SUBSURFACE SEQUENCE DELINEATION AND SALINE WATER MAPPING OF LAGOS STATE, SOUTHWESTERN NIGERIA
AbstractA subsurface sequence delineation and saline water mapping of Lagos State was carried out. Ten (10) deep boreholes with average depth of 300 m were drilled within the sedimentary basin. The boreholes were lithologically and geophysically logged.
The driller's lithological logs aided by gamma and resistivity logs, showed that the area is underlain by clays, sandy/silty clays, clayey sands and sands with shale and limestone in places.
The resistivity logs delineate saline water at shallow depth at Lekki wells I and II, Lakowe and Akodo with fresh/saline water interface at depths ranging from 8 - 15m. Confined saline water was delineated at deep levels at Eredo and Akodo. Saline seawater incursion has extended in land to within 2.5 - 12.5km from the coastline.
KEY WORDS: Subsurface Sequence, Saline Water Mapping
Global Jnl Geological Sciences. Vol.2(1) 2004: 111-123