The sig nif i cance of Up per Cre ta ceous hardgrounds and other dis con ti nu ity sur faces for ba sin-wide cor re la tions,
based on drillcore data from bore holes in north ern Po land
Krzysztof LESZCZYÑSKI1, *
1 Pol ish Geo log i cal In sti tute – Na tional Re search In sti tute, Rakowiecka 4, 00-975 Warszawa, Po land
Leszczyñski, K., 2017. The sig nif i cance of Up per Cre ta ceous hardgrounds and other dis con ti nu ity sur faces for ba sin-wide cor re la tions, based on drillcore data from bore holes in north ern Po land. Geo log i cal Quar terly, 61 (4): 825–844, doi:
10.7306/gq.1375
The pa per pres ents the hardgrounds and some other cor re la tive dis con ti nu ity sur faces found in Up per Cre ta ceous (Cenomanian–Maastrichtian) bore hole sec tions of north ern Po land. They were briefly de scribed, and depositional en vi ron - ment was iden ti fied for both the un der ly ing de posit (UD) and the over ly ing de posit (OD). The sig nif i cance of these fea tures for both ba sin-wide cor re la tions and broadly un der stood se quence strati graphic tech niques is high lighted. They were cor re - lated with other ma jor dis con ti nu ity sur faces iden ti fied in bore holes of north ern Po land in both drill cores and well logs if such iden ti fi ca tion was re li able based on geo phys i cal bore hole data. All these dis con ti nu ity sur faces were re ferred to the bound - aries of the in di vid ual depositional cy cles de ter mined within the Up per Cre ta ceous suc ces sion: K3-II/K3-III, K3-III/K3-IV, K3-IV/K4-I, K3-IV/K4-II, K4-I/K4-II (or II or IV or V), K4-III/K4-IV (or V), K4-IVa/K4-IVb, prob a bly K4-IVb/K4-V, and K4-V/Pc-I.
The dis con ti nu ity sur faces can be re lated to both sea level fluc tu a tions and tec tonic ac tiv ity dur ing the Subhercynian phases.
Most of them de vel oped in rel a tively calm sed i men tary con di tions, out side the cen tral part of the Mid-Pol ish Trough. The ex - cep tions are three hardgrounds from the Cz³opa–Szamotu³y Zone, which seem to be as so ci ated mainly with the Late Cre ta - ceous tec tonic (in clud ing salt tec ton ics) ac tiv ity of this zone. The most com mon UD/OD con fig u ra tion of sed i men tary en vi ron ments is the open-ma rine car bon ate shelf both be neath and above the dis con ti nu ity sur face. The sec ond most com - mon sit u a tion is the open-ma rine car bon ate shelf be neath and the open-ma rine shelf with car bon ate-si li ceous sed i men ta tion above. The gaps at the sur faces span var i ously long in ter vals, rang ing from short pe ri ods (span ning a frac tion of a depositional cy cle) to long pe ri ods (com pris ing one or more depositional cy cles). The po si tion of the dis con ti nu ity sur faces fa cil i tates search ing for any pos si ble hi a tuses in the sec tions of other bore holes, and pay ing at ten tion to lo cal changes in sed i ment dis tri bu tion pat terns, and lo cal tec tonic ac tiv ity.
Key words: Up per Cre ta ceous, dis con ti nu ity sur face, hardground, ba sin-wide cor re la tion, north ern Po land.
INTRODUCTION
Re search on both pres ent-day and an cient depositional en - vi ron ments have re sulted in the iden ti fi ca tion of var i ous types of dis con ti nu ity sur faces (e.g., Goldring and KaŸmierczak, 1974;
Bromley, 1975; Ken nedy and Gar ri son, 1975; Seilacher, 1981;
Clari et al., 1995), which can be man i fested by bed ding planes that are very im por tant fea tures in the sed i men tary suc ces sion.
They re flect a change in the con di tions of sed i men ta tion and are of ten re lated to gaps in the sed i men tary re cord. A dis con ti - nu ity sur face is com monly de fined as a sur face that sep a rates youn ger from older sed i men tary rocks where geo met ric, sedimentological, diagenetic, or biostratigraphic cri te ria en able to in fer a break in sed i men ta tion.
A spe cific kind of dis con ti nu ity sur face is a hardground, very com mon in car bon ate se quences. Hardgrounds are synsedimentarily lithified car bon ate seafloors, ex posed for a sig nif i cant pe riod, that be come hard ened in situ by the pre cip i - ta tion of car bon ate ce ment in pri mary pore spaces (Wil son and Palmer, 1992).
Hardgrounds are of ten bored and/or en crusted with var ied fauna well adapted for hard-sub strate liv ing. They are com - monly im preg nated by iron ox ides, glauconite and phospho - rites. In many re gions, hardground sur faces are traced over large ar eas, re flect ing uni form sed i men tary con di tions (Bromley and Gale, 1982). A com pre hen sive sum mary of knowl edge on hardgrounds is given in Flügel (2004).
The use of hardgrounds and other dis con ti nu ity sur faces and their sig nif i cance for the Cre ta ceous stra tig ra phy are high - lighted in many stud ies on the Eu ro pean Cre ta ceous bas ins, as they are com mon fea tures in the car bon ate/chalk se quences de pos ited un der cal cite sea and green house cli mate con di tions (e.g., Voigt et al., 2008). They are com monly in ter preted as mark ing cy cle bound aries in depositional se quences (e.g., Han cock, 1989; Witzke and Bunker, 1996; Mortimore et al., 1998), in di cat ing a cy clic de po si tion of the car bon ate suc ces -
* E-mail: krzysztof.leszczynski@pgi.gov.pl
Received: March 2, 2017; accepted: June 30, 2017; first published online: August 24, 2017
sion. There fore, hardgrounds are im por tant fea tures in se - quence strati graphic anal y sis as bound aries of var i ously ranked se quences (e.g., Owen, 1996; Pandey et al., 2010).
Hardgrounds can be used to es ti mate both tec tonic and eustatic sea level changes and are thought to mark the re gres - sive troughs on sea level curves (Han cock, 1989), or to have been fol lowed by trans gres sion (James and Bone, 1991; Jones and Desrochers, 1992; Lehrmann and Goldhammer, 1999).
Han cock (1989) used them for the iden ti fi ca tion of sea level changes dur ing the Late Cre ta ceous in the Brit ish re gion. Con - sid ered to rep re sent se quence bound aries, they were used in de vel op ing a strati graphi cal frame work for the Turonian Chalk suc ces sion of south ern Eng land (Gale, 1996).
In north ern Ger many and Den mark, hardground sur faces were found in the Maastrichtian sec tion (cf. Her ring et al., 1996;
Ineson et al., 2006), in the Up per Turonian (Wiese and Kröger, 1998), and near the Cenomanian/Turonian bound ary (Prauss, 2006 – hardground in the up per most Cenomanian). Wilmsen (2003) used a se quence strati graphic anal y sis in the study of the Cenomanian in north ern Ger many, iden ti fy ing a num ber of hardgrounds in the suc ces sion and con clud ing the eustatic na - ture of most Cenomanian sea level vari a tions. In the Subhercynian Cre ta ceous Ba sin, Voigt et al. (2004) re port the pres ence of Up per Turonian/Mid dle Coniacian bound ary hardground. A hardground near the Cenomanian/Turonian bound ary is also known from the Lower Sax ony Ba sin of north - west ern Ger many (at the top of the Plenus Bed) (Hilbrecht and Dahmer, 1994). An other hardground from the up per most Cenomanian (be low the Plenus Bed) is re ported by Prauss (2006) at Wunstorf.
In Lith u a nia, hardgrounds are a char ac ter is tic fea ture of the Up per Turonian–Maastrichtian Mielupis For ma tion (Grigelis and Leszczyñski, 1998).
Hardground sur faces were also found in the Up per Cre ta - ceous de pos its of south ern Po land. In the NE mar gin of the Holy Cross Mts and the Miechów Trough (Fig. 1A), they were re ported from the Cenomanian–Turonian part of the suc ces - sion (Cieœliñski, 1959; Marcinowski, 1974; Peryt, 1983;
Walaszczyk, 1992; Dubicka and Machalski, 2017). An ex cel lent ex am ple of for ma tion of a com pos ite hardground is de scribed by Olszewska-Nejbert (2004) from the east ern mar gin of the Pol ish Jura Chain, north of Cra cow. Krassowska (1973, 1986) iden ti fied a num ber of hardgrounds in the Maastrichtian sec tion of bore holes from the Radom–Lublin re gion (Lublin Trough) (Fig. 1A). In north ern Po land, hardgrounds are par tic u larly com - mon in bore holes drilled in the Gorzów Block and the ad ja cent zone of the Szczecin Trough (this area is also called the Szczecin–Gorzów Synclinorium; Karnkowski, 2010), in the east ern part of the Peribaltic Syneclise and in the Mazury El e - va tion (Fig. 1A).
The drill cores from bore holes of north ern Po land also re - veal the pres ence of other prom i nent dis con ti nu ity sur faces cor - re spond ing to the hardgrounds. Their iden ti fi ca tion is based on fau nal (macrofauna, foraminifers) and sedimentological (rock types and na ture of con tact sur face) ev i dence, sup ported by well log in ter pre ta tions.
In this pa per, the chronostratigraphy is based on com pre - hen sive stud ies of B³aszkiewicz and Cieœliñski (1979), Jaskowiak-Schoeneichowa (1981), Jaskowiak-Schoenei - chowa and Krassowska (1983), and B³aszkiewicz (1997), in - clud ing some mod i fi ca tion with re spect to the Turonian/Co - niacian bound ary (Leszczyñski, 2002a). A pre lim i nary se - quence strati graphic ap proach to the Up per Cre ta ceous suc - ces sion in the Pol ish Low lands, and the iden ti fi ca tion of sed i - men tary cyclicity as well as depositional sys tems and en vi ron - ments have been given by Leszczyñski (1997a, b, 2010, 2012).
MATERIAL AND METHODS
All data re ferred to in this pa per come from ob ser va tion and de scrip tion of drill cores from Up per Cre ta ceous bore holes drilled dur ing the last de cades in north ern Po land. First, in ven - tory of de scrip tions of drill cores from avail able pub li ca tions, manu scripts of M. Jaskowiak-Schoeneichowa, and au thor’s own ob ser va tions was made in search for hardgrounds and other cor re la tive dis con ti nu ity sur faces. The hardgrounds were then clas si fied, and depositional en vi ron ment was iden ti fied for both the un der ly ing de posit (UD) and the over ly ing de posit (OD). They were also cor re lated with some other dis con ti nu ity sur faces iden ti fied in nearby bore holes in both drill cores and well logs, if such iden ti fi ca tion was re li able based on geo phys i - cal bore hole data. Fi nally, the hardgrounds and the other dis - con ti nu ity sur faces were re ferred to the bound aries of the in di - vid ual depositional cy cles de ter mined in the Up per Cre ta ceous suc ces sion by Leszczyñski (1997b, 2010, 2012, 2017). Some drill core in ter vals with the hardgrounds, which are still in a rel a - tively good con di tion, have been pho to graphed by K. Lesz - czyñski in 2017. One photo was taken by M.
Jaskowiak-Schoeneichowa at the early stage of drillcore log - ging. Data from thin sec tion ob ser va tions de rive from manu - scripts of M. Jaskowiak-Schoeneichowa, made avail able to the pres ent au thor.
Un for tu nately, most of the hardground sur faces are cur rently un avail able for di rect study be cause ei ther the drill core has been dam aged and is in com plete, or it is lost and dis carded. This is why, also the dis crim i na tion be tween bur rows and bor ings, and the type of fill ing ma te rial (rep re sent ing ei ther UD or OD) is in most cases not pos si ble. Thus, the de scrip tions of the hardgrounds can un for tu nately lack some im por tant in for ma tion.
UPPER CRETACEOUS HARDGROUNDS OF NORTHERN POLAND
GENERAL INFORMATION
De spite frag men tary cor ing in the Up per Cre ta ceous sec - tions, we are able to rec og nize a con sid er able num ber of hardgrounds in bore holes drilled across the Pol ish Low lands.
Dur ing de tailed lithological log ging of drill cores, Jaskowiak- Schoeneichowa (1972, 1973, 1974, 1978a, b, 1979, 1981;
Jaskowiak-Schoeneichowa and Krassowska, 1983; Jasko - wiak- Schoeneichowa and Leszczyñski, 2014) and Leszczyñski (2014) iden ti fied and de scribed a num ber of hardgrounds in the Up per Cre ta ceous sec tion of some bore holes from north ern Po land. These bore holes are clus tered mainly in two ar eas: (1) in north west ern Po land in the Gorzów Block and the ad ja cent zone of the Szczecin Trough, and (2) in north east ern Po land in the east ern part of the Peribaltic Syneclise and in the Mazury El - e va tion (Fig. 1A). There is also one hardground sur face re - ported from the P³oñsk 8 bore hole in the P³ock Trough (Jaskowiak-Schoeneichowa and Krassowska, 1983; Lesz - czyñski, 2017; Fig. 1A, B-6).
The Gorzów Block and the ad ja cent zone of the Szczecin Trough are lo cated in the dis tal area of the epicontinental Me so - zoic sed i men tary ba sin of Po land, to the south-west of its most subsident, ax ial zone called the Mid-Pol ish Trough. The zone was in verted dur ing and af ter the Late Cre ta ceous to form the Mid-Pol ish Swell (Dadlez et al., 1998; Wag ner et al., 2002;
Krzywiec, 2006; Vejbaek et al., 2010). Dur ing Late Cre ta ceous times, the Gorzów Block was an area of rel a tively qui es cent tec - tonic con di tions, dom i nated by car bon ate sed i men ta tion, es pe -
Fig. 1. Major Mesozoic tectonic units (A) and generalized Late Cretaceous palaeogeography (B)
cially in its west ern part (Jaskowiak-Schoeneichowa, 1981;
Leszczyñski, 2010, 2012; Fig. 1B).
The Peribaltic Syneclise and Mazury El e va tion are lo cated on the other side of the Mid-Pol ish Trough/Swell on the Pre - cam brian Plat form area, also in a tec toni cally qui es cent zone (Fig. 1A). How ever, there are a num ber of prom i nent gaps in the Up per Cre ta ceous sec tion in this re gion, re lated to non-de - po si tion pe ri ods due to bot tom-cur rent ac tiv ity or weak and slow up lift ing move ments (Krassowska, 1997; Leszczyñski, 2012;
Fig. 1B). The Up per Cre ta ceous suc ces sion starts here with car bon ate-siliciclastic, mostly sandy de po si tion to grade up into more muddy fa cies and, fi nally, into car bon ate-si li ceous and car bon ate ones, in clud ing marls and chalk (Fig. 1B).
The Up per Cre ta ceous sec tions of north ern Po land, in which hardgrounds are found, are com posed pre dom i nantly of lime - stone, chalk, marl, opoka (si li ceous marl) and non-sandy to mod - er ately sandy gaize. The macrofaunal and foraminiferal de ter mi - na tions pro vided in Ta bles 1, 2 and 3, and thus the strati graphic po si tion of the hardgrounds and the other cor re la tive dis con ti nu - ity sur faces, are based on the re sults of mi cro- and macro - palaeontological anal y ses, both pub lished (Gawor-Bie dowa, 1972, 1974, 1978, 2014a, b; Jasko wiak-Schoeneichowa, 1972, 1973, 1974, 1978a, b, 1979, 1981; Witwicka, 1973; Cieœliñski, 1974; Jaskowiak-Schoeneichowa and Krassowska, 1983;
Jaskowiak-Schoeneichowa and Leszczyñski, 2014) and those in cluded as manu scripts in fi nal re ports of bore holes, stored at the NGA (Na tional Geo log i cal Ar chives). A very im por tant role was played by re gional cor re la tions of geo phys i cal logs from many bore holes dis trib uted over large ar eas of NW and NE Po - land. Ref er ence to the depositional cyclicity is based on au thor’s own in ves ti ga tions (Leszczyñski, 1997b, 2010, 2012).
The fol low ing hardgrounds have been iden ti fied in the Late Cre ta ceous se quence of north ern Po land:
– Hardgrounds in Choszczno IG 1 and ¯abicko 1 (Gorzów Block; Jaskowiak-Schoeneichowa, 1978b, 1981), which sep a rate K3-III from K3-IV.
– Hardgrounds in Gorzów Wlkp. IG 1 (Gorzów Block;
Jaskowiak-Schoeneichowa, 1981; Jaskowiak-Schoe - nei cho wa and Leszczyñski, 2014), and Bartoszyce IG 1, Kêtrzyn IG 2 and pre sum ably Kêtrzyn IG 1 (Peribaltic Syneclise; Jaskowiak-Schoeneichowa, 1974; Leszczyñ - ski, 2014), found be tween K3-IV and K4-I.
– Hardground in Miêdzychód IG 1 (Gorzów Block; Jasko - wiak- Schoeneichowa, 1972), be tween K3-IV and K4-II.
– Hardground in Lusowo (Gorzów Block; Jasko - wiak-Schoeneichowa, 1981), sep a rat ing K4-I from K4-II.
– Hardground in Bartoszyce IG 1 (Peribaltic Syneclise;
Jaskowiak-Schoeneichowa, 1974), be tween K4-III and K4-IVb(?) – K4-V.
– Hardground in P³oñsk 8 (P³ock Trough; Jaskowiak- Schoeneichowa and Krassowska, 1983; Leszczyñski, 2017), which sep a rates K4-IVa from K4-IVb
– Hardground in Pas³êk IG 1 (Peribaltic Syneclise;
Jaskowiak-Schoeneichowa, 1973), be tween K4-IVa and K4-IVb.
– Hardgrounds in Kêtrzyn IG 1 and IG 2 (Peribaltic Syneclise; Leszczyñski, 2014), sep a rat ing K4-I from K4-III, with a strati graphic gap span ning K4-II.
– Hardground in E³k IG 1 (Mazury El e va tion; Jasko - wiak-Schoeneichowa, un pub lished ma te ri als), which sep a rates K4-I from K4-IV, with a strati graphic gap span ning a long time in ter val of K4-II and K4-III.
– Hardground in Krasnopol 1 (Mazury El e va tion; Jasko - wiak-Schoeneichowa, un pub lished ma te ri als), be tween K4-I and K4-V, with a strati graphic gap also span ning a long time in ter val of K4-II, K4-III and K4-IV.
There are also hardgrounds in the Cz³opa–Szamotu³y tec - tonic zone (Jaskowiak-Schoeneichowa, 1981), namely: an intra-K4-II hardground in Szamotu³y Geo 8 (Szczecin Trough), and hardgrounds in Cz³opa 3 (Szczecin Trough – be tween K3-II and K3-III or less likely be tween K3-I and K3-II) and in Szamotu³y Geo 16 (Szczecin Trough – also be tween K3-II and K3-III). All of them are most prob a bly re lated to halotectonic ac - tiv ity in this salt-cored tec tonic zone, al though a com bi na tion of tec tonic-eustatic fac tors can not be ex cluded in these in stances.
All the hardgrounds are briefly char ac ter ized be low and their po si tion in terms of stra tig ra phy and sed i men tary en vi ron - ment is il lus trated in Fig ure 2. They are roughly cor re lated with the sea level curve of Han cock (1989). For com par i son, the re - cent curve of Haq (2014) is also drawn.
SZCZECIN TROUGH AND GORZÓW BLOCK
In the Gorzów Block and the neigh bour ing zone of the Szczecin Trough, hardground sur faces have been iden ti fied in the fol low ing bore holes: Choszczno IG 1, ¯abicko 1, Gorzów Wielkopolski IG 1, Miêdzychód IG 1, Lusowo, Szamotu³y Geo 8, Szamotu³y Geo 16 and Cz³opa 3 (Fig. 1B and Ta ble 1).
NE POLAND
In the Peribaltic Syneclise and Mazury El e va tion, hardground sur faces have been iden ti fied in the fol low ing bore - holes (Fig. 1B and Ta ble 2): Pas³êk IG 1, Bartoszyce IG 1, Kêtrzyn IG 1, Kêtrzyn IG 2, E³k IG 1 and Krasnopol 1. A dis con - ti nu ity sur face with no sig nif i cant gap is in ter preted in the Olsztyn IG 1 bore hole. In the P³ock Trough, a hardground sur - face was en coun tered in the P³oñsk 8 bore hole.
An other hardground is sug gested to oc cur in the Kêtrzyn IG 1 bore hole (at ~464.0 m depth) be tween K3-IV and K4-I, which is in ter preted from well log re cords, sup ported by the pres ence of the K3-IV/K4-I hardground doc u mented at 598.5 m depth in the drill core from the Kêtrzyn IG 2 bore hole (see be - low). The UD is prob a bly sandy lime stone (open-ma rine siliciclastic-car bon ate shelf), and the OD is chalk (open-ma rine car bon ate shelf).
OTHER CORRELATIVE DISCONTINUITY SURFACES
In the Up per Cre ta ceous car bon ate-dom i nated pe lagic se - quences, each sharp lithological bound ary can be con sid ered a dis con ti nu ity sur face re flect ing a shorter or lon ger break in sed i - men ta tion. Sedimentological in ves ti ga tions sup ported by microfaunal ev i dence al low rec og ni tion of a num ber of dis con ti - nu ity sur faces that do not rep re sent hardgrounds. Some of them may be de fined as dis con ti nu ity sur faces in co her ent at the mo - ment of the re newal of sed i men ta tion, at which part of the sed i - men tary re cord is miss ing, and re ferred to as omis sion sur faces.
Ta ble 3 pro vides a sum mary of ex am ples of some other prom i nent dis con ti nu ity sur faces cor re la tive to the hardgrounds, iden ti fied in the drill cores from bore holes of north ern Po land.
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egieb thgil ,draHlatirtedonagrohtiw ,enot semiletinocualg rus eht no
- rac etihw dna ylram hs ineerg htiw dellif sgn irob su ore mun dna ecaf
- drah otni sdra wnwod gn issap ,tiso ped gn iy lrevo eht fo lai re tam et anob e tam ylram hs ineerg fo skaerts htiw eru txet ekil-ra l udon fo enot semil- OCaC .lair8.78–0.25 :tne tnoc .% :arefinimaroFanacnurtobolG3 itnerappal .ravsediollubrelgöV ,atanigram .G( ssueR ,) .Gitnerappal .ravatanorocilloB , .GsedioniregibolgneztorB , .Gitnerappal.rav itnerappalneztorB ,setilatorobolGanainilehcim( yngibrO’d ,)anilamonA inilehtreb.relleK flehs et ano brac eni ram-nepO.
hs ineerg-yerg ,draHlatirtedonagroemilylram/lram - su ore mun htiw ,enot semil/enotsstsalcoib,sevla vib fo sdionihce.esab eht raen secart ruocs ,seti nm eleb dna OCaC39.19–0.67 :tne tnoc .%anuaforcaM :sihtuetoinoG sutalunarg :arefinimaroF .)ellivnialB( allenilevaG atalutsoc ,)ei raM(allessueRasolunipsoduespnesleorT, anacnurtobolGitnerappal.ravataniracitsugnaiflodnaG, .Gitnerappal .ravsediollubrelgöV ,atanigram .G (ssueR ,) .Gitnerappal .ravatanorocilloB , .Gitnerappal .ravitnerappalneztorB , .GsedioniregibolgneztorB, anilamonAinamlaht( neztorB ,)setilatorobolGatpesitlum neztorB ,anieoisnetSatplucsxe (ssueR.) .flehs et ano brac eni ram-nepO
e rroc ot deter pre tni si SD sihT
- dnuob II-4K/VI-3K eht htiw etal- eb to nnac ti hguoh tla ,yra eht taht dedul cerpDUe rper - .I-4K el cyc stnes owosuL m 1.782 II-4K/I-4K )4 ,2 .sgiF dna 3-B1 .giF(
a htiw ,enot semilylram hs ineerg-yerg ,draHetinocualg rus no gn itaoc
- emilegieb-yerg thgil ,drah yrev fo sesnel dna sel udon htiw dna ,ecaf- eraR .enotsetinocualg :arefinimaroF .sniarg airalunalPisubeil neztorB ,anacnurtobolGitnerappalitnerappalneztorB , .Gitnerappal ataniracitsugnaiflodnaG, .G sedioniregibolgneztorB , .Gitnerappal sediollubrelgöV ,setilatorobolGatpesitlum( neztorB,) aireniluvlavoduesParegillets,)ei raM( anilamonAinamlaht (neztorB,) airalugnasOanaireidroc( yngibrO’d ,)anillebalfoeNasogur ( yngibrO’d ,) anieoisnetSacinolopakciwtiW .S ,atplucsxe .rav silicargneztorB, allenilevaGatalutsoc.)ei raM( flehs et ano brac eni ram-nepO.
su ore mun htiw ,enot semilylram hs ineerg-yerg ,draH etinocualg ,)mm 5.0–1.0( sniarg dimareconidna smsirp OCaC .selucips egnops3:arefinimaroF .%0.66 :tne tnoc setilatorobolGanainilehcim( yngibrO’d ,) .Gatpesitlum (neztorB ,)anacnurtobolGitnerappalitnerappalneztorB, .Gitnerappalatanoroc illoB .G ,sedioniregibolgneztorB, .GitnerappalsediollubrelgöV ,allessueR asolunipsoduespnesleorT ,aireniluvlavoduesParegillets ,)ei raM(anilamonAinamlaht (neztorB ,)airalugnasO anaireidroc( yngibrO’d ,)anillebalfoeNasogur (yngibrO’d ,)anieoisnetSacinolopakciwtiW , .Satplucsxe .ravsilicargneztorB ,allenilevaGalutacilibmukuiltajM. .flehs et ano brac eni ram-nepO
1el baT sdnuorgdraHdna hguorT nicezczS eht ni wózroGkcolB
DISCUSSION
It is usu ally in ter preted that chalk was de pos ited in a rel a - tively calm pe lagic en vi ron ment, and so were much of pe lagic high-CaCO3 lime stones and the so-called “chalk-like” lime - stones. Many open-ma rine car bon ate set tings, in clud ing those of the Cre ta ceous chalk se quences of North west Eu rope, con - tain nu mer ous hardgrounds which can be traced over large dis - tances. Wide spread cor re la tion of these hardgrounds across the ba sin may sug gest allocyclic fac tors re lated to eustatic fluc - tu a tions. They rep re sent in ter vals of highly re duced sed i men ta - tion rate, sed i ment star va tion, or non-de po si tion, in di cat ing breaks in sed i men ta tion, e.g., due to a shallowing event, fol - lowed by a rel a tive sea level rise and ba sin deep en ing. How - ever, re cent stud ies of pe lagic chalk set tings from the Dan ish area show also a pos si bil ity of highly dy namic depositional en vi - ron ment due to strong and long-liv ing bot tom cur rents which cre ated highly di verse seafloor re lief (Lykke-Andersen and Surlyk, 2004; Surlyk and Lykke-Andersen, 2007). The hardgrounds found in the Up per Cre ta ceous car bon ate-dom i - nated suc ces sion of NW and NE Po land de vel oped in ar eas of rel a tively calm sed i men tary-tec tonic con di tions, which may have been af fected by bot tom cur rents, al though not as strong as those de scribed by Lykke-Andersen and Surlyk (2004) as no broad val leys, ridges, chan nels, drifts and mounds are ob - served. How ever, there is also ev i dence for tec tonic ac tiv ity that may have in flu enced the for ma tion of the hardgrounds.
Con sid er ing the pres ence of hardgrounds rel a tive to tec - tonic zones, we can see that there are three cases of hardgrounds de vel oped in the Cz³opa–Szamotu³y Zone – a tec - toni cally ac tive area dur ing the Late Cre ta ceous. These are: (1) mid-Santonian hardground found in the Szamotu³y Geo 8 bore - hole, (2) mid-Cenomanian hardground from the Szamotu³y Geo 16 bore hole, and (3) the likely mid-Cenomanian hardground from the Cz³opa 3 bore hole. They were un doubt - edly as so ci ated with tec tonic (in clud ing halokinetic) ac tiv ity within this zone, cor re lated with the early stages of tec tonic in - ver sion of the Mid-Pol ish Trough and ma jor tec tonic zones in the Pol ish Ba sin (e.g., Leszczyñski, 2000, 2002a, b; Krzywiec, 2006; Krzywiec et al., 2009). There is also pos si bil ity of a com bi - na tion of bot tom-cur rent ac tiv ity and sea level fluc tu a tions (ei - ther of tec tonic or eustatic or i gin, or both), which may have fa - voured the for ma tion of hardgrounds, as ev i denced by Eberli et al. (2010).
More over, some fur ther com ments should be made as re - gards the hardgrounds in the Cz³opa–Szamotu³y Zone. Based on foraminiferal ev i dence and well log cor re la tion, the Szamotu³y Geo 16 hardground is in ter preted to oc cur within the Cenomanian suc ces sion and is sup posed to rep re sent the K3-II/K3-III bound ary. The Cz³opa 3 hardground likely rep re - sents the K3-II/K3-III bound ary as well, al though a K3-I/K3-II po si tion (near the Up per Albian/Cenomanian bound ary; cf.
Jaskowiak-Schoeneichowa, 1981) can not be ex cluded, as no clear fos sil ev i dence is avail able. No dis tinct dis con ti nu ity sur - face has been rec og nized in this re gion, which could cor re - spond to the K3-II/K3-III hardgrounds. How ever, a nod u lar lime - stone ho ri zon has been re ported from the mid dle part of the Cenomanian sec tion in some bore holes, which can be cor re - lated with the hardgrounds (cf. Han cock, 1989). As the for ma - tion of hardgrounds and other dis con ti nu ity sur faces in the Cz³opa–Szamotu³y Zone was highly con trolled by tec - tonic/halotectonic move ments, they may not be straight for ward age-equiv a lent to dis con ti nu ity sur faces in ar eas of low tec tonic ac tiv ity and thus to bound aries be tween the depositional cy cles.
When ana lys ing the li thol ogy on both sides of the dis con ti - nu ity sur faces we no tice that most of the un der ly ing de pos its (UD) at the hardgrounds are lime stones or chalk with some ex - cep tions where the UD is rep re sented by sandy marl topped
elo heroB htpeD noi ti sop la cihpar gitartS( tiso ped gn iy lre dnu fo sci ts ire tc arahCDU,sli ssof ,yg oloh til :) lanoitisopedtne mno ri vne sof ,yg oloh til :)DO( tiso ped gn iy lrevo fo sci ts ire tc arahC- ,slislanoitisopedtne mno ri vne setoN utomazS8 oeG y³ m 0.283 II-4K-artnI 4 ,2 .sgiF dna 4-B1 .giF()
,el b airFcitinocualg-ydnas,sniarg ztrauq resraoc el gnis htiw lram em ,drah ,tca pmoc fo reyal kciht mc-wef a ,niht a htiw deppot- su o era clac ylhgih deniarg-muidetinocualg-ztrauqda htiw enot sdnas - dednuor dna sniarg esraoc fo eru tximstsalcdeniarg-enifyerg thgil fo tneu qer fni gn inia tnoc enot sdnasetinocualgnim su ore mun dna sniarg - etudimareconi.smsirp eni ram-nepOet ano brac-citsalcicilisflehs .
ztrauq ylram/su o era clac deniarg ylsu o irav hs ineerg-yerG htiw enot sdnasetinocualgotni dra wpu gn issap , hs ineerg-yergcitinocualg-ydnassniarg ztrauq htiw lram OCaC .)mm 0.2(3.%0.22 :tne tnoc eni ram-nepOet ano brac-citsalcicilis.flehs
ot deta ler si SD sihT cinotcetolaheht fo yt ivi tca zC³apo–utomazSderoc-tlas y³ .eru tcurts utomazS61 oeG y³ m 7.013 III-3K/II-3K )4 ,2 .sgiF dna 1-B1 .giF(
hs ineerg ylthgils ,yerg thgiLlatirtedonagroylram yerg htiw enot semil sresalfylthgils ,yerg thgil fo reyal kciht mc-lar eves a htiw deppot , ,enot semildrah fo sesnel dna sel udon htiw ,enot semilhs ineerg etinocualg :arefinimaroF .eca frus no gn itaoc aireniluvlavoduesP acinamonec .rav acinamonec (neztorB ,)aihtoroDatadarg( nilehtreB,) sedicibiCasomrof neztorB ,sedionilamonAasobolg neztorB, aropilatoRilehcierdonroM. flehs et ano brac eni ram-nepO.
thgilotni dra wpu gn issap )m 2.2( lram yeyalc yerg kraD yerglatirtedonagro .enot semilanuaforcaM :sumareconI isppirclletnaM :arefinimaroF .anacnurtobolgearP inahpets .ravinahpets (iflodnaG ,) .Pinahpets.rav atanibrut (iflodnaG ,)aireniluvlavoduesPacinamonec .rav acinamonec (neztorB ,)anilamonAinilehtreb.relleK .flehs et ano brac/ylram eni ram-nepO
ot deta ler yl b aborp si SD sihT cinotcetolahtlas eht fo yt ivi tca a ,rev ewoh ,htae neb eru tcurts fo noi ta ni bmoccet- citatsue-cinoteb to nnac sro tcaf .dedul cerp zC³apo3 m 5.023 ylekilssel ro( III-3K/II-3K )II-3K/I-3K )4 ,2 .sgiF dna 1-B1 .giF(
latirtedonagrOhtiw enot semildimareconi ,stne mgarf llehs etinocualg ,sed ixo nori ,eca frus no gn itaocetirohpsohpni mc 0.3 ot pu sel udon .sla tsyrc eti ryp el gnis ,ezis flehs et ano brac eni ram-nepO.
egieb-yerg ,draHlatirtedonagrohtiw enot semil dimareconioN .smsirp cihpargitartsoib liava si ecne d ive - .elba .flehs et ano brac eni ram-nepO
ot deta ler yl b aborp si SD sihT cinotcetolahtlas eht fo yt ivi tca a ,rev ewoh ,htae neb eru tcurts fo noi ta ni bmoccet- citatsue-cinoteb to nnac sro tcaf .dedul cxe 1 OCaC3dei f iceps ton dohtem lacitylana ;gni ggol lacigolohtil rof edam snoi ta ni mre ted dna stro per elo herob la nifmorfgn imoc atad la c iro tsih era stne tnoc
.tnoc 1 .baT
elo heroB htpeD noi ti sop la cihpar gitartS( tiso ped gn iy lre dnu fo sci ts ire tc arahCDU,sli ssof ,yg oloh til :) lanoitisopedtne mno ri vne ,sli ssof ,yg oloh til :)DO( tiso ped gn iy lrevo fo sci ts ire tc arahC lanoitisopedtne mno ri vne setoN ³saPkê1 GI m 2.002 aVI-4K/bVI-K )5 ,2 .sgiF dna 6-B1 .giF(
htiw lram yerg krad htiw dellif sei t ivac ,klahc ylram etihW etinocualgOCaC .tiso ped gn iy lrevo eht fo 3.%5.87 :tne tnoc anuaforcaM :setihpacsolpoH .fc sutcirtsnoc( ybrewoS,) etnodoncyPsiralucisev( kcramaL ,)netceP ,.psalucuN.ps .flehs et ano brac eni ram-nepO
klahc htiw enot semilylram yerg ,draHsdebretnilram dna sdebretnienif ,etinocualgcitah psohp dna ,sniarg ztrauq dna dna )mm 40.0–1.0( ztrauq enifsu ore muN .snoi ter cnoc etinocualgOCaC .sniarg 3 .%5.88–1.97 :tne tnoc anuaforcaM: amotyxOacinadnvaR,adeL ,.psamiLataclusimes (nossliN ,) .LiztiniegwonegaH , .Lps.ni morf( arefinimaroF .sr ehto dna - :)m0.402-0.991 la vretallenilevaGimolbke (neztorB,) sedionilamonAsisneoniknagajakceN , .Asiugnip.)sgninneJ( .flehs et ano brac eni ram-nepO ecyzsotraB1 GI m 1.224 I-4K/VI-3K )5 ,2 .sgiF dna ,3 ,2-B1 .giF(
ot pu sniarg ztrauq htiw )m 2.0( enot semilydnas yerg thgil ,draH su ore mun ssorca mm 5stsalcoib fo dimareconiegral dna smsirp tna dnuba ,sllehsetinocualg llams ,etirohpsohpsgn irob ,sel udon ehT .tiso ped gn iy lrevo eht fo enot semilylram yerg thgilhtiw dellif otni dra wnwod sessap kcorcitinocualg-ydnasOCaC .lram 3noc - – m 0.424 :arefinimaroF .%5.57 :tnetanacnurtobolgearPinahpets atanibrut( lehcieR ,)anilamonAinilehtreb ,relleK allenilevagolugniL asobolg( neztorB ,)anacnurtobolGizneriflodnaG. eni ram-nepOet ano brac-citsalcicilis.flehs
,eti ryp ,ztrauq enifhtiw enot semilylram yerg thgil ,draH etinocualgdna eti vo csumOCaC .sniarg 3.%8.28 :tne tnoc – m 2.124 :arefinimaroFanieoisnetSacinolopakciwtiW ,.S atplucxeearp ,)relleK( setilatorobolGanainilehcim (yngibrO’d ,)allessueRasolunipsoduespnesleorT, anacnurtobolGatanigram ( ssueR ,)anilamonAinilehtreb .relleK .flehs et ano brac eni ram-nepO
et iso pmoc yl b aborP dnuorgdrah. ecyzsotraB1 GI m 0.242 /III-4KbVI-4KV-4K-)?( )5 ,2 .sgiF dna 6 ,5-B1 .giF(
suo rop yerg thgiLakopohtiw ,)lram suoe ci lis( etinocualg ,)mm 2.0( etirohpsohp ,)mc 5.1 ot pu( sel udon stsalcoib fo desitahpsohp krad htiw dellif stsen ,segnopsyregsu ore mun ,lai re tam ylram-ytlis wo leb m 0.1~ ta reyal ytrehc kciht mc 03 ,stnilf yerg krad dnuorgdrahOCaC .eca frus 3 .%9.63 :tne tnoc anuaforcaM: alletinmeleB ,.psetnodoncyPsiralucisevkcramaL ,netceP.fc sutagrivnossliN :arefinimaroF .setilatorobolGatpesitlum (neztorB ,) .Ganainilehcim( yngibrO’d ,)allenilevaGsisneleretnom .)ei raM( .)noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO
htiw lram ydduMstrehc ,sdebretni fo seziagenifsu ore mun , ,ztrauqetinocualgdna eti vo csumdehsurc eroc llird( sniarg OCaC .)sgol llew morfnoi ta ter pre tni ,seceip llams otni3noc - .%1.67 :tnet suoe ci lis-et ano brac cid oi rep htiw( flehs ylram eni ram-nepO .)noi ta tne m ides nyzrtêK1 GI m 7.304 III-4K/I-4K )5 ,2 .sgiF dna 3-B1 .giF(
yltrap dna dei fici lis ,drah yreVdesinodeclahchtiw enot semilylram strehccida rops ,eca frus dedo rroc ylgnorts dna etinocualg, ,stset refinimarofdimareconiOCaC .selacs hsifel gnis ,smsirp 3 :arefinimaroF .%8.27 :tne tnocanieoisnetSatplucxeearp,)relleK( anilamonAinilehtreb ,relleK allenilevaGsimrofilinom (ssueR), anacnurtobolGatanigram (ssueR,) .G itnerappalatanoroc .rav illoB .G ,sedioniregibolgneztorB ,anidioryGaditin (ssueR.) .flehs et ano brac eni ram-nepO
suo rop yerg thgil ,draHeziaghtiw etinocualgztrauq enifdna eraR .)mm 80.0–20.0( sniargeti vo csumdna sekalfdecrepsid OCaC .eti ryp3 :arefinimaroF .%3.94 :tne tnoc anacnurtobolG atanigram(ssueR) .G ,sedioniregibolgneztorB ,anieoisnetS atplucxe (ssueR ,)anilebalfoeNasogur ( yngibrO’d,) sedioniviloBatagiveal ,ei raMaireniluvlavoduesParegillets ,)ei raM(sediodicibiCsisneyagalutka( oknelissaV.) .)noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO nyzrtêK2 GI m 0.895 I-4K/VI-3K 5 ,2 .sgiF dna 3 ,2-B1 .giF()
yerg ,draHcitinocualg-ydnas rob/swo rrub dna sei t ivac ,enot semil- htiw dna tiso ped gn iy lrevo eht fo klahc etihw htiw dellif sgni etinocualgsnoitatsurcne;)ezis ni mc 1~( sel udon citah psohp ; dimareconisniarg ztrauq enif ,stset refinimarof ;smsirp OCaC .)mm 2.0–60.0(3nwod sessap kcor ehT .%4.36 :tne tnoc - ,ylram ,deniarg-enif ,yerg thgilotni drawcitinocualgdnas - OCaC .lram ydnas/enots3:arefinimaroF .%1.33 :tne tnoc alleniraciDatacirbmi ( donroM ,)anacnurtobolgotevleHacitevleh (illoB ,)allenilevaGinilehtreb.)relleK( eni ram-nepOet ano brac-citsalcicilis.flehs
OCaC .stset refinimarof ,stnilf llams htiw klahc etihw ,tfoS3 :arefinimaroF .%1.79–8.49 :tne tnocanacnurtonigraM atanigram( ssueR ,) .MsediollubrelgöV, .Manaiennil (yngibrO’d ,)aniregibolgeahcrAaecaterc( yngibrO’d,) setilatorobolGsunainilehcim( yngibrO’d ,)anieoisnetS atplucxeearp ,)relleK( .SacinolopakciwtiW ,allenilevaG simrofilinom( ssueR.) .flehs et ano brac eni ram-nepO
2el baT sdnuorgdraHeht ni citlabirePesilcenyS ,yruzaM³P dna noi ta v elE kcohguorT
elo heroB htpeD noi ti sop la cihpar gitartS( tiso ped gn iy lre dnu fo sci ts ire tc arahCDU,sli ssof ,yg oloh til :) lanoitisopedtne mno ri vne ,sli ssof ,yg oloh til :)DO( tiso ped gn iy lrevo fo sci ts ire tc arahC lanoitisopedtne mno ri vne setoN nyzrtêK2 GI m 5.705 III-4K/I-4K )5 ,2 .sgiF dna 5 ,3-B1 .giF(
fo su tir ted ,klahc etihw ,draHdimareconita ,segnops dna sllehs hs inworb - pot ehtdeifitrehc,noitatsurcne norihtiw )mc 8( kcor ,tiso ped tsoh eht fo klahc htiw dellif swo rrubsrefinimarofOCaC .3 .g.e :arefinimaroF .%2.69 :tne tnocanieoisnetSatplucxeearp ,)relleK(.Satplucxe (ssueR,) .S acinolopakciwtiW.sr ehto dna , .flehs et ano brac eni ram-nepO
su o era clac yerg krad ,suo rop dna draHeziaghtiw etinocualgdna eti ryp desre psid ,eti vo csumra lu gna enifdna , lram yerg kraD .)mm 8.0-30.0( sniarg ztrauqsdebretnidna OCaC .skaerts ylram3:arefinimaroF .%6.25 :tne tnoc anacnurtobolGsedioniregibolgneztorB ,aireniluvlavoduesP aregillets ,)ei raM( setilatorobolGatpesitlum( neztorB,) anieoisnetSeannaaksyra¿oP, .S anaremmopneztorB. .)noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO 1 GI k³E m 5.843 VI-4K/I-4K 5 ,2 .sgiF dna 3 ,2-B1 .giF()
,draHsselerutcurtshtiw dellif stsen et unim ,stnilf htiw klahc etihw etinocualg ,noi taz il ar enim eti ryp dna stsalcoibOCaC .3:tne tnoc ,%0.69–3.68anuaforcaM:aertsO .ps .flehs et ano brac eni ram-nepO
htiw lram deta n imal ylla tno z iroh yerGsdebretniop drah fo - suorakopo/eziag ,etinocualg ,larefinimarofesab eht tA .stset ztrauq enifhtiw dehci rne )mm 2-1( eanimal tcni tsid ,)m 6.0( ,sniargetinocualgOCaC .acim dna 3,%6.77–9.65 :tne tnoc .esab eht ta %4.83 suoe ci lis-et ano brac cid oi rep htiw( flehs ylram eni ram-nepO .)noi ta tne m ides loponsarK1 m 0.642 V-4K/I-4K )5 ,2 .sgiF dna ,3 ,2-B1 .giF(
roc nev enu ,den edrah htiw ,enot semildei fici lis ylthgils etihw ,draH- tfos htiw dellif snr evac ,eca frus re ppu dei fici lis ylhgih dna dedor ydnasekil-eziagOCaC .tiso ped gn iy lrevo eht fo lai re tam 3:tne tnoc .%0.49 .flehs et ano brac eni ram-nepO
yeyalc yerg krad ,suo rop ,tfoSeziagesraoc ot enifhtiw dna sniarg ztrauqetinocualgOCaC .3.%5.24 :tne tnoc .)noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO
sel cyc snaps pag ehT .VI-4K dna III-4K ,II-4K loponsarK1 m 0.991 I-cP/V-4K 5 ,2 .sgiF dna ,6-B1 .giF()
ytrehc yerGeziag rub dna snr evac htiw ,tca pmoc dna drah yrev ,- tca pmoc ssel htiw dellif sworcitinocualg-ydnaseziagy lrevo eht fo
- su o era clac yerg ,drah otni dra wnwod sedarg kcor sihT .tiso ped gni eziagOCaC ..)m 0.102 htped( %8.06 :tne tnoc 3 .)noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO
ydnas-su o era clac ,suo rop dna drah ylet ar edom ,suo rop yerG eziaghtiw etinocualgsag dna evla vib fo su tir ted emos dna - OCaC .sllehs do port3.)m 0.891 htped( %2.43 :tne tnoc .)noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO ³Pksño8 m 9.414 aVI-4K/bVI-4K 5 ,2 .sgiF dna 6-B1 .giF()
htiw dellif swo rrub dna snr evac ,enot semilylram yerg thgil ,draH .enot semilydnas .flehs et ano brac eni ram-nepO
htiw enot semilylram yerg thgil ,draHakoposdebretnier fni ,- ( su tir ted la nuaf tneuqsdimareconi ,segnops ,setilucab leb ,- niht ,)seti nmeakoposdebretniOCaC .3.%7.27-5.56 :tne tnoc :arefinimaroFsediodicibiCsisneyagalutkaoknelissaV ,.C atatcnuporipsdna ya wo llaG( yerroM ,)sedioniviloBalutaciled ,namhsuCaniviloBatassarcnissueR ,sedicibiCxibmeb.rav xibmeb( nossraM.) .flehs et ano brac eni ram-nepO
.tnoc 2 .baT
elo heroB htpeD( tiso ped gn iy lre dnu fo sci ts ire tc arahCDU,sli ssof ,yg oloh til :) lanoitisopedtne mno ri vne ,sli ssof ,yg oloh til :)DO( tiso ped gn iy lrevo fo sci ts ire tc arahClanoitisoped tne mno ri vnesetoN ta eca frus yt iu ni tno csiDbVI-4Kdna loP WN ni yr adnuob V-4K/ lewicohC1 GI m 4.613 )4 ,2 .sgiF dna 6-B1 .giF(
wef htiw enot semilylram yerg thgil ,draHstrehcecracs , etinocualgOCaC .sla tsyrc eti ryp dna sekalfacim ,sniarg 3noc - .%8.67 :tnetanuaforcaM: sagaMsulimupybrewoS, amenolcycnyS .fcmuecanarbmem( nossliN ,)aehtieN.ps :arefinimaroFallenilevaGasutrep( nossraM ,) .Gimeolbke (neztorB ,)atuca .G ,)remmulP(aniregivuoduesPatatsirc (nossraM.) flehs et ano brac eni ram-nepO.
htiw lram ydnas ,yerGetinocualgniht htiw ,dei fici lis ylla col ,sreyalretni fo sniarg ztrauq enifsu ore muN .esab eht ta lram ydnas-non yerg thgil OCaC .eca frus lasab deruocS .sla tsyrc eti ryp dna )mm 51.0–20.0(3noc - .%2.53 :tnetanuaforcaM :alletinmeleBroi nuj ,kawoN siryhtienraC ,.ps .C aenrac( ybrewoS ,)aeaponaP ,.ps sulydnopS ,.ps symalhC.ps :arefinimaroFsedicibiCatulovnissueR ,sediodicibiCatatcnuporips laG( - te ya wolyerroM ,)aniregivuoduesPatatsirc (nossraM ,)allenilevaG imeolbke (neztorB ,) .Gimeortslhas( neztorB ,)aniviloBsnerruced (grebnerhE,) eni ram-nepOet ano brac-citsalcicilis.flehs
rus ruocs a si SD sihT
- tna c ifi ngis on htiw ecaf .pag VI-3K/III-3K eht ot gn idnop se rroc seca frus yt iu ni tno csiDsdnuorgdraheht morf( onzczsohC¯ dna 1 GI okcibadna loP WN ni )selo herob 1 owezsiluS1 m 5.779 )2 ,1-B1 .giF(
( enot semilylram yerg thgil ,draHetircimoib ,enotsekcaw uge rri ,)- ,eanimal lram raldimareconidna stne mgarf llehs arefinimarof :arefinimaroF .swo rrub fo secart ,stsetanilamonAinilehtreb ,relleKsedionilamonAasobolg neztorB ,aireniluvlavoduesP acinamonec .rav acinamonec( neztorB ,)anacnurtobolGinahpets .ravatanibrutlehcieR ,aihtoroDatadarg( nilehtreB ,)aropilatoR acinorut .rav iemohtngaHte ,lieZ .RilehcierdonraM , .Racinorut .ravacinorut( neztorBOCaC .)3.%0.17 :tne tnoc .flehs et ano brac eni ram-nepO
ops ,sekalfacim ,snoi ter cnoc eti ryp ,enotsyalc su o era clac ytalp kcalB- dna ztrauq enifcidaretinocualgecracs ,sniarg dimareconi.smsirp :arefinimaroFsedionilamonAasobolg neztorB ,anilamonAinilehtreb OCaC .relleK3.%7.71 :tne tnoc .flehs tnei ci fed-ne g yxo dna -et ano brac eni ram-nepO wózroGikslopokleiW1 GI m 0.166 )2 ,1-B1 .giF(
etihw ,draHcitilep( enot semiletircimoib ,enotsdumecracs htiw ) arefinimarofdna stset dimareconiniht tneu qer fni ,smsirp OCaC .seti lo lyts ,)mc 0.1–2.0( eanimal lram hs ineerg-yerg3noc - 3.69 :tnet .%anuaforcaM :aertsO.ps .flehs et ano brac eni ram-nepO
hs iknip-etihw ,draHlatirtedonagro/cinegonagro udon htiw enot semil- ( eru txet ekil-raletircimoib ,enotsekcaw ;stsalcoibylniam( arefinimarof enot semilylram nworb yb deta n imal ,)kcor fo %07~ rof tnuo cca )stset OCaC .sed ixo nori fo skaerts htiw37.29 :tne tnoc .%anuaforcaM: sumareconIsutaibalmiehtolhcS :arefinimaroF .aireniluvlaVatalucitnel (ssueR ,)sedicibiCioknebrogzemikA ,aihtoroDsirrut( yngibrO’d,) anacnurtobolgearPatacirbmi ( donroM ,) .Pinahpets( iflodnaG ,).P sisneivarosisneivaroavorenbiehcS ,anacnurtobolG .fc izneriflodnaG. .flehs et ano brac eni ram-nepO
dnuob lacigolohtil ehT- neew teb yraDUDO dna no dekram llew osla si .sgol llew 1 GI nicezczS m 5.2941 )1-B1 .giF(
ytlis ev ilo-yerg ,draHakoposyrc eti ryp eniferar desre psid htiw - ,ztrauq enifdna slateti vo csumdna etinocualg.sniarg :arefinimaroFanilamonAinilehtreb ,relleK allenilevagolugniL asobolg( neztorB ,)allenilevaGacinamonec( neztorB ,) .Gacitlab neztorB. .)noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO
erar htiw )m 8.0( elahs yalc ylram ytalp ,yerg krad ot kcalBarefinimarof dna ztrauq enifel gnis ,stseteti vo csumed ixo noridna ,sniarg stelniev, htiw enot semilylram yerg otni gn issapsdimareconi :sumareconI.fc sutaibalmiehtolhcS. .flehs tnei ci fed-ne g yxo dna -et ano brac eni ram-nepO dragowoN1 m 0.1401 )1-B1 .giF(
OCaC .swo rrub fo secart ,lram ev ilo-yerG3.%6.03 :tne tnoc :)m 4.5401( arefinimaroFaireniluvlavoduesPacinamonec.rav acinamonec( neztorB ,)anilamonAinilehtreb ,relleK aihtoroD atadarg (nilehtreB ,)aropilatoRilehcierdonroM. .flehs ylram eni ram-nepO
lram niht htiw elahs yalc ytalp ,yerg krad ot kcalBsdebretniOCaC .3noc- :arefinimaroF .%3.3 :tnetanacnurtobolG .fc inahpets .rav atanibrut lehcieR ,sedionilamonA .fcasobolgneztorB. .flehs tnei ci fed-ne g yxo dna -et ano brac eni ram-nepO eciloD1 m 0.1101 1-B1 .giF()
htiw enot semildeta n imal yerg thgil ,draHdimareconi.smsirp :arefinimaroFaireniluvlavoduesPacinamonecacinamonec (neztorB ,)sedicibiCasomrof neztorB ,aropilatoRacininneppa acioninneppa (zneR ,) .RilehcierdonroM. .flehs et ano brac eni ram-nepO
.swo rrub fo secartdna acim htiw lram ytalp yerg kraDanuaforcaM: sumareconI.ps :arefinimaroFanacnurtobolGatacirbmi donroM ,.G atalfniilloB. .flehs ylram eni ram-nepO I-4K/VI-3K eht ot gn idnop se rroc seca frus yt iu ni tno csiDdnuorgdrahmorf( wózroGikslopokleiWdna loP WN ni )1 GI 1 GI nicezczS m 0.8141 )2-B1 .giF(
ev ilo-yerg ,drah yreVakopoOCaC .sekalfacim erar ,3:tne tnoc .%3.27anuaforcaM :sumareconIsnatsnocni.sdooW :arefinimaroFanacnurtobolgearPacitevleh( illoB ,)anacnurtobolG atanigram( ssueR ,) .GitnerappalataniracitsugnaiflodnaG. .)noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO
lram niht htiw ,dei fici lis yltrap ,enot semilylram yerGsresalfdna sdebretniOCaC .swo rrub fo secart ,3%3.28 :tne tnoc .anuaforcaM: sumareconIsnatsnocni :arefinimaroF .sdooWanacnurtobolGitnerappal itnerappalneztorB, .G itnerappalataniracitsugnaiflodnaG ,anieoisnetS atplucsxeearp.)relleK( .flehs et ano brac eni ram-nepO
rus noi ssimo el pmiS?
- pag elb azi ng ocer – ecaf .tn eserp ton si
3el baT dna loP EN dna WN ni seca frus yt iu ni tno csid evi ta le rroc rehtO
elo heroB htpeD( tiso ped gn iy lre dnu fo sci ts ire tc arahCDU,sli ssof ,yg oloh til :) lanoitisopedtne mno ri vne ,sli ssof ,yg oloh til :)DO( tiso ped gn iy lrevo fo sci ts ire tc arahClanoitisoped tne mno ri vnesetoN dragowoN1 m 0.339 2-B1 .giF()
,swo rrub fo secarthtiw lram yerg ,draHdimareconidna ,smsirp ,ztrauq enifcida ropseti vo csumdna eti ryp ,etinocualg.sniarg OCaC3 .%7.95 :tne tnocanuaforcaM: sumareconI.ps .flehs et ano brac eni ram-nepO
lram niht htiw enot semilylram yerg thgiLsdebretnied erar ,swo rrub dna - fo su tirtdimareconi :arefinimaroF .sllehs anilamonAinilehtreb,relleK anacnurtobolGatanigram ( ssueR ,)anieoisnetSatplucsxeearp.)relleK( OCaC3.%5.08 :tne tnoc .flehs et ano brac eni ram-nepO ¯okciba1 m 0.417 )2-B1 .giF(
ytlis yerg kraDakopo :arefinimaroF .acim tna dnuba ,swo rrub htiw anacnurtobolGitnerappalitnerappalneztorB ,anieoisnetS.fc atplucxeearp.)relleK( .)noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO
,lram yerg ,draHresalf .swo rrub dna noi ta n imal anuaforcaM: sumareconI :arefinimaroF .psanacnurtobolGitnerappalitnerappal neztorB ,anieoisnetSatplucxeearp ,)relleK( setilatorobolGanainilehcim (yngibrO’d.) .flehs ylram eni ram-nepO owosuL m 5.392 )2-B1 .giF(
ylram yerg thgil ,ra l udon ylhgih ,tca pmoc ,drah fo deb kciht m 2 ylram neerg-yerg ra l uge rri ,seca frus ruocs htiw ,enot semil ,sesnelstrehcdra wnwod sessap kcor ehT .esab eht ta stnilf dna yerg thgilotniakopoOCaC .3 .%0.58 :tne tnocanuaforcaM: sumareconI :arefinimaroF .psanacnurtobolGitnerappal itnerappalneztorB , .GsedioniregibolgneztorB , .Gitnerappal sediollubrelgöV ,setilatorobolGatanigram (ssueR ,)anieoisnetS atplucsxeearp.relleK .)noi ta tne m ides suoe ci lis-et ano brac/et ano brac( flehs eni ram-nepO
yerg thgil ,draHakopo ,ztrauq cida rops ,etinocualgdna eti vo csum :arefinimaroF .sniargsetilatorobolGanainilehcim( yngibrO’d ,).G atpesitlum (neztorB ,)anacnurtobolGitnerappalsediollubrelgöV, anieoisnetSatplucsxe (ssueR ,)aireniluvlavoduesParegillets.)ei raM( OCaC3.%0.37 :tne tnoc .)noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO II-4K/I-4K eht ot gn idnop se rroc seca frus yt iu ni tno csiDdnuorgdrahmorf( owosuLdna loP WN ni ) wózroGikslopokleiW1 GI m 0.435 )3-B1 .giF(
yerg thgiLlatirtedonagro( larefinimarof rihtiw enot semilylram )- ylram rekrad ra l ugersresalf fo stne mgarfecracs ,dimareconi OCaC .hteet dna selacs hsifdna sllehs36.28–0.96 :tne tnoc,% :arefinimaroFanieoisnetSatplucsxeearp ,)relleK( .Satplucsxe (ssueR ,) .SacinolopakciwtiW ,anacnurtobolGitnerappal itnerappalneztorB , .GsedioniregibolgneztorB , .Gitnerappal sediollubrelgöV ,airalugnasOanaireidroc( yngibrO’d,) setilatorobolGanainilehcim( yngibrO’d ,)anillebalfoeNasogur (yngibrO’d ,)allenilevaGatalutsoc.)ei raM( .flehs et ano brac eni ram-nepO
,draHyerg thgilcitilepylram ra l uge rri htiw enot semilsresalfpu gn issap ,- htiw enot semilylram otni drawanuaforcam :sumareconIsediossidrac ssufdloGOCaC .swo rrub dna 3:arefinimaroF .%4.37 :tne tnoc anacnurtobolGitnerappalitnerappalneztorB , .Gitnerappalsediollub relgöV, airalugnasOanaireidroc( yngibrO’d ,)allenilevaGsimrofilinom (ssueR,) .G aregillets ,)ei raM(anieoisnetSatplucsxe( ssueR ,).S acinolopakciwtiW ,anillebalfoeNasogur ( yngibrO’d ,) .Nanainiuoduab (yngibrO’d.) .flehs et ano brac eni ram-nepO onzczsohC1 GI m 0.567 )3-B1 .giF(
ylram yerg ,drah yreVakopo ,ztrauq enifsu ore muN .swo rrub htiw eti vo csumdna eti ryp ,etinocualg .sniarg dimareconIera smsirp OCaC .ecracs3 .%4.36–1.65 :tne tnocanuaforcaM :sumareconI sutalucicsaf ,enieH .IsutatigidybrewoS, .IineneokrellüM. .)noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO
,ztrauq enifsu ore muN .swo rrub htiw lram yerg ,draHeti vo csumeti ryp , dnaetinocualg .sniarg dimareconIOCaC .ecracs era smsirp 3:tne tnoc .%4.95–5.45anuaforcaM :sucsidyhcaPps ,.alucuNps ,.setilucaBps,. sumareconIpssutalucicsaf .I ,..enieH .flehs ylram eni ram-nepO zC³apo3 m 5.592 )2-B1 .giF(
ylram yerg krad ,tfos ylevi t aler dna tca pmoc ylet ar edom ,draH enotstlis/enotsdum .anuaforcaM :sumareconI.ps eni ram-nepOcitsalcicilisflehs .
ytlis yerg ,draHakopohtiw eti vo csumnehw hguor ,ecna dnuba ni sekalf .su tir ted llehs etinomma dna evla vib ,ne korbanuaforcaM :sumareconI ffa .sutalucicsaf ,enieHsetinaxetaraPsutanigramotarres (rehcabnetdeR :arefinimaroF .)aninappaTsimrofiniregivuoe.)relle
K( .)noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO nytzslO1 GI m 1.236 II-4K/I-4K )5 ,2 .sgiF dna 3-B1 .giF(
etihw ,draHcitilepylram yerg krad yvaw niht htiw enot semil htiw ,eanimalstrehccitah psohp ,selacs hsifel gnis ,stnilf dna gn idnuob deruocs eht ta swo rrub dna )mc 5.0 ot pu( snoi ter cnoc .deb gn iy lrevo eht fo lai re tam ytlis su o era clac htiw dellif eca frus anuaforcaM :sihtuetoinoGinergdnul (yellotS:arefinimaroF .) anieoisnetSatplucxeearp ,)relleK( .Satplucxe (ssueR,) anacnurtobolGeta noroc illoB ,atanigram .G(ssueR), setilatorobolGanainilehcim( yngibrO’d ,)allenilevaGsisnebmov neztorB. .flehs et ano brac eni ram-nepO
su o era clac yerg krad ,draHenotstlis tna dnuba htiw )m 6.0( etinocualg, erardimareconiztrauq enifsu ore mun ,hteet hsif fo stne mgarfdna sllehs ,)mm 60.0–20.0(eti vo csum ,etinocualgOCaC .sniarg eti ryp dna 3noc - yerg otni dra wpu sessap kcor ehT .%73 .ac :tneteziag:arefinimaroF . anieoisnetSatplucxeearp ,)relleK( .Satplucxe (ssueR ,) .Sacinolop akciwtiW ,anacnurtobolGitnerappalneztorB ,allenilevaGsisnebmov neztorB , .Gataniracirt (uaereuQ.) eni ram-nepOet ano brac-citsalcicilisno brac( flehs eni ram-nepo/flehs - .)noi ta tne m ides suoe ci lis-eta
rus ruocs a si SD sihT
- tna c ifi ngis on htiw ecaf pag.
.tnoc 3 .baT
elo heroB htpeD( tiso ped gn iy lre dnu fo sci ts ire tc arahCDU,sli ssof ,yg oloh til :) lanoitisopedtne mno ri vne ,sli ssof ,yg oloh til :)DO( tiso ped gn iy lrevo fo sci ts ire tc arahC lanoitisopedtne mno ri vne setoN I-4K/VI-3K eht ot gn idnop se rroc seca frus yt iu ni tno csiDdnuorgdrahmorf( ecyzsotraBdna 1 GI nyzrtêKdna loP EN ni )2 GI 1 GI pad³oG m 4.933 )2-B1 .giF(
fo su tir ted ecracs ,klahc etihw ,tfoSdimareconiylla coL .sllehs decrepsidOCaC .eti ryp 3:arefinimaroF .%1.19 :tne tnoc anilamonAinilehtreb ,relleK anieoisnetSacinolopakciwtiW ,.S atplucxeearp ,)relleK( setilatorobolGatpesitlumneztorB ,.G anainilehcim( yngibrO’d ,)allenilevaGsisneleretnom,)ei raM( sedicibiCetu lo vni ssueR. flehs et ano brac eni ram-nepO.
,)ezis ni mc 01 ot pu( stnilf kcalb htiw enot semilylram yerg ,draH ,selacs hsifecracsarefinimarofdna dimareconicida rops ,smsirp el gnis ,)mm 50.0–20.0( sniarg ztrauq ra lu gna enifetinocualgyp ,- dna etireti vo csumOCaC .sniarg 3.%3.77 :tne tnoc .flehs et ano brac eni ram-nepO )re ppu ro( III-4K/I-4K eht ot gn idnop se rroc seca frus yt iu ni tno csiDdnuorgdrah ,1 GI k³E morf( nyzrtêKdna ,2 GI dna 1 GI loponsarKdna loP EN ni )1 ecyzsotraB1 GI m 5.873 )3-B1 .giF(
lo-yerg niht ,stnilf yerg krad htiw enot semilekil-klahc etihw ,draH- ,skaerts dna )mc 5.0( sr eyal lram dna enot semilylram evi dimareconiOCaC .eti ryp desre psid ,swo rrub tdna smsirp 3noc - .)enot semilekil-klahc( m %5.19 ,)enot semilylram( %4.77 :tnet :arefinimaroFanieoisnetSatplucxeearp ,)relleK( anacnurtobolG itnerappalitnerappalneztorB , .GsedioniregibolgneztorB ,.G itnerappalsediollubrelgöV. flehs et ano brac eni ram-nepO.
su o era clac de ddeb yerg krad ,draHeziagwef htiw strehcun ,- ,)mm 70.0–20.0( ztrauq enifsu oremetinocualgdna eti vo csum OCaC .sniarg3 :arefinimaroF .%2.14 :tne tnoc anacnurtobolG itnerappalitnerappalneztorB , .GitnerappalsediollubrelgöV, allenilevaGaregillets ,)ei raM( setilatorobolGatpesitlumneztorB. .)noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO
pag tne n imorp A. eht ot gn idnop se rroc eca frus yt iu ni tno csiDaVI-4K/bVI-4Kdnuorgdrah³P morf( ksñodna loP EN ni )8 ebêD2 m 0.224 )6 ,5-B1 .giF(
.klahc etihW flehs et ano brac eni ram-nepO.
.enot semilylraM .flehs et ano brac eni ram-nepOa ter pre tni no desaB- sgol llew fo noit. V-4K - )?(VI-4K /III-4K eht ot gn idnop se rroc eca frus yt iu ni tno csiDdnuorgdrahmorf( ecyzsotraBdna loP EN ni )1 GI ebêD6 m 0.044 )6 ,5-B1 .giF(
akopO.)lram suoe ci lis( )noi ta tne m ides suoe ci lis-et ano brac( flehs eni ram-nepO.
.enot semiL .flehs et ano brac eni ram-nepOa ter pre tni no desaB- sgol llew fo noit.
.tnoc 3 .baT
.2 .giFsdnuorgdraHdnaloP N fo snoitces eloherob suoecaterC reppU eht ni
Fig. 3. Examples of discontinuity surfaces in drill cores from N Poland
A – Gorzów Wielkopolski IG 1, depth 652.4 m, K3-IV/K4-I: hardground – bur row be neath the hardground sur face (b) and a marly lime - stone-filled cav ern (c); B – UD: organogenic/organodetrital lime stone, open-ma rine car bon ate shelf (the most com mon UD sed i men tary en - vi ron ment), depth ~653.0 m (pol ished sur face), K3-IV; C – Kêtrzyn IG 2, depth 598.0 m, K3-IV/K4-I: hardground – nu mer ous phos phatic nod ules (p), bur row/bor ing filled with white chalk (b), and glauconite encrustation on the hardground sur face (g); D – Bartoszyce IG 1, depth 422.1 m (pol ished sur face, Geo log i cal Mu seum PGI-NRI, War saw, coll. M. Jaskowiak), K3-IV/K4-I: ?com pos ite hardground – bor ings (b), frag ments of thick-shelled inoceramids (i), quartz grains (q), and small phos phatic nod ules (p); E – Olsztyn IG 1, depth 632.1 m, K4-I/K4-II:
dis con ti nu ity sur face – bur row (b) and a small phos phatic nod ule (p); DS sur faces are ar rowed; photo A by M. Jaskowiak-Schoeneichowa, pho tos B, C, D and E by K. Leszczyñski
Fig. 4. Correlation of hardgrounds in boreholes from the Szczecin Trough and the Gorzów Block
fo noitalerroC .5 .giFsdnuorgdrahdnaloP EN morf seloherob ni
with highly cal car e ous sand stone, opoka, sandy and sandy- glauconitic lime stone, and cherty gaize.
All the en vi ron ments in which the dis con ti nu ity sur faces have been iden ti fied rep re sent open-ma rine shelf, but with vary ing pro por tions be tween car bon ates and fine clastics, and a vary ing de gree of sili ci fi ca tion, so that the fol low ing sub-en vi - ron ments can be dis tin guished (Fig. 2): (1) open-ma rine car - bon ate shelf, (2) open-ma rine marly shelf, (3) open-ma rine car - bon ate- and ox y gen-de pleted shelf, (4) open-ma rine siliciclas - tic-car bon ate shelf, and (5) open-ma rine shelf with car bon - ate-si li ceous sed i men ta tion (opoka and gaize).
Dis con ti nu ity sur faces (in clud ing hardgrounds) are used for cor re la tions be tween var i ous re gions of the Cre ta ceous sed i - men tary bas ins of Po land and else where in Eu rope. In the Cenomanian through Maastrichtian sec tions, a num ber of hardgrounds have been found in south ern Po land and in the ad ja cent bas ins of Ger many and the Czech Re pub lic. How ever, the great est fre quency of hardgrounds, in both north ern and south ern Po land, is ob served in the Turonian–Coniacian in ter - val (e.g., Walaszczyk, 1992; Olszewska-Nejbert, 2004).
For ex am ple, a well-de vel oped com pos ite hardground has re cently been de scribed and ana lysed in de tail by Olszewska- Nejbert (Olszewska-Nejbert, 2004; Olszewska-Nej bert and Œwierczewska-G³adysz, 2013). Ini ti a tion of the for ma tion of this com pos ite hardground is in ter preted by those au thors as cor re - spond ing with a ma jor Mid–Late Turonian un con formity de - scribed as Se quence Bound ary Tu 4 at the base of the Seugast Mem ber Roding For ma tion in the Bodenwöhrer Senke (NE Ba - varia), near the south west ern mar gin of the Bo he mian Mas sif (Niebuhr et al., 2011), and at the ero sional base of the Soest Greensand Mem ber of the Salder For ma tion rec og nized in the Werl bore hole in the south ern Münsterland Cre ta ceous Ba sin (Richardt and Wilmsen, 2012). This is cor re lated with the lat est Turonian-Coniacian Subhercynian compressional tec tonic ac - tiv ity of the Ilsede Phase that sig nif i cantly af fected the evo lu tion of the Kraków Swell re gion. The com pos ite hardground is in ter - preted by Olszewska-Nejbert and Œwierczewska-G³adysz (2013) as cor re spond ing to the Late Turonian sea level drop.
The lat est Turonian–Coniacian Subhercynian compres - sional tec tonic ac tiv ity of the Ilsede Phase has been rec og nized in the Ger man and An glo-Paris bas ins by up lift move ments, an - gu lar discordances, sed i men tary gaps, fa cies changes, sub ma - rine slumps, turbiditic de po si tion and hardgrounds (Mortimore and Pomerol, 1997; Mortimore et al., 1998). In those bas ins, Subhercynian tectonism cre ated a tec tonic to pog ra phy that, com bined with the Late Cre ta ceous sea level fluc tu a tions, re - sulted in the for ma tion of hardgrounds.
More over, in Ba varia (south ern Ger many), Niebuhr et al.
(2012) also re ported the pres ence of a hardground in the Turonian sec tion, at se quence bound ary Tu 5 cap ping the Großberg For ma tion dated as the Late Turonian intra-Mytiloides scupini Zone. Those au thors cor re late the hardground with the se quence bound ary rec og nized by Richardt and Wilmsen (2012) in the Erwitte For ma tion of south - ern Münsterland. In Eng land, it cor re sponds to a con densed hardground se quence im me di ately above the Hitch Wood Event (Jarvis et al., 2006) and a high Up per Turonian se quence bound ary of Gale (1996). Niebuhr et al. (2012) stated that the deeper ma rine marls of the lower Hellkofen For ma tion (up per - most Turonian–Lower Coniacian), abruptly over ly ing the un - con formity at the top of the Großberg For ma tion (se quence bound ary Tu 5), may be re lated to tec tonic in ver sion at the south west ern mar gin of the Bo he mian Mas sif. This is tem po - rarily co in ci dent with the on set of the Late Cre ta ceous tec tonic in ver sion pro cesses also in the Mid-Pol ish Trough.
Wiese and Kröger (1998) rec og nized a hardground in ter - preted as mark ing a re gres sive event in the Up per Turonian suc ces sion of north ern Ger many (Late Turonian scupini Zone in the Lower Sax ony Ba sin). This may be cor re la tive ap prox i - mately with the same event ex pressed by the hardground at the K3/K4 bound ary in ter preted in the bore holes drilled in the Pol ish Low lands.
The pres ence of the Up per Turonian hardground over lain by Mid dle Coniacian marls is re ported also from the Subher - cynian Cre ta ceous Ba sin (Voigt et al., 2004 and ref er ences therein).
An other ex am ple co mes from the Czech Re pub lic, where Žitt et al. (2006) de scribe a hardground from the Cenoman - ian/ Lower Turonian bound ary in the Cre ta ceous Bo he mian Ba - sin, ac com pa nied by ero sion events and con densed sed i men - ta tion in ter vals at this bound ary.
In the Cenomanian–Turonian sec tion, hardgrounds (es pe - cially nu mer ous around the Cenomanian/Turonian bound ary) are re ported from the north east ern mar gin of the Holy Cross Moun tains in south east ern Po land (Cieœliñski, 1976;
Marcinowski and Walaszczyk, 1985; Walaszczyk, 1987, 1992;
Dubicka and Machalski, 2017). Walaszczyk (1987, 1992) re - ported the pres ence of mid-Cenomanian (DS3), Cenoman - ian/Turonian bound ary (DS4), and top-Lower Turonian (DS5) hardground and omis sion sur faces, and cor re lated them with equiv a lent phe nom ena re corded in the Cre ta ceous sed i men - tary bas ins of Po land and other re gions. These sur faces are ac - com pa nied by strati graphic gaps of vari able ex tents. The Cenomanian/Turonian bound ary hardground/omis sion sur face (DS4) is in ter preted by Walszczyk (1987) in terms of both sea level changes and the ef fect of the bound ary anoxic event (OAE2). At Annopol, Dubicka and Machalski (2017) at tempted to as sess to what ex tent the global mid-Cre ta ceous sea level changes can be iden ti fied within a condenced suc ces sion. Pay - ing spe cial at ten tion to sed i men tary dis con ti nu ities (in clud ing hardgrounds) and as so ci ated strati graphic gaps, they con - cluded that all transgressive peaks and re gres sive troughs of the rel e vant por tion of the Brit ish sea level curve of Han cock (1989) are re corded in the Annopol suc ces sion.
In north ern Po land (Gorzów Block), the only hardgrounds rec og nized from near the Cenomanian/Turonian bound ary are those in the Choszczno IG 1 and ¯abicko bore holes (Jaskowiak-Schoeneichowa, 1978b, 1981). In the for mer, the hardground sur face is de vel oped on marly lime stones and the OD is rep re sented by clay shales. This hardground can also be cor re lated with the phe nom ena re lated to the anoxic event OAE2 and a prom i nent sea level fall on the curves of Han cock (1989) anf Haq (2014).
SUMMARY AND CONCLUSIONS
In the Up per Cre ta ceous se quence of north ern Po land, hardgrounds and other prom i nent cor re la tive dis con ti nu ity sur - faces are fairly com mon fea tures ob served in the cores of bore - holes drilled in the Gorzów Block and in the ad ja cent zone of the Szczecin Trough, in the east ern part of the Peribaltic Syneclise, and in the Mazury El e va tion.
In these ar eas, hardgrounds have been iden ti fied and de - scribed from 15 bore holes. At the hardground sur faces, the over ly ing de pos its (OD) rep re sent a va ri ety of lithologies in clud - ing lime stone, chalk, marl, gaize, opoka, cal car e ous claystone and marly sand stone. The most com mon UD/OD con fig u ra tion of sed i men tary en vi ron ments is the open-ma rine car bon ate shelf both be neath and above the dis con ti nu ity sur face. The
