Episodic rapid uplift in the Himalaya revealed by 40Ar/39Ar analysis of detrital K-feldspar and muscovite, Bengal fan

Abstract

Research Article| April 01, 1990 Episodic rapid uplift in the Himalaya revealed by 40Ar/39Ar analysis of detrital K-feldspar and muscovite, Bengal fan Peter Copeland; Peter Copeland 1Department of Geological Sciences, State University of New York at Albany, 1400 Washington Avenue, Albany, New York 12222 Search for other works by this author on: GSW Google Scholar T. Mark Harrison T. Mark Harrison 1Department of Geological Sciences, State University of New York at Albany, 1400 Washington Avenue, Albany, New York 12222 Search for other works by this author on: GSW Google Scholar Author and Article Information Peter Copeland 1Department of Geological Sciences, State University of New York at Albany, 1400 Washington Avenue, Albany, New York 12222 T. Mark Harrison 1Department of Geological Sciences, State University of New York at Albany, 1400 Washington Avenue, Albany, New York 12222 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1990) 18 (4): 354–357. https://doi.org/10.1130/0091-7613(1990)018<0354:ERUITH>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 Email Permissions Search Site Citation Peter Copeland, T. Mark Harrison; Episodic rapid uplift in the Himalaya revealed by 40Ar/39Ar analysis of detrital K-feldspar and muscovite, Bengal fan. Geology 1990;; 18 (4): 354–357. doi: https://doi.org/10.1130/0091-7613(1990)018<0354:ERUITH>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 Detrital K-feldspar and muscovite samples from Ocean Drilling Program Leg 116 cores have been dated by the 40Ar/39Ar technique and have depositional ages from 0 to 18 Ma. From 4 to 13 individual K-feldspars and 1 to 12 individual muscovites have been dated from 7 stratigraphic levels. In every level at least one K-feldspar and one muscovite yielded a minimum age identical, within uncertainty, to the age of deposition. These results indicate that a signiflcant portion of the material in the Bengal fan is first-cycle detritus derived from the Himalaya. Therefore, the substantial amount of sediment deposited in the distal fan in early to middle Miocene time can be ascribed to a significant pulse of uplift and erosion in the collision zone at this time. Moreover, these data indicate that throughout the Neogene, some part of the Himalayan orogen was undergoing rapid erosion (1 to 10 mm/yr); this erosion must have been less than or equal to uplift relative to sea level. The lack of granulite facies rocks in the eastern Himalaya and Tibetan plateau suggests to us that very rapid uplift must have been distributed in brief pulses over different parts of the mountain belt. These data are incompatible with tectonic models in which the Himalaya and Tibetan plateau are uplifted either uniformly over the past 40 m.y. or mostly within the past 2 to 5 m.y. 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.