Abstract
New40Ar/39Ar thermochronological and deformation temperature analyses in the Scandian (c. 435–420 Ma) orogenic retrowedge of northern Scotland demonstrate accelerated cooling during late syn-to post-orogenic exhumation of the high-grade orogenic core. Initial cooling rates of 10–30°C myr−1 immediately following peak orogenesis transitioned to rapid rates of 45–90°C myr−1 during final exhumation of the Naver thrust sheet in the orogenic core. The flanking ductile thrust sheets exhibit a similar, albeit less pronounced, acceleration of cooling, with rates increasing by c. 150–300% following peak orogenesis. Closer to the foreland, the Moine thrust sheet did not experience increased cooling rates. Calculated unroofing rates of 3.75 mm a−1 in the high-grade Naver thrust sheet suggest increasing, rapid exhumation in the orogenic core during a presumed collapse phase of orogenesis. This is contrary to the expectation of decreasing erosional efficiency as topography is diminished and is interpreted to suggest that unroofing of the Scottish Caledonides may have been partially enhanced by upper crustal extensional deformation during ductile flow of the infrastructure of the orogenic core. Similar processes have been interpreted in the East Greenland Caledonides, which form the northern extension of the Scandian retrowedge.
Original language | English (US) |
---|---|
Article number | jgs2020-022 |
Journal | Journal of the Geological Society |
Volume | 178 |
Issue number | 1 |
DOIs | |
State | Published - 2020 |
ASJC Scopus subject areas
- Geology
Fingerprint
Dive into the research topics of 'Rapid cooling during late-stage orogenesis and implications for the collapse of the scandian retrowedge, northern scotland'. Together they form a unique fingerprint.Datasets
-
Rapid cooling during late stage orogenesis and implications for collapse of the Scandian retrowedge, northern Scotland
Spencer, B. M. (Contributor), Thigpen, J. R. (Contributor), Law, R. D. (Contributor), Mako, C. A. (Contributor), McDonald, C. S. (Contributor), Hodges, K. (Contributor) & Ashley, K. T. (Contributor), figshare Academic Research System, 2020
DOI: 10.6084/m9.figshare.c.5087057.v1, https://geolsoc.figshare.com/collections/Rapid_cooling_during_late_stage_orogenesis_and_implications_for_collapse_of_the_Scandian_retrowedge_northern_Scotland/5087057/1
Dataset
-
Rapid cooling during late stage orogenesis and implications for collapse of the Scandian retrowedge, northern Scotland
Spencer, B. M. (Contributor), Thigpen, J. R. (Contributor), Law, R. D. (Contributor), Mako, C. A. (Contributor), McDonald, C. S. (Contributor), Hodges, K. (Contributor) & Ashley, K. T. (Contributor), Geological Society of London, 2020
DOI: 10.6084/m9.figshare.c.5087057, https://geolsoc.figshare.com/collections/Rapid_cooling_during_late_stage_orogenesis_and_implications_for_collapse_of_the_Scandian_retrowedge_northern_Scotland/5087057
Dataset