This research was partially funded by a grant from the Petroleum Research Fund

Rotational Folding:

Rotation of the western Transverse Ranges in California was partially facilitated by rotational folding along the north side of the rotated domain. I am investigating these folds both in the field and theoretically to develop models of rotational folding that will help identify and measure vertical-axis rotation without paleomagnetic data, and show how this style of folding can influence paleomagnetic corrections.

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Testing models of tectonic rotation in the Mojave Desert and along the “break-away zone” of the western Transverse ranges:

We are using paleomagnetic data to evaluate the spatial distribution and amount of rotation associated with the Central Mojave Metamorphic Core Complex, and the offshore Borderland of southern California. This is building on work I did for my PhD on tectonic rotation of the western Transverse Ranges.

Recently, Nolan Blackford used detailed mapping and paleomagnetic data to investigate the history and style of slip along the detachment fault and to see if rotation in the central Mojave during the Miocene was a regional event or confined to the hanging wall of the core complex. Nolan’s mapping and stratigraphic work has resulted in a better understanding of the upper plate of the CMMCC, but much of the rocks sampled for paleomagnetic work were remagnetized, so we still don’t know the details of how vertical-axis rotation relates to Miocene extension in the area.

Ryan Stewart collected new paleomagnetic data from rocks on Catalina island to re-evaluate anomalous data previously collected from the island about 30 years ago by Luyendyk’s group at UCSB, and to test models of extensional rotation in the offshore borderland. Ryan’s data confirmed previous interpretations of a large amount of Miocene clockwise rotation of the island and also captured the cessation of rotation, which appears to have occurred in the Miocene as well. This data will be combined with data previously collected by Solomon Seyum (senior thesis at CalStateLA) on the Palos Verdes peninsula to give us a better picture of the spatial distribution of rotation in southern California.