NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
The Mantle and Basalt-Crust Interaction Below the Mount Taylor Volcanic Field, New MexicoThe Mount Taylor Volcanic Field (MTVF) lies on the Jemez Lineament on the southeastern margin of the Colorado Plateau. The field is centered on the Mt. Taylor composite volcano and includes Mesa Chivato to the NE and Grants Ridge to the WSW. MTVF magmatism spans approximately 3.8-1.5 Ma (K-Ar). Magmas are dominantly alkaline with mafic compositions ranging from basanite to hy-basalt and felsic compositions ranging from ne-trachyte to rhyolite. We are investigating the state of the mantle and the spatial and temporal variation in basalt-crustal interaction below the MTVF by examining mantle xenoliths and basalts in the context of new mapping and future Ar-Ar dating. The earliest dated magmatism in the field is a basanite flow south of Mt. Taylor. Mantle xenolith-bearing alkali basalts and basanites occur on Mesa Chivato and in the region of Mt. Taylor, though most basalts are peripheral to the main cone. Xenolith-bearing magmatism persists at least into the early stages of conebuilding. Preliminary examination of the mantle xenolith suite suggests it is dominantly lherzolitic but contains likely examples of both melt-depleted (harzburgitic) and melt-enriched (clinopyroxenitic) mantle. There are aphyric and crystal-poor hawaiites, some of which are hy-normative, on and near Mt. Taylor, but many of the more evolved MTVF basalts show evidence of complex histories. Mt. Taylor basalts higher in the cone-building sequence contain >40% zoned plagioclase pheno- and megacrysts. Other basalts peripheral to Mt. Taylor and at Grants Ridge contain clinopyroxene and plagioclase megacrysts and cumulate-textured xenoliths, suggesting they interacted with lower crustal cumulates. Among the questions we are addressing: What was the chemical and thermal state of the mantle recorded by the basaltic suites and xenoliths and how did it change with time? Are multiple parental basalts (Si-saturated vs. undersaturated) represented and, if so, what changes in the mantle or in the tectonic regime allowed their coexistence or caused the transition?
Document ID
20110008787
Acquisition Source
Marshall Space Flight Center
Document Type
Presentation
Authors
Schrader, Christian M.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Crumpler, Larry S.
(New Mexico Museum of Natural History and Science Albuquerque, NM, United States)
Schmidt, Marick E.
(Brock Univ. Saint Catherines, Ontario, Canada)
Date Acquired
August 25, 2013
Publication Date
December 13, 2010
Subject Category
Geosciences (General)
Report/Patent Number
M11-0141
M11-0170
Meeting Information
Meeting: American Geophysical Union (AGU) Fall Meeting 2010
Location: San Francisco, CA
Country: United States
Start Date: December 13, 2010
End Date: December 20, 2010
Distribution Limits
Public
Copyright
Public Use Permitted.
No Preview Available