Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8134270 | Icarus | 2018 | 17 Pages |
Abstract
Parga Chasma is a discontinuous rift system marking the southern boundary of the Beta-Atla-Themis (BAT) region on Venus. Along a 1500â¯km section of Parga Chasma, detailed mapping of Magellan Synthetic Aperture Radar images has revealed 5 coronae, 11 local rift zones distinct from a regional extension pattern, and 47 graben-fissure systems with radiating (28), linear (12) and circumferential (7) geometries. The magmatic centres of these graben-fissure systems typically coincide with coronae or large volcanoes, although a few lack any central magmatic or tectonic feature (i.e. are cryptic). Some of the magmatic centres are interpreted as the foci of triple-junction rifting that form the 11 local rift zones. Cross-cutting relationships between graben-fissure systems and local rift faults reveal synchronous formation, implying a genetic association. Additionally, cross-cutting relationships show that local rifting events postdate the regional extension along Parga Chasma, further indicating multiple stages of rifting. Evidence for multiple centres of younger magmatism and local rifting against a background of regional extension provides an explanation for the discontinuous morphology of Parga Chasma. Examination of the Atlantic Rift System (prior to ocean opening) on Earth provides an analogue to the rift morphologies observed on Venus.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Space and Planetary Science
Authors
J.R. Graff, R.E. Ernst, C. Samson,