Trilobites, their traces and as so ci ated sed i men tary struc tures as in di ca tors of the Cam brian palaeoenvironment of the Ociesêki Range
(Holy Cross Moun tains, Po land)
Micha³ STACHACZ1, *
1 In sti tute of Geo log i cal Sci ences, Jagiellonian Uni ver sity, Oleandry 2a, 30-063 Kraków, Po land
Stachacz M. (2013) Trilobites, their traces and as so ci ated sed i men tary struc tures as in di ca tors of the Cam brian palaeoenvironment of the Ociesêki Range (Holy Cross Moun tains, Po land). Geo log i cal Quar terly, 57 (4): 745–756, doi:
10.7306/gq.1124
En rolled spec i mens of tri lo bite spe cies Strenuella polonica, partly pre served within their es cape struc tures and bur rows from the Cam brian Se ries 2 Ociesêki Sand stone For ma tion, are de scribed. The spec i mens are in ter preted as bur ied dur ing storm ep i sodes. Their oc cur rence in a few ho ri zons, the pres ence of non-bioturbated tempestites with com bined wave-cur rent rip - ples and groovemarks interbedded with bioturbated beds sug gest a depositional en vi ron ment be tween nor mal and storm wave base. The trace fos sils Monomorphichnus and some Rusophycus have been in ter preted as struc tures formed dur ing the storm when an i mal tried to take ref uge. Well-pre served syndepositional Rusophycus and its dif fer ent taphonomic vari - ants are dis cussed. The part of the Ociesêki Sand stone For ma tion stud ied is in ter preted as de pos ited on a lower shoreface with storm in flu ence.
Key words: trilobites, ichnology, sedimentology, Holy Cross Moun tains, Ociesêki For ma tion, Cam brian Se ries 2.
INTRODUCTION
The trilobites of the Ociesêki Sand stone For ma tion have been the sub ject of sev eral stud ies (Czarnocki, 1926, 1927;
Samsonowicz, 1959a, b, c; Or³owski, 1974, 1985a, 1987; ¯y - liñska, 2013a, b). The ar ti cles cited con cen trate on sys tem atic de scrip tions and biostratigraphic data of the trilobites but do not in di cate the pre cise lo ca tion of trilobites within the sec tions.
¯yliñska (2013a, b) pre sented new data and in ter pre ta tion on the evo lu tion of trilobites and biogeographical con nec tions dur - ing Cam brian Se ries 2 and 3. Or³owski (1992b), Or³owski and
¯yliñska (2002) and Stachacz (2012) de scribed the di verse tri lo - bite trace fos sils of this for ma tion.
Trilobites are known as ar thro pods able to ven trally flex and en roll their car a paces. This abil ity was very use ful and ef fec tive as de fence against pred a tors and also stress ful en vi ron ment con di tions. Such be hav ior in trilobites has been doc u mented from the Early Cam brian on wards (Ortega-Hernández et al., 2013 and ref er ences cited there).
Re cently, ¯yliñska and Kin (see ¯yliñska, 2013b) de scribed a de fense strat egy of the tri lo bite Strenuella polonica Czarnocki, 1926 from the Ociesêki Sand stone For ma tion, in which in di vid u - als en roll when at tacked by a pred a tor. Strenuella polonica has
been in tro duced twice by Czarnocki (1926, 1927: p. 190) with out any fig ures or sys tem atic de scrip tion, and it is clearly a nomen nudum (see ¯yliñska, 2013b for de tails). This spe cies was cor - rectly de scribed for the first time by Samso nowicz (1959c). How - ever, ¯yliñska (2013b) as cribed this spe cies to Czarnocki’s pub - li ca tion of 1926, and this as sig na tion is ac cepted herein.
The depositional struc tures of the Ociesêki Sand stone For - ma tion have never been de scribed in de tail. Based on li thol ogy and some sed i men tary struc tures ob served in cores Studencki (1988) as cribed sand stones of the Ociesêki For ma tion to a tran - si tional zone be tween lit to ral sands and shelf muds. Ac cord ing to him, sand stones with silty in ter ca la tions were de pos ited in shal low ma rine en vi ron ments dis tant from the coast line. Ac cord - ing to Or³owski (1989), the rocks of the lower part of the Ociesêki Sand stone For ma tion orig i nated from near to wave base, how - ever, his in ter pre ta tion was based only on trace fos sil as sem - blages.
This study pro vides an in ter pre ta tion of the pres er va tion of com plete and en rolled spec i mens of Strenuella polonica from the Ociesêki Range, their es cape struc tures and pos si bly bioturbational struc tures. Droser and Bottjer’s (1986) di a gram was used for ichnofabric anal y sis. The six cat e go ries of the di a - gram are equiv a lents of the fol low ing per cent age of de posit dis - tur bance: (1) non-bioturbated, all pri mary sed i men tary struc - tures pre served; (2) iso lated trace fos sils, up to 10% of orig i nal bed ding dis turbed; (3) bur rows are mostly iso lated, but lo cally over lap, 10–40% of orig i nal bed ding dis turbed; (4) bur rows over - lap, only rel ics of bed ding are vis i ble, 40–60% dis turbed; (5) bed ding is com pletely dis turbed, but fab ric is not mixed; (6) bed - ding is to tally or al most to tally ho mog e nized. How ever, it must be em pha sized that Droser and Bottjer (1986) used a 10 cm scale
* E-mail: michal.stachacz@uj.edu.pl
Received: April 16, 2013; accepted: October 3, 2013; first published online: October 23, 2013
in their di a gram and, con se quently, me dium or thick beds in ter - preted as mod er ately-bioturbated can be com posed of a se ries of bioturbated and non-bioturbated lay ers.
The pres ent pa per fo cuses on event-beds show ing pri mary depositional struc tures, mostly cur rent-wave rip ples and groove marks. The pa per crit i cally eval u ates the taphonomy of some trilobites, their trace fos sils and their tax o nom i cal and palaeo - eco logi cal sig nif i cance.
GENERAL GEOLOGICAL SETTING
The Holy Cross Moun tains are tra di tion ally sub di vided into the £ysogóry and Kielce re gions. The north ern £ysogóry Re gion lies within the £ysogóry Block, whereas the south ern Kielce Re - gion forms the north ern part of the larger Ma³opolska Block (e.g., Bu³a, 2000; Cocks and Torsvik, 2005). Both tec tonic units may have been sit u ated near to the Baltica palaeocontinent (Cocks and Torsvik, 2005; Malinowski et al., 2005; Nawrocki and Poprawa, 2006). Ac cord ing to these au thors, the Ma³opolska Block was a prox i mal terrane al though oth ers have sug gested an ex otic or i gin of the unit (e.g., Belka et al., 2000).
The Cam brian sys tem in the Holy Cross Moun tains com - prises a suc ces sion of siliciclastic de pos its with a to tal thick ness of at least 2500 m (e.g., Or³owski, 1975, 1988, 1992a, 1997;
Kowalczewski et al., 2006). The Ociesêki Sand stone For ma tion con tains mostly fine-grained sand stones with thin in ter ca la tions of siltstones (Or³owski, 1975; Kowalczewski et al., 2006). Sed i - men tary struc tures and di verse trace fos sils as sem blage in di - cate de po si tion in a shal low ma rine en vi ron ment (Studencki, 1988; Or³owski, 1989, 1992a; Mizerski et al., 1999; Or³owski and
¯yliñska, 2002). The study area is sit u ated in the cen tral part of the Kielce Re gion, where the Ociesêki Sand stone For ma tion oc - curs over an ex tended area (e.g., Or³owski, 1975; Mizerski et al., 1991; Fig. 1A).
The en tire sec tion of the Ociesêki Sand stone For ma tion shows nu mer ous and di verse trace fos sils, with sev eral ichnotaxa of tri lo bite traces (Or³owski, 1989, 1992b; Or³owski and ¯yliñska, 2002; Stachacz, 2012). The sec tions de scribed here are typ i cal of the lower part of the Ociesêki Sand stone For - ma tion. This part of the for ma tion con tains the fol low ing
trilobites: Holmia marginata Or³owski, 1974, H. glabra Or³owski, 1974, Kjerulfia orcina Or³owski, 1974, K. orienta Or³owski, 1974, Schmidtiellus panovi (Samsonowicz, 1959), Sch. nodosus Or³owski, 1985; Strenuella polonica Czarnocki, 1926, S.
sandomirensis Or³owski, 1985 and S. zbelutkae Or³owski, 1985, which clearly sug gest a biostratigraphic level in the Schmidtiellus–Holmia Superzone of the Cam brian Se ries 2 (e.g., Or³owski, 1974, 1985a; ¯yliñska, 2013b). Berabichia ora - trix (Or³owski, 1985); Strenuella polonica Czarnocki, 1926;
Holmia marginata Or³owski, 1974; Kjerulfia orcina Or³owski, 1974; Schmidtiellus nodosus Or³owski, 1985; Acanthomic - macca klimontowi Or³owski, 1985; Postfallotaspis spinatus Or³owski, 1985 and Atops granulatus Or³owski, 1985 have been de scribed from the Ociesêki Range ex po sures at Sterczyna, JaŸwina and the Igrzyczna hills and have con firmed the Schmidtiellus–Holmia Superzone (¯yliñska, 2013b).
The up per part of the Ociesêki Sand stone For ma tion (not stud ied here) yields the trilobites Kingaspidoides santacrucen sis (Samsonowicz, 1959) and Issafeniella orlowinensis (Samsonowicz, 1959) which in di cate the Protolenus–Issafe - niella Zone of the Cam brian Se ries 2 (Or³owski, 1985a; Mizerski et al., 1986; ¯yliñska and Szczepanik, 2009; ¯yliñska, 2013a).
The pres ence of the trilobites Ornamentapsis guerichi (Or³owski, 1959), O. opatowi (Or³owski, 1985), O. puschi (Or³owski, 1985) and Orodes usarzowi (Or³owski, 1985) in the up per most part of the Ociesêki Sand stone For ma tion sug gests a biostratigraphic level near the base of Se ries 3, as signed to the Paradoxides insularis Zone (Or³owski, 1985b; Mizerski et al., 1986; ¯yliñska and Szczepanik, 2009; ¯yliñska, 2013a).
DESCRIPTION OF LOCALITY
The rocks stud ied crop out in a few small ex po sures along the Ociesêki Range, on the Sterczyna, JaŸwina and Igrzyczna hills (Fig. 1B). The first ex po sure is a small quarry near the peak of Sterczyna Hill (Sterczyna Quarry on Fig. 1B, GPS co or di - nates: N 50°43’45.2’’; E 20°58’15.5’’), the sec ond is in a small pit on the east ern slope of the Sterczyna Hill (Sterczyna East on Fig. 1B, GPS co or di nates: N 50°43’24.7’’; E 020°58’44.2’’), the third com prises nat u ral ex po sures by the Grodno Stream
Fig. 1A – lo cal ity and sim pli fied geo log i cal map of the Pa leo zoic core of the Holy Cross Moun tains (ge ol ogy ac cord ing to Or³owski, 1975 and Mizerski et al., 1991); B – top o graphic map of the Ociesêki area show ing lo ca tions of the ex po sures
(JaŸwina on Fig. 1B, GPS co or di nates: N 50°44’4.7’’; E 20°57’08.8’’). The fourth and the fifth ex po sures lie on the slope of Igrzyczna Hill (Igrzyczna North and South on Fig. 1B). All of the ex po sures rep re sent the lower part of the Ociesêki Sand - stone For ma tion (e.g., Mizerski et al., 1986), which con sists mainly of fine-grained, thin- to me dium-bed ded greywackes and quartz arenites. How ever, a mo not o nous se ries of al most bur - row-churned quartz arenite or greywacke with out skel e tal fos sils pre dom i nate. The trilobites, in clud ing com pletely pre served and en rolled spec i mens, were col lected ex clu sively in the Sterczyna Quarry and at the Igrzyczna North ex po sure. The Sterczyna Quarry ex poses a four-metre-thick sec tion of yel low ish gray quartz arenite with a few greywacke beds (Fig. 2A) and the small pit at Sterczyna East ex poses a 1.6-m-thick sec tion of quartz arenites in ter ca lated with wackes and rare beds of siltstone (Fig. 2B). JaŸwina Hill ex poses 3 m of thick, thin- to me - dium-bed ded arenites and wackes (Fig 2C), The Igrzyczna North ex po sure shows 1.3 metres of quartz arenites and wackes, and con tains at least one bed with com pletely pre - served and en rolled trilobites (Fig. 2D) while Igrzyczna South ex - poses 3 m of sim i lar rocks with out skel e tal fos sils. The greywackes and arenites of all the sec tions stud ied are pre dom i - nantly com posed of poorly abraded quartz grains and un com - mon mica flakes.
OCCURRENCE OF THE ENROLLED TRILOBITES AND ASSOCIATED TRACE FOSSILS IN THE
STERCZYNA AND IGRZYCZNA SECTIONS
The quarry on Sterczyna Hill (Fig. 1B) is known in the lit er a - ture be cause it con tains well-pre served tri lo bite re mains (e.g., Or³owski, 1987; ¯yliñska, 2013a, b). By con trast, the Sterczyna East pit does not yield tri lo bite skel e tal fos sils, al though tri lo bite trace fos sils are com mon (Stachacz, 2012). Tri lo bite re mains in the Sterczyna Quarry are gen er ally com mon, but com pletely pre served spec i mens oc cur only in a few beds (Fig. 2A) and at least in one bed at Igrzyczna North (Fig 2C). At least twenty-two spec i mens of com plete trilobites have been found by the pres ent au thor. Only two straight spec i mens from the Sterczyna Quarry and one from the neigh bor ing lo cal ity, Igrzyczna North, in di cate that most of the com plete trilobites are pre served as en rolled spec i mens (Fig. 3). The most fre quent of the com pletely pre - served trilobites ana lysed is Strenuella polonica. How ever, the weakly pre served, de formed spec i mens do not per mit de ter mi - na tion. Such en rolled spec i mens were men tioned by Samsonowicz (1959c), ¯yliñska and Kin (see: ¯yliñska, 2013b) and ¯yliñska (2013b), and usu ally oc cur in nest-like ac cu mu la - tions in thin to me dium beds of quartz arenite beds (Fig. 3B–D).
Beds with en rolled trilobites usu ally show less bioturbation.
Some of the trilobites are found at the ter mi na tions of es cape struc tures (fugichnia; Fig. 4A) or bur rows (repichnia; Fig. 4B–D).
The tri lo bite es cape struc ture il lus trated (Fig. 4A) shows a zig-zag shaped, strat i fied back fill within the bioturbated and non-bioturbated lay ers of amal gam ated beds. In fill ing is com - posed of a set of downwardly curved spreite vis i ble in ver ti cal sec tion. The lower part of the struc ture is more than 2 cm wide and shows subparallel spreite, which are dis tinctly steeper in the up per part.The exoskeleton of the en rolled tri lo bite is lo cated not ex actly in the ter mi na tion of fugichnion but slightly higher. The length of the tri lo bite can be es ti mated as sim i lar to the width of fugichnion in its lower part. In cross-sec tion the bur rows with en - rolled trilobites show a typ i cal back fill com posed of curved, U-shaped laminae with their con cave sides to wards the tri lo bite;
how ever, laminae are in dis tinct near the trilobites. The
meniscate bur rows with trilobites (Fig. 4B–D) are rep re sented by at least three traces infilled by sed i ment re worked in dif fer ent di - rec tions. These struc tures were formed by at least three bur row - ing trilobites pre served in the same bed. The bur rows are oblique to bed ding planes. Both es cape struc tures and bur rows with en rolled trilobites are vis i ble only in a few sec tions and more pre cise iden ti fi ca tion is im pos si ble.
SEDIMENTARY STRUCTURES AND ASSOCIATED TRACES OF DRAGGED TRILOBITES
ON THE SEA FLOOR
Thin amal gam ated beds (2–10 cm thick) of arenite pre dom i - nate in the Sterczyna Quarry, whilst both arenite and wacke beds pre dom i nate in ex po sures on the Igrzyczna slopes. Thin- to thick beds (5–50 cm thick) of arenites and wackes are typ i cal of JaŸwina. Thin- to me dium beds (5–12 cm thick) of arenites sep a rated by wackes oc cur at Sterczyna East. The greywacke and most of the arenite beds are com pletely or al most com - pletely bioturbated (Fig. 2), and their orig i nal sedimentological struc tures are usu ally not pre served. In ad di tion, amal gam ated beds com posed of thin lay ers with var i ous de grees of bioturbation are quite com mon in the all the sec tions stud ied (Fig. 2). Com pletely bioturbated arenites with out orig i nal sed i - men tary struc tures pre dom i nate in the Sterczyna Quarry, whilst bioturbated wackes in ter ca lated with non-bioturbated arenites with rip ple-cross lam i na tion are typ i cal of the pit on the east ern slope of the Sterczyna Hill, JaŸwina and Igrzyczna (Fig. 2). Most beds are amal gam ated, com posed of lay ers in which the bioturbation de gree var ies (Figs. 4–7). Iso lated beds of quartz arenite are not bioturbated and show orig i nal sed i men tary struc - tures, mostly rip ple-cross lam i na tion (Figs. 2, 5 and 6A, B) and rel ics of hor i zon tal lam i na tion (Fig. 6C). Very few iso lated non-bioturbated beds also show long straight and sym met ri cal or al most sym met ri cal usu ally rounded wave rip ples on their sur - faces with x-shaped lam i na tion (Fig. 5; cf. Raaf et al., 1977), and there are some climb ing rip ples (Fig. 5A; cf. Jopling and Walker, 1968; Allen, 1970). Some of rip pled beds, es pe cially from Sterczyna East, show casts of groove marks and trace fos sils in - clud ing Rusophycus isp. and Monomorphichnus lineatus Crimes, Legg, Marcos and Arboleya, 1977 and
?Monomorphichnus isp. on their soles (Fig. 7B, C). One of the rip pled beds of arenite con tains a de formed cubichnion of Rusophycus isp. in the ter mi na tion of a tri lo bite trace be tween repichnion and groovemark (Fig. 7A, ar rowed). This trace does not show fea tures typ i cal of Cruziana, but only casts of scratchmarks from the car a pace and pos si bly legs. The trace is curved, slightly in clined to other groovemarks, su per fi cially im - printed and its depth in creases to ward the Rusophycus, whilst the Rusophycus is rel a tively deeply im printed. Other spec i mens of deeply im printed Rusophycus from Sterczyna East and the Igrzyczna hills are de scribed as R. carbonarius Dawson, 1864, R. dispar Linnarsson, 1869 and R. crebrus (Or³owski, 1992b;
Stachacz, 2012). Spec i mens of R. crebrus (Or³owski, 1992b: fig.
11, 12.5–6; Stachacz, 2012: fig. 3A) are char ac ter ized by del i - cate groovemark-like ridges on the lobes and oc cur on the sole of beds with dis tinct groovemarks. The spec i mens of Monomorphichnus lineatus and ?Monomorphichnus isp. are con vex semireliefs com posed of sets of slightly curved, al most mu tu ally par al lel, thin ridges and fur rows. The set is wider in one ter mi na tion and in the other it pen e trates the bed. How ever,
?Monomorphichnus isp. is very sim i lar to the casts of groovemarks of tools or dead ar thro pods, and closer de ter mi na - tion is im pos si ble.
Fig. 2. Lithological col umns for the se lected sec tions
A – Sterczyna Quarry, B – Sterczyna East, C – Igrzyczna North, D – JaŸwina;
ichnofabric in dex de ter mined the method of Droser and Bottjer (1986)
DISCUSSION
Body fos sils are not usu ally found with their cor re spond ing trace fos sils (Fuchs, 1895). How ever, some ex cep tions are known. Well-pre served trilobites, bur ied in life po si tion in heterolithic muddy-silty-sandy rocks in South China were noted by Degan et al. (1995). Com pletely pre served and en rolled trilobites were re corded from the Cam brian of Green land (Geyer and Peel, 2011) and Can ada (Ortega-Hernández et al., 2013).
Other oc cur rences of trilobites pre served in situ with their bur - rows, such as Thalassinoides nets with Asaphus raniceps, are known from car bon ate fa cies of the Swed ish Or do vi cian (Cherns et al., 2006). En rolled trilobites have been re corded from early Mid dle Cam brian strata in the Lemdad Syncline, High At las Moun tains by Geyer et al., (1995) and Geyer and Land ing (2006).
Mu tual ex clu sion of skel e tal and the trace fos sils is clearly vis i ble in the Sterczyna East pit, where the tri lo bite body fos sils do not oc cur, while well-pre served Rusophycus fos sils are abun - dant (Stachacz, 2012). How ever, in the case of the Sterczyna Quarry, rare re mains of trilobites oc cur partly to gether with trace fos sils ob vi ously pro duced by trilobites.
The beds with com pletely pre served and en rolled trilobites and iso lated, usu ally non-bioturbated beds with com bined cur - rent-wave rip ples, groovemarks, tri lo bite scratchmarks and some Rusophycus are in ter preted here as tempestites. The ar - range ment of the en rolled trilobites and their oc cur rence in nest-like ac cu mu la tions in beds de pos ited dur ing storms sug - gests that the trilobites were cov ered by sed i ment alive. Af ter burial and death, the body would have re laxed and re turned to the out stretched po si tion. There fore, the pres er va tion of en rolled trilobites re quires rapid burial of in di vid u als dur ing the life (Ortega-Hernández et al., 2013 and ref er ences cited there).
Some of the in di vid u als at tempted to es cape to the sur face but died within the sed i ment. It is as sumed that death was caused by suf fo ca tion. Some in di vid u als formed dis tinct es cape traces di - rected more or less di rectly to wards the sed i ment sur face. A spreite-like ecsape struc ture (Fig. 8) was prob a bly formed by a wrig gling tri lo bite mov ing up wards. The en rolled tri lo bite at this es cape struc ture is not lo cated ex actly in the ter mi na tion of fugichnion but has been moved, prob a bly by taphonomic pro - cesses. Nev er the less, the oc cur rence of com pletely pre served and en rolled trilobites in strongly bioturbated sed i ment points to rapid de po si tion and burial dur ing their life time. Sim i larly well-pre served Cam brian trilobites in life po si tion have been in - Fig. 3. Strenuella polonica Czarnocki, 1926 from the Sterczyna sec tion
A – a sin gle en rolled spec i men, INGUJ214P/T31; B–D – a pair en rolled spec i mens oc cur ring in thin beds of mod er ately bioturbated sand stone: B – INGUJ214P/T13, C – non cat a logued,
D – INGUJ214P/T17
ter preted as rap idly bur ied within mud rocks interbedded with hummocky cross-strat i fied sand stones (Degan et. al., 1995).
Apart from non-bioturbated beds with out tri lo bite re mains, some beds in clude com bined cur rent-wave rip ples, which ad di - tion ally sug gests rapid burial of ben thic an i mals by sandy ma te - rial (e.g., Figs. 5–8). Climb ing rip ples (Fig. 5A) sug gest rapid de - po si tion of ma te rial by trac tion and sus pen sion (Jopling and Walker, 1968; Allen, 1970). Such con di tions were pos si ble dur - ing storm con di tions, when ma te rial was sup plied from shal lower en vi ron ments (cf. Mo naco, 1996).
The pres ence of casts of dragmarks and wave-rip ple cross-lam i na tion com bined with an ab sence of graded bed ding
is typ i cal of tempestites (e.g., Einsele and Seilacher, 1991; Mo - naco, 1996).
These struc tures sug gest in ter pre ta tion at least in part as storm de pos its. Ad di tion ally, the pres ence of tri lo bite scratch - marks such as Monomorphichnus in rip pled arenites in di cates that some trilobites were moved by the cur rents dur ing high en - ergy ep i sodes and that they tried to catch hold of the bot tom.
One spec i men of Rusophycus in the ter mi na tion of its dragmark (Fig. 6A) is in ter preted as the trace of a tri lo bite which was moved by a cur rent and took ref uge in a silty de posit on the bot - tom. Pos si bly some of the well-pre served Rusophycus de - scribed by Stachacz (2012; Figs. 2A–D, 3A, B and 4) from the Fig. 4. Ver ti cal sec tion of a thin sand stone bed with tri lo bite re mains and bur rows
A – spec i men of Strenuella polonica (et) with its es cape struc ture; B–D – views of the same sand stone bed with sev eral spec i mens of S. polonica and their bur rows; symbols: n-b – non-bioturbated rock, b – bioturbated, T – Trichophycus isp., et – en rolled trilobites, esc – es cape struc tures, bu – bur rows with sed i ment re worked in dif fer ent di rec tions; in dis tinct spreite-like struc tures con toured (dot ted lines)
Fig. 5A – climb ing rip ples and ripple-cross lam i na tion, Sterczyna Quarry;
B – wave rip ples and rip ple-cross lam i na tion, Sterczyna East
1 cm 1 cm
A
B
Fig. 6A – frag ment of amal gam ated bed: bioturbated wacke in the up per part and rip ple cross-lam i nated sand stone in the lower part, JaŸwina; B – amal gam ated bed com posed of bioturbated wacke in the lower part and rip - ple-cross lam i nated sand stone in the up per part, Igrzyczna North; C – amal gam ated bed com posed of hor i zon tal lay ers of non-bioturbated quartz arenite and bioturbated wacke, JaŸwina
Ociesêki Sand stone For ma tion were formed in this mode dur ing the storm. Es pe cially R. crebrus (Or³owski, 1992b), the di ag nos - tic fea tures of which are lobes cov ered by del i cate sets of ridges which rep re sent the trace of a tri lo bite which took ref uge and was dragged for a short dis tance within silty de pos its. The sets of ridges rep re sent casts of groovemarks of tri lo bite exopodites trans ported by rap idly flow ing wa ter. In such case R. crebrus should be in cluded in R. polonicus Or³owski, Radwañski and Roniewicz, 1970 as a taphonomic vari ant of pres er va tion.
The amal gam ated beds com posed of thin lay ers of non-bio - turbated arenites and bioturbated wackes (Figs. 4 and 6) rep re - sent rel ics of very thin dis tal tempestites or tempestites slightly mod i fied by shal low bioturbation (cf. Droser and Bottjer, 1988;
Droser et al., 1999).
Very shal low bur row ing of the sed i ments dur ing the Cam - brian (see Droser, 1991; Droser et al., 1994) sug gests that the tempestites were only slightly thicker than the pre served storm-lay ers and usu ally less than 5 cm thick. Only Teichichnus or Trichophycus pro duc ers pen e trated the com plete tempe stite.
Hor i zon tal domichnia such as Monocraterion are rel a tively rare in this en vi ron ment. The pres er va tion of very thin tempe stites was con trolled by fre quent storms which de ter mined whether the de posit feed ers were able to sur vive or were bur ied (cf. Pem ber - ton et al., 2001).
Such shal low trace fos sils in tempestites are typ i cal of the Early Pa leo zoic. Dur ing this time, in en vi ron ments deeper than the Skolithos ichnofacies, the only sed i ment-reworkers were worm-like or gan isms (Sepkoski, 1978, 1979; Droser, 1991;
Fig. 7A – casts of dragmarks and de formed Rusophycus (R) in the ter mi na tion of a curved tri lo bite repichnion (ar rowed) dis cor dant to the toolmarks, on the sole of a rip pled arenite bed, Sterczyna East, INGUJ214PMr29; B – casts of scratchmarks Monomorphichnus lineatus Crimes, Legg, Marcos and Arboleya, 1977, hypichnion on the sole of a thin rip pled bed of arenite, Sterczyna East, INGUJ214PMr47; C – ?Monomorphichnus isp., hypichnia on the sole of a thin rip pled bed of arenite, Igrzyczna South, INGUJ214P/IgS9
Droser et al., 1994), prob a bly mostly priapuloids (Vannier et al., 2010). Deeper-reach ing bur row ing only took place in mid dle shoreface and shal lower en vi ron ments dur ing the Early Pa leo - zoic (Droser, 1991; Droser et al., 1994). Recolonization of the seafloor was pos si ble af ter a storm dur ing phases with low wa ter en ergy. Be tween storm ep i sodes, a low sed i ment ac cu mu la tion rate al lowed re work ing, which usu ally led to ho mog e ni za tion by in tense bur row ing. There fore, storms were a strongly re stric tive fac tor that con trolled the pres ence or ab sence of ben thic life and bioturbation on the shoreface (e.g., Reinson, 1984; Pem ber ton et al., 2001).
The dom i nant strongly bioturbated sandy and silty ma te rial (wacke and quartz arenite with silty in ter ca la tions) and dis tinct tempestites iso lated by more silty in ter ca la tions in di cate a depositional en vi ron ment be tween the nor mal and storm wave
bases (e.g., Reinson, 1984; Pem ber ton et al., 2001). Trace fos - sil as sem blages typ i cal of a prox i mal Cruziana ichnofacies (sensu Pem ber ton et al., 2001) also sug gest an en vi ron ment in - flu enced by wave ac tion (Pem ber ton et al., 2001).
The ichnological and sedimentological fea tures, in clud ing dom i nance by sand stones with wave rip ples and bur rowed silty sand stones of this part of the Ociesêki Sand stone For ma tion, strongly sug gest that this part has been de pos ited on a lower shoreface which cor re sponds to prox i mal Cruziana ichnofacies.
The depth of de po si tion sug gests an in ter val be tween nor mal and storm wave base (Pem ber ton et al., 2001 and ref er ences cited therein). How ever, the to tal thick ness of the Ociesêki Sand stone For ma tion ex ceeds 2500 m and its up per part was pos si bly de pos ited in a dif fer ent en vi ron ment.
Fig. 8. Tempestite beds from the Ociesêki Range
A – sche matic sec tion with iso lated, non-bioturbated tempestite bed with rip ple cross-lam i na tion and rip - ples within bioturbated greywacke beds; B – vari able pres er va tion of rel ict tempestites in clud ing a bed with en rolled trilobites and their es cape struc tures and bur rows; C–E – re con struc tion of the for ma tion of a tri lo bite es cape struc ture; 1–4: stages of es cape of the trilobites to wards the sur face of the sed i ment;
other ex pla na tions as in Fig ure 2
CONCLUSIONS
The Ociesêki Sand stone For ma tion of the Sterczyna sec tion is dom i nated by bioturbated quartz arenites and wackes in which, in some beds, en rolled trilobites oc cur.
Some en rolled trilobites are vis i ble at the ends of their es - cape struc tures or bur rows. These are in ter preted as tempestites and sug gest that the trilobites were bur ied by sed i - ment which re sulted in tri lo bite death prob a bly by suf fo ca tion.
The iso lated non-bioturbated beds of quartz arenites, usu ally con tain com bined cur rent-wave rip ples, casts of dragmarks and syndepositional trace fos sils.
The pres ence of rip ple cross-lam i na tion and wave-rip ples in iso lated beds is typ i cal of tempestites. Dom i na tion of bioturbated sandy to silty ma te rial and the scat tered dis tri bu tion of tempestites points to de po si tion be tween nor mal and storm wave bases.
Some of the Monomorphichnus and Rusophycus were formed dur ing storms, when an i mals tried to catch the hold of the bot tom.
Sedimentological and ichnological fea tures of the lower part of the Ociesêki Sand stone For ma tion sug gest that this part was de pos ited on a lower shoreface.
Ac knowl edg ments. I would like to thank to G. Geyer (Bayerische Jul ius-Ma ximilians-Universität Würzburg), R. Gozalo (Uni ver sity of ValÀncia, Burjassot) and A. ¯yliñska (War saw Uni ver sity, War saw) for their crit i cal com ments. How - ever, the au thor is fully re spon si ble for the con tent. I am grate ful to B. Ko³odziej (Jagiellonian Uni ver sity, Kraków) for his help dur - ing the lat est field work. I thank A. Uchman (Jagiellonian Uni ver - sity, Kraków) for dis cus sion of trace fos sils. I thank A. Wieczorek (Jagiellonian Uni ver sity, Kraków) for the lin guis tic help. I would also like to thank J. Zalasiewicz (Great Brit ain) for fi nal cor rec - tion. This study was sup ported by the Pol ish Min is try of Sci ence and Higher Ed u ca tion (grant no. NN 307 102935).
REFERENCES
Allen J.R.L. (1970) A quantitive model of climb ing rip ples and their cross-lam i nated de pos its. Sedimentology, 14: 5–26.
Belka Z., Ahrendt H., Franke W., Wemmer K. (2000) The Baltica–Gond wana su ture in cen tral Eu rope: ev i dence from K-Ar ages of de tri tal mus co vites and biogeographical data. Geo log i cal So ci ety Spe cial Pub li ca tions, 179: 87–102.
Bu³a Z. (2000) The Lower Palaeozoic of Up per Silesia and West Ma³opolska (in Pol ish with Eng lish ab stract). Prace Pañstwowego Instytutu Geologicznego, 171: 1–63.
Cherns L, Wheeley J.R., Karis L. (2006) Tun nel ing trilobites: Ha bit - ual infaunalism in an Or do vi cian car bon ate seafloor. Ge ol ogy, 34: 657–660.
Cocks L.R.M., Torsvik T.H. (2005) Baltica from late Pre cam brian to mid-Palaeozoic times: The gain and loss of terrane’s iden tity.
Earth-Sci ence Re views, 72: 39–66.
Crimes T.P., Legg I., Marcos A., Arboleya M. (1977) ?Late Pre cam - brian-Lower Cam brian trace fos sils from Spain. Geo log i cal Jour - nal, Spe cial Is sue, 9: 91–138.
Czarnocki J. (1926) Stratygrafia i fauna kambru w czêœci œrodkowej Gór Œwiêtokrzyskich. Posiedzenia Naukowe Pañstwowego Instytutu Geologicznego, 14: 7–9.
Czarnocki J. (1927) Kambr i jego fauna w œrodkowej czêœci Gór Œwiêtokrzyskich. Sprawozdania Pañstwowego Instytutu Geologicznego, 4: 189–207.
Dawson J.W. (1864) On the fos sils of the ge nus Rusophycus. Ca na - dian Nat u ral ist and Ge ol o gist, new se ries, 1: 363–367.
Degan S., Geyer G., Ling C., Xinglang Z. (1995) Redlichiacean trilobites with pre served soft-parts from the Lower Cam brian Chengjiang fauna (South China). Beringeria, Spe cial Is sue, 2:
203–241.
Droser M.L. (1991) Ichnofabric of the Palaeozoic Skolithos ichnofacies and the na ture and dis tri bu tion of piperock. Palaios, 6: 316–325.
Droser M.L., Bottjer D.J. (1986) A semiquantitative field clas si fi ca - tion of ichnofabric. Jour nal of Sed i men tary Pe trol ogy, 56:
558–559.
Droser M.L., Bottjer D.J. (1988) Trends in ex tent and depth of Early Pa leo zoic bioturbation in the Great Ba sin (Cal i for nia, Ne vada, and Utah). In: This Ex tended Land, Geo log i cal Jour neys in the South ern Ba sin and Range (eds. D.L. Weide and M.L. Faber).
Geo log i cal So ci ety of Amer ica, Cordilieran Sec tion, Field Trip Guide book: 330.
Droser M.L., Hughes N.C., Jell P.A. (1994) Infaunal com mu ni ties and tier ing in Early Palaeozoic nearshore clastic en vi ron ments:
trace-fos sil ev i dence from the Cambro-Or do vi cian of New South Wales. Lethaia, 27: 273–283.
Droser M.L., Gehling G.J., Jensen S. (1999) When the worm turned: Con cor dance of Early Cam brian ichnofabric and trace fos sil re cord in siliciclastic rocks of South Aus tra lia. Ge ol ogy, 27:
625–628.
Einsele G., Seilacher A. (1991). Dis tinc tion of tempestites and turbidites. In: Einsele G., Ricken In., Seilacher A. (eds.), Cy cles and Events in Stra tig ra phy: 377–382. Springer Verlag. Berlin, Hei del berg, New York.
Geyer G., Land ing E. (2006) Ediacaran–Cam brian depositional en - vi ron ments and stra tig ra phy of the west ern At las re gions. In: Mo - rocco 2006 Ediacaran–Cam brian depositional en vi ron ments and stra tig ra phy of the west ern At las re gions (eds. G. Geyer and E.
Land ing). UCL Maghreb Pe tro leum Re search Group, Infracambrian/Early Palaeozoic Field guide Se ries 1 and Beringeria Spe cial Is sue, 6: 47–112.
Geyer G., Peel J.S. (2011) The Henson Gletscher For ma tion, North Green land, and its bear ing on the global Cam brian Se ries 2–Se - ries 3 bound ary. Bul le tin of Geosciences, 86: 465–534.
Geyer G., Land ing E., Heldmaier W. (1995) Fau nas and depositional en vi ron ments of the Cam brian of the Mo roc can At - las re gions. Beringeria, Spe cial Is sue, 2: 7–46.
Fuchs T. (1895) Studien über Fucoidenund Hieroglyphen. Akademie der Wissenschaften zu Wien, Denkschriften der mathematisch-naturwissenschaftlichen Klasse, 62: 369.
Jopling A., Walker R.G. (1968) Mor phol ogy and or i gin of rip ple-drift cross-lam i na tion, with ex am ples from the Pleis to cene of Mas sa - chu setts. Jour nal of Sed i men tary Pe trol ogy, 38: 971–984.
Kowalczewski Z., ¯yliñska A., Szczepanik Z. (2006) Kambr w Górach Œwiêtokrzyskich. In: Procesy i zdarzenia w historii geologicznej Gór Œwiêtokrzyskich (eds. S. Skompski and A.
¯yliñska), Materia³y 77 Zjazdu Naukowego Polskiego Towarzystwa Geologicznego w Ameliówce k. Kielc, 28–30 czerwca 2006: 14–27. Pañstwowy Instytut Geologiczny, Warszawa.
Malinowski M., ¯elaŸniewicz A., Grad M., Guterch A., Janik T.
(2005) Seis mic and geo log i cal struc ture of the crust in the tran si - tion from Baltica to Palaeozoic Eu rope in SE Po land – CELEBRATION 2000 ex per i ment, pro file CEL02.
Tectonophysics, 401: 55–77.
Mizerski W., Or³owski S., Ró¿ycki A. (1986) Tec tonic of the Pasmo Ociesêckie and Pasmo Zamczyska Ranges in the Góry Œwiêtokrzyskie Mts (in Pol ish with Eng lish sum mary). Kwartalnik Geologiczny, 30 (2): 187–200.
Mizerski W., Or³owski S., Waksmundzki B. (1991) New data on ge - ol ogy of the Kamieniec Shale For ma tion (Lower Cam brian, Holy Cross Mts). Geo log i cal Quar terly, 35 (2): 149–162.
Mizerski W., Or³owski S., Przybycin A., Skurek-Skurczyñska K.
(1999) Large-scale ero sional chan nels in the Lower Cam brian sand stones, Gieraszowice en vi ron ments (Kielce Block, Holy Cross Mts.). Geo log i cal Quar terly, 43 (3): 353–364.
Mo naco P. (1996) Ichnofabric as a tool to iden tify turbiditic or tempestitic sub strates: two ex am ples from Early Ju ras sic and Mid dle Eocene in the Cen tral Apennines (It aly). Comunicación de la II Reunión de Tafonomia y Fosilización, 1996: 247–254.
Nawrocki J., Poprawa P. (2006) De vel op ment of Trans-Eu ro pean Su ture Zone in Po land: from Ediacaran rift ing to Early Palaeozoic ac cre tion. Geo log i cal Quar terly, 50 (1): 59–76.
Or³owski S. (1959) Paradoxidae from lower Mid dle Cam brian strata in the vi cin ity of Sandomierz (cen tral Po land). Bul le tin de l’Academie Po lo naise des Sci ences, Série des sci ences chimiques, géologiques et géographiques, 7: 441–446.
Or³owski S. (1974) Lower Cam brian biostratigraphy in the Holy Cross Mts., based on the tri lo bite fam ily Olenellidae. Acta Geologica Polonica, 24: 1–16.
Or³owski S. (1975) Cam brian and up per Pre cam brian lithostratigraphic units in the Holy Cross Mts. (in Pol ish with Eng - lish sum mary). Acta Geologica Polonica, 25: 431–448.
Or³owski S. (1985a) Lower Cam brian and its trilobites in the Holy Cross Mts. Acta Geologica Polonica, 35: 231–250.
Or³owski S. (1985b) New data on the Mid dle Cam brian trilobites and stra tig ra phy in the Holy Cross Mts. Acta Geologica Polonica, 35:
251–263.
Or³owski S. (1987) Stra tig ra phy of the Lower Cam brian in the Holy Cross Moun tains, Cen tral Po land. Bul le tin of the Pol ish Acad emy of Sci ences, 35: 91–96.
Or³owski S. (1988) Stra tig ra phy of the Cam brian Sys tem in the Holy Cross Mts. Kwartalnik Geologiczny, 32 (3/4): 525–532.
Or³owski S. (1989) Trace fos sils in the Lower Cam brian se quence in the Œwiêtokrzyskie Moun tains, Cen tral Po land. Acta Palaeontologica Polonica, 34: 211–231.
Or³owski S. (1992a) Cam brian stra tig ra phy and stage sub di vi sion in the Holy Cross Moun tains, Po land. Geo log i cal Mag a zine, 129:
471–474.
Or³owski S. (1992b) Tri lo bite trace fos sils and their strati graphi cal sig nif i cance in the Cam brian se quence of the Holy Cross Moun - tains, Po land. Geo log i cal Jour nal, 27: 15–34.
Or³owski S. (1997) Fun da men tal strati graphic prob lem of the Cam - brian in the Holy Cross Mts. – dis cus sion. Geo log i cal Quar terly, 41(1): 77–84.
Or³owski S., ¯yliñska A. (2002) Lower Cam brian trace fos sils from the Holy Cross Moun tains, Po land. Geo log i cal Quar terly, 46 (2):
135–146.
Or³owski S., Radwañski A., Roniewicz P. (1970) The tri lo bite ichnocoenosis in the Cam brian se quence of the Holy Cross Moun tains. Geo log i cal Jour nal Spe cial Is sue, 3: 345–360.
Ortega-Hernández J., Esteve J., Butterfield N.J. (2013) Hum ble or i gins for a suc cess ful strat egy: com plete en rol lment in early Cam brian olenellid trilobites. Bi ol ogy Let ters, 9: 1–5.
Pem ber ton S.G., Spila M., Pulham A.J., Sound ers T., MacEachern J.A., Rob bins D., Sinclair I.K. (2001) Ichnology and sedimentology of shal low to mar ginal ma rine sys tems: Ben Newis and Avalon res er voirs, Jeanne D’Arc Ba sin. Geo log i cal As so ci a tion of Can ada Short Course, 15.
Raaf J.F.M., Boersma J.R., Gelder A. (1977). Wave-gen er ated struc tures and se quences from a shal low ma rine suc ces sion, Lower Car bon if er ous, County Cork, Ire land. Sedimentology, 24:
451–483.
Reinson G.E. (1984) Bar rier is land and as so ci ated strand-plain sys - tems. In: Fa cies Mod els, sec ond edi tion (ed. R.G.Walker):
119–140. Geoscience, To ronto.
Samsonowicz J. (1959a) On the Holmia fauna in the Cam brian of the Anticlinorium of Klimontów. Bul le tin de l’Academie Po lo naise des Sci ences, Série des sci ences chimiques, géologiques et géographiques, 7: 447–452.
Samsonowicz J. (1959b) On Strenuaeva from Lower Cam brian in Klimontów Anticlinorium. Bul le tin de l’Academie Po lo naise des Sci ences, Série des sci ences chimiques, géologiques et géographiques, 7: 521–525.
Samsonowicz J. (1959c) On Strenuella and Germatopyge from Lower Cam brian in the Klimontów Anticlinorium. Bul le tin de l’Academie Po lo naise des Sci ences, Série des sci ences chimiques, géologiques et géographiques, 7: 525–529.
Sepkoski J.J. Jr (1978) A ki netic model of Phanerozoic tax on omy di - ver sity. I. Anal y sis of ma rine or ders. Palaeo bi ol ogy, 4: 223–251.
Sepkoski J.J. Jr (1979) A ki netic model of Phanerozoic tax on omy di - ver sity. II. Early Phanerozoic fam i lies and mul ti ple equi lib ria.
Palaeo bi ol ogy, 5: 222–251.
Stachacz M. (2012) New finds of Rusophycus from the lower Cam - brian Ociesêki Sand stone For ma tion (Holy Cross Moun tains, Po - land). Geo log i cal Quar terly, 56 (2): 237–248.
Studencki M. (1988) Sed i men tary con di tions of the Ociesêki Sand - stone and Kamieniec Shale For ma tions (Lower Cam brian) in the Holy Cross Mts. (in Pol ish with Eng lish sum mary). Kwartalnik Geologiczny, 32 (3/4): 533–540.
Vannier J., Calandra I., Gailard C., ¯yliñska A. (2010) Priapulid worms: Pi o neer hor i zon tal bur row ers at the Pre cam brian-Cam - brian bound ary. Ge ol ogy, 38: 711–714.
¯yliñska A. (2013a) Evo lu tion of tri lo bite as sem blages from the Cam brian Se ries 2 and 3 of the Holy Cross Moun tains and their biogeographic sig nif i cance (in Pol ish with Eng lish sum mary).
Przegl¹d Geologiczny, 61: 30–39.
¯yliñska A. (2013b) The old est Cam brian trilobites from the Holy Cross Moun tains, Po land: tax o nomic, strati graphic and biogeographic re ap praisal. Acta Geologica Polonica, 63: 57–87.
¯yliñska A., Szczepanik Z. (2009) Tri lo bite and acritarch as sem - blages from the Lower–Mid dle Cam brian bound ary in ter val in the Holy Cross Moun tains (Po land). Acta Geologica Polonica, 59:
413–458.
