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Structure of the southern Rio Grande rift from gravity interpretationRegional Bouguer gravity anomalies in southern New Mexico have been analyzed by two-dimensional wave number filtering and poly-nomial trend surface analysis of the observed gravity field. A prominent, regional oval-shaped positive gravity anomaly was found to be associated with the southern Rio Grande rift. Computer modeling of three regional gravity profiles suggests that this anomaly is due to crustal thinning beneath the southern Rio Grande rift. These models indicate a 25 to 26-km minimum crustal thickness within the rift and suggest that the rift is underlain by a broad zone of anomalously low-density upper mantle. The southern terminus of the anomalous zone is approximately 50 km southwest of El Paso, Texas. A thinning of the rifted crust of 2-3 km relative to the adjacent Basin and Range province indicates an extension of about 9 percent during the formation of the modern southern Rio Grande rift. This extension estimate is consistent with estimates from other data sources. The crustal thinning and anomalous mantle is thought to result from magmatic activity related to surface volcanism and high heat flow in this area.
Document ID
19860053057
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Daggett, P. H.
(ARCO Oil and Gas Co., Exploration and Production Research Dept., Plano TX, United States)
Keller, G. R.
(ARCO Oil and Gas Co. Dallas, TX, United States)
Wen, C.-L.
(Texas, University El Paso, United States)
Morgan, P.
(Lunar and Planetary Institute, Houston, TX; Purdue University West Lafayette, IN, United States)
Date Acquired
August 12, 2013
Publication Date
May 10, 1986
Publication Information
Publication: Journal of Geophysical Research
Volume: 91
ISSN: 0148-0227
Subject Category
Geophysics
Accession Number
86A37795
Funding Number(s)
CONTRACT_GRANT: NASW-3389
CONTRACT_GRANT: NSF EAR-70-25371
Distribution Limits
Public
Copyright
Other

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