T101 From Outcrops to the Base of the Crust: Integrated Geophysical and Geological Illumination of Earth’s Tectonic Fabrics to Refine Understanding of Crustal Evolution and Natural Resources (Posters)

Monday, 10 October 2022
9:00 AM - 1:00 PM
Exhibit Hall F

GEOPHYSICAL AND GEOLOGICAL INVESTIGATION OF THE SPATIAL AND SUBSURFACE EXTENT OF THE SEGWAGWA AND MASOKE RING COMPLEXES IN SOUTHEAST BOTSWANA: GEOTECTONIC IMPLICATIONS

Paper number: T101-1
Program: Technical Sessions
Time: 9:00 AM – 1:00 PM

Authors

Abstract

The Segwagwa-Masoke Igneous Ring Complex (SMIRC) occurs within the Kanye Basin and is part of a suite of elliptical igneous complexes in SE Botswana. We used map analyses and three-dimensional (3D) joint inversion modeling of airborne magnetic and ground gravity data to examine the internal structure and configuration of the SMIRC. Our results show the SMIRC as nested ring-within-ring structures characterized by high magnetic intensity and high gravity anomalies. The Segwagwa and Masoke Complexes are both elliptical in shape and cover surface areas of 127 km2 and 26 km2, respectively. Additonally, our results revealed two new intrusions, termed here Intrusion A and B, which form part of the SMIRC, bringing the total number of individual intrusions in the SMIRC to four. The 3D models reveal the Segwagwa and Masoke Complexes to be vertically oriented and steep-sided, extending to 12 km and ~5 km depths, respectively. Two-dimensional (2D) forward modeling of the ground gravity data confirms the Segwagwa Complex to be a steep-sided and having a depth extent of 13 km. We interpret the ring-shaped magnetic anomalies to represent magma crystallization along concentric fracture zones that developed in association with the collapse of calderas.

Geological Society of America Abstracts with Programs. Vol. 54, No. 6

doi: 10.1130/abs/2022AM-378206

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