Biostratigraphy and palaeoenvironment of deposition of Nsukka Formation,Anambra Basin,southeastern Nigeria

作     者：S.A.Bankole A.O.Ola-Buraimo 

作者机构：Department of Chemical and Geological SciencesAl-Hikmah UniversityllorinNigeria Department of GeologyFederal UniversityBimin KebbiNigeria 

出 版 物：《Journal of Palaeogeography》 (古地理学报（英文版）)

年 卷 期：2017年第6卷第1期

页      面：45-59页

核心收录：

学科分类：0303[法学-社会学] 0710[理学-生物学] 070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 07[理学] 0708[理学-地球物理学] 0705[理学-地理学] 0815[工学-水利工程] 0813[工学-建筑学] 0833[工学-城乡规划学] 

基　　金：Palystrat Limited for her continuous financial and material support in making this research study a reality 

主　　题：Biostratigraphy Palaeoenvironment Assemblage Gonyaulacacean/Peridinacean ratio Index fossil Anambra Basin 

摘      要：Biostratigraphy investigation of Nsukka Formation was carried out by subjecting weLt cutting samples obtained from Nzam-1 weLL to patynotogicat studies with the view towards determining the relative geologic age and pataeoenvironment of deposition of the sediments. SampLes were treated in the Laboratory through digestion with hydrofluoric acid, sieving with 5 μm, oxidation with Nitric acid and mounting of the sLides into sections with DPX mountant. A fairLy high abundance and diversity of miospores were recovered, white the interval （847-1372 m） contains distinctive and diagnostic patynomorphs which are stratigraphicatty important. A Spinizonocolpites baculatus assemblage zone was established based on the basal occurrence of S. baculatus, Spinizonocolpites echinatus, Constructipollenites ineffectus, Periretisyncolpites sp. Periretisyncolpites giganteus, Monocolpites sp 1, Foveotriletes margaritae, Syncolporites marginatus, and Longapertites marginatus. The upper part of the intervat is marked by association of Anacolosidites luidonisis （at top）, Mauritiidites crassibaculatus, Retistephanocolpites williamsi, Proteacidites dehaani, Echitriporites trianguliformis, Proxapertites cursus, Retidiporites magdalenensis, S. baculatus, Retitricolpites gigeonetti, F. margaritae and Araucariadtes sp. The Nsukka Formation is dated as Late Maastrichtian based on the cooccurrence of recovered index fossits. Importantly, Cretaceous-Tertiary （K/T） boundary is marked by high fossil content in the Maastrichtian sediments compared to paucity in patynomorph that characterises the overtying Pateocene facies. Pataeoenvironment of the anatyzed section varies atternatety from marginaL marine to continental setting based on the presence of land-derived miospores and dinoflagettates.