Mathematics – Logic
Scientific paper
Dec 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007agufm.p34a..02w&link_type=abstract
American Geophysical Union, Fall Meeting 2007, abstract #P34A-02
Mathematics
Logic
5480 Volcanism (6063, 8148, 8450), 8148 Planetary Volcanism (5480, 8450), 8450 Planetary Volcanism (5480, 6063, 8148)
Scientific paper
The fact that lava flows spread down-slope away from their sources to a very much greater extent than they spread laterally has long been recognized as an indication that they behave as non-Newtonian fluids, having a yield strength as well as a plastic viscosity (and possibly other complications such as strain rate- and time- dependent rheology). However, a significant criticism of the earliest models of lava flow emplacement is that they assumed that all parts of the flow - channel and levees - had the same non-Newtonian rheology. Theoretical expectations that channels and levees should have significantly different rheologies are confirmed by analyses of field measurements on terrestrial flows. Here I revisit morphometric measurements on lava flows on the Moon and used these to deduce volume eruption rates for some mare flows. The Gratz number criterion can be used to determine the volume effusion rate of a cooling-limited flow from its length, width and thickness. In so far as the flow may be supply-volume-limited rather than cooling-limited, this method provides a lower limit on the effusion rate. Dividing the volume flux by an estimate of the length along strike of the active part of the fissure feeding the flow gives a value for the product of the magma rise speed and the width of the feeding dike. Using petrological indications of the magma source depth in the mantle, the pressure gradient driving the magma rise through the dike system can be estimated, and balancing wall friction against driving stress then gives the dike width. The requirement that the magma should not cool excessively while rising from the mantle provides a limit on the permutations of feeder dike width and horizontal length of active fissure that can produce a given flow unit. Some values of these parameters for typical mare lava flows will be presented and their implications for the geometries of the dikes feeding them will be discussed.
No associations
LandOfFree
Eruption Conditions of Mare Lavas does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Eruption Conditions of Mare Lavas, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Eruption Conditions of Mare Lavas will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1406518