Are crustal thickness variations in old mountain belts like the Appalachians a consequence of lithospheric delamination?

Research Article| June 01, 1992 Are crustal thickness variations in old mountain belts like the Appalachians a consequence of lithospheric delamination? K. D. Nelson K. D. Nelson 1Institute for the Study of the Continents, Cornell University, Ithaca, New York 14853 Search for other works by this author on: GSW Google Scholar Author and Article Information K. D. Nelson 1Institute for the Study of the Continents, Cornell University, Ithaca, New York 14853 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1992) 20 (6): 498–502. https://doi.org/10.1130/0091-7613(1992)020<0498:ACTVIO>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation K. D. Nelson; Are crustal thickness variations in old mountain belts like the Appalachians a consequence of lithospheric delamination?. Geology 1992;; 20 (6): 498–502. doi: https://doi.org/10.1130/0091-7613(1992)020<0498:ACTVIO>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Comparison of Moho geometry and reflection character of active collision zones, like the Alps, with those of fossil collision zones, like the Appalachians, lends support for the view that lithospheric delamination is both a common and fundamentally important component of collisional orogeny. In particular, the relative crustal thinning commonly observed beneath the internides of old collisional orogens is an expected consequence of delamination. Neither precollisional crustal thickness variations nor an unrelated postcollision extensional event is required to produce this feature. Acceptance of the delamination hypothesis, in turn, fundamentally alters one's view of the tectonic evolution of old collisional orogens. In the case of the Appalachians, delamination has direct implications for the interpretation of Alleghanian granites, the direction of subduction leading to final closure between Laurentia and Gondwana, and the thermal state of the lithosphere at the onset of Atlantic rifting. A corollary of the delamination hypothesis is that lateral reflectivity variations cannot be used to define paleogeographic terranes in the deep crust of old orogens. Conversely, the observation that delamination leaves a distinctive geophysical imprint on the crust itself provides an important additional clue for deciphering the tectonic evolution of such regions. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.