TOPIC: DELIMITATION OF CONTINENTAL-OCEANIC CRUSTAL BOUNDARY IN THE SOUTHEAST SECTOR OF NIGER DELTA USING FILTERED MAGNETIC DATA: IMPLICATIONS ON HYDROCARBON GENERATION.
PROF. NSIKAK E. BASSEY
GEOLOGY DEPARTMENT, AKWA IBOM STATE UNIVERSITY, NIGERIA
ABSTRACT
This work attempts to define the continent – ocean crustal boundary (COB) offshore the Niger delta (southeast sector) using aeromagnetic data. The study area is located within longitude 6-8o E, and latitude 3-5o N and is about 50, 625 km2.The delta formed following the Mesozoic rifting of the Atlantic and has a total stratal thickness of about 12 km overlying the basement. These consist of continental, parrallic and marine Formations. The total intensity magnetic data over the study area were subjected to reduction to pole and 4th degree polynomial filtering. These generated magnetic stripes (seafloor spreading anomalies) and deep seated basement magnetic signatures respectively. An isometric projection of the total intensity magnetic anomaly map of the area was also produced. Based on distinct magnetic signatures from the three data sets, over onshore and offshore zones, the continental crust (granitic), transitional zone and oceanic crust (basaltic) in the study area are mapped. COB delimitation is of profound importance in determining limits of hydrocarbon generation zones in offshore basins. The more the granitic crust advances seaward the higher the hydrocarbon generation potential of the basin. From this work the COB is delimited to be circa 70 km in the west, and 100 km in the east from the coast line of the data.
