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Fault Growth And Propagation During Incipient Continental Rifting: Insights From A Combined Aeromagnetic And Shuttle Radar Topography Mission Digital Elevation Model Investigation Of The Okavango Rift Zone, Northwest Botswana, Baraka D. Kinabo, John Patrick Hogan, Eliot A. Atekwana, Mohamed G. Abdel Salam, Motsoptse P. Modisi
Fault Growth And Propagation During Incipient Continental Rifting: Insights From A Combined Aeromagnetic And Shuttle Radar Topography Mission Digital Elevation Model Investigation Of The Okavango Rift Zone, Northwest Botswana, Baraka D. Kinabo, John Patrick Hogan, Eliot A. Atekwana, Mohamed G. Abdel Salam, Motsoptse P. Modisi
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Digital Elevation Models (DEM) extracted from the Shuttle Radar Topography Mission (SRTM) data and high-resolution aeromagnetic data are used to characterize the growth and propagation of faults associated with the early stages of continental extension in the Okavango Rift Zone (ORZ), northwest Botswana. Significant differences in the height of fault scarps and the throws across the faults in the basement indicate extended fault histories accompanied by sediment accumulation within the rift graben. Faults in the center of the rift either lack topographic expressions or are interpreted to have become inactive, or have large throws and small scarp heights indicating waning …
Natrolitite, An Unusual Rock -- Occurrence And Petrographic And Geochemical Characteristics (Eastern Turkey), Emin Ciftci, John Patrick Hogan, Hasan Kolayli, Emin Cadirli
Natrolitite, An Unusual Rock -- Occurrence And Petrographic And Geochemical Characteristics (Eastern Turkey), Emin Ciftci, John Patrick Hogan, Hasan Kolayli, Emin Cadirli
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Very unusual rocks consisting of natrolite (>95 vol.%) ± pargasite (<5 vol.%) and rare albite (<1 vol. %) have been discovered in the Kop mountain range, eastern Turkey. We propose to call these rocks 'natrolitite' and 'pargasite natrolitite'. They were produced by Na Si metasomatism of dikes and stocks of diorite through replacement of the intermediate primary igneous plagioclase to produce natrolite. The metasomatic alteration produced concentric elliptical zones characterized by distinct mineral assemblages centered on intrusions of diorite. The Central Zone 1 consists of variably albitized diorite with preserved magmatic textures (albite ± andesine ± pargasite ± quartz). Transition Zone 2 comprises natrolite-bearing diorite (natrolite ± albite ± andesine ± pargasite ± calcite ± quartz). Marginal Zone 3 is a rock made up almost entirely of natrolite (natrolite ± pargasite ± albite ± calcite ± chlorite). Outer Zone 4 occurs along the boundary between the natrolitite and the surrounding serpentinite and consists of listvenite, a rock which comprises magnesite, quartz, calcite, mica, talc, and hematite, indicating a role for CO2 in the metasomatic reactions, consistent with the presence of calcite in the alteration zones. Zone 5 consists essentially of brecciated serpentinite with numerous hydrothermal quartz veins and calcite veins. Whole-rock compositions document an increase in Na2O, Al2O3, and H2O from the core (central zone) to the margin while CaO, MgO, and SiO2 decrease. Plagioclase abundance and composition also varies outwards from the central core rocks where it occurs as a primary magmatic phase (~95 vol.% An41-38) …