Transform Faulting and Growth of the Gulf of California Since the Late Pliocene

Abstract

Seismic-reflection and magnetic profiles over more than 6000 kilometers suggest that spreading of the sea floor on the East Pacific Rise, at the mouth of the Gulf of California, began to broaden a proto-gulf about 4 million years ago. Movement occurred, on transform faults, offsetting the rise and other centers of crustal growth within the gulf, and translated the end of the peninsula about 200 kilometers to the northwest. Thick pelagic sediments on the east flank of the rise indicate that there was a lapse of spreading by crustal growth between 4 and 10 million years ago.

Late Pliocene to Holocene Benthic Foraminifers of the Guaymas Basin, Gulf of California, Sites 477 through 481

“…A proto-Gulf of California probably existed during the early-to-middle Miocene and early Pliocene epochs, prior to the present phase of spreading (Moore and Buffington, 1968;Karig and Jensky, 1972;Moore, 1973). The presence of planktonic foraminifers indicates that the lowest part of the section in Hole 479 was deposited in the latest Pliocene epoch (Matoba and Oda, this volume).…”

Geologic and Tectonic History of the Gulf of California

“…Moore and Buffington (1968) proposed an age of 4 Ma for the beginning of the present spreading regime, based on an axial spreading rate and the distance to the base of the slope off the tip of the Baja Peninsula. They also noted that on the eastern flank of the ridge southwest of Islas Tres Marias (Fig.…”

Pliocene and Quaternary Mud Turbidites in the Gulf of California: Sedimentology, Mass Physical Properties, and Significance

“…The Gulf of California is about 1000 km long and 100-200 km wide. It is a young ocean basin with passive margins (Larsen et al, 1968;Moore and Buffington, 1968;Karig and Jensky, 1972;Moore, 1973;Rusnak et al, 1964), divided into a complex series of linked basins, which are successively deeper from about 800 meters in the north to 4000 meters at the mouth (Rusnak et al, 1964;Bischoff and Niemitz, 1980). Site 474 sampled a perimeter basin plain sandwiched between the juncture of subsided continental crust and the flanks of the youthful spreading center of the East Pacific Rise (Fig.…”