A N N A L E S D E L A S O C l E T E G f i O L O G I Q U E D E P O L O G N E
T om (V olum e) X X V III — 1958 Z e szy t (F ascicu le) 3 Kuraków 1959
STANISŁAW DŻUŁYŃSKI, ANDRZEJ ŚLĄCZKA
SEDYMENTACJA I WSKAŹNIKI KIERUNKOWE TRANSPORTU W WARSTWACH KROŚNIEŃSKICH
(Tabl. XXIV — X X X IX i 15 fig.)
Directional structures and sedimentation of the Krosno beds (Carpathian flysch)
(PI. XXIV — X X X IX and 15 fig.)
STRESZCZENIE
Pom iary kierunku transportu w warstwach krośnieńskich dokonane zostały na podstaw ie szeregu w skaźników na spągu (hieroglify), oraz w e wnątrz ław ic piaskowcowych.
Syndepozycyjne hieroglify nieorganiczne podzielić można na dw ie zasadnicze grupy: 1) h ieroglify pow stałe bezpośrednio, w w yniku oddzia
ływ ania sam ego prądu, 2) h ieroglify utw orzone przez różne przedm ioty w leczone po dnie przez prąd.
Grupa pierwsza obejm uje hieroglify prądowe w ścisłym słow a tego znaczeniu (tafel. X X V i X X V I), o d lew y śladów opływ ania (Tabl.
X X V II fig. 1), od lew y pręg falistych (tabl. X X V III fig. 2) i zagadkowych
„żłobków ściek ow ych ” (tabl. X X V II fig. 2).
Do drugiej grupy należą od lew y śladów stykania się z dnem różnych przedm iotów niesionych przez prąd zaw iesinow y, w leczonych lub toczo
nych po dnie. Są to rozm aite „hieroglify uderzeniow e” (tabl. X X V fig. 1, tabl. X X V I fig. 3), h iercg lify w leczen iow e (tabl. X X X III fig. 1, 2, tabl.
X X X IV fig. 2), odciski śladów toczenia kręgów ryb itp. (tabl. X X X , tabl. X X IX fig. 2). W niektórych przypadkach można zidentyfikow ać przedm ioty, które pozostaw iły po ©obie ow e ślady. Okazały się nim i ka
w ałki drewna, okruchy łupkow e, ziarna piasku, kości ryb itp.
W szystkie w ym ien ione ogólnie hieroglify są cennym i wskaźnikami kierunku prądu. N ie należy jednak utożsamiać hieroglifów prądowych z hieroglifam i „uderzeniow ym i”, ponieważ prowadzi to nieuchronnie do błędnego odczytania kierunku transportu.
Do grupy wskaźników w ew nątrz ław ic piaskow cowych należy m ię
d zy innymi: dachów kow e ułożenie w ydłużonych ziarn, w arstw ow anie
przekątne i sm ugi gruboziarnistego piasku osadzone za przeszkodami, które opływ ał prąd zaw iesinow y.
W ławicach gruboziarnistych piaskowców obserw uje się często uło
żen ie dachów kow ate takie, jakie w ystęp uje w żwirach rzecznych, to zn.
osie w ydłużonych ziarn zapadają w górę prądu. O dczytyw anie kierunku na podstaw ie przekątnego uw arstw ienia zostało oparte na now ej m eto
dzie. Okazało się bow iem , że pochyłe lam iny przekątnego w arstw ow ania byw ają często odciśnięte na spągowej powierzchni piaskow ców w po
staci znam iennych łukow ych struktur (tabl. X X V III fig. 1, rys, 11) zw ró
conych wypukłością w górę prądu.
Cennym i wskaźnikam i prądu okazały się również skupienia bardziej gruboziarnistego m ateriału, które w form ie płom ienia lub sm ugi w y k li- nowującej się z prądem osadziły się za przedmiotami, które utk w iły cza
sowo lub na stałe w dnie. W skaźniki te w idoczne są na spągu ław ic pias
kow cow ych w ykazujących słab y stopień przesortowania m ateriału (fig. 13).
W a r u n k i s e d y m e n t a c y j n e
W w arstwach krośnieńskich w ystępują ław ice osadzone przez prądy zaw iesinow e i osuwiska podmorskie. N iektóre z ław ic piaskow cow ych po
w stały w w yniku ruchów m asow ych łączących w sobie cechy osuwiska i prądu zawiesinowego. Część spiaszczonych łupków jest również rezulta
tem osadzania przez prąd zaw iesińowy.
W arstwy krośnieńskie, podobnie jak inne skały fliszu karpackiego, osadzały się poniżej podstaw y falow ania i pom inąw szy może m argle w stropie tych warstw, są osadem morza stosunkow o głębokiego.
W yniki pom iarów kierunków transportu wskazują, że lądy, które dostarczały m ateriału do w arstw krośnieńskich, znajdow ały się w ew nątrz geosynkłiny karpackiej (zob. tabl. X X X V I — X X X IX , fig. 1 4 — 15). P o m iary tę, potw ierdziły słuszność niektórych przypuszczeń odnośnie do um iejscow ienia źródłow ych kordylier uzyskanych na podstaw ie badań nad m ateriałam i egzotycznym i w e fliszu.
W zachodniej części geosynk łiny karpackiej zaznaczył się siln ie w p ływ kordyliery śląskiej, który ku w schodow i sięgał do rejonu sanockiego.
W południow o-wschodniej części depresji centralnej gruboziarniste pias
kowce b y ły donoszone prądami zaw iesinow ym i z południow ego wschodu i południa. Źródłem tych osadów był przypuszczalnie m asyw marmaro- ski i hip otetyczn y ,,wał du kielski”. Drobnoziarniste skorupowe piaskow
ce przeła wica jące wspom niane w yżej gruboziarniste ław ice w ykazują czę
sto przeciw ny kierunek transportu i jak wynika z pomiarów, m ateriał ich był donoszony z zachodu lub południow ego zachodu.
Innym źródłem osadów krośnieńskich był w yraźnie zaznaczający się w sedym entacji w arstw krośnieńskich ląd sanocki (kordyliera sanocka), który wznosił się nad poziom morza w eocenie i oligocenie m iędzy obec
nym rejon em inoceram ow ym (płaszczowina iskolska), a centralną depres
ją (płaszczowina śląska). W pływ sanockiej kordyliery zaznacza się głó w nie w północnym inoceram ow ym rejonie, w m niejszym natom iast stop
niu w obrębie depresji centralnej.
Tak zwana „facja m arglista” w obrębię dolnych w arstw krośnień
skich w obszarze na południe i południow y wschód od Krosna pokryw a się z rejonem , do którego dochodziły prądy zaw iesinow e i osuw iska z róż
nych kierunków i źródeł, to znaczy z centralną częścią basenu sedym en tacyjnego. Przypuszczalnie prądy te utraciły ipo drodze znaczną część niesionego m ateriału klastycznego i to było powodem m niej intensyw nej sedym entacji piaskow cow ej.
Podczas sedym entacji w yższego ogniw a w arstw krośnieńskich w a
runki ulegają zmianie. W pływ m asyw u m arm aroskiego i w ału du kiel
skiego stopniow o ustaje, a na południow o-w schodnich obszarach w arstw krośnieńskich w granicach państw a zarysow uje się w yraźna przew aga kierunków transportu z północnego zachodu.
Zm iany w kierunkach dopływ u m ateriału i w charakterze osadów są odbiciem zm ian w ukształtow aniu basenu krośnieńskiego. Zachodnia część tego zbiornika zaczyna się podnosić w ciągu trwania sedym entacji krośnieńskiej, przy rów noczesnym zanurzaniu się kordylier na obszarze całej geosynkliny. Punkt zw rotny w ew olucji geosynkliny karpackiej (w zew nętrznej strefie fliszow ej) nastąpił w m om encie zniknięcia kordy
lier pod powierzchnią wód. Ten krytyczny m om ent odzw ierciedla się w sedym entacji Warstw krośnieńskich pojaw ieniem się ostatnich dużych osuw isk i prądów zaw iesinow ych, których osady w ystępują w w arstw ach środkow o-krośnieńskich.
Po zanurzeniu się kordylier rozpoczyna się now y etap sedym entacji w geosynklinie. M argle, które odpowiadają tem u now em u okresow i choć integralnie związane są z w arstw am i krośnieńskim i, n ie mają już cha
rakteru fliszow ego osadu. Podczas sedym entacji tych utw orów ruchy orcgeniczne trw ały nadal i uw ieńczone zostały paroksym alnym sfałdo- w aniem i w yciśnięciem zawartości daw nych basenów sedym entacyjnych,.
Z problem em sedym entacji warst krośnieńskich w iąże się zagadnie
nie w ielkości skrócenia oraz ruchów poziom ych w geosynklinie. Istnienie w ew nętrznych kordylier pociąga za sobą konieczność przyjęcia dużego zwężenia stref geosynklinalnych.
Pracownia Geologiczno-Stratygraficzna P A N w Krakow ie K arpacka Stacja IG w K rakow ie
*
* *
A b s t r a c t . Distribution of the turbidity currents in the Krosno beds implies the existence of at least three major sources. They were situated w ithin the Car
pathian geosynclinal belt. The Krosno sandstones resulted from the activity of turbidity currents and w atery slides. In several sections, interstratification of coarse and fine-grained sandstones with opposita directions of supply occur. Va
rious types of sole markings are discussed from the point of their applicability as current indicators. The descriptions of some hitherto undescribed markings are given in detail, i. e. casts of spinal joints of fish rolled over the bottom, brush casts, prod casts, vibrations marks, spiral groove casts etc. Some intrastratal di
rectional structures are also discussed.
INTRODUCTION
The accum ulation o f th e flysch sedim ents in the w estern part of the Carpathian geosyncline cam e to its end during the Oligocene. The m arine clays and sands of Tortonian age rest unconform ably upon the folded and denuded flysch rocks.
The upperm ost flysch sedim ents in the Carpathians are called Krosno beds, nam ed so by T. T i e t z e (1889) from th e sm all tow n of K rcsno in the Central Carpathians. It is w id ely agreed that the bulk of th e Krosno beds is o f O ligocene age. N everth eless the stratigraphical position of the low est and upperm ost horizons o f th e strata discussed m ust not be considered as d efin itely determ ined. According to F. B i e- d a (1947) and H. S w i d z i n s k i (1950) the low est portion of the Krosno beds belongs still to the uppermost Eocene. It seem s also probable that in the Eastern Carpathians the sedim entation of the Krosno beds con
tinued up to the M iddle M iocene ( V T a s l a k o v a 1955).
The deposition o f the Krosno beds was synchronous w ith the la te stages o f the A lpine orogeny. The strata described here g iv e the clear
est evidence as to th e m ovem ents preceding the final folding and thrust
ing w ithin subsiding zone o f geosynclin al belts.
PREVIOUS SEDIMENTOLOGICAL STUDIES
A lthough various sedim entary structures displayed b y th e Krosno beds have been know n for m any years, very little has been w ritten about them .
M. K s i ^ z k i e w i c z (1956, 1958) published the first maps show ing the direction o f turbidity currents in the Carpathian flysch. The Krosno beds were also included and the fan-like arrangem ent o f 'currents spread
ing aw ay from the source situated south of the present m argin o f th e Magura nappe, clearly dem onstrated.
Z. O b u c h o w i c z (1957) gives a sum m ary of recent sedim entolo- gical studies carried out w ithin a lim ited area south o f Besko. A n im por
tant fact which em erges from this study is a regional difference in the direction of supply b etw een the low er and upper parts of the Krosno beds. Conditions of deposition o f th e Krosno beds are also discussed by O b u c h o w i c z and th e conclusion is that the strata here decribed have been laid down both in deep and sh allow w aters on th e slope and top of the sh elf.
The first detailed description of subm arine slum ps in the Krosno beds has been given by O. G a n s s (1941, 1942). The above nam ed author called attention to the fact that th e sedim entation o f the Krosno beds w as accompanied by differential uplift o f som e parts o f the original sea floor.
Som e observations are also to be found in num erous regional re
ports, especially in those of J. and St. W d o w i a r z, but space does not allow an adequate review here. A ll necessary references are given in
the text.
This paper ow es its origin to th e sedim entological investigations and m easurem ents o f current directions carried out by the present w riters during the field season 1957. The directions of turbidity currents from th e outcrops situated in the w estern part o f the Carpathians h a v e been kindly supplied by Prof. M. K s i ą ż k i e w i c z .
ACKNOWLEDGMENTS
The authors wish to express their thanks to Prof. M.* K s i ą ż k i e w i c z and Prof. Ph. H. K u e n e n for reading the m anuscript o f the present paper and m any helpfu l suggestions. Prof. M. K s i ą ż k i e w i c z gave us th e m anuscript o f his paper on „Sedim entation in th e Carpa
thian F lysch S ea” in advance o f publication and this is here greately acknow ledged. The authors are also indebted to Dr. A lec S m i t h from th e U n iversity C ollege in London for kind and help fu l discussion of som e problem s set forth in this paper. Thanks are also due to Dr. J.
B u r t a n, Prof. St. W d o w i a r z , and Prof. H. S w i d z i ń s k i for d is
cussions concerning the stratigraphy of th e Krosno beds. The present w riters are indebted to their colleagues W. Si k o r a and K. Ż y t k o for perm ission to compare results of m easurem ents in som e section w ith their observations. Important help in carrying on the m easurem ents of current directions was received from Miss Doc. Dr. J. B u r t a n, Mr®.
D cc. Dr. K. C i s z e w s k a amd Miss F. S z y m a k o w s k a who show ed to the present w riters the best outcrops in the area oif Strzyżów , U strzy
ki, Szczyrzyc and Bochnia.
STRATIGRAPHY AND LITHOLOGY OF THE KROSNO BEDS
A brief outline of the stratigraphy and lith ology Krosno beds w ill be given. For more com plete inform ations the reader is referred to th e pa
pers by Z. O p o l s k i (1933) and Z. O b u c h o w i c z (1957) 1.
The Krosno beds are of widespread occurrence and w ith th e excep
tion of the Magura Nappe th ey appear in a ll tectonic units in th e Polish Carpathians. T hey are m arine throughout and w ere laid down in rather deep water.
The Krosno beds occupy th e larger part of the Central D epression (see maps attached). Here the fu llest succesion is found and th e strata discussed occur in their typical developm ent. T hey com prise fine and m edium -grained sandstones of gray and ligh t-gray colours, m arly shales and silts. The shales are usually also ligh t coloured but intercalations o f black shales are not infrequent in the low est and upper parts of the Krosno beds.
Taken as a w hoie th e Krosno beds show no strong contrasts in their lithological character. Sim ilar rock types appear again and again at d if
ferent lev els and places. Such a behaviour im plies the repeated return
1 The Krosno beds have been mapped and worked up by numerous geolo
gists. The papers and maps of J. St. W d o w i a r z , L. H o r w i t z and H. Ś w i * d z i ń s k i concerning the eastern part of the Carpathians and those of J. B u r t a n , K. C i s z e w s k a and M. K s i ą ż k i e w i c z concerning the w estern part are of special interest. The preparation of the presents paper would have been im pos
sible without their extensive studies.
14 (Rocznik PTG
o f sim ilar depositional conditions and the unexpected uniform ity of. the supplied m a te r ia lK
In the absence of su fficien t paleontological data the stratigraphy o f th e Krosno beds is based upon lithological differences, although it is know n that particular rock typ es m erge one into another, being only facies of original sea floor deposits.
There are o n ly few w idespread and easily distinguished rocks units to apply as key beds in making correlations. U nquestionable stratigra
phical criteria have not y e t been found in spite of num erous in v esti
gations approaching th e problem from various points o f view . A t the present tim e the best m eth ods available, seem s, to be tracing and 'com
paring of rock groups from place to place as it w as su ggested by Z.
O p o l s k i (1933). This m ethod o f correlation has been adopted b y se veral geologists m apping th e Krosno beds.
It has been pointed out b y Z. O b u c h o w i c z (1957) that a detailed stu dy of sole m arkings m ight greately contribute to the explanation of stratigraphical problems in the Krosno beds. The above author succeeded in finding a tectonic repetition in the section of th e Krosno beds in Besko, hitherto regarded as uninterrupted sequence. He arrived at this conclusion by comparing directions of current m arkings in th e low er and upper m em bers of th e Krosno beds.
The Krosno beds have been divided in to three m em bers, i. e. Lower, M iddle and Upper m em bers. In som e areas there are, how ever, on ly two m em bers, su fficien tly d istin ct to ju stify their separation.
L o w e r K r o s n o b e d s are composed largely of thick-bedded sandstones w ith poorly developed sh aly intercalations. T hey pass dow n
wards into the M enilite beds 2.
M i d d l e K r o s n o b e d s are built up largely by thin and m edium bedded sandstones separated by m arly and silty shales. The proportion o f sandstones to shales is sm aller than in th e low er part o f th e strata discussed. The sandstones display a profusion of convolute bedding which is thought to be a characteristic featu re of this horizon.
Inclusions of thick-bedded sandstones are not infrequent in the eastern part of the Central Depression, thick-bedded glauconite sand
ston es appear. They have been recognized as a good guiding horizon traceable for a distance o f m any tens of kilom etres (J. B u r t a n, St.
W d o w i a r z , W. S i k o r a , K. Ż y t k o ) . Last tim e (1958) K. Ż y t k o seam s this sandstone is contem poraneous to the „Jasło sh a les”. The glau
conite sandstones belong throughout to th e M iddle Krosno beds 3.
1 Data concerning the petrology of the Krosno beds are to be found in the papers .of St. J a s k o l s k i (1931), A. O b e r e (1947. The summary of recent petro
logical studies on the Krosno beds carried out by several petrologists are given by Z. O b u c h o w i c z (1957).
2 The stratigraphical link between the Krosno and M enilite beds (Upper Eoce
ne) is called Passage beds. These latter comprise sandstones of the Krosno beds type and black* shales resem bling the M enilite shales from below. A part of the M enilite beds seems to be equivalent to the Krosno beds.
3 Over wide areas they are separated from the thick-bedded sandstones of the Lower Krosno beds by a series of thin and medium -bedded sandstones, b u t in some places they seem to rest directly upon the thick-bedded sandstones.
The layers of' ligh t coloured m arls called „Jasło sh ales” are thought to b e another im portant k ey bed (see H. S i w i d z i ń s k i 1947 and Sit. J u c h a 1957).
It is o f in terest to n ote that in th e Sk ole unit, northeast of Sanok layers of diatom ites have been recen tly discovered by J. K o t l a r i c z y k (1957, 1958). T hey are thought to be also a guide horizon.
U p p e r K r o s n o b e d s comprise m arly shales interbedded w ith few and thin layers of fine-grained sandstones only. In th e closing sta
ges o f accum ulation of th e Krosno beds diatom ite layers w ere being laid down in th e area of th e Skole unit (J. K o t l a r c z y k , 1958).
A lthough the proportion o f shales to sandstones as m easured verti
cally increases upwards, th ere are areas w here large shaly deposits occur in th e low er part of the Krosno beds. The paleogeographic im por
tance of this w ill be discussed later.
In the present sta te o f know ledge it is d ifficu lt to g iv e a precise esti
m ate concerning the thickness of th e Krosno beds in each section. In the Central Depression w here th e strata discussed sh ow their typical developm ent th e thickness o f th e Krosno beds has been estim ated b y H. S w i d z i ń s k i at 3 210 m. in th e B esko profile.
To the w est the thickness of th e Krosno beds decreases. A lthough in m any places tectonic squeezing m ust also be responsible for reduction o f the Krosno beds 1y there is good reason to b eliev e that in the W estern Carpathians their original thickness was much sm aller than that in the Central Depression. The sam e accounts for th e poorly developed Krosno beds w ithin the Dukla Folds.
The Krosno beds afford a com paratively safe ground for reconstruc
tion of current directions. T hey reveal far less tectonic deform ations than m any other units in the Carpathians w ith the exception o f the Podhale flysch.
In the eastern part of th e P olish Carpathians the K rosno beds fill elongate synclines and cover the lim bs of long and narrow asym m etric anticlines. These latter run parallel to th e m ain trend of th e Carpathians w ithout conspicuous changes in strike. The axes of th ese folds plunge g en tly either to the east or to the w est. Therefore th e error in m easu
rem ents of current indices due to the pitch of folds are slig h t and m ay be ignored.
To avoid errors, current reading from all in ten sely deform ed strata has been discarded. It is im possible, how ever to trace current marks on the sam e bed oyer large areas. The results of m easurem ents plotted on th e maps correspond to com paratively sm all units inside a given m em bers. F ortunately current indicators, although varying from one layer to another, do not differ generally in sections of im portant thickness.
This m eans that the sam e direction of supply, w hether from one source or not, persisted in a given region over a su fficien tly long period to make comparison o f distant sections possible w ithout drastic errors even if a detailed stratigraphy has not y et been adequately established.
1 According to M. K s i ^ z k i e w i c z (1930, 1936), and J. B u r t a n (1937) the Krosno beds in the W estern Carpathians are stripped off from their base.
2*
Judging from th e present island arcs w e m ay assum e that th e geo- syn clin al troughs w ere artcuate. If no farther changes in the shape o f these troughs have occurred th e present orientation o f current indi^
cators would give approxim ately the true direction o f supply. If not, a correction should be m ade. As a m atter o f fact it seem s probable that th e original curvature of th e troughs underw ent som e changes, both du
ring the accum ulation o f flysch and afterwards, but the am ount o f change is not known. Therefore the paleogeographic reconstructions show n on the maps attached are based upon the present shaipe o f the Carpathian arc as if no changes intervened.
SEDIMENTARY STRUCTURES AND TYPES OF BEDDING DISPLAYED BY THE KROSNO BEDS
A brief review o f various structures exhibited by the Krosno beds w ill be given. S everal typ es discussed are depicted in fig. 1 — 9.
NO N -G R A D FD , TH ICK -BED D ED SAN D STO N ES
As lit was noted already th ey are o f widespread occurrence in th e low er and in the m iddle part of the Krosno beds. The sandstones here described appear often , one upon another, separated b y v ery thin and insignificant intercalations o f silts or m arly shales. Som e are w ell sor
ted w ith obscure stratification, other display a poor degree of sorting w ith sm all pebbles and slabs o f sh ale dissem inated in th e m atrix (fig. 1).
Fig. 1. Piaskow isc o nieuporządkowanej strukturze. Besko Fig. 1. Non-graded coarse sandstone. Besko
The coarse m aterial m ay occur in the shape of obscure layers w ithin th e sandstone bed (fig 2 and 4). Clay m atter becom es usually more abun
dant towards the top surface and cross-bedding of the current-ripple type, convolute bedding o f lam ination m ay appear. T he soles o f the sand
stone discussed display groovings, flu te casts, bounce casts etc. but there are alS'O num erous exam ples of sm oth low er surfaces.
A large part o f these sandstones seem s to be produced by dense tur
b id ity currents. The deposits of such currents are frequently devoid o f
grading (Ph. H. K u e n e n 1951). In som e cases w atery slides w ere res
ponsible for their deposition. Prof. Ph. H. K u e n e n proposes th e term
„fluxo-turbid ites” for this typ e of beds As a m atter o f fact there are transitional types b etw een th e sandstones above m entioned to „slurry m ud-flow s” and silides.
Fig. 2. Ławica złożona. Besko Fig. 2. Composite bed. Besko
In several sections accum ulation o f sands w as due to the supply at such short intervals and at changing rates so that sihaly inter
calations could not develop or w ere washed aw ay by the n ex t current (see fig. 3) 2. H ence „com posite beds” o f sandstones resulted, ranging in thickness up to 10 or m ore m etres.
Composite beds consist o f tw o or several com ponents w hich m ight be nam ed „sub-layers”. It is not to be im plied that th e m echanism of deposition w as the sam e in d ifferent sub-layers. Lam inated or cross
bedded 'm em bers of the section shown on fig. 3 w ere obviously depo
sited by currents differing in their properties from those w hich had laid dow n poorly graded „m assive” sub-layers.
It is w orth noting that in the sandstones here discussed th e elon ga te grains show up-current inclination, i.e. th ey dip in the direction w h ence the current came. In rare occasions on ly dow n-current inclina
tion has been found. This opposite im brication was due to the „lateral sedim entation” (see van S t r a a t e n 1951) on the slopes o f poorly mark
ed foreset lam inae.
D ue consideration should be given to the com posite beds w hich con
sist of d ifferen t sub-layers closely fittin g together along the uneven, eroded surface of th e preceding mem ber. Good exam ples o f such compo
site beds are illustrated in fig. 2, 4, 5, PI. X X IV , fig. 1.
The upper part o f the com posite beds shown by fig. 4 consists of th e sandstone w ith an adm ixture o f coarse m aterial of pebbles. The low e r su b-layers are composed of more fine-grained sandstones. N um erous
1 A discussion concerning „fluxo-turbidites” w ill be given in a joint paper
„Turbidites in flysch of Polish Carpathians” by M. K s i ^ z k i e w i c z , Ph. H.
K u e n e n and St. D z u l y n s k i (in press).
2 This section m ight be considered as typical for the low er part of the Krosno beds in the eastern region on the Polish Carpathians.
Fig. 3. Fragment odsłonięcia gruboławicowych piaskowców w warstwach dolnokrośnieńskich.
U strzyki Dl.
Fig. 3. Sketch section of the Lower Krosno beds. Ustrzyki Dolne
protuberances m ay appestr along the boundary sur
face b etw een these sub*- -layers. O bviously th e pro
tuberances w ere largely due to th e differential sinking o f coarse sed i
m ent into th e soft sub
stratum . Such „load-casts”
(Ph. H. K u e n e n 1953a) inside the sandstone layer are identical w ith those found on th e soles o f sandstones (flow -casts in the m eaning of R. R.
S h r o c k 1948) or w ith load-casts produced ex p e
rim ental b y E. M. K i n d l e (1917) and Ph. H. K u e n e n (see N a t l a n d &
K u e n e n 1951). T he structure o f th e coarse upper com ponent and bending dow n of lam inae in th e su b-layer below m ight help to distinguish the protuberances discus
sed from short w ash-outs produced b y erosion.
In m any cases bath erosion and load-casting occurred. It m ust be no
ted that structures produ
ced by th ese processes do not necessarily indicate a break deposition. T hey m ay result from an in
crease of in ten sity of th e sam e current 1.
In norm al com posite beds the m aterial o f d iffe rent sub-layers comes from the sam e direction.
1 Load-casts in the Krosno beds are often deformed by creep of new ly depo
sited sediment. The resulting structures m ight be classified as „flow -casts” in the meaning of J. E. P r e n t i c e (1956) see also Ph. H. K u e n e n & J. E. P r e n t i c e (1957). Possibly a part of them represent also deformed current markings;
They m ay be named according to G. K e l l i n g & E. K. W a l t o n (1957) „flute- -load -casts”, ,groove-load-casts”„. etc.).
T h ere are instances also w h er e d ifferent or even op
p osite transport m ay occur.
A n exam ple o f such a com
posite bed is shown in fig 7, PL X X IV fig. 1.
The sandstone bed B con
sists of tw o d istin ct su b-lay
ers tig h tly w elded togeth er, th e boundary surface b etw een them being uneven.
It is evident that the lower part (a) of th e com posite bed described has in part been cut aw ay by th e action of current which subsequently deposited the more coarse com ponent (b). The older sub-layer (a) displays w ell developed flu te casts on its sole. Both current bedding and flu te casts indicate that
this part has been laid down b y a current from NW (310°).
The coarse component (b) has no hieroglyphs of its o wn but the axes o f elongate grains dip south- or south
east along th e strike 160°.
In view of w hat has been said about the imbrication, th e suggestion m ay be ad
vanced that the upper part of th e com posite bed in question has been derived from th e south or south-east.
As doubt m ay arise, w h eth er the conclusion drawn from im brication is reliable, w e give here other observations w hich in our opinion su stain th e suggestion set forth above.
In th e excep tion ally w ell exposed outcrops o f the K rosno beds at Sieniaw a both, fine-grained and coarse-grained sandstones occur. The m aterial o f the former does not differ essen tially from that of the su b
l a y e r (a). On the other hand all the coarse-grained sandstones bear strik ing resem blance to the upper com ponent o f the com posite bed describ
ed. F lu te casts and current bedding in the fine-grained beds indicate that th ey originated from currents coming from the w est or more pre
cisely from NW (310°) w hereas th e coarse-grained sandstones h ave been derived from the south (160°) as indicated by current m arkings on their soles (see fig. 7 and 10). Special emphasis is placed here on the fact that intercalations of sandstones deposited by currents coming from various directions (often from opposite directions) are by no m eans exceptional in the Krosno beds.
Fig 4. Ławica złożona. W arstwy środkowo- krośnieńskie. Sieniaw a
Fig. 4. Sketch section w ith composite beds.
Sieniaw a
In a ll the coarse-grained sandstones, th e su b-layer (b) included, th ere is th e sam e im brication. Conclusions as to th e direction o f su p p ly draw n from the im brication are everyw here consistent w ith th e ev i
den ce provided b y the sole-m arkings.
Fig. 5. Ławica złożona. A — pozostałości rozmytej ław icy drobnoziarnistego piaskowca; B — piaskow iec gruboziarnisty; C — soczwy ankerytow e. Besko Fig. 5. Composite bed. A — remnants of eroded fine-grained sandstone; B •—
coarse grained sandstone; C — ankerites. Besko
£ or
Fig. 6. Ławica złożona. Fragment odsłonięcia w arstw środkowokrośnieńskich w Sieniaw ie
Fig. 6. Composite bed w ith load-casted erosion surface betw een fine-grained and coarse-grained components. Sieniaw a
A nother argum ent rests upon the essential likeness b etw een th e upper com ponent (b) and other coarse-grained sandstones w ith w ell established direction of supply.
In summary: Poorly graded or non-graded com posite beds m ight b e deposited either by th e sam e turbidity current or w atery slide, changing on ly its intensity and character, or th ey m ay originate from d ifferen t currents. In the latter case th e transporting currents m ight com e from various even opposite directions.
Fig. 7. Fragment odsłonięcia w Sieniawie. W arstwy środkowokrośnieńskie- z ławicam i, których m ateriał pochodzi z różnych kierunków
Fig. 7. Sketch section showing interstratification of beds w ith various directiore of supply (Explanation in text)
TH ICK -BEDD ED SA N D ST O N E S W ITH SLUM P-STRUCTURES
One of the m ost striking features o f slum ps in the Krosno beds is th e (predominance o f incoherent „slurry” slum ps. True gliding, i. e.
downward m ovem ent o f plastic m aterial in w hich lam inae are folded w ithout loss o f their id en tity is com paratively rare. Several factors m ight account for th e widespread occurrence o f this typ e of slumps.
One can im agine that the sliding mass, although more or less coherent w h en first set to m ove, g rew m ore and m ore dispersed because o f inter
m ixture o f sliding m asses and w ater (W. H. M e n a r d & P. C. L u d - w i c k 1951) or by loss of internal cohesion w ithout addition o f w ater (Ph. H. K u e n e n 1955). Another explanation is that already set forth b y C. B e e t s (1945), i.e. that the sands form ing the present slum p bed m ust have rem ained poorly cem ented until th e beginn in g of th e m ovem ent.
T he above m entioned author proposes th e term „flow age of quicksand”
for this kind of slide 1. Possibly both explanations m ight account for the widespread occurrence o f th e incoherent slum ps in the Krosno beds.
Fig. 8. Rekonstrukcja w ycinka pierwotnych osadów dennych w yjaśniająca pocho
dzenie przerwy w ław icy A na fig. 7
Fig. 8. 'Reconstruction of a sand layer w ith a half-burried trunks (Explanation in text)
&
Fig. 9. Fragment ław icy osuwiskowej. W arstwy dolnokrośriieńskie. Besko Fig. 9. Slump bed w ith contorted ankerite lenses. Besko
In consideration of various agencies that m ay have produced such slum ps w e should take into account th e influence o f m ineralogical com
position both o f sands and m uds and a ll the conditions o f deposition of the Krosno beds.
1 We shall use the term „flow of sand” or „sand flow ” in this meaning.
E xcellent exposures o f th e Krosno beds along th e W isłok river south o f B esko provide abundant exam ples of slum ps. One o f them is depicted in fig. 9. The bulk of sedim ent in this case consists o f rather fine-grai
ned muddy sandstone w ith obscure traces of „fluidal structure” . N um e
rous slabs o f shales and contorted lenses o f ankerite 1 are scattered in haphazard arrangem ent w ithin th e m atrix. Som e ankerite lenses show ,,hook-like” overfolds sim ilar to those described b y J. C. C r o w e l l (1957) w hich provide a good indicator of the direction of m ovem ent.
The ty p e discussed m ay be regarded as typical for m any slum ps in the Krosno beds in the area of the Central Depression.
A nother type o f slum p is depicted on fig. 10. It is probably very m uch like the „pebbly m udstones” of J. C. C r o w e l l (1957). Such pebbly m udstones and sandstones are w ell exposed at Sieniaw a (the upper part of th e M iddle Krosno beds). Their thickness ranges up to 2 m etres. The beds in question consist o f friable, loosely cem ented m ud
dy sandstone w ith num erous slabs of shale, contorted len ses of ankerite and irregular inclusions of better cem ented sandstone. A ll these struc
tures m ight be classified according to Ph. H. K u e n e n (1948) as „slum p- -b'alls” „crumpled balls” and „slip-blocks”.
The structural details o f these slum ps vary throughout the bed but th e general appearance is th e sam e. The slip-blocks enclosed are som e
w hat harder than the m atrix itself and serve to accent the slum ping that has taken place.
The slum p-beds in question are o f the „slu m p-sheet” type 2, i. e.
their soles are rather flat w hereas their upper surfaces tend to be une
ven. G enerally speaking this kind of slum p seem s to be very common in the Krosno beds.
In the slum p-beds depicted in fig. 10, slip-blocks appear at som e distance from the base of these layers. There is a progressive dim inution in the size o f fragm ents enclosed as w e proceed towards the bottom of th e bed. W hile the upper parts of the beds in question are typical se m i-coherent slum ps, their lower portions resem ble turbidite beds. The turbidite character of the low er portions is accentuated by the presence of flu te casts and imbrication. This latter disappears upwards. There is no boundary betw een the turbidite-like lower part and the slum p structure above, the form er graduating im perceptibly into the unarran
ged slum p. The explanation w hich can be given of th ese beds is that th ey w ere produced by a combined action of turbidity current and slum ping. The latter follow ed im m ediately the turbidite current, both phenom ena having been the events subordinate to the essen tially one m ass-m ovem ent along the bottom (see K u e n e n & M i g l i o r i n i 1950, K u e n e n et. al. 1957).
In the section of the Krosno beds exposed at Sieniaw a coarse slum p- -beds alternate w ith silty or m arly shales and fine-grained sandstones.
1 According to W. N a r ^ b s k i (1957) the term „ferrous dolom ite” is more adequate.
2 The term „slum p-sheet” is here used in accordance w ith the definition given by Ph. H. K u e n e n (1948).
— w
— 140 W
140 NE
—
120(v/;
ziarniste piaskowce. Kierunek transportu z W albo WNW;
B — gruboziarniste piaskow ce o strukturze częściowo osu
wiskowej. Kierunek transpor
tu z S albo SSE; 1 — poroz
rywane fragm enty ław ic dro
bnoziarnistych piaskowców;
2 — fragm enty łupków; 3 — buły ankerytowe; 4 — niere
gularne skupienia gruboziar
nistego piaskowca; 5 — frag
menty węglisty-ch piaskowców;
C —■ ław ica ankerytu Fig. 10. Sketch section show ing interstratification of beds with different direction of supply. A — fine-grained sandstones. Supply from WNW or NW; B — coarse slump and turbidity beds. Supply from S and SSE. 1 — torn- -apart sandstone layers; 2 — fragm ents of shales; 3 — an- kerite lenses (displaced and contortes); 4 — irregular clu
sters of coarse-grained sand
stones; 5 — slip-blocks of soft sandstone w ith coal seams;
C — ankerite layer. Sieniawa
A s already noted fine-grained sandstones have been derived from WNW, w hereas th e slum p-beds and other coarse-grained layers came from south or south-east. This means that the bottom has been alternately affected by th e action of currents and slum ps coming from various directions (see PL X X IV fig. 1 and 2). It w ill be show n later, that sim ilar condi
tions prevailed over vast areas o f the original sea-floor in th e eastern part of the Central Depression and persisted during rather a long period.
Coaly plant rem ains tend to be abundant toward the tops o f th e slum p-beds. In m ost cases the coaly m atter appears as thin bands of v itrite 1. In connection w ith this there rem ains an interesting, though on account o f its lim ited occurence not im portant structural detail reveal
ed by the sandstone layer A depicted in fig. 8. The bed w hich has been spoken o f rests upon the silt on the top o f a slum p. It is interrupted just above a buried and coalified trunk although there is on evidence of slum ping in the broken bed itself. O bviously th e pull-apart m ust not be taken into account. The follow ing explanation is here proposed. The trunk laid down on the bottom obviou sly projected through th e thin cover of sand brought by a turbidity current (fig. 9). H aving been m ore susceptible to the subsequent compaction than the sand itse lf it chan
ged into a flattened inclusion of vitrified coaly m atter. Thus the top surface of this originally half-burried trunk has been pressed dow n b e
low the sole of the sandstone bed. O nly branches or roots enclosed tig h t
ly in sand persisted in their original position and form at present tubu
lar coaly apophyses w ithin th e sandstone bed.
The slum ps previously described contained fragm ents of rocks sim i
lar to, if not identical w ith those from below and above the slump layer.
T here are instances, how ever, that slip-blocks embedded differ in their composition from the surrounding rocks being not necessarily typical exotics, i.e. older than the flysch in w hich th ey occur. Som e slip-blocks consist of fin ely stratified sandstones composed of alternating layers of coal and sands, large p ieces o f coal w ith num erous fresh-w ater gastro
pods or slip-blocks charged w ith shells of shallow w ater m ollusca are also to be found in the Krosno beds. Such rocks have been derived from littoral zones o f the flysch sea and are largely contem poraneous or pene- contem poraneous w ith the turbidite in w hich th ey sam e to rest.
Pebbly m udstones or silts w ith exotic boulders decidedly older than th e enclosing flysch sedim ents are not so conspicuous in the Krosno beds as in the Cretaceous or Eocene flysch of the Carpathians. T h ey have been found, how ever, in several places, w ithin the Krosno beds.
As it was pointed out b y S c h a r d t (1898) H e i m (1909), B a i l e y , C o l e t & F i e l d (1928) and others, clays w ith exotic boulders resu l
ted from submarine m ud-flow s and slides.
B efore closing this part of the subject som e consideration w ill be g iven as to th e nature of m ass-m ovem ents along the sea floor o f the flysch basins.
Judging from the evidence available both turbidity currents and slum ps occurred over large areas of the original sea floor. T here is an
1 Most of this vitrite seams and lenses originated from wood and a part of it possibly from kelp brought down by turbidity currents and slides.
intim ate connection and in som e instances m ingling of slum ps and tur
bidites, the interm ediate link b etw een them being the deposits o f slu r
ry, incoherent and w atery slid es or ,,fluxo-turbidites”. Subm arine slides initiated turbidity currents and on the other hand, n ew ly deposited tur- bidites m ight m ove farther as slum ps. In som e instances, as was recen tly pointed out by C r o w e l l (1957), the „m om entum ” or „kick”
from a vigorous gravel bearing turbidity current m ay set off sliding m asses thait otherw ise w ould not take place. Exam ples o f turbidite beds converted into slum ps contem poraneous or penecontem poraneous w ith th e deposition of the turbidite layer have been also show n by D z u - l y n s k i & R a d o m s k i (1957) from the M enilite beds (Carpathians).
There are good reasons to b elieve that in large shifts of sedim ents va
rious kinds of m ass-m ovem ents took place sim ultaneously. The resu ltin g deposits are characterized by far more com plex structure than the gra
ded turbidites of pure turbidity currents. Such beds have been observed b y K u e n e i n & C a r o z z i (1953) in th e A lps and by C r o w e l l (1957.) in California.
Slum ps require slop es steep enough to produce un stable condi
tions of accum ulating sedim ents 1. H uge slum ps once set in m otion m ight, how ever, slid e over a very g en tle slop e (A. H e i m 1908). M ud-flow s heav
ily charged w ith argillaceous m atter sand and boulders can apparently m ove on a practically flat bottom for a distance o f m any kilom etres. In som e cases the distance travelled by huge slum ps and m ud-flow s m ust h ave exceeded 30 km. e.g. large slumps at Bukow iec and Baligrod, south east of Sanok 2. In v iew of such large distances a vague but yet u sefu l idea m ay be formed concerning the redeposition of slum p sed i
m ents over th e slopes of m igrating subm arine sw ells.
S A N D ST O N E S W IT H C O N V O LU TE L A M IN A T IO N , C U R R E N T B E D D IN G A N D L A M IN A T IO N
None of the types m entioned in the headline is necessarily confined to a given thickness or textu re (grain-size and composition). T hey appear, how ever, m ostly in the fine-grained and thin - or m edium -bedded sand
stones.
Convolute bedding (Ph. H. K u e n e n 1953), known hith erto among others as „corrugated bedding” has been recorded from the Krosno beds by several geologists. A t first im pression it appears to have been origi
1 According to A. D. A r c h a n g u e l s k y (1930)slips m ay occur even if the angle of the slope does not exceed 1°. This, however, applies to rather small slumps or creep of hydro-plastic sediments. Large slumps such as observed in the Krosno beds m ust have originated on the more steeply inclined slopes. The occurrence of these slumps m ay indicate tectonic m ovem ents w ithin the geosynclinal belt as has been pointed out by several writers, or it m ay be that oversteepening by rapid sedimentation is responsible. Submarine slumps in the Krosno beds have been named „fossil seism ographs” by O. G a n s s (1942) and this name m ight be applied possibly to many of the turbidites in the strata discussed.
2 The Babica clays, charged with exotic boulders are thought to h ave been derived from a source situated -in the north-east and in this direction they can be traced at a distance of at least 30 km ( B u k o w y 1957).
nated by sm all-scale subm arine slum ps or creep, or resulted from compaction of w ater-saturated sedim ents. These conclusions as to the origin of the „corrugations” discussed seem to have been arrived at in dependently by various geologists. W ith regard to the convolute bed
ding in the Krosno beds the first conclusion has been advocated by G a n s s (1942), D z u l y r i s k i & R a d o m s k i (1956) and O b u c h o - w i c z (1957).
E lem ents of w eakness in this hypothesis have been pointed out by Ph. H. K u e n e n (1953) whose current-rippling hypothesis seem s to provide better explanation. Considerations which need not to be set forth in detail indicate that d ifferential pressure upon the crests and troughs o.f ripples and pow erful drag exerted by turbidity currents upon n ew ly deposited and very m obile sedim ents account largely for th e developm ent of the convolute bedding (see Ph. H. K u e n e n 1953).
N evertheless gravitational sliding (see PI. X X X V fig. 2) and compactio- nal changes associated w ith expulsion o f w ater surplus (M i g i o> r i n i 1950) m ust have iplayed an im portant role in the final developm en t of the convolute bedding (see also ten H a a f 1956).
In som e cases convolute bedding m ay be traced throughout the w h ole layer but in most instances it occupies on ly a part of it and is associated w ith current bedding and lam ination. In th e case w hen th e convolute bedding occupies th e w h ole bed its bottom surface m ay be undulated and th e shale pushed upwards b etw een troughs of convolution in the man ner described by K o p s t e i n (1954). In the know n cases the strike of these undulations is perpendicular to the direction o f flow . A great v a riety of forms is exhibited by w eathered surfaces of convolute bedding.
T hese surfaces are divided into innum erable elevations and depressions in shapes of irregular knobs, hillocks and pockets. Som etim es these knobs associated w ith depressions are scattered random ly over the sur
face; more often, how ever, th ey appear arranged in furrows and ridges.
The latter run parallel or at right an gle to the direction of flow , the form er arrangem ent being predom inant. The shapes of elevations and depressions are w id ely diverse and in m any cases the rugose belt of hillocks and depressions grades into an irregular w avy surface. In rare cases, strongly individualized conical knobs project over a com paratively flat or g en tly undulated surface. In sections cut at right angle to the bedding plane the convolute bedding in the Krosno beds does not differ from that described by M i g 1 i o r i n i (1950), S i g n i o r i n i (1936), K u e n e n (1953), ten H a a f (1956) and others.
We sh all g iv e now consideration to som e features associated w ith current bedding and con volu te bedding, the im portance o f which in the flysch rocks has not perhaps been recognized hitherto. The soles of sandstones w ith combined current and convolute bedding often display arcuate bands. O bservation in oblique lighting of the soles o f fine-grain
ed sandstones in th e M iddle Krosno beds hardly ever fails to disclose th e delicate pattern o f th ese arcuate bands. (PI. X X V III fig. 1). They alw ays show their convex sides towards the direction w hence the current cam e from. This has been proved trustw orthy by a comparison w ith oth er current indicators. H ence w e have a criterion of current direction
of much value since th e arched bands are su fficien tly comm on in the Krosno beds to g iv e them w ide application 1.
The bands described are evid en tly im prints of foreset lam inae of current bedding. Such a pattern has been discovered by J. S c h m i d t (1932) on the horizontal sections of current bedding. G. G ii r i c h (1933) had observed sim ilar arcuate bands in a sandstone in the Nama- -Transvaal system and W. H a n t z s c h e l (1935) in the recent sedim ents of the W atten Meer. The term „Schragschichtungsbogen” introduced by G. G ii r i c h is used in the German literature for these structures.
R. R i c h t e r (1932) pointed out that „Schragschichtungsbogen” appear to be formed by current rippling and this explanation holds true for all th e cases in the Krosno beds.
Successive arched bands appear either on the surfaces devoid of m arkings and sm oothed or on the surfaces, sculptured by flu te casts.
These latter do not influence the shape and orientation o f arched bands but the axes of flu te casts and those o f the arcs are parallel and apices turned in the sam e direction (up-current).
The origin of the arcuate bands on the soles of the Krosno sandstones appears from a comparison o f sections cut parallel and at the right angle to the direction of flow (see fig. 11). The former section displays a ty p i
cal current bedding w ith steep ly inclined foreset lam inae and gen tly dipping topnset lam inae. The section cut at right angle to the direction of flow and at the sam e tim e perpendicularly to th e axis of th e arcs show s criss-cross bedding of th e „lenticular ty p e” (see R. S h r o c k 1948) or trough-cross stratification (Me K e e, G. W. W e i r 1953).
The m ain conclusion arrived at w ith regard to th e arcuate bands in the Krosno beds is that already reached by R i c h t e r (1932) and show n experim en tally by K u e n e n , B a g n o l d , Me K e e and others that rip
ples form ed by steady flo w o f w ater consist o f „hillocks and pockets which show no ten dency to straightness” ( B a g n o l d 1954 I.e. page 163).
B y m oderate supply of sand barchan-like dunelets appear. The arcuate bands in question point out th e actual position of slip-faces of these subm arine crescent-shaped du nelets or „cusp ripple-m arks” (Me K e e 1954).
It is of interest to note that th e depressions embraced by th e crests and slip-faces of these dunelets coincide in m any cases w ith broad „syn- clines” of the convolute bedding and w in gs o f th e adjacent „barchans”
w ith narrow „anticlines” . These latter as seen on sections cut at right angle to the direction o f flow are truncated by another set of lam inae or bent down and tw isted towards the depressions. The sam e applies to the crests which are overfolded in the direction of flow . Such a diversion out o f normal position is su ggestive of the combined action of drag, cur
rent rippling and gravity w hich is consistent w ith th e explanation given b y Ph. H. K u e n e n w ith regard to th e origin o f convolute bedding.
Innum erable sm all subm arine crescentic du nelets provide thus th e basis upon the convolute bedding is built up.
It is in rare occasions on ly w hen ripples appear on the top surfaces o f-th e Krosno sandstones. T h ey h ave been found at Sieniaw a on the
1 Sim ilar structures have been observed also by Dr. A. S m i t h in the Silurian flysch of A berystw yth (personal communication).
Fig. 11. Schemat struktur łukowych na spągu piaskowców
Fig. 11. Sketch showing arcuate bands (A) and crescent dunelets in new ly deposited sand (B)
top^surface of the bed w ith arcuate bands on its sole. U nlike the „bar- ch an-like” structures on the sole, th e ripples on the top-surface w ere bent dow n-current, i. e. th ey showed their con vexities in the direction o f flow , hence they are of the normal linguloid type 1.
Obviously, in aqueous environm ents like under subaerial conditions crescentic dunes result from m oderate supply of sand laid dow n upon th e com paratively hard and im m obile ground.
Emphasis should be laid once again on the fact that the arcuate bands provide a reliable m ethod o f reading th e direction of current and current bedding, m inim um expenditure of tim e being required.
Laminated bedding w ill now be discussed. This kind o f bedding is of widespread occurrence in th e Krosno beds. It is also combined w ith convolute, current and graded bedding. It is not necessary to give a d e
tailed description here o f th e lam ination in the strata described as it does not differ from that described by M. K s i ^ z k i e w i c z (1954) from various units of the Carpathian flysch. A ll the types described b y the above m entioned author seem to exist in th e Krosno beds.
1 The pattern .of arched bands as seen on the horizontal section cut in the top-npart of the bed in question was sim ilar to that from below but w ith the d iffe
rence that the apices of arcs pointed down-current.
15 (Rocznik PTG
A lthough lam ination m ight be independent o f turbidity currents, m ost of the beds w ith lam ination in the Krosno beds appear to have been produced by turbidity currents. Som e of th em w ere laid dow n by d ilu te turbidity currents flow ing along the bottom , others, especially those more fine-grained, m ight have resulted from the suspended cur
rents (see D z u l y r i s k i & R a d o m s k i 1956). Most of th e lam inated beds in .the Krosno beds are to be accounted for in the manner .suggested by Ph. H. K u e n e n (1953) and K o p s t e i n (1954) i.e. th ey originated from clouds differing slig h tly in den sity of turbulence and velocity in th e sam e turbidity current and during tractional transport.
S A N D S T O N E S W IT H G R A D E S BBIDDING
Sandstones w ith distinct graded bedding are not so com m on as the typ es discussed previously. It m ust be rem em bered, how ever, that there is alm ost in every case the accum ulation of coarse grains at or near the base of the sandstone layers and a fine grading is easy to d etect in thin sections. A ll the types o f graded bedding described by various authors seem to be present in the Krosno beds.
SOLE MARKINGS IN THE KROSNO BEDS
A lthough hieroglyphs on th e soles of the flysch sandstones have been know n and described for m ore than a century, it is only w ith in the last few years that th ey have been w id ely recognized as im portant indica
tors of the directions of supply. The rapid extension of the theory o f tu r b id ity current (Ph. H. K u e n e n & C. I. M i g l i o r i n i 1950, Ph. H.
K u e n e n 1953, 1957) stim ulated n ew investigations of various hiero
gly p h s w hich after the first brilliant worik of J. C. H a l l (1843), T.
F u c h s (1895) and others have often b een overlooked in the in vestiga
tion o f flysch ro'bks.
The importance w hich the sole markings, esp ecially those of inorgan
ic origin have for th e theory of turbidity (currents and other typ es o f m ass-m ovem ents along the sea-bottom is undisputable. A considerable im portance m ust also be attached to these features as guides to paleo- geography of th e geosynclinal belts.
W e g iv e below a review of various types of hieroglyphs found on th e soles of the Krosno sandstones. Particular attention w ill be given to those markings which to our know ledge have not y e t been described.
O R G A N IC H IE R O G L Y P H S
The soles o f th e Krosno sandstones display usually num erous h ie roglyphs. Those of organic origin are rem arkably scanty. It does not im ply, how ever, that th e floor of the Krosno basin was devoid of ben- thonic life. As a m atter o f fact there is good reason to b eliev e that ben- thonic life flourished and th at th e conditions for living organism s had
