A widely held hypothesis suggests that Venus experienced catastrophic resurfacing about 500 million years ago, resulting in the burial of 80% of Venus' surface.
This hypothesis predicts that Venus' surface should record only the post-catastrophic history, because postulated catastrophic resurfacing would have buried an earlier record.
In this study, results of global mapping of ribbon-tessera terrain (RTT), a structurally distinctive unit that represents some of Venus' oldest surfaces formed prior to the postulated global catastrophic resurfacing, challenges the catastrophic resurfacing hypothesis.
The global geologic RTT map delineates unit exposures and structural trends based on NASA Magellan data. Map relations illustrate that the RTT displays planet-scale patterns that, together with altimetry, record a rich geologic history. RTT records a regional-scale history of deformation phases or events that vary in space and time. At a global scale, patterns within RTT outcrops and fabrics extend over millions of square kilometers; individual suites record variable temporal evolution, which could potentially be used to correlate temporally distinct events over large regional scales.
The picture that emerges is one in which Venus' surface records a rich and prolonged history that awaits discovery. RTT formed during a specific geologic era, marked by relatively unique environmental conditions, conceptually similar to Earth's Archean Eon.
This research, by V.L. Hansen and I. López, Institute for Frontier Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan is published in the April 2010 issue of Geology.
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