Robert C. Speed by Richard Sedlock

Biografia transcrita por Rubem Queiroz Cobra do site
The Geological Society of America – Memorials
Visitado em 07-02-2011

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from 1981 to 1983 and was appointed William Deering Professor (endowed chair) in 1991. While at Northwestern, Bob completed and published a formidable body of research that focused on the structural geology and tectonics of active continental margins. Most of Bob’s early field work was undertaken in Nevada, where he continued to work throughout his career; later, he targeted the eastern Caribbean, particularly Barbados.

Bob profoundly influenced our perception of the geology of the western Great Basin. For hisdissertation at Stanford University, he identified, mapped, and analyzed the igneous rocks of theEarly Jurassic Humboldt lopolith in northwestern Nevada. During his early years at NorthwesternUniversity, he and his students evaluated late Paleozoic deformation in the region associated withthe Sonoma orogeny. He also identified and differentiated coeval Mesozoic basin and carbonate platform rocks composing the upper and lower plates of the Fencemaker thrust system. His eye for detail and his gift for integrating diverse types of data enabled him to construct a regional tectonic framework that still underlies current views of the region’s tectonic history. During the 1970s and 1980s, Bob and his students attacked long-standing stratigraphic and structural problems in westcentral Nevada. He focused his attention on the late Paleozoic history of this region just as the terrane concept was coming of age, and concluded that substantial parts of the western Great Basin are allochthonous, possibly far-traveled, arc complexes that collided in the Paleozoic with the long-standing (late Proterozoic–early Paleozoic) passive margin of western North America. The clear, cogent logic of his research papers precipitated debate and stimulated research in the western Great Basin for more than three decades.

Bob’s work on the Paleozoic accretionary prism of the Roberts Mountain Allochthon in Nevada stimulated him to investigate the much younger prism on Barbados, West Indies, which hadn’t been affected by much subsequent tectonism. From the late 1970s to the 1990s, Bob and his students and colleagues collected and interpreted data from accreted Tertiary turbidites of the Scotland District, structurally overlying forearc-basin rocks, and even the tilted Quaternary reefs that cover most of the island. Results of this work included structural and stratigraphic studies of remarkably detailed scope, wider-ranging tectonic syntheses and speculations, and a geologic map of the entire island (expected posthumous publication).

Bob recognized that folds and faults of the Barbados accretionary prism are oriented at a high angle to the current Caribbean-Atlantic subduction zone boundary, leading him to propose that the Antilles arc collided obliquely with northern South America in the mid-Tertiary and to undertake field studies in Trinidad and Tobago and in Venezuela. His ground-breaking efforts in all these areas triggered much additional work by others, including several DSDP and ODP legs on the Barbados Ridge and ongoing investigations of the Caribbean-South America plate boundary. His Barbados work also is basic reading for anyone studying fossil or modern accretionary prisms anywhere in the world.

In the 1970s, Bob chaired the panel that developed Northwestern’s Integrated Science Program (ISP) for high-level undergraduates and was its first director from 1975 to 1978. This program emphasized the interdisciplinary nature of fundamental scientific and mathematical principles and techniques, and the deep-level learning and innovation that could result. The rigorous mathematical basis of the program reflected Bob’s conviction that advances in science would be obtained only through mathematics as the medium of communication.

Throughout his career, Bob served the earth science community in a variety of roles besides research and education. For NASA, he was a member of the Scientist Astronaut Selection Board (1966–68) and the Advisory Panel on Lunar Exploration (1967). For the USGS, he was a member of Earthquake Hazards Reduction Program (1975–1978) and a Faculty Associate from 1978. He was associate editor of Neotectonics from 1984 to 1990 and of GSA Bulletin from 1985 to 1989. Bob was chair of the U.S. Geodynamics Committee’s North American Continent-Ocean Transects

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