T108 Great Maps in the History of Geology

Monday, 23 October 2017
8:00 AM - 12:00 PM
Skagit 3

TECTONIC MAPS IN REVOLUTIONS: VINE'S (1966) REINTERPRETATION OF RAFF'S AND MASON'S MAGNETIC MAP OF THE NE PACIFIC, AND SIGOCH'S AND MIHALYNUK'S (2017) AUSTRALIA-INDONESIA ANALOGUE FOR LATE MESOZOIC WESTERN NORTH AMERICA

Paper number: T108-15
Program: Technical Sessions
Time: 11:20 AM – 11:35 AM

Authors

Abstract

Early magnetic intensity maps of the northeast Pacific by A. D. Raff, R.G. Mason, V.Vacquier, and others, published in 1961 (before the plate tectonic revolution but while Harry Hess's ocean basin history ideas circulated in preprint form) exhibited a striking N-NE trending series of linear magnetic anomalies that suggested large left lateral displacements along the Pioneer, and Mendocino "faults" of a 265 and 1160 km, respectively. These maps were highly controversial in some geologic circles. The proposed displacements were comparable to the also then-controversial maximum displacement proposed for the San Andreas fault of 640 km by Hill and Dibblee (1953), but also without a mechanism. Hess explained continental drift by proposing that "continents ride passively on convecting mantle" (1960-1962).

Vine (1966) reinterpreted the Vacquier, Raff, and Mason maps as portraying symmetrical magnetic anomalies formed by sea floor spreading. This new insight eliminated the need for large left-lateral offsets, and recast NE Pacific oceanic motions as part of the global sea floor spreading system. Publication in 1968 of seminal global maps of mid-ocean ridges and spreading rates by Le Pichon, tectonic plates by Morgan, global marine magnetic anomalies by Hiertzler et al., and global distribution of earthquakes by Isacks et al. led to the plate tectonic revolution.

Applications of "the New Global Tectonics" to geology started appearing in the late 1960's-early 1970's. For example, evidence accumulated for "archipelago-style" orogenies (e.g., Moores, 1970, 1998, van Staal et., 2007), involving collision of island arcs with the western and eastern margins of North America.

A new revolution incorporating deep mantle tomography and surface tectonics may now be in progress. Sigloch's and Mihalynuk's (2017) "Australia-Indonesia" portrayal of the late Mesozoic western North America margin confirms earlier archipelago-style interpretations and arguably has explanatory power comparable to Vine's (1966) reinterpretation of the NE Pacific.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-298314

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