Microcontinent breakup and links to possible plate boundary reorganization in the northern Gulf of California, México

Tectonics
By: , and 

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Abstract

Faults on microcontinents record the dynamic evolution of plate boundaries. However, most microcontinents are submarine and difficult to study. Here, we show that the southern part of the Isla Ángel de la Guarda (IAG) microcontinent, in the northern Gulf of California rift, is densely faulted by a late Quaternary-active normal fault zone. To characterize the onshore kinematics of this Almeja fault zone, we integrated remote fault mapping using high-resolution satellite- and drone-based topography with neotectonic field-mapping. We produced 13 luminescence ages from sediment deposits offset or impounded by faults to constrain the timing of fault offsets. We found that north-striking normal faults in the Almeja fault zone continue offshore to the south and likely into the nascent North Salsipuedes basin southwest of IAG. Late Pleistocene and Holocene luminescence ages indicate that the most recent onshore fault activity occurred in the last ∼50 kyr. These observations suggest that the North Salsipuedes basin is kinematically linked with and continues onshore as the active Almeja fault zone. We suggest that fragmentation of the evolving IAG microcontinent may not yet be complete and that the Pacific-North America plate boundary is either not fully localized onto the Ballenas transform fault and Lower Delfin pull-apart basin or is in the initial stage of a plate boundary reorganization.

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Publication type Article
Publication Subtype Journal Article
Title Microcontinent breakup and links to possible plate boundary reorganization in the northern Gulf of California, México
Series title Tectonics
DOI 10.1029/2021TC006933
Volume 41
Issue 1
Publication Date January 24, 2022
Year Published 2022
Language English
Publisher American Geophysical Union
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description e2021TC006933, 18 p.
Country Mexico
Other Geospatial Gulf of California
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