Acta Geologica Polonica, Vol. 49 (1999), No.3, pp. 175-213

The Upper Cretaceous succession (Cenomanian­ Santonian) of the Staffhorst Shaft, Lower Saxony, northern Germany: integrated biostratigraphic, lithostratigraphic and downhole geophysical log data

BIRGIT NIEBUHR 1, REINHARD BALDSCHUHN2, GUNDOLF ERNST3, IRENEUSZ WALASZCZYK4, WOLFGANG WEISS5 & CHRISTOPHER J. WOOD6

I Institut fiir Palaontologie, Bayerische lulills-Maximilians-Universitat, Pleicherwall I, D-97070 Wiirzburg, Germany. E-mail: [email protected] 2 Ernst-Pfliiger-Str. 7, D-30938 Burgdorf-Wettmar, Germany 3 Institutfiir Paliiontologie, Freie Universitat Berlin, Malteser Str. 74-100, D-12249 Berlin, Germany. E-mail: [email protected] 4 Institute of Geology, University of Warsaw, AI. Zwirki i Wigury 93, PL-02-089 Warszawa, Poland. E-mail: [email protected] 5 Bundesanstalt fur Geowissenschaften und Rohstoffe, Stilleweg 2, D-30655 Hannover, Germany. E-mail: [email protected] 6 Scops Geological Services Ltd., 20 Temple Road, Croydon, Surrey CRO I HT, United Kingdom.

ABSTRACT:

NIEBUHR, B., BALDSCHUHN, R., ERNST,G., WALASZCZYK, 1., WEISS, W. & WOOD, C.J. 1999. The Upper Cretaceous succession (Cenomanian ~ Santonian) of the Staffhorst Shaft, Lower Saxony, northern Germany: integrated biostratigraphic, lithostratigraphic and downhole geophysical log data. Acta Geologica Polonica, 49 (3),175-213. Warszawa.

The Cenomanian to Santonian succession of the Staffhorst shaft, ca. 50 km south of Bremen, because of its struc­ tural position in the northel11 Gelman Upper Cretaceous basin, is intermediate in character and fossil content between the pelagic sediments characterizing the Pompeckj Block in the north and the proximal sediments of the Lower Saxony Block in the south. The biostratigraphic subdivision of the shaft is based on inoceramids, echi­ noids, belemnites and foraminifera. The vm10us biozonations and zonal boundm'ies used in the Boreal Realm are compared and applied to the zonation of the shaft succession, and the biostratigrapy of the individual fossil groups is described. A new inoceramid zone, that of Inoceramus gibbosus, is proposed for the topmost Lower Coniacian; and an echinoid assemblage zonation is introduced. The existing benthic foraminiferal zonation of the Middle Turonian to Santonian has been modified, with changed age assignments based on the macrofossil zona­ tion. The proposed basal stage boundary criteria of the "Second International Symposium on Cretaceous Stage Boundaries" (Brussels, 1995) could be applied only in some cases. The proximity of the Staffhorst shaft to the trial borehole, situated only 39 m away, has permitted the Self Potential (SP) and Resistivity (R) logs to be uniquely directly calibrated against the lithostratigraphical and biostratigraphic succession of the shaft. The pre­ vious identification of some stage and substage boundaries on the logs of northel11 Gel111an boreholes based on foraminiferal zonation will need to be shifted by several tens of metres as a result of this calibration. Key words: Upper Cretaceous, Northern Germany, structural geology, electric borehole logs, stratigraphy, inoceramids, belemnites, echinoids, foraminifers. 176 BIRGIT NIEBUHR & al.

Contents

1. History (B. NIEBUHR) ...... 82 6. Echinoid stratigraphy (G. ERNST) ...... 97

2. Objectives (B. NIEBUHR) ...... 82 7. Belemnite stratigraphy (G. ERNST) ...... 102

3. Structural development in the Staffuorst 8. Supplementary faunal records (C.J. WOOD) .. 104 area (R. BALDSCHUHN) ...... 83 9. Foraminiferal stratigraphy (W. WEISS) ...... 106 4. Borehole log peak stratigraphy and lithostratigraphy (B. NIEBUHR) ...... 85 10. Multistratigraphic correlation and conclusions...... 110 5. Inoceramid stratigraphy (1. WALASZCZYK & c.J. WOOD) ...... 91 References ...... 1 J 6

1. HISTORY (B. NIEBUHR) sponges) is incorporated into the collection of the University of Hamburg. The echinoids and belem­ The Staffuorst shaft is situated at the boundary of nites also belong to the collection of the University the Lower Saxony and Pompeckj blocks ca. 50 km of Hamburg, but are temporarily on loan to G. south of Bremen on the ordnance survey map sheet ERNST, Berlin, for further investigation. 3219 (Affinghausen). Boreholes drilled by the Part of the Staffuorst shaft Upper Cretaceous German oil/gas companies (Staffuorst 2 and 3 bore­ succession (Middle Turonian to Lower Coniacian) holes) prov'ed the Staffuorst Dogger iron ore deposit was already illustrated by WOOD & al. (1984). in 1954. In order to investigate this deposit in detail, Stratigraphic data were published by ERNST & al. the Staffuorst trial borehole was drilled in September (1983). FRIEG & al. (1989) worked on the Albian/ 1960 at grid reference 3492 152/58 44943. One year Cenomanian boundary succession and calibrated the later the excavation of the 6.75 m wide shaft was aranaceous microfauna against the electric borehole started, 39 m south of the Staffuorst trial borehole at logs. By means of the boreholes of the Staffhorst grid reference 3492 152/58 44 904. The Barbara area, KOCKEL (1998) demonstrated certain effects of Erzbergbau GmbH (now Barbara Rohstoffbetriebe the northern German inversion tectonics in the GmbH) was able to prove reserves of oolitic iron Coniacian to Santonian. BALDSCHUHN & al. (1998a) ores of the phosphorite-rich chamositic-sideritic dealt with salt intrusions into the bedrocks. type of ca. 500 Mio. tonnes over an area of ca. 60 km2 (THIENHAUS 1960). Because of the technical problems involved in mining this deposit, the pilot 2. OBJECTIVES (B. NIEBUHR) plant was abandoned in August 1965 and the Staffuorst shaft was closed (ROHRS 1992). This paper deals with the Upper Cretaceous suc­ Weare grateful for permission to use the logging cession of the shaft, which spans the interval from ca. data and fossil content of the shaft of the Barbara 240 - 790 m. Because of its structural position, the Rohstoffbetriebe GmbH (Porta Westfalica). The fos­ section mediates between the different facies areas of sil and lithologic material was collected by SPIEGLER the "proximal" Lower Saxony Block, to the south, & SPIEGLER (1964) from the heaps of rock excavat­ and the "pelagic" Pompeckj Block, to the north. Due ed from the shaft, but not directly from the shaft to the close proximity of the shaft and the the trial itself. Normally each unit of excavated material borehole, Staffhorst provides a unique opportunity, spanned about 4-7 m of strata. The collections of using a variety stratigraphic methods (1) to investi­ Bundesanstalt flir Geowissenschaften und Rohstoffe gate the appplicatbility to the shaft succession of the (BGR) and the Niedersachsisches Landesamt flir Stage and Substage boundary criteria that were pro­ Bodenforschung (NUB), Hannover, contain the posed at the Second International Symposium on inoceramids and the microfauna. The supplementary Cretaceous Stage Boundaries, Brussels, 8-16 fauna (ammonites, bivalves, brachiopods, corals, September, 1995 (Cenomanian: TRaGER & KENNEDY UPPER CRETACEOUS OF THE STAFFHORST SHAFT 177

1996; Turonian: BENGTSON 1996; Coniacian: fig. 5) to the left and right of the SP log of the KAUFFMAN & al. 1996; Santonian: LAMOLDA & Staffhorst trial borehole respectively. In chapter 10, HANCOCK 1996); (2) to calibrate the electric logs of "Mulstistratigraphic correlation and conclusions" the trial borehole against the lithostratigraphy and the interpretation of the stratigraphy and the ratio­ biostratigraphy of the shaft; (3) to apply the recali­ nale behind the revised positioning of the Stage and brated electric logs to the interpretation of the electric Substage boundaries is comprehensively discussed. logs of the numerous other north German boreholes. This recalibration will be of particularl value to the German oil/gas companies, since the Upper 3. STRUCTURAL DEVELOPMENT IN THE Cretaceous in the older boreholes was almost invari­ STAFFHORST AREA (R. BALDSCHUHN) ably never cored and the positioning of the Stage and Substage boundaries was mostly based on electric The Staffhorst shaft is situated on the lower logs calibrated by means of foraminiferal biostatig­ northern flank of the Staffhorst inversion and thrust raphy, using now outdated stage concepts. In chap­ structure (Text-figs 1-2), which continues towards ter 4, "Borehole log peak stratigraphy and lithos­ the east into the Blenhorst structure and towards the tratigraphy", the previously applied (BALDSCHUHN west into the Scholen structure. This elongated & JARITZ 1977; KOCH 1977a) and the herein revised structure is part of a thrust fold belt 70 km long and Stage and Substage boundaries are shown (see Text- 15-20 km wide, on the northern margin ofthe invert-

go

I I Upper Cretaceous ~ subcrop of the Upper Cretaceous ~ " ~ ....•• 0<""""'" ...... ~()______Upper Cretaceous isocontour lines .::::::::::::::: Lower Cretaceous /' in 100m below mean sea-level

r--'('" /, -::-" ~.\/- I ...... ,.",~,,~ I: ._ I - "-, !, I Triassic and Jurassic normal fault o 10km ! I. 1Zechstein (salt dome) .. .. v reverse fault or thrust I

Fig. I. Structural location map of the Staffhorst area, Lower Saxony 178 BIRGIT NIEBUHR & al. ed western Lower Saxony Basin, which can be fol­ The structural development began as early as the lowed from the Steinhuder Meer lineament at the Triassic. In Middle Buntsandstein and Lower Weser river in the east to the Cloppenburg area in Gipskeuper (km1) times, an active synsedimentary, the westnorthwest (BALDSCHUHN & KOCKEL 1998). longitudinal W-E striking, north-dipping fault devel­ A system of basement faults at the base of the Upper oped along the southern margin of the present day Permian Zechstein, the so-called Goldenstedt - Staffhorst structure (BALDSCHUHN & aI. 1998b). Blenhorst lineament, separates the Lower Saxony This fault bordered a half-graben, which in Liassic Basin in the south from the Pompeckj Block in the and Middle Jurassic times developed towards the north. The southern margin of the Pompeckj Block north into a graben with synsedimentary active is subdivided into the Southern Oldenburg and Hoya listric boundary faults rooting in the Rot evaporites. blocks, and is characterized by deep marginal Following regional erosion during the Early troughs with Upper Cretaceous sedimentary infill. Kimmeridgian, transgressive Middle Kimmeridgian, The inversion structures, including the Staffhorst Portlandian and Berriasian sediments were deposit­ structure, which form the northern margin of the ed in the Staffhorst graben. above-mentioned thrust fold belt, are characterized The northern graben shoulder was situated during by intrusions of Zechstein salt into the level of the the Late Jurassic and Berriasian in the area between Upper Buntsandstein ("Rot") evaporite layer, and by the boreholes Mellinghausen 1 and Staffhorst E 14, subhorizontal detachment planes which partly root which today is the most uplifted part. During the in thrusts within the basement and cut through the Early Cretaceous (Hauterivian to Aptian) this area entire pre-Upper Cretaceous overburden. These was incorporated into the complex Staffhorst graben thrusts had been formerly normal faults and were in the course of the progressive enlargement of the reactivated as thrusts during the Late Cretaceous Lower Saxony Basin towards the north. (see Text-figs 1-2). The northernmost block of the Staffhorst structure The structural development of the Staffhorst in which the Staffhorst shaft is situated remained in structure, like all other inversion structures in the the position of a graben shoulder until the Late western Lower Saxony Basin, follows a cycle with a Aptian. DUling the Early and Middle Albian it was duration of 70 my, which can be subdivided into four also incorporated into the Lower Saxony Basin along genetic stages (BALDSCHUHN & al. 1991). a marginal flexure zone. The Albian transgression, The first genetic stage commenced with the caused by an eustatic sea level rise, flooded the south­ taphrogenetic development of the Lower Saxony rift ern fringe of the Pompeckj and south Oldenburg basin, which started in the Late Jurassic, and during blocks, including the Asendorf salt pillow. This area which rapidly subsiding synsedimentary troughs, had been uplifted during the Late Jurassic taphrogen­ grabens and half-grabens formed. esis and subsidence of the Lower Saxony Basin and The second genetic stage comprised the Albian, eroded down to the Lower Middle Jurassic. Cenomanian and Turonian ages. The tectonic activi­ The interval from the end of the Albian until the ties decreased, the depocentres were gradually filled Turonian was tectonically quiet. This is also con­ without faulting and sedimentation extended over firmed by SPIEGLER & SPIEGLER (1964) for the the basin margins. Staffhorst shaft. In the Early Coniacian the subher­ The third genetic stage, the inversion of the cynian inversion of the Lower Saxony Basin (Ilsede Lower Saxony Basin, started in the basin centre in phase of STILLE 1924) was initiated. The centre of the Coniacian and proceeded during the Santonian the inversion and uplift was the axis of the North towards the margins of the basin. During this stage, Westphalian - Lippe trough, which transformed into the entire basin was uplifted, as well as the individ­ the North Westphalian - Lippe swell. The basement ual component troughs and grabens. The former nor­ underneath this swell became uplifted by several mal faults became reversely reactivated and changed thousand metres (BALDSCHUHN & KOCKEL 1997 a, b). to reverse faults or thrusts. The Staffhorst graben, together with the Siedenburg During the fourth and final genetic stage, which structure, became uplifted and inverted to a much lasted from the Campanian until the Maastrichtian lesser extent, due to the external position at the according to the distance from the basin centre, i.e. northern margin of the Lower Saxony Basin. The the former North Westphalia - Lippe trough, the non­ basement beneath the Siedenburg structure was ruptural and flexural uplift of the structures gradual­ thrust onto the Staffhorst Block. SPIEGLER & ly ceased, accompanied by deep erosion of the struc­ SPIEGLER (1964) described evidence of tectonic tural crests and infill of the marginal troughs. influence on the Lower Coniacian to Santonian sed- ACTA GEOLOGICA POLONICA, VOL. 49 B. NIEBUHR & al., FIG. 3

Staffhorst E 9 borehole Staffhorst trial borehole

~-·-in compar1son to Staflhonrt... ",-tE 9 borehole t----In comp8rison to staffhorst.. -.~"'­ 7 borehole

Fig. 3. SP and SN log correlation of the Staftborst trial borehole in comparision to Staffhorst 7 and E 9 boreholes UPPER CRETACEOUS OF THE ST AFFHORST SHAFT 179

BLO CK LOWER SAXONY BA SIN POMPECKJ

ASENDORF SIEDENBURG STAFFHORST

SOQOm 50DOm R. BALOSCHUHN & F. KOCKEL o 1 2km '------'------BGA Hannover 1998

Fig. 2. SSW to ENE section of the StatIhorst area through the boundary region between the Lower Saxony Basin in the south and the Pompeckj Block in the north iments from ca. 460 m depth in the Staffhorst shaft. beginning of the Middle Oligocene and in the Early The former normal faults in the basement, as Miocene (MURAWSKI & at. 1983). These Tertiary well as the south-dipping parallel faults in the sediments were partly removed in Pliocene times post-Zechstein sedimentary pile, became reversely when the Lower Saxony mountainous area became reactivated in the compressional stress field and uplifted in compensation to the subsidence of the became thrusted against the Pompeckj Block in the North Sea Basin. north. The thrust front of the detachment plane in the Rot evaporites reached the Asendorf salt pillow in the north. Zechstein salt became mobilised and 4. BOREHOLE LOG PEAK STRATIGRAPHY intruded into the Rot evaporites at the boundary AND LITHOSTRATIGRAPHY (B. NIEBUHR) faults of the uprising Staffhorst graben and the South Oldenburg Block in the north. The South Oldenburg Geophysical methods Block itself subsided synsedimentarily and, over its southern margin, a system of marginal troughs The wire line logs investigated comprise the (VOIGT 1963) developed, which received the eroded Spontaneous or Self-Potential (SP) logs, expressed material from the southern inversion structures. in millivolts, and the Resistivity or Normal (N) logs, Erosion of the crests of the inversion structures expressed in ohmmetres. started already in Coniacian and Santonian times. The SP logs primarily reflect the lithology, and On the northern flank of the structure are found the resistivity of the formation waters, and not the onlap unconformities of the transgressive Santonian permeability (NORTH 1985; HATZSCH 1994). They as well as Lower and Upper Campanian that are sim­ are particularly valuable for distinguishing between ilar to those observed by NIEBUHR (1995) in the east­ shale and non-shale rocks. The highest (right-hand­ ern Lower Saxony Basin. The transgressions were ed = positive) SP values correspond to the highest caused by eustatic events which interfered with the clay contents and, due to the absence of sandy inter­ final stages of the inversion. During the Late calations within the Upper Cretaceous carbonates, Campanian and Maastrichtian, beds of Early the lowest (left-handed = negative) SP values corre­ Campanian age became uplifted on the northern spond to the sediments with the highest carbonate flank of the structure. content. Following the regressions in Maastrichtian and, The N logs were used to differentiate the specif­ especially, in Middle Palaeocene times, linked to ic resistivities of the layers penetrated, as well as to eustatic sea level changes (GRAMANN & KOCKEL specify the lithologies and geophysical properties of 1988), the crest of the structure became eroded down the rocks. They also allow the recognition of bed­ to the Turonian and Cenomanian. This peneplain ding planes. The logging procedure usually compris­ was flooded by the Late Palaeocene - Early Eocene es the short normal (SN), with 16" separation of the sea, with further transgressions taking place at the electrodes, and the long normal (LN) with 64" sepa- 180 BIRGIT NIEBUHR & at. ration. However, the LN log has not been figured The Cenomanian to Upper Coniacian strata of here since, due to the massive lithology of the Upper Staffhorst dip at ca. lOoN-NE. Due to the location of Cretaceous rocks, it shows only minor excursions. the trial borehole 39 m to the north of the shaft, a correlation value of +7 m for a correlation from the SP and SN log correlation shaft to the trial borehole, and -7 m from the trial borehole to the shaft has to be used (see Text-fig. 5). The geophysical data have proved to be the Two separate depth values are therefore given in the most reliable tool for correlation (see ALBERTI chapters "Borehole peak stratigraphy and lithos­ 1968). Consequently, a log peak stratigraphy for tratigraphy" and "Multi stratigraphic correlation and the Late Cretaceous of northern Germany was conclusions", the first of which is the shaft depth and established by BALDSCHUHN & JARITZ (1977) and the second (in brackets) is the trial borehole depth. calibrated against the microfossil biostratigraphy of Upsection of 303 m depth, above a major hiatus of KocH (1977a). The log peak stratigraphy was based ca. 90 m in the Upper Coniacian, the Santonian sed­ on distinctive negative SP peaks, which were con­ iments are apparently flat-lying and no correlation tinuously numbered from the base (Cenomanian) to factor is needed. SPIEGLER & SPIEGLER (1964) also the top (Maastrichtian). The Late Cretaceous stan­ recognized a dip only well below the prominent hia­ dard SP logs (BALDSCHUHN & JARITZ 1977) were tus at 379 m shaft depth. subdivided into 84 correlatable units, defined by SP The bedding of the intervals 243-388 m log peaks 0-83. (243-394 m) of the Upper Santonian to Middle In the SP log of the Staffhorst trial borehole the Coniacian and 411-453 m (418-460 m) of the Lower SP peaks 0-8, 11-16 and 20-30 were proved, repre­ Coniacian was described by SPIEGLER & SPIEGLER senting the newly interpreted stratigraphic interval (1964) as "tectonically disturbed", this being linked from the Albian/Cenomanian boundary to the lower to the inversion of the Staffhorst graben in the Early Upper Coniacian. A log peak stratigraphy of the Coniacian (BALDSCHUHN & al. 1985, 1991). Due to Santonian is not possible because of the numerous the following progressive uplift and erosion, the sec­ hiati and the strong condensation in the Staffhorst tions are generally incomplete. Only the Santonian trial borehole succession. transgressions overlap the inversion structure. The stratigraphic completeness of the Upper Cretaceous succession of the Staffhorst area increas­ es from S to N (Text-fig. 2), whereas the thickness Litho- and log peak stratigraphy remains constant or is slightly reduced (Text-fig. 3). A comparison with the stratigraphically more com­ The lithostratigraphic investigation of the Staffhorst plete electric borehole logs of the Staffhorst 7 (Sth 7, shaft (Text-fig. 5) was caITied out using the material in ca. 13 km NE of the Staffhorst trial borehole) and the collections of the BGRlNLtB, Hannover. In this Staffhorst E 9 (Sth E 9, ca. 2 km NNW of the way, it was possible to check and, where necessaly, to Staffhorst trial borehole) boreholes (see Text-fig. 1) revise the descriptions given by SPIEGLER & SPIEGLER by means of log peak stratigraphy reveals the fol­ (1964). For a definition of the related litho-units and lowing hiati within the Upper Cretaceous succession events see ERNST & al. (1979, 1983), WOOD & al. of the Staffhorst trial borehole (Text-figs 3-4): (1984) and ERNST & WOOD (1995). 654 m: Cenomanian/Turonian boundary - 11 m (to 5th 7) with 5P peaks 9 + 10; The Albian/Cenomanian boundary lies in the 563 m: lower Upper Turonian - 17 m (to 5th 7), 24 m (to Bemeroder Schichten (KEMPER 1973) and is litholog­ 5th E 9) with 5P peaks 17-19; ically poorly characterized. In the electric borehole 491 m: lower Lower Coniacian - 6 m (to 5th 7), 7 m logs it is taken at a marked negative SN peak at (to 5th E 9); 779 m shaft (786 m trial borehole), the so-called 407 m: Lower/Middle Coniacian boundary - 7 m "Bemeroder Einschnurung" (Bemerode constric­ (to 5th 7), 10 m (to 5th E 9); tion), biostratigraphically defined by the associated 357 m: Middle Coniacian - 6 m (to 5th 7), 8 m (second) occurrence of the ostracod Physocythere (to 5th E 9); steghausi (FRIEG & al. 1989). 303 m: Upper Coniacian - 86 m (to 5th 7), 87 m Lower Cenomanian: The Bemeroder Schichten (to 5th E 9) with 5P peaks 31 + 32; of the basal Cenomanian, between 753-779 m 243 m: Upper 5antonian to basis of Tertiary - ca. 700 m (760-786 m), are marly with fine silty concretions (to 5th 7) with 5P peaks 36-66. and streaks and lithologically scarcely distinguish- UPPER CRETACEOUS OF THE STAFFHORST SHAFT 181

Staffhorst E 9 (2kmNNW) Staffhorst trial borehole (13 km NE) Staffhorst 7

320 29 Upper UpperCo. ______e ____ ------_ .. _- ...... -----

A/V"\ 28 600 Middle Coniacian Middle Middle Coniacian Coniacian 27 27

-_. A/V"\ --- lower 1360 lower Coniacian 430 CD

25 A/V"\ 24 lower ~24 lower.~ Lower Conia- Coniacian Coniacian cian 23 520 23 } UpperTu. ~} UpperTu. i UpperTu 78 G

550

Fig. 4. Hiati in the Staffhorst trial borehole section in comparision to Staffllorst 7 and E 9 boreholes

able from the Upper Albian. These are interpreted in here on the SP und SN logs show relative high val­ a sequence stratigraphic context as a shelfal low­ ues. Two inoceramid debrites in this marl unit at stand sediment beneath the Lower Cenomanian 730-735 m (737-742 m) and 722-726 m (729-733 m) transgression horizon. In northern Germany, the respectively may represent sequence boundaries. Bemeroder Schichten, with a maximum thickness of Within the uppermost Lower Cenomanian sequence up to 40 m, are only locally developed; in many III the glauconite content gradually decreases and places, as in the Salzgitter area, the sediments of the the carbonate content concomitantly gradually Lower Cenomanian transgression lie directly on the increases. Up to 683 m (690 m) the sediment con­ Flammenmergel (FRIEG & al. 1989). sists of calcareous marlstones. Intervals with distinct The most important marker horizon, SP peak 0 at alternations between calcareous and marly beds, 750 m (757 m) with distinctly more negative (= thus with high SP and SN values, occur between more calcareous) SP values, is the sediment of the 683-707 m (690-714 m) at the level of SP peaks 4-6. Lower Cenomanian transgression, which here, as This lithological and sequence development of the locally in England (WOOD, pers. comm.) is com­ Lower Cenomanian is comparable with that found in posed of massive hard glauconitic limestone. more proximal depositional areas around Salzgitter, Upsection there is a distinct facies change to glau­ southern Lower Saxony (cf. WILMSEN, in: NIEBUHR conitic marlstones with inoceramid debris. From & al., in prep.); however, in Staffhorst the upper- I

182 BIRGIT NIEBUHR & al.

most Lower Cenomanian sequence III (Mariella upwards into grey (SPIEGLER & SPIEGLER 1964). In sequence of ERNST & REHFELD 1997) is two to three the overlying beds with SP peaks 11 + 12, the sedi­ times thicker. ment becomes increasingly calcareous and paler. Middle Cenomanian: A particularly marked glau­ Middle Turonian: The so-called WeiBe I conitic marl bed with high SP values is found at the Grenzbank is represented by a well defined lime­ I base of the Middle Cenomanian above SP peak 6 at stone bed at the top of sequence VII (ERNST & WOOD 682 m (689 m), and marks a sequence boundary. 1995), at the level of SP peak 13, between Associated with this sequence boundary is a debrite 614-621 m (621-628 m). This peak is one of the composed of abundant comminuted irregular echi­ most conspicuous Upper Cretaceous peaks in the SP noids at 678 m (685 m). The Mid-Cenomanian event and SN borehole logs of the Lower Saxony Block between 676-678 m (683-685 m) is developed as a (see Text-fig. 3) and is also easily identifiable in the bioturbated nodular calcareous marlstone, associated borehole logs of the Pompeckj Block (see as usual, with the occurrence of Holaster subglobosus BALDSCHUHN & JARITZ 1977). The WeiBe (ef ERNST & al. 1983; ERNST & REHFELD 1997). After Grenzbank terminates in the sequence boundary of increasing carbonate content to SP peak 7 at 662 m the marl bed Moat 614 m (621 m) and the corre­ (669 m) the dark marly and glauconitic sequence sponding marked positive SP peak. This spectacular boundary of the Pyenodonte event at 659 m (666 m) is dark grey marl layer with included inoceramid indicated by a marked positive SP peak. This sequence debris appears to be of allochthonous origin. ERNST IV of the Middle Cenomanian is thus expressed in the & REHFELD (1998) postulated an hiatus at the hori­ SP log in exactly the same way as sequence III of the zon of marl bed Mo. upper Lower Cenomanian: above a marly-glauconitic Disturbed alternations of calcareous marlstones sequence boundary with an abrupt, positive SP peak, and marly limestones with intercalated, mostly the increase in carbonate content is expressed by a allochthonous, marl beds mark the 587-602 m falling SP trend. The top of the sequence, at SP peak 6 (594-609 m) interval. The red coloration of the sed­ for sequence III, and at SP peak 7 for sequence IV iments of the Middle and Upper RotpHiner of the respectively, shows the lowest SP values in each case. more proximal depositional area near Salzgitter Thus presumably completely developed sequences in (ERNST & al. 1998b) is not developed in Staffhorst. this lithology are expressed in the SP logs by typical Between 575-587 m (582-594 m) the limestones "saw-tooth" signatures (see Text-fig. 5). exhibit omission surfaces. These limestones termi­ Upper Cenomanian: Of the overlying sequence nate in a debrite with inoceramid debris at 573 m V of the Upper Cenomanian Arme rhotomagense (580 m), which can be interpreted as a sequence Kalke (STROMBECK 1857), only the basal part up to boundary between sequences VIII and IX. the Amphidonte event could be proved. In contrast Upper Turonian: At 556 m (563 m) log peak to the S6hlde section, near Salzgitter (see ERNST & correlation indicates an hiatus comprising SP al. 1998b), the upper ca. 15 m of the Arme rho­ peaks 17-19 (Text-figs 3-4), which can be tomagense Kalke, the plenus Bed and the lowest 4 m assigned to the lower part of the Upper Turonian. of the Turonian are all missing. Compared to the Above the hiatus the sediment in the following Staffhorst 7 borehole on the pelagic Pompeckj Lower Limestone Unit becomes increasingly Block, in which all the SP peaks of the more calcareous. At 534-537 m (541-544 m) an Cenomanian/Turonian boundary interval are demon­ alternation of hard, splintery white limestones strable, 17 m of sediment are missing here (Text­ with dark grey marls could correspond to the figs 3-4). In Staffhorst, SP peaks 9 + 10 are absent at stratigraphic level of the Hyphantoeeras event the omission surface with Amphidonte and phospho­ (see chapter 6). Between SP peaks 22 + 23 at ca. rites at 647 m (654 m). The base of SP peak 10 ofthe 520 m (ca. 527 m) there is a distinct facies change Staffhorst 7 and E 9 boreholes within sequence VI from the Lower Limestone Unit into massive corresponds to the plenus Bed (see Text-fig. 4; ef greenish-grey marlstones, which represent the NIEBUHR, in: NIEBUHR & al., in prep.). stratigraphic equivalent of the GrauweiBe Lower Turonian: From 641-647 m (648-654 m) Wechselfolge, and are expressed by uniform appear reddish and greenish coloured calcareous small-scale changes in SN values ranging from marlstones, the so-called Lower Rotpliiner of the low to medium levels. ALBERTI (1968) had already Lower Turonian. The base of the Rotpliiner is com­ distinguished this stratigraphic interval as a con­ posed of greenish-grey, followed by reddish-brown, spicuous marker in electric borehole logs of the marly limestones. The reddish coloration passes boreholes of the Pompeckj Block. UPPER CRETACEOUS OF THE STAFFHORST SHAFT 183

stages! depth lithology and lithoevents sub­ trial of Staffhorst shaft stages bore- this paper hole shaft

greenish spiculitic mar1stones, between 324-330rn 1-5mm thick coarse sitty marl layers (intervaI1-5cm) ) ------28 350 ~ysterbed I greenish spiculitic marlstones c I coarse silty dark marfstones ns Emscher Marls ·u 27~ c ns mar1stonas, between 388-402m several marl layers, .~ ~ ·u 400 2-3cm thick in the upper part - lii rvv'\ ? .!!! 400 and 10-15cm thick in the lower part c o marlstones with several 1-5cm thick marl layers I-0_O-+-~_+_--___:""'-,.~------~~o o ~ysterbed Transffional Unit: calcareous marlstones to dark. manstones 450 (decrease of Cae03), 26~ between 455-465m 5-8cm thick dark mart layers ..J

25 Upper Umestone Unit: 1-3m thick marly limestone beds with 1-3cm thick marl layers 2y 500 500 23~~::----+--I----l Grau-WelBe Weohselfolge: bioturbated marlstones ... Lower Umestone Unit: 22 III limestones with less 10·15cm thick marl layers,s, c.. between 531-531.5m 4 conspicuous marts, 21 c.. 550 ~e~~~~:~d~~~;'0t~\ciPcm thick, :::J rvv'\ 20 III =a "0 ~ 600

12 ------.J 11 - ---1--:-1----1 650 8 ::i ... 7 c IIIc.. ns c.. '2 :::J £: ns .!!! E c 700 o ns c E Q) o o c Q) o 750 750 ... c..G> SamarOOl!tr Schloht:en: c.. silty marlstones :::J t"V'./'\ 800 II peak strati- I 800 II Qraphic hiatus

Fig. 5. SP log of the Staffl10rst trial borehole and lithology of the Staffborst shaft. Note the 7 m correction factor between shaft and trial borehole as well as the previously applied (BALDSCHUHJ\ & JARITZ 1977; KOCH I 977a) and newly interpreted stage and substage boundaries (this paper) 184 BIRGIT NIEBUHR & aT.

Lower Coniacian: In the lowermost Coniacian, upper Upper Coniacian, since above the hiatus basal above SP peak 23 at 504 m (511 m), the massive Lower Santonian has been proved (see chapter 5). marlstones pass up into the marly limestones of the Santonian: The Santonian of Staffhorst is con­ following Upper Limestone Unit. The equivalent of densed and full of hiati; consequently no attempt has the GrauweiBe Wechselfolge would thus have in been made to number the log peaks of the trial bore­ Staff'norst a ca. 14 m thick "Turonian part" and a ca. hole. This situation relates to the structural position 2 m thick "Coniacian part" . This ca 7 : 1 ratio is very of the Staffhorst area on the top of the inversion similar to the 6 : 1 ratio found in the Salzgitter­ structure (see chapter 3). The Lower and Middle Salder area (WOOD & ERNST 1998, p. 95). According Santonian succession is developed as spiculitic to the electric borehole logs, the Upper Limestone marlstones with pigment-glauconite, and is scarcely Unit probably extends up to above the SP peak 25 at distinguishable lithologically from the underlying 473 m (480 m). However, it is lithologically not Upper Coniacian. Here again there are some more clearly separable from the overlying Transitional calcareous layers. At 268-271 m and 249-253 min Unit, since this contains repeated calcareous interca­ the shaft and trial borehole coarse detrital, bioclast­ lations in the basal part. rich marls tones with mass occurrences of Above 453 m (460 m) the boreholes can be corre­ Pseudoperna boucheroni are interpreted as tem­ lated only by means of SN logs. This facies change pestites. Between 261-263 m, centimetre-sized shows the onset of inversion tectonics in the Lower phosphorites were found, indicating a distinct hiatus Coniacian on the Lower Saxony Block (BALDscHuHN with an associated transgression horizon. & al. 1991; see chapter 3).The SP logs of boreholes on both the Lower Saxony and Pompeckj blocks The Late Cretaceous succession in both shaft and exhibit relatively small values on a low level. trial borehole is truncated at 242 m by the Lower Between 413-483 m (420-490 m) alternations of bio­ Eocene transgression (SPIEGLER & SPIEGLER 1964; turbated marlstones and calcareous marlstones occur, KOCH 1977b). with the alternation being particularly strikingly developed between 443-447 m (SP peak 26 at 450- 454 m in the trial borehole). Above an oyster bed at 5. INOCERAMID STRATIGRAPHY 426 m (434 m), in the upper Lower Coniacian, the (1. W ALASZCZYK & C.J. WOOD) sediment is even more uniform, comprising dark marlstones with less calcareous layers, and represent­ The Staffhorst shaft provides extremely rich and ing the stratigraphic equivalent ofthe Emscher Marls. taxonomically diverse inoceramid material, allowing Middle Coniacian: The onset of distinctly more precise stratigraphic subdivision of the succession in negative SP values, approximately marking the end terms of the existing zonal scheme (Text-fig. 6). of the typical Emscher Marls, appears at SP peak 28 However, as in the case of the other macrofossils, the in the Middle Coniacian on the "pelagic" Pompeckj inoceramid samples generally represent intervals that Block (see BALDscHuHN & JARITZ 1977), on the are several metres thick, so that only a broad picture Lower Saxony Block, however this monotonous of the succession of assemblages and the location of marly facies may locally continue up into the Lower critical event beds can be obtained. It must also be Campanian. In Staffhorst, according to log correla­ emphasised that much of the material is to a greater tion, two small hiati occur within the Emscher Marls or lesser extent distOlted through compaction. of the Middle Coniacian at 350 m (357 m) and 400 m In the Cenomanian and Turonian parts of the suc­ (407 m) respectively, but these cannot be identified cession, the inoceramid record is surprisingly biostratigraphically. At 352 m (359 m) another oys­ incomplete, but it is unclear whether or not this is a ter bed is found: result of the collection method from heaps of rock Upper Coniacian: In the Staffhorst area, the excavated from the shaft (the Halde, in German) or Upper Coniacian succession is marked by the of selective collecting of particular fossil groups. renewed intercalation of gradually paler and more cal­ With the exception of some event occurrences, the careous portions. At 303 m in the shaft and trial bore­ available material is not particularly impressive. hole (Coniacian/Santonian boundary) log peak corre­ However, the inoceramids can be used to locate the lation identifies a distinct hiatus, which in the approximate position of most of the stage and sub­ Staffhorst trial borehole is expressed by the absence stage boundaries. of some 90 m, corresponding to SP peaks 31 + 32 (see The Coniacian assemblages are of particular Text-fig. 3). This hiatus comprises the middle and importance in that they pennit a further elaboration of

'I 1 UPPER CRETACEOUS OF THE STAFFHORST SHAFT 185

Staffhorst shaft stages I macro­ sub­ fossil- stratigraphic range stages zones of inoceramids inoceramid events and associations c Ii ~phenoceramu ,~ :::I pinniforrnis C ---- ...... "Ci Cordiceramus .sc i cordiformis CU ···ciiia:·iinCiii:····· tn .J latoplieatus

Magadi­ ceramus I. fasciculatus events subquadratus ~

! Platyceramus belts Volviceramus Platyceramus belts eI) involutus =c i ~ I. mantel/l event "CI ." i·························· P/atyceramus belts c Volviceramus ~ j i ~ CU koeneni ",.- ~ I: ~ ~ V. koenenl event '(3 ...... ~~~ ~ Platyceramus belts t---- transition zone characterised by ,~ Inoceramus ""' - ~o sulcate Inoceramus ex gr./amarcki complex C gibbosus ~ : ! o () ···c~·~~;~~~·/·· ~ Iii oS Cr. deformis g, :

~ Cr. cr:ssus 450' J; ...J inconstans • ~ C. c. inconstans event ~ C. w. hannovrensis event ~ cw~e~~~f~ee~.:!1!~o~~~~ waffersdotfensis ·~··0~ ~ C. deformis erectus I event Cr. walters- . ., g ., ..- Didymotis I event C. waltersdorfensls event ....•.. 9.9.rt.f!!7~!~ .. _/ i ~ j r­ ei) 0. .. ~r;~~~!.~...... ~ ; ~ 0. I. perplexus ~ ~ :::I ...... 550 ~ ~ large I. ex gr. NV'\ '" '" lamarckil .~ ~ c I. inaequivalvis {g ~ ,~ ...... 0 g - large fragments of large Inoceramus ex gr. Jamarcki c ~ ~ e Inoceramus ~ ~ I. lamarcki events (overtying T cJ 1 with undifferentiated lamarcki group and :::J lamarcki 600 I- ~ Inoceramus inaequivalvis modestus at 588~592m !!! "'inoc:'cu;jieri""' g - FO Inoceramus lamarcki ---- ...... ~ - FO Inoceramus cuvieri ' My/. labiatus / ~ ...J M. my/i/oides ,.. A.,... II ~ Myti/oides events ::J C. guerangeri ,"""" ~ Amphidonte event ---- ~; .. uKes}jr6w;;el 650 ~ Pycnodonte event :E ···1.j\::,iioiij:······ ____:!: .....c:.ma!l77e: rn.l1gense .•...... ~ minor Pycnodonte event c not zoned with Inoceramus ct. schoendorti CU Mantelliceras '2 ~ I. vlrgatus event CU dixoni E ovenap of I. crippsi and I. virgatus o c Mantelliceras Q) mantelli ~ I. ;:ffv~::t ~,::g~J'kreide" fecie. of Helgoland. () ~ and of "1st Inoceramid Bed" of eastern England ,~ N. ultimus / Aucellina event equivafent of "Paradoxica Bed" of eastern England

not zoned r­ Q) 0. 0. ::J 800

Fig. 6. Vertical ranges and abundances of inoceramids in the Upper Cretaceous of the Staffhorst shaft 186 BIRGIT NIEBUHR & al. the present inoceramid zonal scheme that is applicable HEINZ from the marly chalk facies of the former at least in the European Province. A new upper Lower Liineburg quarries (cf HEINZ 1926). The diverse Coniacian inoceramid zone, that of Inoceramus gib­ Upper Coniacian assemblages include four of the five bosus, is proposed for the interval between the last new species that were originally documented by HEINE cremnoceramids (the group characterising the greater (1929) in his work on the Emscher inoceramids of the part of the Lower Coniacian) and the entry of volvice­ Westphalian coal-shaft successions, but which have ramids at the base of the Middle Coniacian. The subsequently been only sporadically reported and usu­ Middle Coniacian assemblages permit morphological ally without detailed stratigraphic data. The higher changes within the volviceramids to be investigated Upper Coniacian assemblages appears to be absent as and correlated with horizoned material collected by the result of an hiatus. 'I

1 zonation '1 inoceramid phylogeny zonation as u;~~1 I applied here in Ernst & dl983 j

I

crassus­ deformis Zone I deformis Zone I

.. ~!!constans Ev. inconstans Zone I .~ ,.~------IsomEiaster-Ev, ~ .g~ erectus Zone ~ ~ hannovrensis ~ Zone U ,------~-.. ~ erectus III Ev ~ hannovrensis Ev Z 50 !2 0 49 "' ereetus II Ev. I U ~'" ! .... ."i1 V ~ g" rotundotus Zone ~ .g 0 b ...... :l .~ i ~~ erectus Zone '"~ Q"' ~ 06

I I ereotus lEv I 0 I waftersdor- walters- woltersdorfensis I FenSis II Ev ! Didymotisll dOli Z. ~g~ifsSPfJ- I Zone I I

I Didymotisl off. frechi Zone I scupini Zone I

I !

interval with mixed record in Staffhorst

Fig. 7. Inoceramid succession, phylogeny, and zonation at the Turonian/Coniacian boundary in comparison to the Salzgitter-Salder quarry, Lower Saxony UPPER CRETACEOUS OF THE STAFFHORST SHAFT 187

The Santonian assemblages are dominated by which is present in rock-forming quantIties in sphenoceramids. orange-brown sediments (Rotpliiner lithology) in the A detailed palaeontological description of the 641-647 m sample, constituting the Lower Turonian Coniacian inoceramids and full discussion of the Mytiloides event(s) of the standard event scheme. new biostratigraphic results will be presented in a Morphotypes present include forms referable to M. separate paper following further investigation of the labiatus and M. mytiloides (MANTELL). The absence Staffhorst material and comparative material from of the earliest Early Turonian mytiloids, i.e. M. hat­ other shaft and outcrop successions (WALASZCZYK & tini ELDER and M. kossmati (HEINZ), indicates an WOOD, in prep.). hiatus comprising the Cenomanian/Turonian bound­ ary interval and the basal Lower Turonian. The transiens morphotype of Mytiloides subher­ Cenomanian cynicus (SEITZ) is found in the topmost part of the 641-647 m sample in pale green limestones, associ­ The available inoceramid material provides only ated with M. ex gr. labiatus-mytiloides. This form a surprisingly incomplete record of the stage. On the has its FO in the upper part of the Lower Turonian, other hand, some of the main inoceramid events are but it ranges up into the basal Middle Turonian (see well represented. Inoceramus ex gr. crippsi, includ­ TROGER 1989, HARRIES & al. 1996). ing I. crippsi crippsi MANTELL, occurs in abundance Middle Turonian: The base of this substage is in the 715-735 m interval. The basal sample taken at the first appearance of small Inoceramus (731-735 m), in which the inoceramids are present in cuvieri (J. SOWERBY) at 628 m. However, the sub­ rock-forming quantities, both as shell fragments and stage base may actually lie some distance below this complete valves, is lithologically comparable with level. As currently defined, in terms of inoceramid the 1st Inoceramus bed of the eastern England suc­ stratigraphy, the boundary is drawn at the FO of cession, which is usually attributed to the Mytiloides hercynicus (PETRASCHECK). However, as Sharpeiceras schlueteri Subzone (GALE 1995) of in the case of other condensed northern German suc­ the Lower Cenomanian Mantelliceras mantelli cessions, M. hercynicus is also missing here. Since Zone. The overlying samples with I. ex gr. crippsi, this datum cannot be recognised in the Staffhorst suc­ including material preserved in pale coloured lime­ cession, the substage boundary is drawn only approx­ stones, could belong either to this subzone or to the imately, somewhere in the interval between the high­ overlying Mantelliceras saxbii Subzone. The occur­ est M. subhercynicus and the lowest I. cuvieri. rence of I. virgatus SCHLUTER in association with I. The first unequivocal Inoceramus lamarcki ex gr. crippsi in the 706-715 m interval suggests the PARKINSON appear higher, at 619 m. I.lamarcki and basal part of the Mantelliceras dixoni Zone. The related forms occur in mass abundance (the I. lamar­ intra-M. dixoni Zone I. virgatus event (ERNST & al. cki events of the outcrop successions) in the 1983) is well represented in the 702-706 m interval, 586-598 m interval. Unfortunately, current know­ occurring as usual in limestones. This event marks ledge of this group is inadequate to allow it to be the top of the lowest of the three parts into which used for a more refined subdivision of this part of the GALE (1995) divided the M. dixoni Zone. Turonian. The occurrence of Inoceramus schoendorfi Upper Turonian: In Europe, the base of the HEINZ in the 678-682 m sample indicates the lower Upper Turonian was traditionally placed at the FO of Middle Cenomanian Cunningtoniceras inerme or Inoceramus costellatus WOODS. It appears, howev­ Acanthoceras rhotomagense zones. There is no evi­ er, that forms commonly referred to WOODS' species dence for the beds with Inoceramus atlanticus at the are different from the English type (W ALASZCZYK & base of the terminal Middle Cenomanian WOOD 1999) and are conspecific with the North Acanthoceras jukesbrownei Zone, although the American species Inoceramus perplexus WHITFIELD immediately overlying oyster-rich Pycnodonte (see WALASZCZYK & COBBAN, in press). I. costella­ event is well represented at 659 m. tus (of authors, non I. costellatus sensu WOODS) thus falls into synonymy of WHITFIELD'S species, which consequently becomes the Middle/Upper Turonian Turonian boundary marker, as provisionally adopted at the Brussels Symposium (see BENGTSON 1996). The base of the Turonian is taken at the appear­ Accordingly, the boundary event, formerly referred ance of Mytiloides ex gr. labiatus (SCHLOTHEIM), to as the Mytiloides costellatuslSternotaxis plana 188 BIRGIT NIEBUHR & al. event becomes the Inoceramus perplexuslSterno­ (with the old name, where different, in parentheses): taxis plana event, and the basal Upper Turonian M. Didymotis I event, C. waltersdorfensis I event, costellatus/large I. cuvierilI. lamarcki stuemkeilI. Didymotis II event, C. waltersdorfenis II event (the inaequivalvis Zone becomes the I. perplexus/large I. three latter events were formerly refened to as the C. cuvierilI. lamarcki stuemkeil1. inaequivalvis Zone. waltersdorfensislDidymotis II and C. waltersdor­ The apparent FO of Inoceramus perplexus fensis events), C. erectus I (= C. rotundatus) event, WHITFIELD occurs in the 543-548 m interval. C. erectus II (= C. brongniarti) event, C. han­ However, the occunence, in the 572-575 m interval, novrensis (= C. waltersdorfensis hannovrensis) of fragments of large Inoceramus ex gr. lamarcki, a event, and C. erectus III (C. erectus) event. characteristic feature of the basal Upper Turonian Lower Coniacian: The base of this substage is Inoceramus perplexus/large I. cuvierilI. lamarcki taken here at the FO of Cremnoceramus deformis stuemkeill. inaequivalvis Zone in northern Germany erectus (MEEK), which was recently shown (ERNST & al. 1983; WOOD & al. 1984), suggests that (WALASZCZYK & COBBAN, in press) to be a senior the base should be taken at the base of this interval. synonym of C. rotundatus (TROGER non FIEGE) , the This is supported by the fact that below this level in inoceramid marker of the base of the Coniacian fol­ the shaft inoceramids are rare, and represented by lowing the Brussels decision (KAUFFMAN & al. single moderately sized I. lamarcki forms, these 1996). In the shaft succession, this datum is drawn in being features which are characteristic of the upper the middle part of the interval (504-509 m) that Middle Turonian succession of central Europe. includes the inoceramid assemblages of the There is no inoceramid material indicative of the Turonian/Coniacian boundary transition. The inoce­ succeeding Mytiloides labiatoidiformisl"Ino­ ramids from this interval are dominated by C. wal­ ceramus" striatoconcentricus Zone of the ERNST & tersdorfensis waltersdorfensis (ANDERT) and C. al. (1983) scheme, i.e. the level of the main deformis erectus (MEEK). Mass-ocunences of these Hyphantoceras events. Mytiloides scupini (HEINZ), taxa characterize the boundary itself, ANDERT'S form the zonal index of the penultimate Late Turonian occuning immediately below the boundary in the C. inoceramid zone (the 1. aff.Jrechi Zone of earlier zonal waltersdorfensis I and C. waltersdorfensis II events schemes), first appears in the 534-537 m interval, asso­ (see WOOD & al. 1984; KAUFFMAN & al. 1996; ciated with large Inoceramus ex gr. lamarcki and I. ex WALASZCZYK & WOOD 1998), with C. deformis erectus dominating the basal Coniacian assemblage. gr. inaequivalvis. In the absence of other data, the base I of the M. scupini Zone is taken at 537 m. The associ­ In the candidate basal boundary stratotype 'I ation with large I. ex gr. lamarcki supports assignment Salzgitter-Salder section (WOOD & al. 1984; to the lower part of the M. scupini Zone. KAUFFMAN & al. 1996), the C. erectus I (= C. rotun­ datus) event closely follows the Didymotis II and C. ~i waltersdorfensis II events, and its base is taken as Coniacian the base of the Coniacian. In more expanded succes­ sions, e.g. the Vistula section in Poland, both these The zonation of the Lower Coniacian follows the events are even more distinctly separated than at one recently worked out by WALASZCZYK & WOOD Salzgitter-Salder, and the C. erectus event is actual­ (1999; see also KAUFFMAN & al. 1996), comprising, ly situated slightly above the FO of C. deformis in ascending order, the Cremnoceramus deformis erectus. In the Staffhorst succession, Didymotis erectus Zone, C. hannovrensis Zone, C. crassus appears to be missing from the terminal Turonian C. inconstans Zone and C. crassus crassuslC. waltersdorfensis waltersdorfensis assemblage. The deformis deformis Zone. This scheme consists of a only record of Didymotis is an unornamented form sequence of interval range zones, and differs from the 509-514 m interval, differing significantly markedly from the traditional scheme based on the from the radially ornamented morphotype that char­ C. rotundatus-erectus-deformis lineage (see e.g. acterizes the Didymotis II event, and conesponding KAUFFMAN & al. 1978; HERM & al. 1979; ERNST & to the morphotype characterizing the Didymotis I al. 1983; WOOD & al. 1984). The two schemes are event of the M. scupini Zone. shown side by side for comparison (Text-fig. 7). For From the base of the Coniacian up to 484 m, the the terminal Lower Coniacian, a new zone, that of inoceramids are dominated by representatives of the Inoceramus gibbosus is proposed herein. We like­ Cremnoceramus deformis lineage, comprising the wise follow here the revised event terminology pro­ subquadrate, upright forms of the chronosubspecies posed in the same paper. In ascending order these are erectus with subordinate small C. waltersdorfensis UPPER CRETACEOUS OF THE STAFFHORST SHAFT 189 waltersdorfensis. This association suggests still a Of particular importance in the Staffhorst suc­ very low position in the Coniacian, i.e. below the C. cession is the succeeding interval, comprising the hannovrensis event (bed 52) of the Salzgitter-Salder terminal Lower Coniacian, which shows the manner succession (see WOOD & aZ. 1984; WALASZCZYK & in which the diverse, albeit Cremnoceramus-domi­ WOOD 1999). nated, assemblages are replaced by Inoceramus The inoceramid assemblage from the succeeding assemblages comprising representatives of the I. samples, up to the 463-467 m interval, shows much lamarcki group, prior to the entry of volviceramids greater diversity and includes C. waltersdorfensis at the base of the Middle Coniacian. This interval, hannovrensis (HEINZ), C. spp. of the deformis lin­ and its inoceramids, appears to be better developed eage, Tethyoceramus ex gr. madagascariensis here than in any other European succession known at (HEINZ) and Inoceramus ?annuZatus GOLDFUSS. present. Above the last cremnoceramids and below Situated above an interval dominated by C. deformis the FO of VoZviceramus koeneni (MULLER), there is erectus, and below the FO of C. crass us inconstans an interval characterized by both non-sulcate and (WOODS), this interval represents the C. hannovren­ sulcate large- and medium-sized representatives of sis Zone. However, the absence of any evidence for the I. lamarcki group, together with extremely rare I. the interval dominated by C. waltersdorfensis han­ kleini MOLLER and I. cf. kleini. The non-sulcate I. novrensis at the base of this zone, a conspicuous lamarcki group forms are provisionally refened to I. level in every complete succession in central annuZatus, as in the case of the forms of this type Europe, suggests an hiatus conesponding to the C. from the underlying undivided C. c. inconstanslC. c. hannovrensis event and probably also to the C. erec­ crass us Zone. Non-sulcate representatives of the I. tus III event. lamarcki group first become common, albeit inegu­ The appearance of C. crass us inconstans in the larly, even lower. Already in the 460-463 m interval, 463-467 m interval marks the base of the C. c. i.e. only some metres above the C. c. inconstans inconstans Zone, and equates in part with the C. c. event, an assemblage is found that is dominated by inconstans event (of WOOD & al. 1984). Other Inoceramus annuZatus. The sulcate forms are col­ inoceramids from the same interval include C. wal­ lectively refened here provisionally to Inoceramus tersdorfensis hannovrensis, C. sp. of the deformis gibbosus SCHLOTER, the earliest available name for lineage, Tethyoceramus ssp., and C. crassus crassus these forms (see discussion below). (PETRASCHECK), as well as non-sulcate forms of the The interval between the LO of the genus I. lamarcki group, provisionally refemed here to I. Cremnoceramus and the FO of Volviceramus annulatus GOLD FUSS. The co-occunence of forms koeneni is proposed herein as a separate inoceramid referable to C. crassus crass us and C. crassus zone characterized by Inoceramus gibbosus. Since inconstans, interpreted here as two successive the index taxon ranges into the basal Middle chronosubspecies (see WALASZCZYK & WOOD Coniacian Volviceramus koeneni Zone, i.e. well 1999), may possibly indicate condensation, but above the FO of V. koeneni, the new zone has the could equally well have resulted from the sampling status of an interval range zone. The use of the name method. The C. c. inconstans and C. c. crassuslC. d. I. gibbosus must be provisional at present, since deformis zones are, consequently, not distinguished there are cunently four morphologically similar and, as separate zones in this account. at least in part, probably conspecific, taxa known We have included within our concept of C. cras­ from the terminal Upper Coniacian and basal Middle sus crass us the morpho type referred by FIEGE Coniacian of the European area. These are: (1930) to the new subspecies Inoceramus incon­ Inoceramus gibbosus SCHLOTER, 1877 from the stans woodsi, which he documented from the Emscher Marl facies of Westphalia; I. lezennensis Westphalian shaft successions. FIEGE'S morphotype (DECOCQ, 1874) (BARROIS 1878, 1879) from the is characterized by the earliest ontogenetic ornament chalk facies of northern France; I. percostatus of typical C. crass us crassus extending further onto MOLLER, 1888 from the Middle Coniacian V. the disc than usual. Some of the stratigraphically koeneni Zone "Form Sands" of the Subhercynian highest Staffhorst material includes several speci­ Cretaceous Basin, and I. russiensis NIKITIN, 1888 mens that match FIEGE'S morphotype, and we cannot from the chalk facies of Russia. Apart from I. per­ exclude the possibility that this form represents a costatus, which is represented by rich and well pre­ late cremnoceramid development with some bio­ served three-dimensional material, in association stratigraphic significance. This problem requires fur­ with Inoceramus kZeini and Volviceramus koeneni, ther investigation. all the other taxa are based either on a single (I. 190 BIRGIT NIEBUHR & al. russiensis, I. gibbosus) or a few specimens (I.lezen­ V. grandis of American authors, occurs commonly, nensis), which precludes detailed study of popula­ together with subordinate V. involutus s.s. in the tion and intra-specific variability. The possible rela­ white chalk facies in England, at the top of the beds tionship between the first three taxa was briefly dis­ with abundant Volviceramus. cussed by SEITZ (1962, pp. 355-356, footnote). Apart from Volviceramus, Inoceramus gibbosus Although we have provisionally chosen I. gibbosus and rare small questionable early Cordiceramus sp., as the zonal index, it is actually possible that the the Middle Coniacian of Staffhorst is characterized DECOCQ (1874) description of his new species is by common Platyceramus. There is a tendency for valid and available - it describes the main morpho­ Platyceramus-dominated assemblages to alternate logical characters well, but lacks an illustration; with assemblages dominated by Volviceramus. The however, this description appears in a report of a Platyceramus predominantly comprise the morpho­ paper read by DECOCQ, and not in an actual paper. types referred by SEITZ (1962) to the subspecies BARROIS (1878) gave a more detailed description Platyceramus mantelli mantelli (DE MERCEY) and P. and, one year later, in another paper (BARROIS 1879), mantelli angustus (SEITZ), the latter subsequently he repeated the 1878 description word for word, but renamed by SEITZ (1965) P. mantelli beyenburgi. with the addition of a figure. Furthermore, the These two morphotypes are respectively thick and Staffhorst material assigned here to I. gibbosus dis­ thin-shelled, quite apart from differing in the hinge plays an increasing degree of sulcation up-section, and in the shape of the growth trace on the disc. culminating in the distinctive I. gibbosus s.s., above Other morphotypes cannot be assigned satisfactorily which the degree of sulcation appears to reduce to either of these forms, and may possibly include again. It may eventually prove necessary to recog­ forms close to P. mantelli subrhenanus (SEITZ). nize an additional chronosubspecies for the earlier, Upper Coniacian: Following the Brussels crite­ less strongly sulcate forms that characterize the ter­ rion (KAUFFMAN & al. 1996), the base of this sub­ minal Lower Coniacian. stage is drawn at the entry of Magadiceramus sub­ Middle Coniacian: The base of this substage is quadratus SCHLUTER. TRaGER (1989) recognised well documented by the appearance of two Magadiceramus-dominated inoceramid assem­ Volviceramus koeneni in the 397-400 m interval. blages (assemblages 23 and 24 of TRaGER 1989) Immediately below this, in the 400-406 m interval, within the Upper Coniacian, the lower containing two specimens of an inoceramid with a rounded, late Volviceramus, and the higher, in which this internally striate right valve umbo, may represent a genus is absent. possible Volviceramus precursor but require further In Staffhorst, the index Upper Coniacian inoceramid investigation. Volviceramus is particularly well rep­ is extremely rare and, moreover, TRaGER'S two assem­ resented in the Staffhorst collections, and includes blages cannot be distinguished at all. Although a specimens of all sizes, many preserving the shell, twofold subdivision of the Upper Coniacian by means and fully articulated. A strongly developed V. koe­ of inoceramids is possible, the observed inoceramid neni event is located somewhere in the 387-393 m assemblages are different from those distinguished by interval. Every morphological gradation between TRaGER (1989). This is also the case in certain other typical V. koeneni and the inrolled V. involutus (J. shaft sections (e.g. Ickern IV), in which the lower Upper DE c. SOWERBY) is present in Staffhorst, showing the Coniacian is represented by a taxonomically rich assem­ general trend within the population to flattening of blage without Magadiceramus, while the upper Upper the initial distinctive, highly elevated, right valve Coniacian is characterized by an almost mono specific umbo of V. koeneni. The relationship between some Magadiceramus subquadratus assemblage. It is possi­ of these morphotypes and the North American taxa ble that the pattern of vertical distribution of magadice­ Volviceramus umbonatus (MEEK) and V. exogy­ rarnids follows the facies characteristics of the region in roides (MEEK) is unclear, and requires further inves­ question, and has no general biostratigraphic signifi­ tigation. The Volviceramus morphotypes match cance, but this needs further investigation. The only quasi-horizoned material collected by HEINZ (1926) unequivocal Magadiceramus, apart from an anomalous from the former Liineburg quarries. In the higher (and possibly displaced) specimen from the 412-416 m part of the succession (330-333 m), immediately interval of the Middle Coniacian, is a single specimen below the entry of inoceramids of Upper Coniacian from the 311-313 m interval. In the absence of aspect, a morphotype with a large, flat, antero-poste­ Magadiceramus-dominated assemblages, the base of riorally elongated right valve is found together with the substage is taken at the appearance of other typical­ V. involutus. This morphotype, which is possibly the ly Upper Coniacian forms, notably "Sphenoceramus"

1 UPPER CRETACEOUS OF THE STAFFHORST SHAFT 191 subcardissoides (SCHLUTER) and four of the new tion and, in part, for the designation of stratigraphic species described by HEINE (1929) from the units, e.g. the Holaster subglobosus, Sterno taxis Westphalian coal shafts: Inoceramus Jasciculatus, I. plana, Micraster cortestudinarium, and Micraster latisulcatus, I. canaliculatus and the volviceramid-like coranguinum zones (see ROWE 1899; LAMBERT I. anomalus. The assemblage also includes I. gibbosus 1903a, 1903b; CAYEUX 1965, 1966, 1967). In con­ that are less strongly sulcate than the forms in the beds trast, the echinoid stratigraphy of the lower Upper below. l. Jasciculatus occurs in flood abundance in the Cretaceous (Cenomanian - Coniacian) of northern 315-319 m and the 319-321 mintervals. The absence of Germany is still rather underdeveloped, and is invari­ Magadiceramus-dominated assemblages strongly sug­ ably used only as a supplementary stratigraphy or gests a significant hiatus involving the higher part of the parastratigraphy. The last attempts to establish an Upper Coniacian. The existence of an hiatus is further echinoid zonal scheme for the Boreal German Upper supported by the absence ofthe terminal Coniacian (for­ Cretaceous are now several decades old (ERNST merly basal Santonian) Sphenoceramus Teilzone, with 1970a, 1970b; ERNST & SCHULZ 1974; ERNST & the first Sphenoceramus ex gr. pachti cardissoides, SEIBERTZ 1977). In these schemes it was mainly the which was documented by SEITZ (1961) from the higher Upper Cretaceous that was considered, apart Westphalian coal-shafts. from discussing concepts and methodology relating to the application of echinoids to biostratigraphy in general. For the Cenomanian - Coniacian interval no Santonian single usable independent echinoid zonal scheme existed. According to the Brussels proposals (LAMOLDA & In marked contrast with the situation in the chalk HANCOCK 1996) the base of the stage is taken at the facies of the Boreal white chalk sea, the potential FO of Cladoceramus undulatoplicatus (ROEMER). disadvantages of an echinoid-based zonal scheme This taxon is relatively uncommon in the Staffhorst are much more apparent in the variable lithotopes of material, being first noted as single specimens in the the Lower Saxony and Westphalian Upper 303-300 m interval, and also in the 292-290 m inter­ Cretaceous. Ecomorphological reactions and the link val. This sparse Cladoceramus record matches the to definite facies-belts lead, in many cases, to a rare occurrences of the genus in the Liigerdorf stan­ regional restriction of the echinoid distribution and, dard section (ERNST & SCHULZ 1974). In both inter­ thereby, to marked small-scale endemism. On the vals, the dominant inoceramids are Sphenoceramus other hand, this sensitivity to facies makes the echi­ ex gr. pachti - cardissoides. Sphenoceramids of this noids useful for palaeoecological and sequence group range throughout the remainder of the stratigraphic interpretations (ERNST & WOOD 1996). Santonian part of the shaft succession. The upper In particular, they have proved their worth in the limit of the higher interval with Cladoceramus is development of an event stratigraphic scheme for the taken here, in the absence of other data, as the base of lower part of the Upper Cretaceous and they are used the Middle Santonian. The Middle Santonian assem­ as eponymous marker fossils for eustatic- and bio­ blages are, as in the case of the Lower Santonian events (for example, the M. cortestudinarium and assemblages, dominated by Sphenoceramus ex gr. Isomicraster events of ERNST & al. 1983). pachti - cardissoides, although rare Cordiceramus Absence of space here for detailed discussion of cf. purus (SEITZ) and Platyceramus sp. were also the complex palaeoecological and sequence strati­ noted. The base of the Upper Santonian is taken here graphic questions, and for the treatment of certain at the FO of Sphenoceramus pinniformis (WILLETT) nomenclatorial und taxonomic problems, makes it at 265 m. This datum approximates to the FO, in the necessary for the rich echinoid fauna of the 263-265 m interval, of "Inoceramus" muelleri Staffhorst shaft to be treated in a separate paper PETRACHECK, a taxon known to appear close to the (ERNST, in prep.). MiddlelUpper Santonian boundary (see TROGER 1989; OPPERMANN 1996). Cenomanian

6. ECHINOID STRATIGRAPHY (G. ERNST) In comparison to the nearest exposures (Wunstorf and Misburg), Staffhorst has provided In the chalk facies of England and France irregu­ only few Cenomanian echinoids, with only three lar echinoids were used from an early date for zona- species having been recognised. 192 BIRGIT NIEBUHR & al.

Lower Cenomanian: The Mantelliceras dixoni hardening, which was linked to a shallowing phase Zone of the higher Lower Cenomanian has yielded and to cold water influences. single examples of Holaster bischoffi from the The FO of Sterno taxis plana in the 559-562 m 695-702 m interval and a questionable Sterno taxis interval could mark a sequence stratigraphically sig­ ex gr. gregoryi - trecensis from the 702-706 m nificant horizon. This occurrence may represent the interval. In comparative sections (Baddeckenstedt, equivalent of a firmground with echinoids in the top Hoppenstedt) H. bischoffi is typical of the basal part of the Upper Rotplaner in the S6hlde section Mariella sequence of the lower M. dixoni Zone (Lesse Syncline) in eastern Lower Saxony (ERNST & (ERNST & REHFELD 1997). al. 1998b). S. plana is used in England and France as Middle Cenomanian: The 673-676 m interval an index fossil for the Sterno taxis (Holaster) plana has yielded three test fragments of Holaster sub­ Zone, which equates with the Upper Turonian in globosus. Although this species actually has a France, and with the higher part of the Upper greater vertical range, its dependency on facies Turonian in England respectively (LAMBERT 1903a; results in it occurring commonly only in the CAYEUX 1966; FOURAY & POMEROL 1985). region of the Mid-Cenomanian event (ERNST & al. A suite of Echinocorys, comprising some 20 1983) of the middle Middle Cenomanian, or examples, which was found above the hiatus recog­ immediately above. The occurrrence of the nized using log peak stratigraphy (see chapter 4) in species at this horizon in the so-called H. subglo­ the 543-553 m interval, is also of stratigraphic inter­ -1 -I bosus bioevent has an inter-regional value in an est. The morphotype in question possesses charac­ event stratigraphic scheme (ERNST & WOOD ters intermediate between those of the Cenomanian 1995), and the species is used in western Europe E. sphaerica and the Upper Turonian E. gravesi (E. as an index fossil of the upper Middle mJ. sphaerica - gravesi in Text-fig. 8). In the Cenomanian (CAYEUX 1965). Wlillen (Westphalia) section this morphotype char­ In the 676-678 m interval is found a tempestite­ acterizes an hardground succession downsection of like accumulation of thin-tested echinoid debris, an hiatus in the Middle/Upper Turonian transition which may well consist of S. ex gr. gregoryi - tre­ (ERNST & al. 1998a). censis. Both these Sterno taxis morphotypes are used, On the basis of biostratigraphically significant for example in England, as indicators for the Middle echinoids, the Middle/Upper Turonian boundary and Upper Cenomanian (OWEN & SMITH 1987). should be drawn at 548 m, above the hiatus identi­ Upper Cenomanian: The limestones typical of fied by means of log peak stratigraphy (see chap­ the Arme rhotomagense Kalke of the lower Upper ter 4), because in the 543-548 m interval Sterno taxis Cenomanian are virtually devoid of echinoids in out­ plana occurs together with the FO of the inoceramid crop sections. This interval in Staffhorst has also Inoceramus perplexus (= Inoceramus costellatus of yielded no echinoids. authors, see WALASZCZYK & WOOD 1999 and chap­ ter 5). The two in combination could mark the I. per­ plexus/So plana event, which is currently the pre­ Turonian ferred choice for the substage basal boundary in northern Germany. However, this echinoid-based Lower Turonian: There are also no echinoids interpretation is disputed on inoceramid evidence by from this level in Staffhorst. It is only in the bound­ WALASZCZYK & WOOD (see chapter 5), who draw ary transition to the Middle Turonian in extensive the boundary much lower, at the base of the 572-575 outcrop sections that the first small irregular echi­ m interval, below an occurrence of large fragments noids appear. of large Inoceramus ex gr. cuvieri. Middle Turonian: Echinoids remain extremely Immediately above this there is a distinct rare. An isolated Echinocorys morphotype (E. aff. turnover in the echinoid assemblages, which proba­ sphaerica in Text-fig. 8) from the 593-602 m inter­ bly reflects another hiatus. In the lower E. gravesi val is of interest but, due to the lack of comparative Zone, the characteristic Echinocorys gravesi splits material, provides no stratigraphic information. off from the above-mentioned transitional form E. Upper Turonian: This is the substage that is mJ. sphaerica-gravesi. At the same horizon are richest in echinoids in Staffhorst. According to found the first transitional forms from Sterno taxis ERNST & al. (1998b), this abundance reflects an plana to S. placenta and the immigration of the first alteration in ecological conditions documented by primitive Micraster, M. (Roweaster) borchardi also starved sedimentation, condensation und substrate- takes place. All three forms together characterize, in UPPER CRETACEOUS OF THE ST AFFHORST SHAFT 193

echinoid assemblage Staffhorst shaft zones stratigraphic range of echinoids echinoid events

, , r , .~ , ~ , 0 +, Q) ,, , "EO c. , >- , ~ 15 u -" co 0:: III e- repeated entries of • 2 0 .l!1 .~ E pulse echinoids in 0> '"0 the course of trans­ :g'" ~ gressive pulses Volviceramus Q III '"co ""'il; involutus -='!'" ~ ~ =a f!? 1:1 III I!! ci. '" 0> (/) <3" ~ i ~ 0:: III Volviceramus -" C ~ I' ca koeneni .!Q" '(3 2 .;]g;:.;.: ., .l!1 <-1 0 .! Inoceramus 0> E gibbosus '"0 .l!l C ·s C/J 0 .r: () Cr. crassus / ill .. Cr. deformis ? ; Cr. crassus 0 ..J inconstans Cr. waltersd. hannovrensis...... III C. C. :;:) large I. ex gr. 1------11 lamarcki/ I. inaequivalvis

Inoceramus ..; 'il; lamarcki E .!Q ~ ]g ..; ~ 0 g'" E co~ E ~ 0 ~ .Q .r:'" 8 Q gj '" 8 0 0> ~ 0 .S "§ .S ti co ""nl 1IJ ~ ~ 0 ~ u .!l! 0 .S ~ .r: I I ill c / .! / c I ca IE I? 0 .~ E ti 0 .!Q " ... .Q '" C ~" Q) .~ () ~ ~ ..J .!l! g, '" ~ ~ 0> "rn rare .!Q ... not zoned ~ moderate III 0 ..ci C. E abundant C. .l!l os::( C/J :;:) CD echinoid event

Fig. 8. Vertical ranges and abundances of echinoids in the Upper Cretaceous of the Staffhorst shaft 194 BIRGIT NIEBUHR & al. northwest German outcrop sections, the middle Micraster decipiens Zone, i.e. lower Lower Upper Turonian interval between tephroevents T E to Coniacian (LAMBERT 1903b), the species name E. T F' including the Hyphantoceras event. The latter gravesi must be retained for the forms of this age (E. event has recently been taken (ERNST & al. 1998a) as gravesi, late morphotype). The index taxon the beginning of a new sedimentary sequence, and is Micraster cortestudinarium is absent in Staffhorst. usually marked by condensation, as it is here in However, a single find of a Cardiaster cotteauanus Staffhorst. in the 480-480 m interval is noteworthy, since its In the 514-521 m interval echinoids temporarily morphological characters show it to be a precursor disappear completely, probably due to the onset of of the Santonian Cardiaster jugatus. the clayey-marly sedimentation of the Grau-WeiBe In the 463-467 m interval M. (Roweaster) bor­ Wechselfolge. Right up to the Turonian/Coniacian chardi is replaced by the "modern" Micraster (M.) boundary, in the 504-509 m interval, the characteris­ bucailli. Sterno taxis simultaneously exhibits certain tic Upper Turonian assemblage compnslllg apparent changes in morphology, but the extremely Echinocorys, Sterno taxis and Micraster is impover­ poorly preserved nature of the material does not per­ ished. The LO of Sterno taxis m.f. plana - placenta mit these changes to be clearly identified. The high is provisionally placed in this interval. A single forms of S. placenta disappear in favour of sporadic poorly preserved small-sized representative of the flat forms. Rare Cardiotaxis sp. and Infulaster sp. Cardiaster/Cardiotaxis group in the 509-514 m also occur. interval is noteworthy. The 447-467 m interval is characterized by a last flourishing phase of E. gravesi (late morphotype) and Micraster (M.) bucailli. Above this lies an over Coniacian 30 m thick succession that is devoid of echinoids. The disappearance of echinoids at 447 m clearly The echinoid stratigraphy of this stage is poorly documents, on the basis of echinoid ecological crite­ known and, moreover, the clayey-marly facies of the ria, the top of the Upper Limestone Unit and the Emscher Marls in the Middle and Upper Coniacian beginning of the Transitional Unit. (see chapter 4) is unsuitable for echinoids. Only the Middle Coniacian: In the Lower/Middle carbonate richer sediments of the Lower Coniacian Coniacian transition, echinoids of the genera have yielded relatively abundant finds in Staffhorst. Micraster and Echinocorys become temporarily Lower Coniacian: The Turonian/Coniacian more abundant. Micraster (M.) mJ. bucailli - stage boundary in the 504-509 m interval is marked coranguinum already appears beneath the hiatus by the FO of Sternotaxia placenta. This species also identified by means of log peak stratigraphy at the characterizes the Turonian/Coniacian transition in substage boundary in the 400-413 m interval (see England and northern Spain (Barranca) and it is chapter 4), Echinocorys of the scutata group is therefore introduced here as the zonal marker for the found just above, in the 393-397 m interval. lower Lower Coniacian. In LAMBERT'S echinoid Upper Coniacian: Echinoids are also under-rep­ scheme for northern France this species is used as a resented in this substage in Staffhorst. In addition to zonal guide fossil for the Middle Coniacian a few Echinocorys sulcata ssp., there are (initially (Volviceramus involutus Zone), in the upper sporadic) occurrences of Echinogalerus(?) sp. aff. Micraster decipiens Zone (FOURET & POMEROL hannoniensis. In the 311-313 m interval, an abun­ 1985). Associated with S. placenta in Staffhorst are dance of this latter taxon, as so-called "pulse echi­ Micaster (R.) borchardi and the last representatives noids", clearly marks an early Late Coniacian trans­ of Echinocorys gravesi (early morphotype). gressive pulse. At 484 m is found another change in the echinoid assemblage, which coincides with another hiatus recognized by means of log peak stratigraphy (see Santonian chapter 4). With 36 examples, Echinocorys reaches its absolute abundance maximum in the 480-484 m The genera Echinocorys and Micraster, which interval. The Upper Turonian forms referred to E. are abundant in the Santonian chalk facies of gravesi (early morphotype) are replaced here by Uigerdorf (ERNST & SCHULZ 1974), are scarcely rep­ morphotypes which already show characters remi­ resented in the marl facies of Staffhorst. On the other niscent of the later E. scutata. However, since the hand, the holectypoidea, represented by stratum typicum of E. gravesi (DESOR) is the Echinogalerus(?) and Conulus, are commoner. UPPER CRETACEOUS OF THE STAFFHORST SHAFT 195

Lower Santonian: The Early Santonian trans­ of the Gonioteuthis lineage, as well as 3 specimens gressive pulse in the 295-300 m interval, which is of Actinocamax verus. In this interval Gonioteuthis also documented by the pulse-like occumence of the traditionally possesses a high stratigraphic resolu­ belemnite Gonioteuthis (see chapter 7), is indicated tion potential (see ERNST 1964). In particular, by a second, short-lived appearance of Gonioteuthis offers the possibility of correlation Echino galerus(?) sp. aff. hannoniensis, associated between Staffhorst and the stratigraphically continu­ with a few small Micraster of the coranguinum ous Lagerdorf standard section on the Pompeckj group; Echinocorys is missing. Block in the north, which has provided extensive Middle Santonian: Only in the middle part of and well studied material of this lineage (see ERNST the substage, in the 260-274 m interval, which in the 1966; ERNST & SCHULZ 1974). Uigerdorf standard section corresponds to the M. coranguinumlG. westfalica Zone, do echinoids reappear, as a result of the Middle Santonian trans­ Gonioteuthis lineage gression. Echinogalerus(?) sp. aff. hannoniensis reaches its abundance maximum at this level. There The discontinuous record of abundances of are in addition a few fragments of Echinocorys scu­ Gonioteuthis in the Staffhorst succession is closely tata ssp .. Also indicative of this transgressive pulse related to the transgressive pulses of the Upper are occurrences of the regular echinoids Tylocidaris Coniacian and Santonian. This is evidenced by the clavigera and Temnocidaris sceptrifera in the regional distribution pattern in northern Germany, 265-271 m interval. which demonstrates that Gonioteuthis preferential­ The position of the three Conulus albogalerus ly occupied proximal, near-shore facies zones collected from Staffhorst cannot be reconstructed (ERNST 1964). Gonioteuthis thus constitutes a fur­ because the specimens in question have been mis­ ther characteristic element of the so-called pulse laid. Since Conulus is an excellent example of a fauna in the course of eustatic movement in the pulse echinoid, these specimens are likewise proba­ sense of sequence stratigraphy. Following two bly also attributable to the Santonian transgressive short-term occcurences in the Upper Coniacian and pulses. C. albogalerus is used in the French echi­ Lower Santonian, Gonioteuthis finally became noid scheme as an indicator of the Santonian established in Staffhorst, as in Lagerdorf, in the (FOURA Y & POMEROL 1985), but it already appears in course of the later Middle Santonian transgression. the higher Coniacian of northern France (CAYEUX The maximum abundance, represented by 22 speci­ 1967). In Uigerdorf it is found in the Grabganglagen mens, is found in the 254-256 m interval which, sig­ (bioturbated horizons) G251 and G252, at the base nificantly, is closely followed by an oyster bed at of the Middle Santonian M. rogalae/G. westfalica 251-253 m. Zone (ERNST & SCHULZ 1974). Preservation: The majority of rostra are repre­ Upper Santonian: Echinoids cannot be sented by fragments, which can be treated statisti­ employed to determine whether or not the Upper cally only in the abundance curve (Text-fig. 9a). Santonian is present - particularly in view of the fact Proximal fragments preserving the pseudoalveolus that Micraster rogalae, which is used in Uigerdorf are evaluated as far as possible (Text-fig. 9c). for the zonation of the Santonian, has not been found However, of these, only 17 specimens (17.5 %) were in Staffhorst. sufficiently complete to allow the stratigraphically significant RIEDEL Quotient and RIEDEL Index to be measured (Text-figs 9d-e). 7. BELEMNITE STRATIGRAPHY (G. ERNST)

Neither the Neohibolites ultimuslAucellina Morphologic and morphometric development gryphaeoides event of the transgressive Lower of Gonioteuthis Cenomanian, nor either of the two Praeactinocamax events (Middle Cenomanian P. primus event and Biostatistic methods have been applied to the Upper Cenomanian P. plenus event respectively) Gonioteuthis lineage for several decades in order to can be confirmed in Staffhorst at their presumed obtain stratigraphic data (e.g. ERNST 1964). This par­ stratigraphic position on the basis of belemnite finds. ticularly applies to the Santonian, when the evolu­ However, the marls of the Upper Coniacian and tion of the statistically relevant characters took place Santonian have provided almost 100 representatives very rapidly. Following the methodology introduced 196 BIRGIT NIEBUHR & al. by ERNST & SCHULZ (1974), the ratios (RIEDEL stronger, but the longitudinal striation does not Index, RIEDEL Quotient) of certain parameters completely disappear. (length of rostrum, depth of pseudoalveolus) are of greater stratigraphic significance than the absolute values of the parameters themselves. Of the two Gonioteuthis stratigraphy and regional RIEDEL values, the RIEDEL Index, i.e. the depth of the correlations pseudoalveolus expressed as a percentage of the ros­ trum length, is better suited for demonstrating evo­ In the Santonian of the Boreal European sub­ lution than the RIEDEL Quotient, which is derived by province, Gonioteuthis stratigraphy maintains its dividing the rostrum length by the depth of the position as a practicable biostratigraphic method pseudo alveolus . next to the inter-regionally more widely applicable Length of rostrum (Text-fig. 9b): No stratigraph­ inoceramid stratigraphy. From the Upper Coniacian ically significant changes in this parameter can be to the Santonian/Campanian boundary, a kind of observed in the Staffhorst material. Variation in the phylostratigraphy can be established, comprising, in mean values, which range between 50-60 mm, is ascending order, the following four phylozones: G. probably controlled by the fluctuating proportion in praewestfalica, G. westfalica, G. westfalicagranu­ the population of immature individuals. lata and G. granulata zones. On the basis of pro­ Depth of pseudoalveolus (Text-fig. 9c): Analysis portions the G. westfalica and G. granulata zones of the section of the curve for this parameter above are each subdivided into Lower and Upper subzones. 272 m, with almost 50 individual values, reveals a G. praewestfalica Zone (296-311 m): This zone discontinuous distribution pattern. Mean values of has been recognised up to now only in Lagerdorf, 4-5 mm in the 256-272 m interval are followed by where apart from isolated records of the index taxon values of 6-7 mm in the 245-254 m interval. This rel­ in the underlying Volviceramus involutus/Micraster atively abrupt change in the mean values points to a bucailli Zone, it conesponds to the upper assemblage break in the Gonioteuthis record in the Santonian zone of the higher, strongly condensed, Coniacian and, consequently, to a significant hiatus. (Micraster bucaillilG. praewestfalica Zone), with RIEDEL Index (Text-fig. 9d): The division of the the index inoceramid Inoceramus Jasciculatus mean values curve for the depth of the pseudoalveo­ (ERNST & SCHULZ 1974, Figs 4-5). In Staffhorst, G. Ius into two distinct parts is particularly strongly praewestfalica enters just above several I. Jascicula­ expressed by this ratio. The lower interval tus events (see chapter 5). The initial transgressive (259-272 m) yields mean values of 8-9 %, while in pulse is additionally emphasized by the ocunence of the higher interval (245-256 m) the mean values are pulse echinoids at 311-314 m (see chapter 6). Due to 11-12 %. According to the standard Lagerdorf curve the absence of belemnites at Lagerdorf, it is not pos­ (ERNST & SCHULZ 1974, Fig. 15), the former values sible to establish whether or not the lower part of the fall within the Lower Gonioteuthis westfalica Zone succeeding Sphenoceramus pachtilCladoceramus and the latter in the G. westfalicagranulata Zone, undulatoplicatus Zone of the Lower Santonian also respectively. belongs to the G. praewestfalica Zone. In Staffhorst, RIEDEL Quotient (Text-fig. ge): The distribution however, the second pulse of Gonioteuthis, docu­ of mean values for this ratio is similar to that for the mented at 296-298 m by 5 fragments which presum­ RIEDEL Index. The lower interval (259-272 m) is ably belong to G. praewestfalica, clearly lies above characterized by mean values of 11-13, the higher the C. undulatoplicatus trangression, and thus falls interval (245-256 m) by values of 8-9. in the basal Lower Santonian. Surface ornament: The strength of longitudinal Above this follows in Staffhorst, as in Lagerdorf, striation and granulation cannot be analysed quanti­ a ca. 25 m thick packet of strata that has not yielded tatively without the expenditure of considerable Gonioteuthis, designated the "Gonioteuthis deplet­ time and effort. All that is possible is a subdivision ed interval" (see Text-fig. 9). into broad classes based on a subjective assessment G. westfalica Zone (256-271 m): The third of the relative strengths of these characters (ERNST strong Gonioteuthis pulse in the Middle Santonian, & SCHULZ 1974). In Staffhorst, only longitudinal at 256-271 m, marks the base of the G. westfalica striation was observed up to a depth of 25 m, with Zone. It can be assumed that this reappearance of only a few specimens exhibiting a mostly only Gonioteuthis in Staffhorst was contemporaneous weakly developed granulation. Above the hiatus at with that at Lagerdorf and that it falls, consequent­ 256 m, the granulation of the rostra becomes ly, at the base of the Micraster coranguinumlG. UPPER CRETACEOUS OF THE STAFFHORST SHAFT 197 westfalica Zone. The fairly constant mean values level. On the basis of the correlation with for the depth of pseudoalveolus, RIEDEL Index and Lagerdorf, the hiatus in Staffhorst therefore spans RIEDEL Quotient clearly show that in Staffhorst most of the Upper G. westfalica Zone. essentially only the Lower G. westfalica Zone is G. westfalicagranulata Zone (245-256 m): On present, with its upper limit marked by an hiatus. the basis of Gonioteuthis morphometric data, this The position of the hiatus must lie at about 256 m, interval clearly belongs to the G. westfalicagranula­ as shown by the shift in the Gonioteuthis morpho­ ta Zone, or to the M. rogalae/G. westfalicagranula­ metric data, but no sedimentary expression for an ta Zone of the upper Middle Santonian and basal hiatus has been detected (see chapter 4). Above the Upper Santonian. However, the Gonioteuthis mor­ hiatus, a renewed transgressive pulse can be phometric means derived from the belemnite fauna inferred, the base being marked by the absolute of bed G236 (which marks the FO of Uintacrinus, abundance maximum of Gonioteuthis. In and hence, by definition, the base of the Upper Uigerdorf, this event is documented in the Santonian) in the middle M. rogaZae/G. westfaZica­ G2511G252 interval by the occurrence of diverse granuZata Zone of Lagerdorf (ERNST & SCHULZ pulse echinoids in association with abundant belem­ 1974, Fig. 15) are not realized in Staffhorst. nites (ERNST & SCHULZ 1974). The base of the lower Consequently, the presence of Upper Santonian sed­ Middle Santonian M. rogalae/G. westfalica Zone, iments cannot be proved by means of belemnite or of the Upper G. westfalica Zone, is drawn at this stratigraphy.

Gonioteuthis Staffhorst depth of number of specimens length of rostrum pseudoalveolus RIEDEL index RIEDEL quotient 40 50 60mm 6 8 10mm 10 12%

• single value X meanvatue ~smoothed mean value curve

echinoids

Fig. 9. Biostatistic morphometry and zonation of the Upper Coniacian and Santonian GOllioteuthis lineage of the Staffhorst shaft 198 BIRGIT NIEBUHR & al.

Actinocamax verus val (Santonian) are reminiscent of Parasmilia fittoni from the Santonian white chalk of southern England. It In the belemnite assemblages of the Santonian, should be noted that the taxonomy of all Chalk corals Actinocamax verus is usually associated with is in urgent need of revision, and that this determination Gonioteuthis. It is proportionally most abundant in should not be regarded as definitive. Nevertheless it is nearer-shore, transgressive sediments. Actinocamax interesting to see this white chalk morphotype in time­ accordingly reacts much more strongly to transgres­ equivalent beds in the Staffhorst succession. Single sive pulses than Gonioteuthis (pulse belemnite). corals attributed to Parasmilia, are much commoner in Only 3 specimens have been collected from the white chalk facies of the Uigerdorf standard sec­ Staffhorst (Text-fig. 9), which suggests that the tion, where ERNST & SCHULZ (1974, Fig. 4) record depositional area at that time occupied a relatively them as ranging from the top of the Coniacian to the distal position. The first rostrum is associated with equivalent of the top of the Staffhorst succession. the Middle Santonian trangressive pulse at J 265-272 m. The two remaining specimens come from the oyster bed at 251-252 m, in which the pulse Brachiopods echinoid Echinogalerus? sp. aff. hannoniensis appears again after an hiatus (see chapter 6). A medium-sized terebratulid was noted from the 251-252 m interval and an unidentified Orbirhynchia is not uncommon in the 265-271 m interval 8. SUPPLEMENTARY FAUNAL RECORD (Santonian). The occurrence of Orbirhynchia may (C.l WOOD) match minor acme-occurrences of this genus in the Middle Santonian of Uigerdorf (ERNST & SCHULZ Apart from inoceramids, irregular echinoids and, 1974, Fig. 4). Additional noteworthy records are a at some levels, belemnites, the fauna of the large Kingena sp. from the 277-279 m interval Staffhorst succession is of surprisingly low diversi­ (Middle Santonian) and a Gibbithyris or ty. The main additional faunal groups recognised are Concinnithyris with straight commissure from the sponges, corals, serpulids, brachiopods, ammonites, 467-473 m interval (Lower Coniacian). bivalves, gastropods, asteroids, crinoids and regular echinoids. This material is housed in the collections of the University of Hamburg and was cursorily Ammonites examined by the author in 1980. Several ammonites collected from the Ceno­ manian were removed for examination from Sponges Hamburg by the late Professor J. WIEDMANN, and are presumably at present in Tlibingen. According to The Middle and Upper Coniacian of Staffhorst are KAPLAN & al. (1998) these mainly, perhaps exclu­ characterized by an abundance of sponges recorded as sively, comprised Schloenbachia varians at 682 m. "massive cylindrical sponges" without further attempt Additional specimens of Schloenbachia varians at determination. A more delicate, funnel shaped were mentioned by SPIEGLER & SPIEGLER (1964) sponge from the 321-324 m interval (Upper Coniacian) between 711-735 m. A single specimen of has been tentatively determined as Rhizopoterion sp. Schloenbachia sp. and Turrilites sp. at 673-676 m and there are several possible Sporadoscinia sp. in the are also present in the BGRINLfB collection. 324-330 m interval (Upper Coniacian), as well as a One of the most remarkable features of the Sporadoscinia type sponge with a very coarse mesh­ Staffhorst material is the unexpected complete work in the 492-500 m interval (Lower Coniacian). absence of any ammonites from the broadly con­ ceived Scaphiten-Schichten of the traditional German stratigraphic scheme and, specifically, from the other­ Corals wise ammonite-rich Hyphantoceras events (ERNST & al. 1983; KAPLAN & KENNEDY 1996). This absence is As would be expected in view of the comparative­ particularly surprising in view of the fact that the level 1 ly argillaceous lithofacies, corals are poorly represent­ of the Hyphantoceras events can be inferred on the ed in the Staffhorst faunas. Two small single corals basis of the echinoid faunas (see chapter 6). It is with strongly ribbed calyces from the 268-271 m inter- unlikely to be attributable to facies control, for the UPPER CRETACEOUS OF THE STAFFHORST SHAFT 199 ammonites of the Hyphantoceras events are found Coniacian) is of interest. This genus has previously throughout northern Europe in lithofacies ranging been recorded from the Middle Santonian Micraster from coccolithlcalcisphere chalks, through Planer rogalaelGonioteuthis westfalicagranulata Zone of limestones to mudstones. However, the absence of the Lagerdorf standard section (ERNST & SCHULZ ammonites is paralleled by the equally remarkable 1974, Fig. 4) and from the white chalk facies virtual absence of the rich inoceramid assemblages of (inferred Santonian) of Helgoland (WOOD & SCHMID the Hyphantoceras events. 1991). There is extensive ammonite material from the top An echinoderm plate from the 251-252 m inter­ beds of the Lower Coniacian upwards. This compris­ val (Santonian) was tentatively identified as es predominantly flattened, weakly pyritised, com­ Uintacrinus and used to assign this interval to the posite moulds. Most of the forms recorded are smooth Upper Santonian Uintacrinus socialis Zone. The and/or unornamented, with some indications of con­ specimen in question has been re-examined for this strictions. These have been listed broadly as Puzosia paper and proves not to belong to Uintacrinus. or puzosiid, although this should not be taken to imply that the genus Puzosia is actually present. It is proba­ ble that this relatively poorly preserved material Regular echinoids includes several generic and/or specific taxa. In addi­ tion, there is one specimen of a tuberculate ammonite Regular echinoids are represented by isolated (presumably a texanitid) from the 265-268 m interval, spines of Hirudocidaris hirudo, Temnocidaris scep­ and fragments of ribbed heteromorphs in the trifera and Tylocidaris clavigera. All three taxa 321-324 m (Upper Coniacian), 400-406 m and occur together in the Santonian in the 265-271 m 416-420 m (Lower Coniacian) intervals. interval. Temnocidaris sceptrifera and Tylocidaris clavigera are also recorded from the Upper Coniacian in the 319-321 m and 315-319 m intervals Bivalves respectively. These three taxa are common in the white chalk The Santonian part of the succession is charac­ facies (Coniacian - Santonian) Micraster coran­ terized by limacean bivalves such as Plagiostoma guinum Zone of southern England, and the first two cretacea and P. hoperi. The P. cretacea are pre­ are recorded (WOOD & SCHMID 1991) from the white dominantly of small size in comparison with speci­ chalk (inferred Santonian) of Helgoland. mens from the white chalk facies, but the P. hoperi include relatively large-sized, albeit rather thin­ shelled, individuals. It should be noted that large 9. FORAMINIFERAL STRATIGRAPHY specimens of P. hoped are particularly characteris­ (W. WEIss) tic of the Santonian chalks of southern England. The occurrence of beds of thin-shelled oysters The re-investigation of the microfaunas from the (Pseudoperna boucheroni and, possibly also Staffhorst section is based on earlier studies (see Acutostrea sp.) in rock-forming quantities towards the above). Preliminary micropaleontogical results were top of the Santonian succession (268-271 m and summarized in an internal BGR short r~port by KOCH 249-251 m intervals) is noteworthy. These beds are (1977a). For the study presented here foraminiferal reminiscent of the Grobkreide lithofacies that spans the micro faunas were studied stratigraphically from terminal Upper Santonian - basal Lower Campanian about 350 samples which were collected from the interval in the Lagerdorf standard section and in correl­ 243.25-813 m interval more or less continuously in ative successions throughout Europe. A comparable units of about 2 m throughout the sequence. approach to Grobkreide facies is found in the lower part The microfaunas found in the slides of the of the basal Upper Santonian Uintacrinus socialis Staffhorst collection consist mainly of planktic and Zone in Yorkshire, eastern England. benthic foraminifers; ostracods and mesofaunal frag­ ments are rare. The planktic foraminiferal component yields specimens from different groups, such as hed­ Crinoids bergellids (H. delrioensis, H. brittonensis, H. paradu­ bia, H. simplex), whiteinellids (w. baltica), The record of a columnal of Austinocrinus gran­ archaeoglobigerinids (A. cretacea), praeglobotrun­ ulata? from the 400-406 m interval (basal Middle canids (P. stephani, P.gibba), dicarinellids (D. imbri- 200 BIRGIT NIEBUHR & al. cata, D. hagni) and double-keeled marginotruncanids posItIOn according to macrofossils = Lower (M. marginata, M. paraventricosa, M. coronata, M. Cenomanian. pseudolinneiana, HM. lapparenti", M. cf.jornicata); Remarks: The Albian/Cenomanian boundary is specimens of the heterohelicids (H. reussi, defined by the (second) occurrence of the ostracod Pseudo textularia cf. elegans) occur very rarely and marker Physocythere steghausi (confirmed by are often absent. The benthic foraminiferal component LUPPoLD, pers. comm.) , which has its Fa in the is composed of specimens of the genera Stensioeina, upper part of the Upper Albian (see KEMPER 1989; Neoflabellina, Bolivinoides (see below), Gavelinella FRIEG & al. 1989). Rotalipora globotruncanoides (G. cenomanica, G. baltica, G. thalmanni) and of (= R. brotzeni), the basal boundary marker taxon for agglutinated specimens (i.e. Marssonella trochus, the Cenomanian stage according to the Brussels con­ Spiroplectinatajaeckeli). The general composition of clusions, was not observed. R. appenninica is rare in the microfauna indicates an epicontinental palaeoenvi­ the 727.5-755.5 m interval. Within the 725-727.5 m ronment which is located roughly between an outer­ interval there are rare specimens of planoconvex shelf to middle part of the sublittoral. rotaliporids which might be assigned to Rotalipora The preservation of the microfaunas is generally micheli. poor. The tests are often covered by sediment over­ Single specimens of Rotalipora appenninica are growth due to slight secondary recrystallisation, typical of the Boreal Lower Cenomanian. The exact which tends to prevent exact taxonomic assignment. stratigraphic assignment of the species is therefore It has therefore proved impossible to produce a com­ often difficult. In the Boreal Realm the species is plete faunal list of all the species present. Text-fig. 10 known from the Upper Albian to Lower shows the distribution of those stratigraphically Cenomanian of northern Germany (KOCH 1977b), important taxa that were positively identified. and from the Lower Cenomanian to lower Middle Cenomanian (R. appenninica and R. reicheli zones) of England (HART & al. 1989). R. micheli was not Stratigraphic ranges known hitherto from the Boreal Realm.

In this study special emphasis was laid on the Rotalipora reicheli (interval) Zone from first and last occurrences (Fa and La) of well­ 668.5-683.5 m: Base = Fa of Rotalipora reicheli at known index markers of the Boreal Upper 683.5 m; Top = Fa of Rotalipora cushmani at Cretaceous (planktic foraminifers, Stensioeina, 668.5 m; Stratigraphic position according to macro­ Neoflabellina and Bolivinoides taxa). These were fossils = terminal Lower Cenomanian to lower used to establish a new and revised foraminiferal Middle Cenomanian. zonation for the Staffhorst succession. The new Remarks: R. reicheli was not recorded previous­ zonation was then correlated with the zonations and ly from this northern region of Germany. It is rare in biostratigraphic assignments based on macrofossils. the Lower/Middle Cenomanian boundary interval The succession of important taxa and of the (e.g. the Mittellandkanal section of the Hannover foraminiferal zones presented here conforms area, ROHDE & BECKER-PLATEN 1998) and is also approximately to the general succession of recorded from Baddeckenstedt (WOOD, pers. Stensioeina and Neoflabellina foraminiferal zones comm.). established earlier by KOCH (1977b) for northern From the Albian/Cenomanian boundary to the Germany. However, the succession of index marker base of the Rotalipora cushmani Zone of the Middle zones has been further refined. Subsequent changes Cenomanian of the Staffhorst section, gavelinellids in stage concepts, and changed stratigraphic inter­ such as G. cenomanica and G. baltica, are not suit­ pretations based on a reassessment of the Staffhorst able as zonal index markers (cf. KOCH 1977b). macrofaunas (see chapter 5), have necessitated a reassessment of the microfossil zones of KOCH Rotalipora cushmani (total range) Zone (pars, (1977b) in relation to the biostratigraphic framework lower part only) from 650-668.5 m: Base = Fa of used today. The succession of the foraminiferal Rotalipora cushmani at 668.5 m; Top = La of zones identified in Staffhorst is as follows: Rotalipora cushmani at 650 m; Stratigraphic posi­ tion according to macrofossils = upper Middle Interval not zoned from 683.5-778.5 m: Base = Cenomanian to lower Upper Cenomanian. Fa of Physocythere steghausi at 778.5 m; Top =Fa Remarks: The upper part of the Upper of Rotalipora reicheli at 683.5 m; Stratigraphic Cenomanian is missing. This is inferred from the UPPER CRETACEOUS OF THE STAFFHORST SHAFT 201

foraminiferal Staffhorst shaft stages I macro- zones.c: sub- fossil- ~ foraminiferal stages zones ~,OllVmOla~~"O stratigraphic range of important foraminifers events sfriqiflafus ~ ;_ C. ~phenoceramu I S. gr. perfecta 250 ~FO , :::I pinniformis m . \Bolivinoides C··················· ... ·· .s -C Cordiceramus Sfensioeina :; i .. ~~~~:~r:::~~ granulafa #'1. ---.-., Clad. undu-.. '. p%nica v, ...I lafoolicafus

.l!l Vo/viceramus .l!! CI) involufus <:: :c .l!l " i·'C .. ·········· .. ····· .. ·.. Q. ~ ~ .S;'" c Volviceramus .~ ~ .§ CU koeneni .l!! .l!l '(3 .l!l ~ ~., ~ Inoceramus <:: ,! ~ c gibbosus ~ o .S;'" .S;'" o Cr. crassus / Sfensioeina .§ Cr. deformis granulafa ,~'" <:: J!l ? granulafa E C/,) 450 C/,) Cr. crassus .<: inconsfans j Cr. walfersd. hannovrensis ···6emn"Q;;e~~~·J------I~ mus deformis 500 erectus Sfensioeina . Cr. walfers- . granulafa \ ...C!.9.rt.'f.rJ.?/.~ .. J levis My/i/oides 8...... ~~~P..~~!...... I------I c.. I. perplexus :::I .. .. ;~~~.;:.~~.~;: Sfensioeina c lamarckil granulafa ,! I. inaequivalvis kelleri c CI) e :c Inoceramus Sfens/oeina :::s 'C lamarcki granulafa I- i .jn~~~;!!t~ ____ :::!~i?

not zoned

800

Fig. 10. Vertical ranges of important foraminifera in the Upper Cretaceous of the Staffhorst shaft 202 BIRGIT NIEBUHR & al. fact that species normally accompanying R. cush­ lata at 487 m; Stratigraphic posItIOn according to mani, such as R. greenhornensis and R. deeckei in macrofossils = upper Upper Turonian to basal Lower the upper Upper Cenomanian, have not been found Coniacian. together with R. cushmani in Staffuorst. Remarks: The FO of Stensioeina granulata levis was used by KOCH (1977b) to define the base of the The Whiteinella archaeocretacea Zone of the Upper Turonian micropalaeontologically [i.e. Lower Cenomanian/Turonian boundary interval is suspect­ Coniacian in modem terms]. Within the ed either to be present in the short 647.1-650 minter­ 492.5-521 m interval planktic foraminifers, such as val, or the zone is completely missing. The index praeglobotruncanids and double-keeled margin­ marker was not observed in the only sample from otruncanids, are common. Lithologically, this part this interval, at 648.5 m. coincides with the GrauweiBe Wechselfolge and the Upper Limestone Unit (see Text-fig. 5). Helvetoglobotruncana helvetica (total range) Zone from 617-647.1 m: Base =FO of Helvetoglo­ Stensioeina granulata granulata (interval) Zone botruncana helvetica at 647.1 m; Top = LO of from 355.2-487 m: Base = FO of Stensioeina gran­ Helvetoglobotruncana helvetica at 617 m; ulata granulata at 487 m; Top = FO of Stensioeina Stratigraphic position according to macrofossils = exsculpta exsculpta at 355.2 m; Stratigraphic posi­ Lower Turonian to basal Middle Turonian. tion according to macrofossils = Lower Coniacian 1 Remarks: This single-keeled, planoconvex and lower Middle Coniacian. I species was hitherto not reported from northern Remarks: According to KOCH (1977b) this index j Germany. The chambers of the final whorl on the marker has its FO in the upper part of the Upper I ventral side of the specimens found are not so Turonian, i.e. within the Lower Coniacian in modem J strongly inflated as is typical for Tethyan specimens, terms. I but the Boreal specimens show the typical rugose ornamentation on the ventral side of the chambers. Stensioeina exsculpta exsculpta (interval) Zone from 334-355.2 m: Base = FO of Stensioeina exs­ Stensioeina granulata interjectalStensioeina culpta exsculpta at 355.2 m; Top = FO of granulata humilis Zone from 589.5-617 m: This Neojlabellina gibbera at 334 m; Stratigraphic posi­ zone is inferred to be present over this interval, and tion according to macrofossils = upper Middle it is definitely proved by the occurrence at 595 m of Coniacian. single specimens of Stensioeina granulata humilis. Remarks: According to KOCH (1977b), who used Stratigraphic position according to macrofossils = a twofold subdivision of the Coniacian, the index Middle Turonian. marker has its first occurrence in the upper part of the Lower Coniacian, i.e. upper Middle Coniacian in Stensioeina granulata kelleri (total range) Zone modem terms. Within this zone one true specimen of from 534-589.5 m: Base = FO of Stensioeina gran­ Dicarinella concavata, a Tethyan planktic ulata kelleri at 589.5 m; Top = LO of Stensioeina foraminiferal species, was observed at 343 m. granulata kelleri at 534 m; Stratigraphic position according to macrofossils = terminal Middle Neojlabellina gibbera (interval) Zone from Turonian to upper Upper Turonian. 315.5-334 m: Base = FO of Neojlabellina gibbera at Remarks: Stensioeina granulata kelleri was pre­ 334 m; Top = FO of Stensioeina granulata poloni­ viously used as the index marker of the upper part of ca at 315.5 m; Stratigraphic position according to the Middle Turonian (KOCH 1977b), i.e. Upper macrofossils = terminal Middle Coniacian and low­ Turonian in modem terms. Within the 585.5-588 m ermost Upper Coniacian. interval planktic foraminifers are strongly reduced, Remarks: The FO of Neojlabellina gibbera has whereas Stensioeina specimens are become domi­ hitherto been used to define the base of the Lower nant for the first time. At 581 m both planktic Santonian micropalaeontologically (KOCH 1977b). foraminifers and Stensioeina specimens show sig­ nificant carbonate dissolution. Stensioeina granulata polonica (total range) Zone from 260-315.5 m: Base = FO of Stensioeina Stensioeina granulata levis (interval) Zone from granulata polonica at 315.5 m; Top = LO of 487 -533 m: Base = FO of Stensioeina granulata levis Stensioeina granulata polonica at 260 m; at 533 m; Top = FO of Stensioeina granulata granu- Stratigraphic position according to macrofossils = UPPER CRETACEOUS OF THE STAFFHORST SHAFT 203 lower Upper Coniacian to Middle (or basal Upper) The FO of specimens of the Stensioeina granu­ Santonian. lata kelleri - levis - granulata group is at 595 m in Remarks: According to CHRISTENSEN & SCHULZ the lower Middle Turonian. (1997, p. 10) the FO of Stensioeina granulata The FO of Neoflabellina (Neoflabellina sutu­ polonica does not coincide with the base of the ralis group, N. gibbera, N. santonica) is at 340 m in Sphenoceramus pachtilCladoceramus undulatopli­ the terminal Middle Coniacian. catus Zone defining the base of the Santonian, it is The FO of Bolivinoides (Bolivinoides strigilla­ within the Volviceramus koeneni Zone of the tus) is at 244 m within the Upper Santonian. Middle Coniacian. These first occunences indicate the onset of a significant change in the paleoenvironmental depth, Stensioeina granulata perfecta (interval) Zone which becomes shallower. from 244.2-255 m: Base = FO of Stensioeina gran­ ulata perfecta at 255 m; Top = FO of Bolivinoides A remarkable hiatus is present from the upper strigillatus at 244.2 m; Stratigraphic position part of the Upper Cenomanian on. It includes the according to macrofossils = Middle (or basal Upper) Oceanic Anoxic event at the Cenomanian/Turonian Santonian to Upper Santonian. boundary. There is no significant change in compo­ Remarks: The FO of Stensioeina granulata per­ sition of the microfossil assemblages; the microfa­ fecta was used by KOCH (1977b) to define the base cies and the planktic foraminiferal composition is of the upper part of the Middle Santonian. similar below and above the hiatus. The reason for this similarity is unclear. Bolivinoides strigillatus Zone from 242.25-244.2 m (last sample studied): Base = FO of Bolivinoides strigillatus at 244.2 m; Stratigraphic 10. MULTISTRATIGRAPHIC position of the base according to macrofossils = CORRELATION AND CONCLUSIONS Upper Santonian. Albian/Cenomanian boundary

General remarks Proposal in Brussels (see TROGER & KENNEDY 1996): FO (first occunence) of the planktic During the later Early Cenomanian the Tethyan foraminifer Rotalipora globotruncanoides. influence increased, as indicated by the occunence This paper: The FO of R. globotruncanoides of planktic foraminifers such as R. appenninica, R. cannot be used because of the absence of the taxon cf. micheli, R. reicheli, R. cushmani and in the Boreal. The Albian/Cenomanian boundary Helvetoglobotruncana helvetica. The planktic in Staffhorst is defined by the re-entry (= second foraminiferal zonation used in the Tethys is applica­ occunence) of the ostracod Physocythere ble for this part of the Staffhorst sequence. steghausi at 779 m shaft (786 m trial borehole), For the interval from the upper Middle Turonian which is accompanied by a conspicuous negative to the Upper Santonian the Boreal benthic SN peak, the so-called Bemeroder Einschntirung foraminiferal zonation established by KOCH (1977b) (Bemerode constriction) within the clayey-marly for northern Germany can be broadly applied, albeit Bemeroder Schichten (KEMPER 1973; FRIEG & al. with considerable modifications, necessitated by 1989). changed stage boundary concepts, as well as revised stratigraphic positions based on macrofossils, event stratigraphy and hiati (cf. Text-fig. 11). Lower Cenomanian Planktic foraminifers from the Tethyan Realm have not been found throughout this part of the suc­ The most important marker bed is the Lower cession. Rare specimens of Tethyan species are pre­ Cenomanian transgression horizon of SP peak 0 at sent, as is indicated by the OCCUlTence of Dicarinella 750 m (757 m) which conesponds to the concavata at 343.5 m which, according to the macro­ Neohibolites ultimuslAucellina event. In marginal fossils, falls in the upper part of the Middle Coniacian. sections, the transgressive deposits onlap older strata with a gap and consequently this horizon is used to The first occunences of key benthic foraminifer­ mark the Albian/Cenomanian boundary on geologi­ al index taxa are related to three separate levels: cal maps (= "base of the Upper Cretaceous"). In the 204 BIRGIT NIEBUHR & al.

Staffuorst area, the transgression horizon is located Middle/Upper Cenomanian boundary ca. 30 m upsection of the Albian/Cenomanian bound­ 1 I ary defined by microfossil biostratigraphy and log Proposal in Brussels (see TRaGER & KENNEDY i peak stratigraphy. At 755m (762m) the first keeled 1996): No agreement was reached. planktic foraminifera (Rotalipora appenninica) This paper: In northern Germany, the appear. Pycnodonte event can usually be used as the bound­ The Lower Cenomanian can be divided into three ary marker (cf. ERNST & al. 1983). In Staffuorst, it sequences (see Text-fig. 11). Two stratigraphically appears at 659 m (666 m). In the electric borehole important inoceramid events can be observed. The I. logs it correlates with a distinct positive SP peak crippsi event of the Mantelliceras mantelli Zone in the upsection of SP peak 7 within the Acanthoceras 715-735 m (722-742 m) interval marks the sequence jukesbrownei and lower Rotalipora cushmani zones boundary between sequence I and II below SP peak 2, respectively. and the I. virgatus event of the Mantelliceras dixoni Zone in the 702-706 m (709-713 m) interval appears in the middle part of sequence III at a conspicuous posi­ Upper Cenomanian tive SP peak up section of SP peak 4. In Staffuorst, only the lower part of the typical Arme rhotomagense Kalke is developed, i.e. the Lower/Middle Cenomanian boundary interval from the Pycnodonte event up to the Amphidonte event; the Metoicoceras geslinianum Proposal in Brussels (see TRaGER & KENNEDY and Neocardioceras juddii zones are completely 1996): FO of the ammonite Cunningtoniceras missing. Likewise, only the lower part of the inerme, with the entry of the inoceramid Inoceramus Rotalipora cushmani Zone is proved. This situa­ schoendorfi and the planktic foraminifer Rotalipora tion is similar to that in the Sarstedt section, where reicheli as secondary markers. the Upper Cenomanian Arme rhotomagense Kalke This paper: C. inerme cannot be proved in are also only a few metres thick (ERNST & SCHMID Staffuorst, and therefore the secondary markers were 1984). used. In Staffuorst, I. schoendorfi is first proved in the 672-682 m (679-689 m) interval. This correlates well with the FO of R. reicheli at 683 m (690 m). Above SP Cenomanian/Turonian boundary peak 6 a distinct positive SP peak occurs at 682 m (689 m in the log ofthe Staffuorst trial borehole). This Proposal in Brussels (see BENGTSON 1996): FO "marl peak" = minor Pycnodonte event at the base of of the ammonite Watinoceras devonense. the Middle Cenomanian, is interpreted as a sequence This paper: In the Staffuorst section, the boundary with a major hiatus (C. inerme hiatus of Cenomanian/Turonian boundary falls into an hiatus, ERNST & REHFELD 1997), and it probably correlates which covers more than three macrofossil zones. with the marl layer M II of Baddeckenstedt. Because of Compared to the succession in Baddeckenstedt the C. inerme hiatus, the FO of C. inerme lies directly (ERNST & REHFELD 1997), the upper half to two­ below the P. primus event in Wunstorf (Lower thirds of the Arme rhotomagense Kalke, the Facies Saxony) (MEYER 1990). In more complete sections, the Change, the plenus Bed and the Mytiloides hattini P. primus event correlates with the base of the suc­ events are missing. Likewise, the planktic ceeding Acanthoceras rhotomagense Zone (PAUL & foraminifer Whiteinella archaeocretacea of the al.1994). Cenomanian/Turonian boundary interval is also absent. In the Staffuorst trial borehole the SP peaks 9 (upper Arme rhotomagense Kalke) and 10 (plenus Middle Cenomanian Bed, topmost Cenomanian) are not recorded. Lower Turonian In Staffuorst, the Mid-Cenomanian event in the 676-678 m (683-685 m) interval is a biotur­ The Lower, not basal, Turonian of Staffuorst starts bated nodular calcareous marlstone, as usual asso­ with the Mytiloides events, which correlate with the ciated with the occurrence of Holaster subglobo­ end of the Oceanic Anoxic event II (ERNST & al. sus (cf. ERNST & al. 1983; ERNST & REHFELD 1983). The FO of Helvetoglobotruncana helvetica, 1997). the index of the second Turonian foraminifer zone, UPPER CRETACEOUS OF THE STAFFHORST SHAFT 205

Staffhorst trial borehole ~ U) ~"C 8 echinoid E U) l!l SP (self-pot ntial) SN (resistivity) .. Iii c: stages! macrofossil­ assemblage !II ~ fii"C 'itl r-----:------:~ .5 U) ~ substages zones zones .§ 2 ~ 1ii:E 16", Ohm/m ~ § ~ ~------~~~--~--~~~--,.----~~~~ Magadi­ 310 ceramus m subquadratus I. fasciculatus events -< 29

Volviceramus Echinocorys 350 scu/a/a ssp. ! CII involutus I. mantelli event -~--- ,==;-~-;=-==-~-0:E-7-;;:t :g Micraster gr. = oyster bed ~~ 'C bucailli- ...... r-./ r-./ coranguinum r-./ r-./ c i r-./ r-./ CU Volviceramus r-./ r-./ koeneni r-./ r-./ '(3 V. koeneni event _-:-___ r-./ r-./ weak echinoid III event ___ r-./ r-./ 400 ,! ...... ?---? r-./ r-./ r-./ r-./ c Inoceramus r-./ r-./ o gibbosus r-./ r-./ ...... not zoned r-./ r-./ o r-./ r-./ Cr. crassus I oysterbed------tzs~~~~~ .. Cr. deformis

? 450 ...I~ ?"Tate? Cr. crassus Echinocorys inconstans ...... gravesi! Mieraster Cr. waltersd. c. w.c. inconstanshannovrensis event event ;~=~::~~~~~~~~ bucaillil hannovrensis = E. gravesi event ---- 25 ...... «M. cortestu- Cremnocera- dinarium» mus deformis Stemotaxis 500 erectus placenta Cr. walters- earty E. Grau-WeiBe .., dorfensis .: : ...... gravesil Wechselfolge Myti/oides Micraster .. scupini borchardil Lower Lime­ CII ...... D. S. m.f. plana- stone Unit I. perplexus Echinocorys/ D...... placental :;;-_-;;:,2;2~~~~~~~~~~ 550 ::J Stern. plana Sternotaxis e~ent 21 large I. ex gr. = Hyphantoceras e.{?) 2~O~~I~::r~=c:~ t seq.X lamarckil --SB.------1 I. inaequivalvis seq.lX c ...... CU ---SB---~ '2 «Conulus subrotundus» 2 CII Inoceramus :g lamarcki ::::I 'C I- i ~~1600 ...... "'iiioc:'cuvieri" «c. truncatus C. castanea ~ Myt. labiatus I rhotomag.1 M. myti/oides ...i D. inferus» Mytiloides events seq.VI t--+--=+-::::--::-===+--:---:-:-h..!:i'-''Y''AmPhidonteC. guerangeri not zoned I I event -a---==i.~~~~f$S5~!~c~ -;?- seq.V :.~:Z~~~~~~9~1.~ 1------;Holaster 3'~ Pycnodonte event --=::=~-"'''''''T- ,; A. rhoto- sub- a::E 7 ~ magense globosus Mid-Cenomanian event ---.::..... >-,.!-~'::"'-,-<'-::=-:,-,.,,....:;;:.. C- i t---'!;==~-l a::h 1i = H. subglobosus event al .. _-- :::::g;:T.tilii'fi)§::::: ---SB ___.,,1/):-1 C ...... not zoned Sterno/axis minor Pycnodonte event-:6:-:::;F~-f""~~ CU gr. gregoryi- - Mantelliceras trecensisl 700 HST ~ '2 Holaster C dixoni I. virgatus event aI CU bischoffi :::s ...... _5k_= c­ E .. al CII 0 not zoned TST I/) C ~ Mantelficeras --SB seq.1I CI) ...I mantelfi I. crippsi event --SB ---'--; (J 750 HST Lower Cenomanian ...... transgression horizon ---0 = N. ultimusiAucellina event not zoned not zoned

Physocythere steghaus",i""I.:..1 ___ ~ (second occurrence) CII ..c:i D. D.

Upper Turonian Middle Turonian In the lower Upper Turonian, compared to the A characteristic lithologic feature of the lower Staffhorst 7 and E 9 boreholes, there is clear evidence Middle Turonian is the increasing carbonate content, of an hiatus in the Staffhorst trial borehole at 556 m accompanied by decreasing SP values, up to the (563 m), comprising SP peaks 17-19. The inoceramid WeiJ3e Grenzbank at SP peak 13 in the 614-621 m association characteristic of the Hyphantoceras event (621-628 m) interval. Within the WeiJ3e Grenzbank, was not found. However, within the the FO of unequivocal Inoceramus lamarcki is EchinocoryslSternotaxis event of the 534-537 m recorded at 619 m (626 m) and the LO (last occur­ (541-544 m) interval, an echinoid association appears rence) of Helvetoglobotruncana helvetica is record­ which is typical of the stratigraphic position of the ed at 617 m (624 m). Hyphantoceras event. Mytiloides scupini has its FO The distinct positive SP peak of the dark marl at the same level, correlating well with the FO of bed at the top of the WeiJ3e Grenzbank at 614 m Stensioeina granulata levis at 533 m (540 m). This (621 m) is interpreted as a sequence boundary and event-bundling shows the pronounced condensation may correspond to the marl bed Mo of S6hlde (cf. of the Staffhorst section in comparision to Salzgitter­ ERNST & WOOD 1995). The subdivision of the Salder, where ca. 40 m of sediments are intercalated remainder of the Middle Turonian is scarcely possi­ between the I. perplexuslS. plana event and the ble; only the I.lamarcki events, which lie in outcrop Hyphantoceras event, and ca. 20 m between the sections above tufflayer Tc (cf. ERNST & al. 1998a) Hyphantoceras event and the FO of M. scupini are recorded in the 586-598 m (593-605 m) interval. respectively (see HORNA & WIESE 1997). In the The FO of benthic foraminifers of the Stensioeina Staffhorst shaft, the Hyphantoceras event (as defined granulata kelleri-levis-granulata group at 595 m by the echinoid assemblage) and FO of M. scupini are (602 m) indicates the first observable change to shal­ in the same interval and only ca. 11-14 m above the lower environments in the Staffhorst area. apparent I. perplexuslS. plana event. This situation is also found in the Staffhorst 7 and E 9 boreholes, and consequently stratigraphic condensation in this inter­ Middle/Upper Turonian boundary val may characterize the whole Staffhorst area. Condensation und event-bundling up section of 1 J Proposal in Brussels (see BENGTSON 1996): No the hiatus support the interpretation of a distinct 1 agreement was reached. sequence boundary and condensation within the suc­ This paper: Following the traditional European ceeding TST. After an abrupt facies change from J concept the FO of the inoceramid Inoceramus per­ white chalky limestones of the Lower Limestone plexus WHITFIELD (= Inoceramus costellatus of Unit at 521 m (528 m) between SP peaks 22-23, this authors, non I. costellatus WOODS) can be used, condensation continues into the GrauweiJ3e which in northern Germany corresponds to the I. Wechselfolge. At 509-514 m (516-521 m), the perplexuslSternotaxis plana event. In Staffhorst an Didymotis I and C. waltersdorfensis events of the apparent FO of I. perplexus is noted in the interval terminal Turonian are found. UPPER CRETACEOUS OF THE ST AFFHORST SHAFT 207

Turonian/Coniacian boundary Middle Coniacian

Proposal in Brussels (see KAUFFMAN & al. Directly above the Lower/Middle Coniacian 1996): FO of the inoceramid Cremnoceramus boundary within the Emscher Marls below the SP rotundatus, which appears to be a junior syn­ peak 27 a subordinate echinoid III event occurs in onym of Cremnoceramus deJormis erectus the 393-397 m (400-404 m) interval; it is followed (MEEK). by the Volviceramus koeneni event at 387-393 m This paper: The proposal of the Brussels sym­ (394-400 m). posium can be applied. In Staffhorst C. deJormis In the terminal Middle Coniacian, rare planktic erectus has its FO in the 504-509 m (511-516 m) foraminifers of the Tethyan Realm, Dicarinella con­ interval at SP peak 23 within the Grau-WeiBe cavata, were found at 343 m (350 m). The FO of the Wechselfolge. benthic foraminifer Neoflabellina at 340 m (347 m) indicates a second noticeable change to shallower environments. Lower Coniacian

The exact position of the top of the GrauweiBe Middle/Upper Coniacian boundary Wechselfolge and its transition into the overlying Upper Limestone Unit is not fully agreed between Proposal in Brussels (see KAUFFMAN & al. the authors of this paper, but is nevertheless well 1996): FO of the inoceramid Magadiceramus sub­ defined. However, according to the lithological quadratus. characters, the transition into the Upper Limestone This paper: In Staffhorst the boundary definition Unit occurs at 504 m (511 m), thereby giving the using the FO of M. subquadratus is difficult, because GrauweiBe Wechselfolge its characteristic ratio of 6- this species is extremely rare. In the absence of 7 "Turonian parts" to 1 "Coniacian part" (cf. WOOD Magadiceramus-dominated assemblages, the base of & ERNST 1998, p. 95). According to faunistic mark­ the substage is taken at the appearance of other inoce­ ers, the GrauweiBe Wechselfolge comprises the ramids characteristic of the Upper Coniacian, notably interval up to the hiatus at 484 m (491 m). Directly "Sphenoceramus" subcardissoides, Inoceramus Jas­ above this hiatus, within the 447-484 m (454-491 m) ciculatus, I. latisulcatus, I. canaliculatus and the interval, the Echinocorys gravesi event is recorded, volviceramid-like I. anomalus. In Staffhorst this marked by the absolute frequency maximum of assemblage first appears at 330 m (337 m) within the Echinocorys within the succession, and the immi­ Neoflabellina gibbera Zone. The FOs of N. gibbera gration of the first "modem" Micraster at 467 m at 334 m (341 m) and Neoflabellina suturalis at (454 m). At the same time, inoceramids of the 332 m (339 m) can consequently be used as secondary Cremnoceramus crass us inconstans group have markers. their first occurrences in the 463-467 m (470-474 m) interval, indicating either a co-migration event or an hiatus. The FO of Stensioeina granulata granulata Upper Coniacian is situated a short distance above the hiatus at 487 m (494 m). In Staffhorst only the lower Upper Coniacian is represented. The I. Jasciculatus mass-occurrence is found in the 315-322 m (322-329 m) interval. The Lower/Middle Coniacian boundary FO of Stensioeina granulata polonica is situated at 315 m (322 m). In the electric borehole logs, the SN Proposal in Brussels (see KAUFFMAN & al. values start to increase at this depth, which is proba­ 1996): FO of the inoceramid Volviceramus koeneni. bly related to the gradual upper transition into the This paper: The proposal of the Brussels sym­ Emscher Marls. posium can be applied. V. koeneni appears in In the 306-311 m (313-318 m) interval occur­ Staffhorst above a subordinate hiatus within the rences of Gonioteuthis and Echinogalerus(?) docu­ Emscher Marls at 400 m (407 m). In the 400-406 m ment a Late Coniacian transgressive pulse. According (407 -413 m) interval a possible evolutionary precur­ to belemnite stratigraphy, the Gonioteuthis praewest­ sor of Volviceramus was found. Jalica Zone starts at this level. ------~

208 & al. BIRGIT NIEBUHR I j Coniacian/Santonian boundary Middle Santonian

In the 265-271 m interval, the occurrence of Proposal in Brussels (see LAMOLDA & HANCOCK Gonioteuthis and Echinogalerus(?) documents the 1996): FO of the inoceramid Cladoceramus undu­ main transgressive pulse of the Middle Santonian latoplicatus. transgression. According to belemnite stratigraphy, This paper: The proposal of the Brussels sym­ it lies at the base of the lower G. westfalica Zone posium can be applied. In Staffhorst C. undulatopli­ and, therefore, at the base of the Micraster coran­ catus appears directly above the conspicuous hiatus guinumlG. westfalica Zone of Uigerdorf (see at 303 m, where, according to log peak correlation ERNST & SCHULZ 1974, there: upper Lower with the Staffhorst 7 and E 9 boreholes, ca. 90 mare Santonian). missing. Up section from the base of the Santonian, the sediments are apparently flat-lying and no corre­ lation factor of 7 m between shaft and trial borehole Middle/Upper Santonian boundary and Upper is necessary. Santonian

Proposal in Brussels (see LAMOLDA & Lower Santonian HANCOCK 1996): FO of the crinoid Uintacrinus socialis. In the 296-300 m interval occurrences of This paper: The occurrence of U. socialis in Gonioteuthis qnd Echinogalerus(?) document a Staffhorst cannot be proved. An echinoderm plate transgressive pulse of the Early Santonian C. undu­ from the 251-252 m interval in the Hamburg latoplicatus transgression (Text-fig. 9). Some ofthe University material was originally identified as Gonioteuthis from this level are corroded. Uintacrinus and used to assign this interval (WOOD, According to belemnite stratigraphy, the C. undu­ unpubl. report) to the Upper Santonian Uintacrinus latoplicatus transgression also falls into the top of socialis Zone. The presumed original specimen, the G. praewestfalica Zone. This zone, therefore, consisting of a tempestite with a mass occurrence of spans the middle and upper Upper Coniacian, as Pseudoperna boucheroni, contains crinoid and well as the basal Santonian, including the major hia­ other echinoderm fragments, but the crinoids appear tus in the late Late Coniacian. In the more complete not to belong to Uintacrinus. It must be emphasized Staffhorst E 9 borehole, where no hiatus is devel­ that, although no specimens of Uintacrinus have oped, the G. praewestfalica Zone would comprise been identified from Staffhorst, the foraminiferal more than 100 m and the Stensioeina granulata evidence unequivocally proves that the Uintacrinus polonica (total range) Zone, which also crosses the Zone is present. Uintacrinus is extremely rare in the major hiatus in the Staffhorst shaft, would be more lower part of its range, and otherwise typically than 140 m thick. occurs in floods, separated by intervals with few or no occurrences. In this paper the following possible boundary markers are discussed: LowerlMiddle Santonian boundary inoceramids: FO of Sphenoceramus pinniformis at Proposal in Brussels (see LAMOLDA & HANCOCK 266 m; FO of "Inoceramus" muelleri at 266 m; 1996): LO of the inoceramid Cladoceramus undu­ foraminifers: FO of Stensioeina granulata perfecta latoplicatus. at 255 m; FO of Bolivinoides strigillatus at This paper: The proposal of the Brussels sym­ 244m; posium can be applied. The LO of the inoceramid belemnites: FO of Gonioteuthis granulata, not re­ C. undulatoplicatus in Staffhorst is at 290 m. corded up to 245 m. According to belemnite stratigraphy, the boundary In the Text-figures of this paper the lies within the "Gonioteuthis-depleted interval", MiddlelUpper Santonian boundary is defined which in the Uigerdorf standard section covers the according to the FOs of the inoceramids "I." muel­ Sphenoceramus pachtilCladoceramus undulato­ leri and S. pinniformis at 266 m. "I." muelleri is a plicatus Zone of the lower Lower Santonian (see Middle/Upper Santonian boundary marker in north­ ERNST & SCHULZ 1974). ern Spain, where S. pinniformis has not been record­ ed (OPPERMANN 1996). In the Uigerdorf standard UPPER CRETACEOUS OF THE ST AFFHORST SHAFT 209

section, uf." muelleri has not been found; here, the biostratigraphy also agrees well with unpublished Fa of S. pinniformis (and only horizoned record) is data from current investigations of the Seaford Head located significantly lower, within the Middle section in the white chalk of southern England. Santonian Micraster rogalaelGonioteuthis westfal­ To summarize, the evidence for placing the base ica Zone, with presumed occurrences extending up of the Upper Santonian is, admittedly, contradictory, to above the Fa of Uintacrinus in bed G236 (ERNST with perhaps the strongest evidence being provided & SCHULZ 1974, Fig. 4). This relatively low placing by the foraminifera. According to the foraminiferal of the boundary in Staffhorst is possibly supported biozonation, the presence of Upper Santonian in by the occurrence of phosphorite pebbles at Staffhorst is unequivocally proved by the Fa of 261-263 m, which could be inferred to document the Bolivinoides strigillatus at 244 m, and almost equal­ Late Santonian transgression. However, on the basis ly certainly indicated by the Fa of Stensioeina of the Gonioteuthis morphometric data, the overly­ granulata perfecta, 11 m lower, at 255 m. However, ing 245-256 m interval still clearly belongs to the G. it is unclear whether or not this represents the true westfalicagranulata Zone (see Text-fig. 9). If one Fa of S. granulata perfecta, since this apparent Fa were to take the FOs of S. pinniformis and uf." is associated with an hiatus. The apparent absence of muelleri at 266 m as the base of the Upper Uintacrinus in Staffhorst is explicable in view of the Santonian, the entire G. westfalicagranulata Zone rarity of this crinoid towards the base of its range, would, both in Staffhorst and in Uigerdorf, fall by and by the fact that it typically occurs in discrete lev­ definition into the Upper Santonian, but such an els of relative flood abundance, and is never con­ interpretation would be completely at variance with spicuous. The oyster-rich horizon in the 251-252 m standard practice in Germany. interval actually supports taking the base of the The mass-occurrence of Pseudoperna bouche­ Upper Santonian near the Fa of S. granulata per­ roni associated with echinoderm debris in the fecta. Although there is definite evidence of a sig­ 251-252 m interval may equate with the Ostrea bed nificant inoceramid turnover at 266 m, it must be recorded by ERNST (1963: 106) in Uigerdorf imme­ accepted that the Fa of Sphenoceramus pinniformis diately overlying F232, close to the base of the at Liigerdorf, if correctly interpreted, clearly falls in Uintacrinus socialislGonioteuthis granulata Zone. the higher part of the Middle Santonian. This inoce­ A comparable oyster-rich event with P. boucheroni ramid Fa and associated inoceramid turnover and Sphenoceramus pinniformis is also known from should perhaps not be used as a definitive criterion eastern England, in the lower part of the Uintacrinus for identifying the base of the Upper Santonian, and socialis Zone, and ca. 1 m beneath an occurrence of more reliance should be placed instead on the Uintacrinus. The Fa of Uintacrinus in Uigerdorf is foraminiferal evidence. For the reasons discussed actually located ca. 4.5 m below the base of the above, two possible interpretations of the base of the UintacrinuslG. granulata Zone in bed G236 Upper Santonian are shown in the Text-figures of (SCHULZ & al. 1984) and, therefore, in the middle of this paper. The entirely contradictory nature of the the ca. 10 m thick M. rogalae!G. westfalicagranu­ evidence provided by the Gonioteuthis lineage, lata Zone. The higher part of the M. rogalaelG. which indicates that both of these interpretations are westfalicagranulata Zone thus falls, by definition, impossible, cannot readily be resolved. into the basal Upper Santonian. At 255 m a break is found in the Gonioteuthis evolution, which is probably connected with an hia­ REFERENCES tus. At the same level, Stensioeina granulata per­ fecta first appears. In Uigerdorf this Fa falls within ALBERTI, H. 1968. Analyse der Oberkreide-Fazies in Bohr­ the Micraster rogalaelGonioteuthis westfalica­ profilen des Weser-Ems-Gebietes. Zeitschrift der granulata Zone, but only a short distance (ca. 1 m) Deutschen Geologischen Gesellschaft, 117,436-447. below the Fa of Uintacrinus in bed G236. The Fa Hannover. of Bolivinoides strigillatus in Staffhorst is at 244 m. BALDscHuHN, R., BEST, G. & KOCKEL, F. 1991. Inversion The Fa of B. strigillatus in Uigerdorf is in the tectonics in the north-west German Basin. In: F226-F227 interval (SCHONFELD 1990), in the higher A.M Spencer (Ed.), Generation, accumulation and part of the Uintacrinus socialislG. granulata Zone production of Europe's hydrocarbons. European As­ (cf. section details in: ERNST 1963). sossiation of Petroleum Geoscientists, 1, 149-159. The stratigraphic levels at Liigerdorf of these two University Press; Oxford. foraminiferal FOs with respect to the macrofossil BALDscHuHN, R., FRISCH, U. & KOCKEL, F. 1998a. Der 1 I j

210 BIRGIT NIEBUHR & ai.

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Manuscript submitted: 15th January 1999 Revised version accepted: 15th March 1999