Spatially Heterogeneous Post-Caledonian Burial and Exhumation Across the Scottish Highlands
Spatially heterogeneous post-Caledonian burial and exhumation across the Scottish Highlands Michelle L. Fame1, James A. Spotila1, Lewis A. Owen2, Jason M. Dortch3, and David L. Shuster4,5 1DEPARTMENT OF GEOSCIENCES, VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY, 4044 DERRING HALL, BLACKSBURG, VIRGINIA 24060, USA 2DEPARTMENT OF GEOLOGY, UNIVERSITY OF CINCINNATI, CINCINNATI, OHIO 45221, USA 3KENTUCKY GEOLOGICAL SURVEY, 228 MINING AND MINERAL RESOURCES BUILDING, UNIVERSITY OF KENTUCKY, LEXINGTON, KENTUCKY 40506, USA 4DEPARTMENT OF EARTH AND PLANETARY SCIENCE, UNIVERSITY OF CALIFORNIA, BERKELEY, CALIFORNIA 94720, USA 5BERKELEY GEOCHRONOLOGY CENTER, 2455 RIDGE ROAD, BERKELEY, CALIFORNIA 94709, USA ABSTRACT The postassembly, postrift evolution of passive margins is an essential element of global continental tectonics. Thermal and exhumational histories of passive margins are commonly attributed to a number of drivers, including uplift and erosional retreat of a rift-flank escarp- ment, intraplate fault reactivation, mantle-driven uplift, and erosional disequilibrium, yet in many cases, a specific factor may appear to dominate the history of a given passive margin. Here, we investigate the complex evolution of passive margins by quantifying exhumation patterns in western Scotland. We build upon the well-studied thermal evolution of the Scottish North Atlantic passive margin to test the importance of spatially heterogeneous factors in driving postorogenic burial and exhumation. Independent investigations of the cooling history from seven different field sites across the western Scottish Highlands using radiogenic apatite helium thermochronometry ([U-Th]/He; n = 14; ca. 31–363 Ma) and thermal modeling confirm that post-Caledonian heating and burial, as well as cooling and exhumation, must have been variable across relatively short distances (i.e., tens of kilometers).
[Show full text]