Abstract/Details

IO: MODELS OF VOLCANISM AND INTERIOR STRUCTURE (JUPITER, MOON, CALDERAS, HEAT FLOW, LACCOLITHS)


1983 1983

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Abstract (summary)

The silicate "magma trigger" model of volcanism on Io has been evaluated numerically with finite element methods by considering the one-dimensional heat transfer between hot silicate magma and initially cold sulfur. It is found that for the probable range of initial magma temperatures and sulfur temperatures, the contact between silicate magma and a sulfur crust will be 700 (+OR-) 100 K, or approximately the vapor point of elemental sulfur. A silicate magma sill or laccolith on the order of 10 m thick will yield energetic vapor for a period of several weeks to several months depending on the vapor temperature and the amount of convective cooling of the silicate magma that occurs at the silicate-sulfur interface. This model may account for the origin of plumes and possible sulfur flows, as well as for their observed temperatures ((TURN) 600-700K) and lifetimes (several days to a few months).

If the conducted heat flow is similar in high and low latitudes, then the low latitude occurrence of plumes may be explained as a result of lower temperatures at higher latitudes. Because the contact temperature of sulfur and silicate magma depends on the pre-existing sulfur temperature, a system in which sulfur vapor temperature is just reached at the equator would not generate sulfur vapor under lower initial sulfur temperatures existing at high latitudes. If the heat flow is higher in high latitudes, then the sulfur crust must be thinner than it is in low latitudes for the model to work as described above.

Most of the heat flow from Io may be moved by convection from the interior to the surface, not by conduction. Heat flow may be modulated by the efficient transfer of silicate melts from 40 to 300 km depth, and emplaced as laccoliths at the sulfur-silicate crustal interfaces at a depth of 5-10 km. Sulfur flows, plumes, calderas and other areas of massive radiant heat dissipation continue the convective cycle to the surface.

The temperature at the base of the sulfur crust may be less than the melting point of sulfur, and the silicate magma temperature can be as low as 1200 K. Low silicate magma temperatures will occur if the crust of Io is as differentiated as terrestrial rhyolites and trachytes. High alkalies in the Io plasma torus suggest the possibility that the Ionian crust is a highly differentiated silicate.

Indexing (details)


Subject
Geophysics;
Astronomy;
Astrophysics
Classification
0373: Geophysics
0606: Astronomy
0606: Astrophysics
Identifier / keyword
Pure sciences; Earth sciences
Title
IO: MODELS OF VOLCANISM AND INTERIOR STRUCTURE (JUPITER, MOON, CALDERAS, HEAT FLOW, LACCOLITHS)
Author
CRUMPLER, LARRY STEVEN
Number of pages
162
Publication year
1983
Degree date
1983
School code
0009
Source
DAI-B 44/12, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
University/institution
The University of Arizona
University location
United States -- Arizona
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
8405493
ProQuest document ID
303113342
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/303113342/fulltextPDF
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