Paleomagnetic evidence that the central block of Salinia (California) is not a far-traveled terrane
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Abstract
New paleomagnetic results from Late Cretaceous (75–85 m.y.) red beds on the central block of Salinia indicate that Salinia was located within 6° (in latitude) of its current cratonal North American position during the Late Cretaceous (after correction for Neogene San Andreas Fault transport). The red beds formed as alluvial-fan overbank deposits with hematite cement deposited directly on Salinian granites in the La Panza Range. Paleomagnetic analysis shows two components of magnetization in the red beds, a low-blocking-temperature present-day overprint residing in goethite and a high-blocking-temperature (>600°) component residing in hematite. The hematite magnetization is a chemical remanent magnetization which formed soon after deposition during pedogenesis. The bedding-corrected hematite remanence contains a magnetic polarity stratigraphy with antipodal normal and reversed directions. Twenty-three Class I sites (α95 < 20°) have an average hematite direction with inclination =54.4° and declination = 18.2° (α95 = 6.1°) after structural correction. These paleomagnetic data suggest that Salinia resided at about 35°N latitude during the Late Cretaceous, within 6° of its current location adjacent to cratonal North America. By contrast, a summary of paleomagnetic data from the Peninsular Ranges terrane and the Sur-Obispo terrane, which are currently outboard of Salinia, shows northward transport of these terranes of 12° to 22° relative to their current locations in North America since the Cretaceous. The offsets increase systematically away from the craton with the most outboard Sur-Obispo terrane (which is composed of accretionary prism and distal forearc material) showing the largest degree of northward translation.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Paleomagnetic evidence that the central block of Salinia (California) is not a far-traveled terrane |
| Series title | Tectonics |
| DOI | 10.1029/97TC03021 |
| Volume | 17 |
| Issue | 3 |
| Year Published | 1998 |
| Language | English |
| Publisher | American Geophysical Union |
| Description | 15 p. |
| First page | 329 |
| Last page | 343 |
| Country | United States |
| State | California |