Nannofossil and planktic foraminiferal events of ODP Site 166-1006 sediments

Detailed biostratigraphy in Site 1006 based on planktonic foraminifers and nannofossils shows large-scale sedimentation rate variability in the Florida Strait west of the Great Bahama Bank. A 'floating' cyclostratigraphy based mainly on resistivity logs and magnetic susceptibility data has been fixed to the biostratigraphy in the absence of magnetostratigraphy. The strongest orbital cycle present is the precessional beat, which is present in the borehole logs throughout the record. Counting the cycles resulted in an accurate time scale and thus a sedimentation rate time series. Spectral analysis of the sedimentation rate time series shows that the short-term cycle of eccentricity (~125 k.y.) and the long term cycle of eccentricity (~400 k.y.) are pervasive throughout the Miocene record, together with the long-term ~2-m.y. eccentricity cycle. The Great Bahama Bank produced pulses of shallow carbonate input once every precessional (sea level) cycle during the Miocene and perhaps two pulses per cycle in the early Pliocene. The amount of sediment exported in these pulses appears to be controlled by eccentricity modulation of the precessional amplitude and therefore the amplitude of the sea-level rise. Finally, an increase in sedimentation rate just after the Miocene/Pliocene boundary is attributed to a change in the location and strength of sediment drift currents in the Florida Strait due to reorganization of the currents following the closure of the Panama Isthmus.

Fossil record of Mollusca from Neogene sediments in Schleswig-Holstein, Germany

Über die Verbreitung, Gliederung und Ausbildung des Jungtertiärs im westlichen Schleswig-Holstein war bisher nicht viel bekannt. Am besten bearbeitet sind die glazial gestauchten Schollen von Morsum/Sylt. Eine Aufzählung erbohrter Miozänvorkommen mit nicht immer überzeugender Begründung lieferte H.-L. HECK 1935. S. THIELE (1941) hat die ihm bekannten Vorkommen hauptsächlich nach faziellen und petrographischen Gesichtspunkten bearbeitet. Er erkannte richtig die Stellung der Braunkohlensande. Die angekündigte palaeontologische Bearbeitung ist nicht erschienen. Eine allgemeine Übersicht über die Entwicklung des Jungtertiärs bringen W. WOLFE und H.-L. HECK 1949. W. HINSCH lieferte wertvolle Beiträge zur Molluskenfauna und zur Gliederung des Miozäns (1952, 1955). Über neue Vorkommen von Braunkohlen-Sanden berichtete E. DITTMER(1 956), eine erste Übersicht über neue Vorkommen der Hemmoorer Stufe gab derselbe Verfasser 1957.

Occurrence and estimated abundance of planktonic foraminifers at DSDP Leg 85 holes

Tropical planktonic foraminifers occur throughout the sequences at all sites of Leg 85, and the standard planktonic foraminiferal zonation of Blow (1969) is applicable to most of the recovered sequences. However, the abundance and state of preservation of foraminifers decline markedly in certain intervals because of the effects of dissolution. Although siliceous microfossils studied on this leg indicate recovery of nearly complete records for the Pleistocene to Oligocene interval, the planktonic foraminiferal biostratigraphy is interrupted by strongly dissolved sections at all sites. Particularly, faunas assignable to Zone N7 (early Miocene) and Zone N15-16 (early late Miocene) are almost totally unrecognizable throughout the eastern equatorial Pacific. Well-preserved and diverse planktonic foraminifers occur in the lower middle Miocene, where the evolutionary developments of Orbulina universa d'Orbigny and Globorotalia fohsi Cushman and Ellisor are well represented. The Orbulina first appearance datum is observed to be nearly coincident with the last occurrence level of the diatom Annellus californicus Tempère, thus .establishing an age of 15 Ma for this datum by using the paleomagnetic calibration of the diatom datum. Moderately well-preserved late Eocene planktonic foraminifers occur in the carbonate sediments immediately overlying the basalt basement at Sites 573 and 574. The Eocene-Oligocene faunal transition, however, is masked at both sites by an intercalation of metalliferous layers containing no planktonic foraminifers.

Miocene molluscan biostratigraphy in Schleswig-Holstein, north Germany

Vierlandian, Behrendorfian (Lower Hemmoorian), Oxlundian (Upper Hemmoorian), Lower and Upper Reinbekian, Langenfeldian and Gramian stages could be proved by evaluation of marine molluscan faunas. The diachrone base of 'Braunkohlensande' is demonstrated by underlying Vierlandian mica clay in the E, and by Hemmoorian substages more to the W, at last the fluviatile facies is replaced completely by euhaline to brachyhaline sandy to silty sediments. Brachyhaline effects in adjacent environments make possible an approximate dating on fluviatile sedimentation. The widest extension of 'Braunkohlensand' is during upper Oxlundian, whilst slightly brachyhaline Katzheide beds, defined in this paper to be of Lower Reinbekian age, indicate a limit of 'Braunkohlensande' more to the E. Winnert-fauna was found to be a mixture of Oxlundian and Langenfeldian; the overlying lignitic sands belong to the Kaolinsand group. Upper mica clay overlying Miocene Braunkohlensande can be divided into beds of Upper Reinbekian, Langenfeldian and Gramian ages.

Quaternary benthic foraminifers from DSDP Sites 95-612 and 95-613

The Quaternary benthic foraminifers from Leg 95 Sites 612 and 613 were examined with respect to paleoceanographic trends. Data from the two sites indicate the presence of markedly different bottom-water masses, during both glacial and interglacial periods. The dominant interglacial species at Site 612 is Uvigerinct peregrina, which is barely present in corresponding intervals at Site 613. Dominant glacial species are Elphidium excavatum and Cassidulina reniforme at Site 612 and Epistominella takayanagii at Site 613.

Planktonic foraminifera stratigraphy and datum events of ODP Leg 198 sites

During Leg 198 of the Ocean Drilling Program (ODP), Paleogene sediments were recovered form 10 holes at four sites along a bathymetric transect from the Southern High of Shatsky Rise. In terms of age, the Paleogene successions span from the Cretaceous/Paleocene boundary to the early Oligocene. Sediments are mainly composed of tan nannofossil ooze with scattered darker layers richer in clay. This data report concerns planktonic foraminiferal biostratigraphy from three holes, specifically Hole 1209A (water depth = 2387 m), Hole 1210A (water depth = 2573 m), and Hole 1211A (water depth = 2907 m). The thickness of Paleogene sediments is 105.90 m in Hole 1209A, 95.05 m in Hole 1210A, and 56.11 m in the deepest Hole 1211A. Preliminary investigations conducted on board revealed that at Site 1209 the succession was mostly complete, whereas the succession was more condensed at Site 1211.