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Aeromagnetic measurements in the Cascade Range and Modoc Plateau of northern California; report on work done from December 1, 1980, to May 31, 1981

Open-File Report 82-933
By:  and 
https://doi.org/10.3133/ofr82933

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Abstract

Spectral analysis of aeromagnetic data collected over 6orth-central California during the summer of 1980 aided in determining magnetic-source bottom depths beneath the survey area. Five regions of shallow magnetic source bottom depths were detected: 1) Secret Spring Mountain and National Lava Beds Monument area, 2) the Mount Shasta area, 3) the Eddys Mountain area, 4) the Big Valley Mountains area, and 5) an area northeast of Lassen Peak. Except for the Eddys Mountain area, all regions exhibiting shallow depths are suggested to be due to elevated Curie-point isotherms. The elevated Curie-point depth beneath Secret Spring Mountain and the National Lava Beds Monument area was found to be 4-7 km BSL (Below Sea Level) and is an extension of a zone mapped beneath an area immediately to the north in Oregon. A similar depth was detected for the Mount Shasta area and the area northeast of Lassen Peak. A depth of 4-6 km BSL was detected beneath the Big Valley Mountains area. The shallow Curie-point depths beneath Secret Spring Mountain, Mount Shasta, Big Valley Mountains, and the area northeast of Lassen Peak appear to form a segmented Zone of elevated Curie-point isotherm depths which underlies the High Cascade Mountains and Modoc Plateau in north-central California. A small area of shallow depths to magnetic-source bottoms, 4-5 km BSL, beneath the Eddys Mountain area is attributed to a lithologic boundary rather than an elevated Curie-point isotherm. Deeper magnetic source bottom depths were mapped throughout the remainder of the study area, with depths greater than 9 km BSL indicated beneath Lassen Peak and greater than ii km BSL indicated beneath the Western Cascades, Eastern Klamath Mountains, and Great Valley.

Suggested Citation

Couch, R.W., and Gemperle, M., 1982, Aeromagnetic measurements in the Cascade Range and Modoc Plateau of northern California; report on work done from December 1, 1980, to May 31, 1981: U.S. Geological Survey Open-File Report 82-933, 34 p., ill., maps ;28 cm., https://doi.org/10.3133/ofr82933.

ISSN: 2331-1258 (online)

Publication type Report
Publication Subtype USGS Numbered Series
Title Aeromagnetic measurements in the Cascade Range and Modoc Plateau of northern California; report on work done from December 1, 1980, to May 31, 1981
Series title Open-File Report
Series number 82-933
DOI 10.3133/ofr82933
Year Published 1982
Language ENGLISH
Publisher U.S. Geological Survey,
Description 34 p., ill., maps ;28 cm.
Additional publication details