Dinoflagellate-Small Acritarch stratigraphy of the Campanian-Danian Interval and Organic Facies Evidence of Sea Level Change

针对美国沿海平原省露头剖面和深海钻探项目/海洋钻探计划提供的海洋盆地岩心剖面，提出了坎帕尼亚、马埃斯特里希特和早期达尼安期沉积物中鞭毛类和小柱头类的地层学研究。目的是对这段地层进行定年，准备鞭毛藻和甲藻带，这些带可以与先前公布的古白垩世的带相联系，并确定白垩纪/第三纪（K/T）边界的甲藻记录的性质。有必要通过调查陆地上的剖面（如阿拉巴马州布拉格的剖面）和海洋盆地的剖面（如D.S.D.P. Site 577的剖面）来校准鞭毛状甲藻地层，这些剖面已经建立了独立的、一致的多学科年龄证据，这些证据由极性反转磁地层学、化学地层学(iridium，碳-13)，以及钙质化石的生物地层学。以往对大西洋沿岸平原（晚白垩世）和犹他/怀俄明逆冲带（中侏罗世）井的研究表明，鞭毛藻种类丰度和孢粉学定义的有机相反映了海侵和回归的事件。生物地层基准面（FAD， LAD）的多次出现表明了海侵对岩性环境的影响，其后是一段时间的无定形碎屑和鞭毛藻种类的增加。回归的特点是在陆生植物碎屑的有机基质中鞭毛藻种类较少。美国东部露头和油井调查。海岸平原将提供孢粉学证据的测试。对邻近北大西洋西部遗址的研究将检验深海相海平面变化的孢粉学证据。

Study of the stratigraphy of dinoflagellate and small acritarch species in sediments of Campanian, Maestrichtian and early Danian ages is proposed for sections occurring in outcropin the U.S. Coastal Plain Province and in cored ocean basinsections available from the Deep Sea Drilling Project/OceanDrilling Program. The purpose is to stratigraphically date this interval, to prepare dinoflagellate and acritarch zonations which can be connected to those previously published for the olderretaceous and to determine the nature of the dinocyst record at the Cretaceous/Tertiary (K/T) boundary. It will be necessary to calibrate the dinoflagellate-acritarch stratigraphy byinvestigating sections on land, e.g. sections at Braggs, Alabama, and in the ocean basins, e.g. sections at D.S.D.P. Site 577, for which there is established independent and concordant-multidisciplinary evidence of age provided by polarity reversalmagnetostratigraphy, chemostratigraphy (iridium, Carbon-13), and the biostratigraphy of calcareous fossils. Previous study of wells in the Atlantic Coastal Plain (Late Cretaceous) and in the Utah/Wyoming Overthrust Belt (Middle Jurassic) suggests that dinoflagellate species abundance andpalynologically-defined organic facies reflect episodes oftransgression and regression. Evidence of transgression indifferent lithological settings is indicated by a multipleoccurrence of biostratigraphic datums (FAD, LAD) which is succeeded by an interval of amorphous debris and increased number of dinoflagellate species. Regression is characterized by fewer dinoflagellate species in an organic matrix of landplantdetritus. Investigation of outcrops and wells of the easternU.S. Coastal Plain will provide a test of the palynologicalevidence. Study of sites in the adjacent western North Atlantic will test the palynological evidence of sea level change in thedeep sea facies.