Refining the Stratigraphy of Venus Using the Distribution of Features in Shield fields: A Numerical Modeling and Mapping Study

Bradley J Thomson, Boston University, Center for Remote Sensing, Boston, United States and Nicholas P. Lang, Mercyhurst University, Erie, PA, United States

Contact First Author: Bradley J Thomson; bthom@utk.edu

Previously Published Material: Preliminary work on this topic was presented in LPSC abstracts in 2013 and 2014 by the two authors. Here we present expanded findings that are soon-to-be submitted to Computers and Geosciences (methods) and JVGR (results).

Abstract ID#: 34242

 

English Abstract:
Inferring the relative age of geologic units on Venus is challenging due to the paucity of impact craters. Although abundant cross-cutting relationships exist to provide insight into relative ages at the local scale, it is difficult to infer relative timing between distant units that do not have any features or structures in common.

Here we attempt to refine our stratigraphic knowledge of geologic units on Venus by using a suite of statistical tools to infer the relative timing between shield fields (clusters of small volcanoes) and the surrounding structures, particularly fracture sets. Specifically, we have developed MATLAB-based models to search for and characterize potential anisotrophy in the distribution of volcanic edifices in shield fields [1, 2]. Numerical model results are then compared with geologic mapping results to test for potential areas of correspondence [3-5]. The objective is to infer which set(s) of fractures may have been active when the shields were emplaced, thus helping to better place the shields into the local stratigraphic column.

An initial examination of four shield fields (Chernava Colles, Ran Colles, Jurate Colles, Urutonga Colles) yields some results as expected as some surprises. In Chernava Colles, the shield field exhibits a preferred orientation consistent with the dominant NNW-trending fracture set. However, in Ran Colles and Jurate Colles, the preferred orientation of the shields are consistent with the trend of wrinkle ridges rather than fractures, suggesting the reactivation of extensional fractures that may have previously served as conduits of flow material [4].

References:

[1] Thomson B.J. & Lang N.P. (2013) LPSC, abstract #2021.

[2] Thomson B.J. & Lang N.P. (2014) LPSC, abstract #2347.

[3] Lang N.P. & Thomson B.J. (2013) LPSC, abstract #1808.

[4] Lang N.P. et al. (2014) LPSC, abstract #2219.

[5] Kelly N.J. et al. (2014) LPSC, abstract #2884.

Back to: Surface Expressions of Volcanism and Associated Tectonism on Venus and Implications for Interior Dynamics