Sedimentological re cord of chang ing hy dro dy namic con di tions in the up per Tremadoc de pos its of the Holy Cross Moun tains, Po land
Wiesław TRELA
Trela W. (2001) — Sedimentological re cord of chang ing hy dro dy namic con di tions in the up per Tremadoc de pos its of the Holy Cross Moun tains, Po land. Geol. Quart., 45 (2): 131–142. Warszawa.
In the upper Tremadoc, in the Kielce re gion of the Holy Cross Moun tains, siltstones and fine-grained sand stones are interbedded with chalcedonites and claystones. The deposits were prob a bly laid down when the late Tremadoc trans gres sion reached its max i mum. Storm cur rents in flu enced de po si tion at times while, during calm pe ri ods, sed i men ta tion of chalcedonites, clayey cherts and clays took place.
Weak bot tom cur rents af fected the de po si tion of si li ceous lay ers. The de pos its ac cu mu lated on a dis tal shelf.
Wiesław Trela, Holy Cross Mts. Branch, Pol ish Geo log i cal In sti tute, Zgoda 21, PL-25-953 Kielce, e-mail: trela@pgi.kielce.pl (re - ceived: Jan u ary 20, 1999; ac cepted: Au gust 30, 2000).
Key words: Holy Cross Mts.,Or do vi cian, Late Tremadoc, chalcedonites, trans gres sion, storm de pos its.
INTRODUCTION
In the Late Tremadoc, af ter the Sandomierz tec tonic move - ments (Tomczyk, 1971; Bednarczyk, 1971; Znosko and Chlebowski, 1976), a ma rine trans gres sion de vel oped in the Kielce re gion of the Holy Cross Mountains, re corded by the de - po si tion of detrital and si li ceous rocks. The character of the de - pos its sug gest chang ing en ergy lev els in the en vi ron ment. This pa per con sid ers the sedimentology of the de pos its, and discusses the sources of the sil ica within the chalcedonites and clayey cherts.
The data co mes from sec tions at Zalesie Nowe and Kędziorka (Chojnów-Dół gorge) near Łagów (Fig. 1) in the south ern part of the Bardo Syncline, where the best ex posed pro files of these de pos its oc cur, and also from the Szumsko Kol. 2 bore hole (Fig. 1). Mac ro scopic ob ser va tions were aug - mented by study of 60 thin sec tions.
HISTORY OF RESEARCH
Chalcedonites from the Holy Cross Moun tains were first men tioned by Czarnocki (1919, 1928) and Samsonowicz (1948). Their petrology was stud ied by Turnau-Morawska
(1958), and Chlebowski (1971, 1976). Palaeontological and strati graphi cal stud ies were car ried by Kozłowski (1948), Górka (1969), Bednarczyk (1962, 1964, 1966a, b, 1971, 1981, 1988, 1996), Bednarczyk and Biernat (1978) and Szaniawski (1980).
Czarnocki (1919) ex plained the for ma tion of the chalcedonites as the re sults of “ad vanced diagenetic changes”.
Samsonowicz (1948) sug gested that the sil ica formed syngenetically on the sea bot tom, where it was de liv ered from land. Turnau-Morawska (1958) sug gested that changes in ba - sin bathymetry took place dur ing the de po si tion of the siltstones and chalcedonites. The siltstones formed in a rel a - tively shal low en vi ron ment, sourced from ero sion on land, while de po si tion of chalcedonites took place during deep en ing ep i sodes. The role played by bot tom cur rents dur ing the de po - si tion of upper Tremadoc siltstones and chalcedonites was first mentioned by Chlebowski (1971).
GEOLOGICAL SETTING
The study area, lo cated south from the Holy Cross Fault, lies in the Kielce re gion of the Holy Cross Moun tains (Fig. 1).
The re gion forms the north ern, ex posed part of the Małopolska Block (Pożaryski, 1990; Dadlez et al., 1994), which dur ing the Or do vi cian was lo cated be tween Baltica and Gond wana (Dzik
and Pisera, 1994). In the Arenig it was close to a lat i tude of 60°
south (Lewandowski, 1987).
The up per Tremadoc strata in the Kielce re gion of the Holy Cross Moun tains have been termed the Zbilutka Siltstone and Chalcedonite Mem ber (Fig. 2) (Bednarczyk, 1981, 1996), while Dzik and Pisera (1994) lifted them to the rank of for ma - tion (Wysoczki Chalcedonite For ma tion) (Fig. 2).
In the Bardo Syncline, Tremadocian siltstones and chalcedonites rest on al most ver ti cally ly ing Lower Cam brian rocks (Czarnocki, 1939; Samsonowicz, 1948; Kowalczewski, 1964, 1965; Bednarczyk, 1971; Chlebowski, 1971). At Kędziorka they are about 33 m thick (Fig. 3), at Zalesie Nowe they are about 7 m thick (Figs. 3, 4) and in the Szumsko Kol. 2 bore hole they are 10 m thick (Fig. 3).
The late Tremadoc age of this unit is doc u mented by brachi o pods (Bednarczyk, 1971, 1981, 1988, 1996;
Bednarczyk and Biernat, 1978), graptolites (Kozłowski, 1948) and cono donts of the Drepanoistodus deltifer prostinus Subzone (Bednarczyk and Biernat, 1978; Szaniawski, 1980;
Bednarczyk, 1981, 1988, 1996, 1998; Dzik and Pisera, 1994).
Bednarczyk (1996) placed the up per part of the unit in the low - er most Arenig, based on the oc cur rence of the brachi o pods Celdobolus mirandus (Barrande) and Eosiphonotreta acrotretomorpha (Goryansky).
Tremadocian rocks have been also re corded in ex ca va tions and bore holes in Wysoczki, around Pułaczów and in the west - ern part of the Bardo Syncline (Koziel, Mokradle) (Fig. 1) (Samsonowicz, 1948; Turnau-Morawska, 1958; Bednarczyk, 1962; Chlebowski, 1971).
In the east ern part of the Kielce re gion (Międzygórz), as well as around Brzeziny, Zbrza and Kielce (Fig. 1), up per Tremadoc to lower Arenig grey-green glauconitic sand stones are pres ent (Samsonowicz, 1928; Tomczyk, 1954;
Turnau-Morawska, 1960; Tomczyk and Turnau-Morawska,
1964; Deczkowski and Tomczyk, 1969; Bednarczyk, 1971, 1981, 1996). Their strati graphic po si tion is doc u mented by the brachi o pods Thysanotos siluricus (Eichwald), Celdobolus mirandus (Barrande) and Rosobolus cf. robertinus (Havliček) and cono donts of the Drepanoistodus deltifer deltifer Subzone (Bednarczyk, 1981, 1996). In the Zbrza re gion these de pos its are interbedded with a few chalcedonite lay ers. Their thick ness var ies from 5 m around Zbrza and Brzeziny to 20 m at Międzygórz.
GENERAL LITHOLOGICAL CHARACTERISTICS
The Lower Or do vi cian pro file in the Bardo Syncline be gins with a thin layer of sandy con glom er ate (cur rently un ex posed) 10–15 cm thick, com posed of peb bles of Cam brian rocks and quartz (Czarnocki, 1928, 1939; Chlebowski, 1971).
Above this con glom er ate lie siltstones and fine-grained sand stones interbedded with chalcedonites and claystones (Figs. 3, 4). Siltstone and sand stone beds both range be tween 3 and 20 cm thick. Claystone lay ers are mostly 2 to 4 cm thick, spo rad i cally reach ing 30 cm. Bed bound aries are sharp, and nu - mer ous load struc tures can be found. Mudstones and fine-grained sand stones re veal a dis tinct green col our, while chalcedonites are grey and blu ish. Lo cally, thin interlayers and laminae of coarse sand and fine gravel oc cur within in di vid ual siltstone-sand stone lay ers.
PETROGRAPHIC CHARACTERS
The overall petrographic char ac ters, mineral com po si tion and tex tural attributes of the main lithological types are given
Fig. 1. Dis tri bu tion of Or do vi cian de pos its in the Holy Cross Moun tains (Tomczykowa, 1968; Bednarczyk, 1971)
here. De tailed petrographic analyses of the Tremadoc deposits from Wysoczki and Bardo Syncline can be found in Turnau-Morawska (1958) and Chlebowski (1971, 1976).
DETRITIC ROCKS
The de tri tal rocks com prise mainly quartz grains with a di - am e ter of 0.02–0.06 mm, lo cally be tween 0.06–0.1 mm (Pl. I, Fig. 3), mak ing them siltstones and fine-grained sand stones.
Quartz grains are an gu lar to slightly rounded, some hav ing re - gen er a tion rims. Glauconite is abun dant, form ing grass-green ag gre gates with di am e ters of 0.02–0.6 mm. Faint green flakes of glauconitised biotites are also pres ent, as well as other micas and feld spars. The ma trix and ce ment are formed by clay min - er als and sil ica (amor phous and fine-crys tal line). Opaque iron ox ides and hy drox ides are also pres ent. Chlebowski (1971) noted oc cur rence of vol ca nic ma te rial (quartz, fresh feld spars and micas) in the de tri tal rocks. Both siltstones and sand stones con tain fine gravel, rep re sented by phos phatic grains, claystone rock peb bles, quartzitic siltstones, coarse-grained quartz and frag ments of si li ceous rocks.
SILICEOUS ROCKS
Si li ceous rocks are com posed of chalcedonite, usu ally de - vel oped in the form of fan-shaped spheru lites (0.1–0.5 mm) (Pl. I, Fig. 2). Very well pre served sponge spicules, with out any traces of me chan i cal or chem i cal ero sion, and frag ments of phos phatic brachi o pod shells can be seen in the chalcedonite ma trix (Pl. I, Fig. 2). Or ganic re mains and de tri tal grains form the nu clei of the chalcedonite spher ules. Glauconite, de tri tal quartz, feld spars, micas and phos phates also form a small pro - por tion of the rock.
Clayey cherts also oc cur (Turnau-Morawska, 1958;
Chlebowski, 1971), be ing a mix ture of sil ica, clay min er als, de - tri tal quartz, feld spars, phos phates, glauconite and ferruginous com pounds (Pl. I. Fig. 4). As in the chalcedonites, sponge spicules are pres ent. In the clayey cherts of the Szumsko Kol. 2 bore hole, cal cite car bon ate lo cally oc curs (Pl. I, Fig. 4), some forms of which re sem ble or ganic re mains. Less abun dantly, cal cium car bon ate oc curs also in the si li ceous de pos its of Zalesie Nowe and Kędziorka. Its pres ence was men tioned by Turnau-Morawska (1958) and Chlebowski (1971).
SEDIMENTOLOGY
SILTSTONES AND SANDSTONES
A char ac ter is tic fea ture of the up per Tremadoc pro files ex - posed in Kędziorka and Zalesie Nowe is a rhyth mic oc cur rence of siltstones/sand stones, chalcedonites and claystones (Figs. 3, 4; Pl. I, Fig. 1). Sedimentological struc tures ana lysed in this sec tion re fer mainly to siltstones and sand stones. The claystones are usu ally mas sive or bioturbated, or in some cases hor i zon tally lam i nated.
Basal sur faces of the siltstone-sand stone lay ers are usu ally sharp, ero sional and in most cases cov ered by coarse sand and
fine gravel (Pl. II, Fig. 5; Pl. III, Fig. 1). Larger peb bles here reach a max i mum di am e ter of 1 cm, and com prise well-rounded intraclasts of green claystone and frag ments of chalcedonites and clayey chert. Groove marks on these basal sur faces reach a dozen or so centi metres in lenght, 1–5 mm in width, and 1–2 mm in depth. Lon gi tu di nal ridges moulds are also pres ent (Pl. IV, Fig. 4).
The siltstone-sand stone lay ers con tain hor i zon tal lam i na - tion or low-an gle cross-bed ding (Pl. II, Fig. 3; Pl. III, Figs.
2, 3). Flaser bed ding and rip ple cross-lam i na tion also oc cur (Pl. I, Fig. 5; Pl. II, Fig. 2). Sur faces of the siltstone-sand stone lay ers are com monly ir reg u lar, de formed and loaded (Pl. II, Fig. 1). In few cases hummocky cross-strat i fi ca tion (Pl. III, Fig. 4) and wavy lam i na tion oc cur. Up per sur faces of some of the claystone and siltstone lay ers are de vel oped in the form of low hum mocks, with a di am e ter of about 10 cm and the height of about 2 cm, sep a rated by de pres sions of sim i lar di men sions.
Graded-bed ding within the lay ers com prises pas sages from coarse sands and fine grav els into siltstones (Pl. II, Fig. 5).
Com monly, lay ers are graded in their lower parts and hor i zon - tally lam i nated in their up per parts, and this may pass up into low-an gle cross-bed ding or rip ple bed ding (Pl. I, Fig. 5; Pl. II, Fig. 2). Cur rent rip ples may oc cur on top sur faces, with an am - pli tude not ex ceed ing 1 cm, and usu ally around 0.5 cm (Pl. I, Fig. 6).
Wash-out struc tures commonly oc cur at the base of siltstone-sandstone lay ers, as small flute marks and ero sional
Fig. 2. Lithostratigraphy of the Or do vi cian de pos its in the Kielce re gion of the Holy Cross Moun tains
1. Ex po sure of the Zbilutka Siltstone and Chalcedonite Mem ber in the Kędziorka (Chojnów-Dół gorge); al ter na tion of siltstone-sandstone and chalcedonite lay ers is vis i ble. 2. Chalcedonite spheru lites around detritic quartz and on the sur face of a phosphatised brachi o pod shell frag ment (lower part of the pic ture); crossed polars; Kędziorka. 3. Hor i zon tal lam i na tion of fine-grained sand stones seen un der the mi cro scope; crossed polars; Zalesie Nowe. 4. Con tact of clay chert, con tain ing an ad mix ture of car bon ates, with siltstone (up per-right cor ner of the pic ture); crossed polars; Szumsko Kol. 2.
5. Hor i zon tally lam i nated siltstone; rip ple lam i na tion and fodinichnias filled with siltstone-chalcedonite ma te rial on a bedding sur face; Kędziorka; scale bar — 1 cm. 6. Cur rent rip ples on the sur face of a siltstone layer; Kędziorka
PLATE I
1. Siltstone with in ter rupted hor i zon tal lamination; bend ing of the lam i na tion at the con tact with the chalcedonite is vis i ble (mid dle part of the pic ture);
oval frag ments of clayey cherts (lower part of the pic ture); Zalesie Nowe. 2. Siltstone-siliceous heterolithic deposit; at the bot tom of a layer the in ter rupted in ter nal struc ture of the de posit is vis i ble, with hor i zon tal and rip ple lam i na tion at the top; Zalesie Nowe. 3. Contact of chalcedonite with a hor i zon tally lam i nated siltstone; in its lower part the chalcedonite con tains an ad mix ture of detrital ma te rial, emphasizing the hor i zon tal lam i na tion; Kędziorka. 4. Bed with an in ter rupted in ter nal struc ture, com posed of re de pos ited frag ments of si li ceous rocks and of a sany and gravel; in the lower part of the pic ture a thin layer of hor i zon tally lam i nated siltstone is vis i ble; Kędziorka. 5. In the lower part of the pic ture — an ero sion sur face capped by a thin sand stone layer with small peb bles; higher — a hor i zon tally lam i nated siltstone; at the top — a claystone with bioturbation traces (dark stripes) and an ad mix ture of siltstone;
Zalesie Nowe. Scale bar — 1 cm
PLATE II
1. Chalcedonite-siltstone con tact; a thin layer of coarse-grained sand stone with small peb bles is vis i ble at the bot tom of the siltstone layer, capped by hor i - zon tal and rip ple lam i na tion; chalcedonite with an ad mix ture of terrigenic ma te rial; Kędziorka. 2. A sharp bound ary be tween a bioturbated siltstone and over ly ing hor i zon tally lam i nated siltstone; Zalesie Nowe. 3. Hor i zon tally lam i nated fine-grained sand stone with es cape struc tures; Zalesie Nowe. 4.
Hummocky cross-stratification (HCS), with an es cape struc ture (right side of the pic ture); Kędziorka. Scale bar — 1 cm
PLATE III
1. Bioturbated siltstone; Kędziorka. 2, 3. Oval and circular animal traces, pre served on the bot tom sur face of a bed of fine-grained sand stone; Kędziorka.
4. Moulds of lon gi tu di nal ridges on the lower sur face of a fine-grained sand stone bed; Zalesie Nowe. Scale bar — 1 cm
PLATE IV
chan nels, with widths reach ing 3–5 cm, and the depths of 1–3 cm, cut into the un der ly ing claystone. These are filled with sand or fine gravel and intraclasts of chalcedonites, which are some times rounded.
In di vid ual, len tic u lar, elon gated or oval chalcedonite frag - ments with a thick ness of few or up to a dozen or so milli metres lo cally oc cur. They re sem ble clay balls, and are com monly torn apart and folded (Pl. II, Fig. 1).
In some cases, thin laminae of siltstone, chalcedonites and clayey chert al ter nate, forming heterolithic layers.
In ter nally de formed lay ers com monly oc cur and com prise torn-apart frag ments of claystone, chalcedonites and clayey cherts, with sandy-gravel ma te rial squeezed in be tween them
(Pl. II, Figs. 2, 4). Sand and fine gravel form ir reg u lar lenses to 1 cm thick, and laminae up to 0.5 cm thick and 3 cm long.
These de formed pack ets are as so ci ated with more co her ent strata, the whole be ing prob a bly due to in sta bil ity as a re sult of den sity strat i fi ca tion (Dżułyński, 1966; An ke tell et al., 1970).
Lenses, intraclasts and grains of sand oc cur within some claystone lay ers, and these usu ally have gradational bound - aries.
Bioturbation com prises mainly endichnias within thin, grey-green claystones and fine-grained siltstones, ar ranged par al lel to the bed ding planes (Pl. II, Figs. 2, 5) and out lined by dark or ganic mat ter. In many cases, pri mary sed i men tary struc - tures have been de stroyed by in tense bioturbation (Pl. IV, Fig. 1). Lo cally bioturbation traces are pre served as hypichnia on bot tom sur faces of the siltstone-sand stone lay ers. They form short, oval forms, up to 1–2 cm long and about 0.5 cm wide (Pl. IV, Fig. 2), and oval traces of di am e ter 0.5 cm (Pl. I, Fig. 3), and straight forms with a max i mum length of 2 cm and widths of 0.3 cm, re sem bling Planolites sp. These traces are built of ma te rial from the over ly ing lay ers. Spo rad i cally, in the top parts of the siltstone lay ers, traces of rain drop-shaped bor ings, up to 2 cm long, and 1 cm across oc cur (Pl. I, Fig. 5). They cut the orig i nal sed i men tary struc tures and are filled by fine-grained, some times chalcedonite sed i ment. They re sem ble Glossifungites (Frey and Pem ber ton, 1984; Ekdale et al., 1984). In di vid ual es cape struc tures are also found within the siltstone-sand stone lay ers (Pl. III, Figs. 3, 4), filled with fine-grained ho mo ge neous siltstone. Ad ja cent to these forms the lam i na tion of the de pos its is de formed.
CHALCEDONITES
Rocks built of chalcedonite spheru lites usu ally form con - tin u ous lay ers, easy to trace in the ex po sures. Lenses, con cre - tions, and clay balls are also pres ent within siltstones and sand stones (Pl. I, Fig. 1). Most com monly they are flat or discoidal and reach di men sions of 1.5 x 3 x 4 cm. Some are load-shaped, or form dis con tin u ous thin laminae, with a max i - mum length of a few centi metres and widths up to 0.5 cm. In some chalcedonite lay ers traces of hor i zon tal lam i na tion, marked by the fine de tri tus can be ob served oc cur (Pl. III, Fig. 3). Con cen tra tions and clay balls of clayey cherts, as well as fine glauconite and quartz grains also oc cur in the chalcedonite ma trix.
Clayey cherts usu ally form ir reg u lar con cen tra tions, lenses or dis rupted ir reg u lar lay ers, or they adopt oval shapes (Pl. II, Fig. 1). They are char ac ter ised by grad ual bound aries and are re placed by chalcedonites and siltstones. Their thick ness is vari able, av er ag ing about 3 cm. Some lam i nated and oval clayey cherts with a higher sil ica con tent have more dis tinct bound aries with the sur round ing siltstone-sand stone rocks, or oc cur as load struc tures in a chalcedonite or siltstone-sand stone ma trix (Chlebowski, 1971). In a few cases traces of lam i na tion are pre served within the bed ded cherts.
Fig. 3. Lithological pro files of the Or do vi cian de pos its in the area stud ied (Czarnocki, 1939; Chlebowski, 1971; Bednarczyk, 1971, 1996; Dzik, 1996)
DISCUSSION
SOURCE OF SILICA
Samsonowicz (1948) sug gested a syngenetic or i gin for the sil ica on the sea bot tom, where it was de rived from the land.
Turnau-Morawska (1958) thought that the sil ica source was
“...dis in te gra tion of min eral pelite suspensed in the sea wa ter for a long time dur ing a pe riod of brake of ero sional pro cesses on the neigh bour ing land...”. Ac cord ing to Chlebowski (1971, 1976) and Kowalczewski (1974), large quan ti ties of sil ica were supplied to the ba sin by vol ca nic ac tiv ity.
Durakiewicz et al. (1998) suggested that the sil ica in the Kielce re gion of the Holy Cross Moun tains was of hy dro ther - mal or i gin possibly con nected with the ac tiv ity of un der sea springs. In case of the Tremadoc chalcedonites, though, there is no ob vi ous source of heat. But, as in the early Pre cam brian of New found land (Simonson, 1985), cool ing igneous in tru sions may have sourced ther mal wa ters bringing sil ica into the ba sin.
There is no ev i dence of in tru sions in the late Tremadoc in the Holy Cross Moun tains. These could oc cur on greater depths, as the prod ucts of nearby vol ca nic ac tiv ity reached the Kielce re - gion of the Holy Cross Moun tains. Chlebowski (1971) sug - gested that the vol ca nism bringing pyroclastic ma te rial into the Holy Cross re gion occured south of the Holy Cross Moun tains, at the dis tance of 30 km or closer. Ac cord ing to Kowalczewski and Wróblewski (1971, 1974) com mon ex am ples of post-volcanic min er ali sa tion are con nected with nearby ac tive vol ca nic zones.
Hy dro ther mal so lu tions and un der sea vol ca nic ex ha la tions, pos si bly con nected with nearby vol ca nism, seem to be the most prob a ble sources of sil ica in the Kielce re gion of the Holy Cross Moun tains in the late Tremadoc. Higher tem per a ture is one of the fa vour ing sil ica dis so lu tion (Siever, 1962; Simonson, 1985). The bot tom sed i ment of the late Tremadoc sed i men tary ba sin in the Kielce re gion was weakly re duc ing, be cause of or - ganic mat ter de cay. Or ganic mat ter in flu ences the pre cip i ta tion of sil ica, as it causes a drop of the so lu tion’s pH and forms pro - tect ing colloids, and there fore pre vents sil ica dis so lu tion (Siever, 1962; Kasiński et al., 1981). These con di tions, also de - ter min ing the Fe3+/Fe2+ ra tio (Harder, 1989), ad di tion ally fa - voured glauconite for ma tion. Bot tom wa ters in the late Tremadoc sed i men tary ba sin be came oversaturated with re - spect to sil ica, and this pre cip i tated where the slightly al ka line bot tom wa ters mixed with the slightly acidic pore wa ters. Ac - cord ing to Krauskopf (1959) a rapid in crease of the sil ica pre - cip i ta tion rate takes place in such con di tions. Pre cip i ta tion of sil ica in oversaturated so lu tions is en hanced in the pres ence of elec tro lytes in the sea wa ter.
It can not be ex cluded that the hy dro ther mal so lu tions mi - grated along fault zones. The Or do vi cian ba sin of the Holy Cross Moun tains was tec toni cally ac tive (Kowalczewski, 1964, 1965, 1994; Tomczyk, 1964; Kowalczewski and Wróblewski, 1971, 1974). In Kędziorka and Zbrza, lo cal tec - ton ics and eustatic sea level changes caused lo cal emer gence dur ing the Arenig and Llanvirn (Figs. 1, 3). In Zalesie Nowe, Mid dle Or do vi cian dolomites, show ing traces of hy dro ther mal al ter ation, over lie the Lower Or do vi cian siltstones, chalcedonites and sand stones (Fig. 3). Hy dro ther mal ac tiv ity in
the Mid dle Or do vi cian might have taken place along fault zones which were ac tive al ready in the Tremadoc.
INTERPRETATION OF SEDIMENTARY CONDITIONS
The sedimentological re cord of the up per Tremadoc pro - files in Kędziorka, Zalesie Nowe and Szumsko Kol. 2 indicates rapid changes in the en ergy of the depositional en vi ron ment.
Siltstone-sandstone lay ers contain sed i men tary struc tures sug - gest ing en er getic de po si tion. Sharp, ero sive basal bed sur faces in di cate a rapid ac cu mu la tion that was pre ceded by ero sion of un der ly ing sed i ments, with the formation of small intraclasts.
Such graded beds are typ i cally left by waning cur rents (Dott and Bour geois, 1982; Walker, 1984; Aigner, 1984, 1985). Wa - ter escape struc tures also indicate rapid ac cu mu la tion.
Wave-generated struc tures are rare in the de pos its stud ied, what sug gests deposition on dis tal shelves, be low nor mal wave base (Aigner, 1984, 1985; Leckie and Krystinik, 1989; Jannette and Pryor, 1993). The re place ment of graded-bedding by hor i - zon tal lam i na tion, or of hor i zon tal lam i na tion by cross-bedding and rip ple-bedding ob served re cord weak en ing storm cur rents (Bhattacharyya et al., 1980; Dott and Bour geois, 1982; Aigner, 1984, 1985; Walker, 1984; Simpson and Eriksson, 1990;
Tucker, 1995). Hummocky cross-stratification (HCS) and wavy lam i na tion are di ag nos tic fea tures of storm de pos its, in - di cat ing rapid de po si tion of the ma te rial from sus pen sion in wan ing flow con di tions as wave ac tion is mod i fied by uni di rec - tional cur rents (Bour geois, 1980; Dott and Bour geois, 1982;
Harms et al., 1982; Walker, 1984; Duke et al., 1991; Jannette and Pryor, 1993; Gal lo way and Hobday, 1996). Hummocky cross strat i fi ca tion is pres ent, though rare in the de pos its ana lysed.
The oc cur rence of graded-bedding, hor i zon tal lam i na tion, low-angle cross-bedding and common ero sional surfaces, as well as the pres ence of small-scale hummocky cross- stratification and wavy lam i na tion, in di cate storm-generated bot tom cur rents, during de po si tion of the siltstones and sand - stones.
The load struc tures and in ter nally deformed lay ers ob - served in di cate rapid sand deposition on a wa ter-saturated clay sub strate, or on a soft and plas tic layer of si li ceous gel. Dense cur rents flow ing on the soft sub strate tore and de formed existing lay ers, the interbedding of sed i ments with dif fer ent den si ties en cour ag ing deformation (Dżułyński and Radomski, 1966). Ac cord ing to Chlebowski (1971), apart from cur rent flow, tec toni cally in duced mass movements were an im por tant fac tor in the for ma tion of load struc tures and clay-ball struc - tures. In deed, some of the bot tom cur rents might have been gen er ated by tec tonic ac tiv ity.
Dur ing calm ep i sodes the sur face of siltstone-sandstone lay ers was pen e trated by or gan isms. Fodinichnias, drilled in firm, semi-consolidated de pos its, pro vided shel ter against ero - sion and bot tom cur rents (Frey and Pem ber ton, 1984; Ekdale et al., 1984). Rapid de po si tion lo cally pre served bur rows as moulds on the undersides of beds.
A rise in wave base led to de po si tion of si li ceous strata and sed i men ta tion of fine detrital ma te rial from sus pen sion. A low de po si tion rate and calm sed i men tary con di tions fa voured the bioturbation ob served in claystone and siltstone lay ers, lo cally caus ing ho mogeni sa tion of the de posit. Individual chalcedonite
and claystone lay ers show the in flu ence of weak cur rents marked by thin layers of sand-gravel or of chert/clay balls in the chalcedonite ma trix. The chalcedonite, as a semi-plastic, sed i - ment was lo cally eroded and re de pos ited by cur rents. Mixed with silt, in tro duced by weak cur rents, it formed clayey cherts.
Traces of cal cium car bon ate oc cur within the clayey cherts, sug gest ing incorporation of this com po nent into the orig i nal sed i ment, which, ac cord ing to Turnau-Morawska (1958), could orig i nally have been cal car e ous and then been re placed by sil ica. Con cen tra tions of cal cium car bon ate re sem bling or - ganic re mains sug gest at least a partly or ganic or i gin. Such calcareous bioclasts were prob a bly cur rent-derived from a shal lower part of the ba sin. pH and Eh con di tions prob a bly fa - voured par tial dis so lu tion of cal car e ous skel e tons, and cal cium ions made pre cip i ta tion of si li ceous gel eas ier (Turnau-Morawska, 1958; Kastner, 1979). Some of the ir reg u - lar cal car e ous con cen tra tions may, though, be of diagenetic or, as Chlebowski (1971) sug gests, of hy dro ther mal or i gin.
The deposits resemble those formed on a deep shelf or ramp (Aigner and Reineck, 1982; Harms et al., 1982; Brett, 1983;
Walker, 1984; Aigner, 1984, 1985). Siltstone-sandstone lay ers represent dis tal cur rent ac tiv ity, per haps gen er ated by storms, in ter rupting calm clay-siliceous sed i men ta tion. High am pli tude storm-generated waves can in flu ence bot tom sed i ment to depths ex ceed ing 200 m (Gal lo way and Hobday, 1996; Col - lins, 1988). It can not be excuded that some of the bot tom cur - rents was gen er ated by tec tonic ac tiv ity.
CONCLUSIONS
1. The up per Tremadoc pro file in the Kielce re gion of the Holy Cross Moun tains comprises thin- and me dium-bedded siltstones, sand stones, chalcedonites and clays, deposited in the fi nal phase of the late Tremadoc trans gres sion.
2. The sediments re cord rapid fluc tu a tions in en ergy. Sand - stones and siltstones were de pos ited in tur bu lent con di tions un - der the in flu ence of storm cur rents. Graded-bedding and horizontal lam i na tion is succeeded by small scale cross-bedding and rip ple cross-lamination within in di vid ual beds. Hummocky cross-stratification and wavy lam i na tion are locally pres ent. Bed bound aries are sharp and com mon load ing of clastic rocks into chalcedonites.
3. Dur ing calm in ter vals sed i men ta tion of chalcedonites and claystones oc curred. Low de po si tion rates fa voured bioturbation. Dur ing pe ri ods of in creased cur rent ac tiv ity some of the chalcedonites and clayey cherts were re worked.
4. Hy dro ther mal so lu tions and vol ca nic ex ha la tions associated with nearby vol ca nic ac tiv ity were the source of the sil ica in the cherts.
5. Sed i men ta tion took place on a dis tal shelf, un der the in - flu ence of wan ing storm or tec toni cally-genetated cur rents.
Fig. 4. Sedimentological pro file of the up per Tremadoc de pos its in Zalesie Nowe
REFERENCES
AIGNER T. (1984) — Dy namic stra tig ra phy of epicontinental car bon ates, Up per Muschelkalk (Mid dle Triass), South Ger man ba sin. N. Jb. Geol.
Paläont. Abh., 169: 127–159.
AIGNER T. (1985) — Storm depositional sys tems. Lect. Not. Earth Sc., 3:
174. Springer-Verlag. Berlin.
AIGNER T. and REINECK H. (1982) — Proximality trends in mod ern sands from Helgoland Bight (North Sea) and their im pli ca tions for ba - sin anal y sis. Senckenberg. Maritima, 14: 183–215.
ANKETELL J. M., CEGŁA J. and DŻUŁYŃSKI S. (1970) — On the deformational struc tures in sys tems with re versed den sity gra di ents.
Rocz. Pol. Tow. Geol., 40 (1): 3–30.
BEDNARCZYK W. (1962) — Dolny ordowik okolic wsi Koziel w Górach Świętokrzyskich. In: Księga Pamiątkowa ku czci Profesora Jana Samso nowicza (ed. E. Passendorfer): 149–170. Wyd. Geol.
Warszaw a.
BEDNARCZYK W. (1964) — The stra tig ra phy and fauna of the Tremadocian and Arenigian (Ölandian) in the Kielce re gion of the Holy Cross Moun tains (in Pol ish with Eng lish sum mary). Biul. Geol.
Wydz. Geol. UW, 4: 3–127, 188–197.
BEDNARCZYK W. (1966a) — Lower Or do vi cian palaeo ge ogra phy of the Kielce re gion in the Holy Cross Mts. (in Pol ish with Eng lish sum - mary). Acta Geol. Pol., 16 (1): 91–106.
BEDNARCZYK W. (1966b) — Li thol ogy of the lower Or do vi cian (Oelandian) in the Kielce re gion of the Holy Cross Mts. (in Pol ish with Eng lish sum mary). Biul. Geol. Wydz. Geol. UW, 8: 4–53.
BEDNARCZYK W. (1971) — Stratygraphy and paleogeography of the Or do vi cian in the Holy Cross Mts. Acta Geol. Pol., 21 (4): 574–616.
BEDNARCZYK W. (1981) — Stratygrafia ordowiku Gór Świętokrzys - kich. Przew. 53 Zjazdu Pol. Tow. Geol., Kielce: 35–41.
BEDNARCZYK W. (1988) — The role of brachi o pods in stra tig ra phy of the low est Or do vi cian of the Holy Cross Mts (in Pol ish with Eng lish sum mary). Prz. Geol., 36 (1): 17–23.
BEDNARCZYK W. (1996) — Międzygórz quarry. Zalesie. In: Sixth Eu ro - pean Cono dont Sym po sium ECOS VI, June 30–July 3. Ex cur sion Guide (eds. M. Szulczewski and S. Skompski): 12–21. Warszawa.
BEDNARCZYK W. (1998) — Strati graphic po si tion of acritarchs from the low er most Or do vi cian of the Holy Cross Mts. in the light of cono donts stud ies. Bull. Pol. Acad. Sc., Earth Sc., 46: 1–8.
BEDNARCZYK W. and BIERNAT G. (1978) — In ar tic u late brachi o pods from the Lower Or do vi cian in the Holy Cross Mts., Po land. Acta Palaeont. Pol., 23 (3): 293–316.
BHATTACHARYYA A., SARKAR S. and CHANDA S. K. (1980) — Storm de pos its in the Late Pro tero zoic lower Bhander sand stone of Vindhyan Supergroup around Maihar, Satna dis trict, Madhaya Pradesh, In dia. J. Sed. Petrol., 50: 1327–1335.
BOURGEOIS J. (1980) — A transgressive shelf se quence ex hib it ing hummocky strat i fi ca tion: the Cape Sebastian Sand stone (Up per Cre ta - ceous), south west ern Or e gon. J. Sed. Petrol., 50: 681–702.
BRETT C. E. (1983) — Sedimentology, fa cies and depositional en vi ron - ments of the Roch es ter Shale (Si lu rian; Wenlockian) in west ern New York and On tario. J. Sed. Petrol., 53: 947–971.
CHLEBOWSKI R. (1971) — Pe trog ra phy of the Or do vi cian de pos its of the Bardo syncline in the south ern part of the Świętokrzyskie Mts (in Pol ish with Eng lish sum mary). Arch. Miner., 29 (1/2): 193–304.
CHLEBOWSKI R. (1976) — Studium petrograficzne skał tufogenicznych starszego paleozoiku Gór Świętokrzyskich. Arch. Miner., 34: 69–134.
COLLINS L. B. (1988) — Sed i ments and his tory of the Rottest Shelf, south west Aus tra lia: a swell-dominated, non-tropical car bon ate mar - gin. Sed. Geol., 60: 15–50.
CZARNOCKI J. (1919) — Stratygrafia i tektonika staropaleozoicznych utworów Gór Świętokrzyskich. (Kambr, sylur, dewon dolny). Pr. Tow.
Nauk. Warsz., 28.
CZARNOCKI J. (1928) — Le profil de l’Ordovicien inférieur et supérieur á Zalesie prés Łagów comparé á celui des autres régions de la partie centrale du mas sif de S-te Croix (in Pol ish with French sum mary).
Spraw. Państw. Inst. Geol., 4 (3/4): 555–581.
CZARNOCKI J. (1939) — Field work in the Święty Krzyż Moun tains in 1938 (in Pol ish with Eng lish sum mary). Biul. Państw. Inst. Geol., 15:
1–41.
DADLEZ R., KOWALCZEWSKI Z. and ZNOSKO J. (1994) — Some key prob lems of the pre-Permian tec ton ics of Po land. Geol. Quart., 38 (2):
169–190.
DECZKOWKI Z. and TOMCZYK H. (1969) — Geo log i cal struc ture of the Zbrza anticline in the south-western part of the Góry Świętokrzyskie (in Pol ish with Eng lish sum mary). Biul. Inst. Geol., 236: 143–175.
DOTT R. H. and Jr. BOURGEOIS J. (1982) — Hummocky strat i fi ca tion:
sig nif i cance of its vari able bed ding se quence. Geol. Soc. Amer. Bull., 93: 663–680.
DUKE W. L., ARNOTT R. W. C. and CHEEL R. J. (1991) — Shelf sand - stones and hummocky cross-stratification: New in sights on a storm de - bate. Ge ol ogy, 19: 625–628.
DURAKIEWICZ T., MIGASZEWSKI Z. and HAŁAS S. (1998) — Oxygene iso tope de ter mi na tions in quartz group min er als (in Pol ish with Eng lish sum mary). Prz. Geol., 46 (2): 167–170.
DZIK J. (1996) — Mójcza quarry. In: Sixth Eu ro pean Cono dont Sym po - sium ECOS VI, June 30–July 3. Ex cur sion Guide (eds. M.
Szulczewski and S. Skompski): 22–26. Warszawa.
DZIK J. and PISERA A. (1994) — Sed i men ta tion and fos sils of the Mójcza Lime stone. Palaeont. Pol., 53: 5–41.
DŻUŁYŃSKI S. (1966) — Sed i men tary struc tures re sult ing from con vec - tion-like pat tern of mo tion (in Pol ish with Eng lish sum mary). Rocz.
Pol. Tow. Geol., 36 (1): 3–21.
DŻUŁYŃSKI S. and RADOMSKI A. (1966) — Ex per i ments on bed ding dis tur bances pro duced by the im pact of heavy sus pen sions upon hor i - zon tal sed i men tary lay ers. Bull. Acad. Pol. Sc., Ser. Sc. Geol. Geogr., 14 (4): 227–230.
EKDALE A. A., BROMLEY R. G. and PEMBERTON S. G. (1984) — Ichnology — the use of trace fos sils in sedimentology and stra tig ra - phy. Soc. Econ. Paleont. Miner., Short Course, 15: 316.
FREY R. W. and PEMBERTON S. G. (1984) — Trace fos sil fa cies model.
In: Fa cies Models. Geoscience Can ada (ed. R. G. Walker): 189–207.
GALLOWAY W. E. and HOBDAY D. K. (1996) — Terrigenous clastic depositional sys tems. Springer-Verlag. Berlin, Hei del berg.
GÓRKA H. (1969) — Mikroorganismes de l’Ordovicien de Pologne.
Palaeont. Pol., 22.
HARDER H. (1989) — Min eral gen e sis in iron stones: a model based upon lab o ra tory ex per i ments and petrographic ob ser va tions. In:
Phanerozoik Iron stones (eds. T. P. Young and W. E. G. Tay lor). Geol.
Soc., Spec. Publ., 46: 7–18.
HARMS J. C., SOUTHARD J. B. and WALKER R. G. (1982) — Struc - tures and se quences in clastic rocks. Soc. Econ. Paleont. Miner., Short Course, 9: 251.
JANNETTE D. C. and PRYOR W. A. (1993) — Cy clic al ter na tion of prox - i mal and dis tal storm fa cies: Kope and Fairview For ma tions (Up per Or do vi cian), Ohio and Ken tucky. J. Sed. Petrol., 63: 183–203.
KASIŃSKI J. R., PIEŃKOWSKI G. and PISERA A. (1981) — Lith o - logic-microfacial char ac ter is tics of the Branisko and Czorsztyn Suc - ces sions along the road from Krośnica to Kąty, Pieniny Klippen Belt, Carpathians (in Pol ish with Eng lish sum mary). Stud. Geol. Pol., 70:
73–94.
KASTNER M. (1979) — Sil ica poly morphs. In: Ma rine Min erals (ed. R.
G. Burns). Miner. Soc. Amer., Short Course Notes, 6: 99–110.
KOWALCZEWSKI Z. (1964) — Wstępne wyniki badań nad kaledonikiem świętokrzyskim w rejonie Dymin i Barda. Kwart. Geol., 8 (2):
463–464.
KOWALCZEWSKI Z. (1965) — Wyniki badań nad tektoniką synkliny bardziańskiej w Górach Świętokrzyskich. Kwat. Geol., 9 (2):
463–464.
KOWALCZEWSKI Z (1974) — Geo log i cal and struc tural as pects of magmatism in the Góry Świętokrzyskie Mts. Against the back-ground of re cent re search (in Pol ish with Eng lish sum mary). Biul. Inst. Geol., 275: 11–62.
KOWALCZEWSKI Z. (1994) — The Holy Cross Mts. in the early Paleozoic. In: Europrobe. Trans-European Su ture Zone Work shop.
Excursion Guide book the Holy Cross Moun tains (eds. Z.
Kowalczewski, M. Szulczewski, Z. Migaszewski and K.
Janecka-Styrcz): 1–18. Kielce.
KOWALCZEWSKI Z. and WRÓBLEWSKI T. (1971) — Wybrane problemy magmatyzmu i mineralizacji w Górach Świętokrzyskich.
Kwart. Geol., 15 (4): 1046–1047.
KOWALCZEWSKI Z. and WRÓBLEWSKI T. (1974) — Prob lem of ore con tents in sed i ments in the light of di as tro phism and vol ca nism of the Świętokrzyskie Mts (in Pol ish with Eng lish sum mary). Kwart. Geol., 18 (3): 535–563.
KOZŁOWSKI R. (1948) — Les graptolithes et quelques nou veaux Groupes d’animaux du Tremadoc de la Pologne. Palaeont. Pol., 3.
KRAUSKOPF K. B. (1959) — The geo chem is try of sil ica in sed i men tary en vi ron ments. In: Sil ica in Sed i ments (ed. H. A. Ire land). Soc. Econ.
Paleont. Miner., Spec. Publ., 7: 4–19.
LECKIE D. A. and KRYSTINIK L. F. (1989) — Is there ev i dence for geostrophic cur rents pre served in the sed i men tary re cord in in ner to mid dle-shelf de pos its? J. Sed. Petrol., 59: 862–870.
LEWANDOWSKI M. (1987) — Re sults of the pre lim i nary paleomagnetic in ves ti ga tions of some Lower Pa leo zoic rocks from the Holy Cross Mts. (Po land). Kwart. Geol., 31 (4): 543–556.
POŻARYSKI W. (1990) — The Mid dle Eu rope Caledonides — wrench ing orogen com posed of ter ranes (in Pol ish with Eng lish sum mary). Prz.
Geol., 38 (1): 1–9.
SAMSONOWICZ J. (1928) — Sprawozdanie z badań geologicznych, wykonanych w 1927 r. w okolicach Międzygórza na arkuszu Sandomierz mapy 1:100 000. Posiedz. Nauk. Państw. Inst. Geol., 19/20: 25–27.
SAMSONOWICZ J. (1948) — Characteristique geologique du tremedoc de Wysoczki. Palaeont. Pol., 3.
SIEVER R. (1962) — Sil ica sol u bil ity, 0–200°, and the diagenesis of si li - ceous sed i ments. J. Geol., 70: 127–150.
SIMONSON B. M. (1985) — Sedimentology of cherts in the Early Pro - tero zoic Wis hart For ma tion, Que bec — New found land, Can ada.
Sedimentology, 32: 23–40.
SIMPSON E. L. and ERIKSSON K. A. (1990) — Early Cam brian progradational and transgressive sed i men ta tion pat terns in Vir ginia:
an ex am ple of the early his tory of a pas sive mar gin. J. Sed. Petrol., 60:
84–100.
SZANIAWSKI H. (1980) — Cono donts from the Tremadocian chal ce dony beds, Holy Cross Moun tains (Po land). Acta Geol. Pol., 25 (1):
101–121.
TOMCZYK H. (1954) — Stra tig ra phy of the Gothlandian of the Międzygórz ba sin — Święty Krzyż Mts on the ba sis of the fauna from grap to lit ic shales (in Pol ish with Eng lish sum mary). Biul. Inst. Geol., 93.
TOMCZYK H. (1964) — New data on stra tig ra phy and tectogenesis of the Older Pa leo zoic in Po land (in Pol ish with Eng lish sum mary). Prz.
Geol., 12 (6): 262–267.
TOMCZYK H. (1971) — The Arenigian trans gres sion in Po land and its re - la tion to ear lier for ma tions. Mem. Bur. Rech. Geol. Miner., 73:
421–430.
TOMCZYK H. and TURNAU-MORAWSKA M. (1964) — Stra tig ra phy and pe trog ra phy of the Or do vi cian in Brzeziny near Morawica (Holy Cross Mts., Cen tral Po land) (in Pol ish with Eng land sum mary). Acta Geol. Pol., 14 (4): 501–546.
TOMCZYKOWA E. (1968) — Stra tig ra phy of the up per most Cam brian de pos its in the Świętokrzyskie Moun tains (in Pol ish with Eng lish sum mary). Pr. Inst. Geol., 54.
TUCKER M. E. (1995) — Sed i men tary Pe trol ogy. Blackwell Sci en tific Pub li ca tions.
TURNAU-MORAWSKA M. (1958) — Chalcedonites and as so ci ated rocks of the Tremadoc in the Holy Cross Moun tains (Cen tral Po land).
A petrographic study (in Pol ish with Eng lish sum mary). Rocz. Pol.
Tow. Geol., 27 (1–4): 169–191.
TURNAU-MORAWSKA M. (1960) — A glauconitic con glom er ate from the Lower Or do vi cian in Międzygórz, Holy Cross Moun tains, Cen tral Po land. Acta Geol. Pol., 10 (2): 123–145.
WALKER R. G. (ed.) (1984) — Fa cies Mod els. Geoscience Can ada. To - ronto.
ZNOSKO J. and CHLEBOWSKI R. (1976) — Re vi sion of the Lower Or - do vi cian stra tig ra phy in the Holy Cross Mts (Cen tral Po land) (in Pol - ish with Eng lish sum mary). Rocz. Pol. Tow. Geol., 46 (1/2): 135–157.
