A GEOPHYSICAL APPROACH TO UNDERSTANDING THE OLDUVAI GORGE BASIN SUBSURFACE: USING MAGNETICS TO TRACK BED I BASALT FLOWS
When taking magnetic measurements of a magnetic body that has been faulted, the values produce a distinctive anomaly wave pattern when moving from hanging wall to footwall and vice versa. The data indicate that the Bed I basalt layers are faulted along the First, Second, Third, and Fifth Faults. Although the basalt is seen being faulted at the Fourth Fault in the gorge, the lack of the signature anomaly pattern could be due to the relatively small offset of the Fourth fault in comparison to the other faults. The Naabi Ignimbrite could not be distinguished from basement rock where it is exposed at granite falls. Whenever a magnetic survey moves over two bodies with different susceptibilities, a bell curve anomaly pattern is produced in the data. Since this doesn’t exist between the granitic basement and ignimbrite, the magnetic properties of the ignimbrite are not distinguishable from the basement and provides evidence that the data collected is from the Bed I basalt. Depth estimates and other filtering and smoothing operations will provide a clearer spatial picture of the basalt. This could redefine the ages for faults where basalt is not exposed, such as the First and Fifth Faults. This leads to a better understanding of how and when the gorge formed.