Palynofacies investigation of Callovian (Middle Jurassic) sediments from DSDP Site 534, Blake-Bahama Basin,Western Central Atlantic |
| |
| Authors: | Richard V Tyson |
| |
| Institution: | School of Environmental Sciences, University of East Anglia, Norwich, Norfolk NR4 7TJ, UK |
| |
| Abstract: | During the extension of Deep Sea Drilling Project (DSDP) Leg 76 a new and previously unpenetrated lithological unit composed mainly of claystones was cored above basalt basement at Site 534 in the Blake-Bahama Basin. The Callovian part of the new unit contains interbedded ‘black shales’ which were hitherto unexpected in this part of the section. This Paper presents a brief palynological examination of lithofacies-kerogen relationships in these sediments and shows that their organic content is almost entirely a function of the re-deposition of terrestial and marine organic matter versus the ambient redox conditions of the depositional environment. Allochthonous organic matter inputs are highest in the interbedded turbidites and decline progressively toward the pelagic black shales in which marine organic matter is comparatively well preserved. The significance of various kerogen and palynomorph indices are discussed. The study emphasizes the absolute necessity for sedimentologically-aware sampling in all palynological and geochemical work on lithologically heterogeneous sequences. |
| |
| Keywords: | Palynology Lithofacies Jurassic |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
