DOI: 10.1002/2017JE005358
Scopus记录号: 2-s2.0-85041549574
论文题名: Signatures of Lithospheric Flexure and Elevated Heat Flow in Stereo Topography at Coronae on Venus
作者: O'Rourke J.G. ; Smrekar S.E.
刊名: Journal of Geophysical Research: Planets
ISSN: 21699097
出版年: 2018
卷: 123, 期: 2 起始页码: 369
结束页码: 389
语种: 英语
英文关键词: heat flow
; lithospheric flexure
; planetary tectonics
; Venus
Scopus关键词: corona
; heat flow
; isostasy
; radar altimetry
; stereo image
; synthetic aperture radar
; topography
; Venus
; Calluna vulgaris
英文摘要: Signatures of lithospheric flexure were previously identified at a dozen or more large coronae on Venus. Thin plate models fit to topographic profiles return elastic parameters, allowing derivation of mechanical thickness and surface heat flows given an assumed yield strength envelope. However, the low resolution of altimetry data from the NASA Magellan mission has hindered studying the vast majority of coronae, particularly those less than a few hundred kilometers in diameter. Here we search for flexural signatures around 99 coronae over ∼20% of the surface in Magellan altimetry data and stereo-derived topography that was recently assembled from synthetic aperture radar images. We derive elastic thicknesses of ∼2 to 30 km (mostly ∼5 to 15 km) with Cartesian and axisymmetric models at 19 coronae. We discuss the implications of low values that were also noted in earlier gravity studies. Most mechanical thicknesses are estimated as <19 km, corresponding to thermal gradients >24 K km−1. Implied surface heat flows >95 mW m−2—twice the global average in many thermal evolution models—imply that coronae are major contributors to the total heat budget or Venus is cooling faster than expected. Binomial statistics show that “Type 2” coronae with incomplete fracture annuli are significantly less likely to host flexural signatures than “Type 1” coronae with largely complete annuli. Stress calculations predict extensional faulting where nearly all profiles intersect concentric fractures. We failed to identify systematic variations in flexural parameters based on type, geologic setting, or morphologic class. Obtaining quality, high-resolution topography from a planetwide survey is vital to verifying our conclusions. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114596
Appears in Collections: 气候减缓与适应
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作者单位: School of Earth and Space Exploration, Arizona State University, Tempe, AZ, United States; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
Recommended Citation:
O'Rourke J.G.,Smrekar S.E.. Signatures of Lithospheric Flexure and Elevated Heat Flow in Stereo Topography at Coronae on Venus[J]. Journal of Geophysical Research: Planets,2018-01-01,123(2)