Physics
Scientific paper
Dec 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011agufm.p31e1736m&link_type=abstract
American Geophysical Union, Fall Meeting 2011, abstract #P31E-1736
Physics
[5420] Planetary Sciences: Solid Surface Planets / Impact Phenomena, Cratering, [5430] Planetary Sciences: Solid Surface Planets / Interiors, [5480] Planetary Sciences: Solid Surface Planets / Volcanism, [8434] Volcanology / Magma Migration And Fragmentation
Scientific paper
Large impact basins are a prime example of an external influence on planetary evolution. However, the resulting basin environment can exert strong control on subsequent internal processes of a planet, e.g., volcanism. We argue that the state of lithospheric stress created by initial basin-filling magmatism creates favorable environments for magma ascent in annular zones around basins. After initial increments of basin-filling magmatism, flexural response of the lithosphere creates upper lithosphere compression beneath the load, thereby inhibiting further magma ascent and favoring formation of a complex of horizontally propagating intrusions (sills) that may contribute to observed mascon gravity anomalies [1]. Observed flows from basin margins have been attributed to mid-lithosphere outward magma transport to the flexural arch, where extensional upper lithosphere stresses again allow ascent [2]. However, a more direct and powerful ascent mechanism involves a favorable combination of extensional membrane stresses (important for wide loads) and upward-increasing extensional flexural stresses (positive "tectonic stress gradient" [3]) at basin margins to drive magma ascent in vertical dikes directly from mantle melt zones to the surface. Moon: The substantial negative buoyancy of dense (Ti-rich) magmas identified in Tranquillitatis and Procellarum mare units could be counteracted by stresses related to Serenitatis and Imbrium loading, respectively. Further, proposed lunar shield volcanoes [4] are all located on the margins of these basins, consistent with enhanced magma ascent. Exposures of olivine (as detected by the SELENE Spectral Profiler) in basin-ringing zones have been attributed to impact transport of deep crustal or mantle material [5]. However, an examination of higher-resolution spectral data from Chandrayaan-1's M^3 at the Crisium basin reveals additional basin-rim olivine exposures, including several clearly associated with magmatic transport of olivine as cumulates or mantle xenoliths. Mars: The Circum-Hellas volcanic province comprises several volcanic edifices and expanses of volcanic ridged plains [6]. Similarly, the relationships of the Elysium Rise to Utopia and the Syrtis Major shield to Isidis suggest magmatic enhancement by loading stress states at the margins of these filled basins. As at the Moon, exposures of olivine near and between large basins like Hellas, Isidis and Argyre [7] suggest a role for circum-basin magmatism. Mercury: The plains around the Caloris basin were suggested to be younger than the basin interior based on Mariner 10 imaging. Analysis of new MESSENGER imaging data [8] indicates that the circum-Caloris plains indeed postdate the basin and interior deposits and are volcanic in origin, consistent with the presence of a trans-basin ascent zone.
Kramer Georgiana Y.
Litherland M. M.
McGovern Patrick J.
Powell Keith
No associations
LandOfFree
Stress-enhanced magma ascent at the margins of large impact basins in the solar system 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 Stress-enhanced magma ascent at the margins of large impact basins in the solar system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stress-enhanced magma ascent at the margins of large impact basins in the solar system will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-870436