NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Stability of sulfur slopes on IoThe mechanical properties of elemental sulfur are such that the upper crust of Io cannot be primarily sulfur. For heat flows in the range 100-1000 ergs/sq cm sec sulfur becomes ductile within several hundred meters of the surface and would prevent the formation of calderas with depths greater than this. However, the one caldera for which precise depth data are available is 2 km deep, and this value may be typical. A study of the mechanical equilibrium of simple slopes shows that the depth to the zone of rapid ductile flow strongly controls the maximum heights for sulfur slopes. Sulfur scarps with heights greater than 1 km will fail for all heat flows greater than 180 ergs/sq cm sec and slope angles greater than 22.5 deg. The observed relief on Io is inconsistent with that anticipated for a predominantly sulfur crust. However, a silicate crust with several percent sulfur included satisfies both the mechanical constraints and the observed presence of sulfur on Io.
Document ID
19810048202
Document Type
Reprint (Version printed in journal)
Authors
Clow, G. D. (Geological Survey Menlo Park, CA, United States)
Carr, M. H. (U.S. Geological Survey Menlo Park, Calif., United States)
Date Acquired
August 11, 2013
Publication Date
November 1, 1980
Subject Category
LUNAR AND PLANETARY EXPLORATION
Funding Number(s)
CONTRACT_GRANT: NASA ORDER W-13709
Distribution Limits
Public
Copyright
Other