is very similar to

the loess distribution. The modal size of the coarse

fraction gradually coarsens from the paleosols and

lacustrine sediments (ca. 6–9F) to the red clay

Fig. 2 Simplified geological profile of the Atkar sand pit (idealsection)

Table 1 Statistical parameters of grain-size distribution of thered clay, loess–paleosol, lacustrine and fluvial sediments (in phiunits)

Sample Mean MSD Skewness Kurtosis Y-value Sediment

Rc–RL 5.59 5.08 2.64 9.06 82.22 Red clayRc–Sz 4.84 4.73 2.14 6.07 65.88Rc–Cs 4.64 4.34 2.21 5.28 53.16Rc–S 4.70 4.37 2.71 8.10 61.52Rc–Ba 4.52 4.23 2.30 5.48 51.08Rc–R 5.49 5.35 2.68 10.98 96.85Rc–B 4.72 4.40 2.34 6.18 57.07Rc–H 3.99 3.70 1.46 0.85 27.46Rc–M 3.58 3.19 0.87 1.12 20.26Rc–P 5.51 5.63 1.49 2.89 83.64Rc–L 5.88 5.91 1.76 4.54 96.69Rc–Y 6.67 6.71 1.48 1.90 117.23L1 2.96 4.21 1.60 2.89 49.59 LoessL2 2.92 4.63 1.61 3.26 62.11L3 2.63 4.65 1.25 2.38 61.91P1 7.63 1.54 0.10 2.53 –12.27 PaleosolP2 7.71 1.46 0.15 2.62 –13.11P3 7.52 1.45 0.15 2.70 –12.27F1 5.37 1.85 1.27 4.01 1.21 FluvialF2 5.68 1.95 0.75 3.10 –0.48F3 5.90 1.90 0.80 2.90 –2.59LA1 7.30 16.00 0.10 0.04 760.19 LacustrineLA2 7.75 17.35 0.05 0.03 896.95LA3 6.98 18.86 0.07 0.03 1067.60

Rc–RL to Rc–Cs are the red clay samples from N Hungary; Rc–Sto Rc–M are the red clay samples from SW Hungary; Rc–P toRc–Y are the red clay samples from W Hungary; L1 to L3 are theloess samples; P1 to P3 are the paleosol samples; F1 to F3 are thefluvial sediment samples; LA1 to LA3 are the lacustrine sedi-ment samples from various sites

Int J Earth Sci (Geol Rundsch) (2008) 97:171–178 173

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(5–7F), loess (4–6F) and fluvial sediments (2–3F).

The lacustrine sediment is poorly sorted and has a

wide grain-size distribution range and very small

kurtosis values. Its grain-size distribution is noticeably

bimodal with a fine clay (8–10F) and a medium silt

fraction (5–6F). The red clay, loess, paleosols and

fluvial sediments also show bimodal character. In the

red clay, loess and paleosol, the coarser fraction is

located between 4 and 6F and the finer fraction be-

tween 7 and 9F. In the fluvial sediments it is between

2–3 and 4–6F. The red clay, loess and paleosols are

moderately sorted, while the fluvial sediment is well

sorted.

All the sediment types show positively skewed to

symmetric grain size-distribution, except the paleosol.

The positively skewed distribution indicates that the

finer fraction is included in the grain-size distribu-

tion. This asymmetry is expressed increasingly from

the red clay onward to the loess and to the fluvial

sediments.

According to Pye (1995), the fraction less then

2 lm (9F) may be formed partly by weathering

processes, and/or may be attributed to long distance

dust transport. Most of the particles are in the 2–

50 lm size range, which is typical eolian silt (Lu

et al. 2001). The lacustrine sediments are character-

ized by fine clay, which can be deposited only in

standing water. The bimodality of the fluvial sedi-

ment is explained by a combination of different

transport modes (Visher 1969). The particles of red

Fig. 3 Grain-size distribution curves of randomly selected red clay, loess, paleosol, lacustrine and fluvial sediment samples (for thesamples, see Table 1)


123

clay finer than 9F are explained mainly as a weath-

ering product, while the particles coarser than 5Fwere transported mainly by dust storm. The particles

between 9 and 5F, the medium and fines silt frac-

tion, were possibly transported by average winds (Lu

et al. 2001).

These analyses demonstrate that the grain-size dis-

tribution of the red clay is similar to that of the loess

and is clearly different from that of the paleosols,

lacustrine and fluvial sediments. Moreover, the red clay

is slightly finer than the loess. This may show that a

weaker wind system transported the dust than that

which formed the red clay, and/or stronger post-

depositional weathering and pedogenesis (Lu et al.

2001; Kovacs 2003).

A–Md plot

A–Md ratios have been plotted in X–Y diagrams

(Fig. 4), in which A is the weight percentage of

particles finer than 4 lm and Md is the median

diameter in micrometres (Passega and Byramjee

1969). In this plot the red clay particle-size distri-

bution is different from the loess–paleosol sediments.

According to Lu et al. (2001) this plot alone cannot

separate samples from the different depositional

environments, and a combination of other grain-size

parameters is needed. The A–Md comparison is very

sensitive indicator of little differences between simi-

lar sediments like red clay and loess–paleosol. This

plot shows that the red clay is finer-grained than the

loess and paleosol sediments. The fine particles are

mainly explained as post-depositional weathering

products (Kovacs 2003).

MSD and skewness

Combined plots of mean, mean square deviation and

skewness are also typical indicators of sedimentary

environments (Folk 1966). These parameters have

been plotted for the red clay, loess, paleosols, fluvial

and lacustrine sediments in Fig. 5. The MSD of the red

clay is positioned close to those of the loesses and

paleosols, which are a little different from the lacus-

trine sediments and are rather different from the fluvial

sediments. The skewness of the red clay lies far to

those of the loesses, paleosols, lacustrine sediments and

the fluvial sediments. The red clay, loess–paleosol and

lacustrine sediments are well sorted, but the fluvial

sediments are poorly sorted. The skewness of the red

clay is very similar to that of the loess–paleosol. The

fine-grained fluvial and lacustrine sediments have

skewness near to zero.

Fig. 4 A–Md plot of the grain-size distribution of the red clay,loess and paleosol sediments

Fig. 5 MSD and skewness of the red clay, loess, paleosol,lacustrine and fluvial sediments as a function of mean grain size


123

The partly overlapping fields of the red clay and

loess–paleosol populations that are seen in the MSD

and skewness plots may point to a similar origin.

Nevertheless, the overlaps in these plots point to that

the skewness and the MSD alone cannot separate

completely the sediments from different depositional

environments. According to Lu et al. (2001), the sedi-

ment transportation dynamics are not the only aspect

controlling the grain-size distributions of the sedi-

ments, because the material source, depositional

topography and even vegetation cover control the

sediment grain-size distribution. This shows that a

combination of numerous grain-size factors is needed

to study the origin of these deposits.

Empirical judgment equation

The empirical judgment equation (Y = –3.5688 M +

3.0716MSD2 – 2.0766 SK + 3.1175 K) is a statistical

method to differentiate between sediment population

using the grain-size distribution of numerous modern

eolian and other samples of which the depositional

environments are known (Sahu 1964). Y-value is an

index to distinguish the sedimentary environment.

The equation can be used to differentiate between

samples from eolian and other depositional environ-

ments (Sahu 1964). The calculated Y value of the red

clay ranges between 20 and 117, that of the loess 49–

62 and paleosol around –12, fluvial sediments from 1

to –2.59 and the lacustrine sediments from 760 to

1,067 (Fig. 6; Table 1). This illustrates that the Y

values of the red clay are close to those of the loess,

but are differ from those of paleosols, fluvial and

lacustrine sediments. In detail it comes out that the

Y value of the red clay is close to that of loess,

which indicates that the origin of the red clay is

wind-blown origin.

Discussion

The comparison of the grain-size distributions of the

red clay and the lacustrine sediments indicates quite

different sedimentary environments. Visible differ-

ences between the grain-size distributions of the red

clay and the fluvial sediments make obvious that the

red clay is unlikely to have had a fluvial origin. The

particle-size characteristics of the Neogene red clay

sediments are very similar to those of the Pleistocene

loess deposits, suggesting an eolian origin for the red

clay. A small amount of slight differences between the

grain-size distributions of these sediment groups,

however, indicate some differences in transport modes

and depositional environment. It appears from the

sedimentological data that the main part of the red clay

is of a wind-blown origin. The red clay was transported

by weak westerly winds and has been modified by post-

depositional alteration. What was the source of the red

clay? Local source was proposed by Smith et al. (1991)

for the loess and paleosols. The Late Miocene sedi-

ments within the Pannonian Basin are loosely consol-

idated sediments, which underlie the Great Hungarian

Plain. The Late Miocene sediments consist of marine

and shallow lacustrine deposits of conglomerates,

marls, sandstones, clays and sands (Ronai, 1985;

Schweitzer 1997; Magyar et al. 1999). Under suitably

arid–semiarid conditions and/or limited vegetation

cover, these sediments would provide a source of loose

granular material, which could be entrained by eolian

processes (Smith et al. 1991; Wright 2001). Recently it

has been held that the desertification of Pannonian

Basin corresponds to the Messinian Salinity Crisis

(Schweitzer 1997; Fabian et al. 2004a, b). The Late

Miocene or Messinian was a semiarid or semidesert

climatic period (Kretzoi 1987; Schweitzer 1997; Kovacs

2003; Fabian et al. 2004a, b). The climate of the Early

Pliocene was a transition between semidesert and

savannah. In that period Hipparion and Rhinoceros

lived in the Pannonian Basin (Fabian et al. 2004a, b).

The desert climate conditions are reconstructed from

the fossils (Meriones, etc.) and the pebbles covered by

desert varnish, which can be found in W. Hungary and

Pest Plain (Schweitzer 1997; Fabian et al. 2004a, b).

Laboratory experiments have demonstrated the possi-

bility that eolian reworking of the Messinian sands and

other similar deposits could theoretically contribute

material to the red clay, loess and loess-like deposits of

the Pannonian Basin (Smith et al. 1991; Kovacs 2003).

Fig. 6 Y-value of grain-size distribution of the red clay, loess,paleosols, fluvial and lacustrine sediments according to the‘empirical judgment equation’ of Sahu (1964). The Y-values ofthe lacustrine sediments are between 760 and 1,170


123

Conclusions

We investigated red clay in order to better understand

their mode of formation. Field observations and labo-

ratory analyses of the red clay and the overlying

Pleistocene loess sequence demonstrate great similar-

ities in grain size, suggesting a wind-blown origin for

the Neogene red clay in the Pannonian Basin. The red

clay is mainly composed of two components: (1) a silt

fraction that is very similar to the silt fraction in the

Pleistocene loess, and (2) a rather abundant clay and

very fine silt fraction. The Neogene red clay accumu-

lated under persistent weak winds and a rather steady

warm-arid climate. Therefore, we infer that the clay

transporting wind came from the west, maybe from

central Europe, and we interpret these winds as driven

by the westerlies. The red clay has been modified by

post-depositional weathering under warm–humid cli-

mate. These environmental characteristics accompa-

nying the deposition and weathering of the red clay are

responsible particularly for the finer grain-size distri-

butions and lower dustfall rate than the overlying loess.

We conclude that the red clay in the Pannonian

Basin is of a wind-blown origin, and that it was con-

sequently affected by weathering processes in the Pli-

ocene. To date, the most important evidence for a

wind-blown origin comes from comparison of grain-

size data of the red clay and the overlying loess, al-

though several aspects of these data require further

analysis.

Acknowledgement The author would like to thank Professor F.Schweitzer, G. Szo}or and Thomas Voigt for their most helpfulcomments and reviews. I also thank my colleagues S.A. Fabianand G. Varga for the discussions and contribution during thefield work. I am grateful to J. Dezs}o (Sediment Lab) for helpingin grain-size analyses.

References

Ballenegger R (1917) About the clay soils of the foothills of theTokaj Mountains (in Hungarian). Foldt Kozl (Bull HungGeol Soc) 48:20–24

Bardossy G, Aleva GJJ (1990) Lateritic bauxites. Developmentsin economic geology, vol 27. Elsevier, Amsterdam, pp 1–624

Berenyi-Uveges J, Horvath Z, Micheli E, Mindszenty A, NemethT (2003) Reconstructing quaternary pedogenesis in apaleosol sequence in Hungary. Quat Int 106/107:61–71

Ding Z, Sun J, Yang S, Liu T (1998) Preliminary magnetostra-tigraphy of a thick eolian red clay-loess sequence at Lingtai,the Chinese Loess Plateau. Geophys Res Lett 25:1225–1228

Fabian SzA, Kovacs J, Nagyvaradi L, Varga G (2004a) Wasthere desert climate in the Carpathian Basin, or not? StudiaGeomorphologica Carpatho Balcanica 38:49–58

Fabian SzA, Kovacs J, Nagyvaradi L, Varga G (2004b) Lowerand Middle Pliocene palaeoclimate sedimentological evi-dences in the Pannonian Basin. Semin Proc 35:258–267

Fekete J (2002) Physical and chemical features of red clays inNorthern Hungary. Acta Geol Hung 45:231–246

Fekete J, Stefanovits P, Bidlo G (1997) Comparative study of themineral composition of red clays in Hungary. Acta AgronHung 45:427–441

Foldvari M, Kovacs-Palffy P (2002) Mineralogical study of theTengelic Formation and the loess complex of the TolnaHegyhat and Moragy Hills areas (Hungary). Acta GeolHung 45:247–263

Folk RL (1966) A review of grain-size parameters. Sedimentol-ogy 6:73–93

Koloszar L, Marsi I (2005) Formations of Late Neogene andPleistocene terrestrial sediments in the region of MoragyHill (Hungary). Acta Geol Hung 48:317–337

Konert M, Vandenberghe J (1997) Comparison of laser grain-size analysis with pipette and sieve analysis: a solution forthe underestimation of the clay fraction. Sedimentology44:523–535

Kovacs J (2003) Terrestrial red clays in the Carpathian Basin: apaleoenvironmental approach. Geomorphologia Slovaca3:86–89

Kovacs J (2006) Wind-blown origin of the Neogene red clay inthe Pannonian Basin (abstract). Geophys Res Abstr 8:04182

Kretzoi M (1987) Remarks on the correlation between Europeanand Asian Late Cenozoic local biostratigraphies. VertebrPalasiat 25:145–157

Loczy L (1886) Report of the detailed geological survey in 1886(in Hungarian). Annual Report of the Geological Instituteof Hungary, pp 1–115

Lu H, Vandenberghe J, An Z (2001) Aeolian origin andpalaeoclimatic implications of the ‘red clay’ (north China)as evidenced by grain-size distribution. J Quat Sci 16:89–97

Magyar I, Geary GH, Muller P (1999) Paleogeographic evolu-tion of the Late Miocene Lake Pannon in Central Europe.Palaeogeogr Palaeoclimatol Palaeoecol 147:151–167

Nemeth T, Berenyi-Uveges J, Micheli E, Toth M (1999) Clayminerals in paleosols at Visonta, Hungary. Acta MinerPetrogr Szeged 40:11–20

Passega R, Byramjee R (1969) Grain-size image of clasticdeposits. Sedimentology 13:233–252

Pecsi M (1985) The Neogene red clays of the Carpathian Basin.Stud Geogr Hung 19:46–60

Pye K (1995) The nature, origin and accumulation of loess. QuatSci Rev 14:653–667

Ronai A (1985) The quaternary of the Great Hungarian Plain.In: Pecsi M (ed) Loess and the quaternary. AkademiaiKiado, Budapest, pp 51–63

Sahu BK (1964) Depositional mechanism from the size analysisof clastic sediments. J Sed Petrol 34:73–83

Schweitzer F (1997) On late Miocene–early Pliocene desertclimate in the Carpathian Basin. Z Geomorphol Suppl110:37–43

Schweitzer F, Szo}or Gy (1997) Geomorphological and strati-graphical significance of Pliocene red clay in Hungary. ZGeomorphol Suppl 110:95–105

Smith BJ, Wright JS, Whalley WB (1991) Simulated aeolianabrasion of Pannonian sands and its implications for theorigins of Hungarian loess. Earth Surf Proc Land 16:745–752

Sun D, Bloemendal J, Rea DK, Vandenberghe J, Jiang F, An Z,Su R (2002) Grain-size distribution function of polymodalsediments in hydraulic and aeolian environments, andnumerical partitioning of the sedimentary components.Sediment Geol 152:263–277

Sun D, Bloemendal J, Rea DK, An Z, Vandenberghe J, Lu H, SuR, Liu T (2004) Bimodal grain-size distribution of Chineseloess, and its palaeoclimatic implications. Catena 55:325–340


123

Sumeghy J (1944) The territory east of the Tisza River (inHungarian). Bull Geol Inst Hung Budapest, pp 1–208

Szabo J, Molnar J (1866) Description and classification of thesoils of the foothills of the Tokaj Mountains (in Hungarian).Bull Math Nat Sci 4:1865–1876

Treitz P (1904) Agrogeological relations of the Mecsek Moun-tains and the Southern Zeng}o Mountain group (in Hungar-ian). Annual Report of the Geological Institute from 1904,pp 174–195

Vadasz E (1956) Bauxite and ‘‘terra rossa’’ (in Hungarian). FoldtKozl (Bull Hung Geol Soc) 84:115–119

Vendl A (1957) Geology I (in Hungarian). Tankonyvkiado,Budapest, pp 1–623

Viczian I (2002a) Clay mineralogy of quaternary sedimentscovering mountainous and hilly areas of Hungary. ActaGeol Hung 45:265–286

Viczian I (2002b) Typical clay mineral associations fromgeological formations in Hungary: a review of recentinvestigations. Geol Carpathica 53:65–69

Visher GS (1969) Grain size distributions and depositionalprocesses. J Sed Petrol 39:1074–1106

Wright JS (2001) ‘‘Desert’’ loess versus ‘‘glacial’’ loess: quartzsilt formation, source areas and sediment pathways in theformation of loess deposits. Geomorphology 36:231–256

Yang SL, Ding ZL (2004) Comparison of particle size charac-teristics of the Tertiary ‘red clay’ and Pleistocene loess in theChinese Loess Plateau: implications for origin and sourcesof the ‘red clay’. Sedimentology 51:77–93


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grain-size analysis of the neogene red clay formation in the pannonian basin

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