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Influence of tectonics and palaeoenvironment on late cretaceous clay sedimentation in the upper benue trough, Nigeria
Author(s) -
Enu E. I.
Publication year - 1986
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.3350210202
Subject(s) - geology , sedimentary depositional environment , illite , cretaceous , outcrop , clay minerals , trough (economics) , kaolinite , cenomanian , sedimentary rock , chlorite , geochemistry , tectonics , paleontology , structural basin , quartz , economics , macroeconomics
The Late Cretaceous sedimentary sequence in the Upper Benue Trough consists of seven formations. Outcrop samples from the type localities of these units were analysed by X‐ray diffraction for their day mineral content. The composition and distribution of the clay minerals are influenced by tectonics, relief and water depth. Three main depositional phases are recognizable on the basis of clay mineral assemblages, two of which are associated with tectonic movements. The first phase, characterized by the presence of chlorite, illite, kaolinite and mixed‐layer clays is common to Albian‐Cenomanian sediments. This phase is succeeded by mixed‐layer clays and smectite‐rich, Turonian‐Early Santonian sediments. The re‐occurrence of chlorite and illite in association with kaolinite and mixed‐layer clays in the Post‐Santonian sediments constitutes the third depositional phase. These clay mineral assemblages are indicative of two periods of tectonism (Albian and Late Santonian) and an intervening Turonian‐Early Santonian period of quiescence in the Upper Benue Trough.