Superficial Deposits As Indicators Of Paleo-hydrological Changes In The Quaternary of Nigeria
by
Bisi Durotoye
Natural History Museum Obafemi, Awolowo University Ile-Ife, Nigeria

Wide spread occurrence of angular pediment gravels and alluvial deposits in Nigeria are interpreted to be products of alternating dry and wet phases that are most probably parts of global pluvials and interpluvial of the Quaternary. Pediment gravels presently consisting of an assorted range of clastic particle sizes but with prominent angular fragments of quartz and rocks, are derived from deeply weathered bedrocks. Marked absence of peat or other organic remains further corroborates the proposition that the gravels were spread during a dry phase of minimal precipitation, with non-forest vegetation cover that engendered the removal of finer fractions of sediments only to concentrate the large ones. Two distinct generations of gravels have so far been recognised, an older cemented gravel and a younger loose gravel, implying two dry phases with an intervening wet phase. Pebbly river gravels and alluvial sand deposits from widely different parts of Nigeria indicatre three phases of precipitation that surpassed the present days in amount and intensity. Dating of these deposits is required to provide a better understanding of the pattern of paleoclimatic changes in the Quaternary.

Date received: April 2, 2001

Copyright © 2001 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cagc-91.