Large sedimentation rate in the Bengal delta: Magnetostratigraphic dating of Cenozoic sediments from northeastern Bangladesh

Abstract

Research Article| June 01, 1998 Large sedimentation rate in the Bengal delta: Magnetostratigraphic dating of Cenozoic sediments from northeastern Bangladesh H.-U. Worm; H.-U. Worm 1Institut für Geophysik, Universität Göttingen, Herzberger Landstrasse 180, 37075 Göttingen, Germany Search for other works by this author on: GSW Google Scholar A. M. M. Ahmed; A. M. M. Ahmed 2Bangladesh Petroleum Exploration Company (BAPEX), Dhaka, Bangladesh Search for other works by this author on: GSW Google Scholar N. U. Ahmed; N. U. Ahmed 2Bangladesh Petroleum Exploration Company (BAPEX), Dhaka, Bangladesh Search for other works by this author on: GSW Google Scholar H. O. Islam; H. O. Islam 2Bangladesh Petroleum Exploration Company (BAPEX), Dhaka, Bangladesh Search for other works by this author on: GSW Google Scholar M. M. Huq; M. M. Huq 2Bangladesh Petroleum Exploration Company (BAPEX), Dhaka, Bangladesh Search for other works by this author on: GSW Google Scholar U. Hambach; U. Hambach 3Geologisches Institut, Universität zu Köln, Germany Search for other works by this author on: GSW Google Scholar J. Lietz J. Lietz 4Federal Institute for Geosciences & Natural Resources (BGR), Hannover, Germany Search for other works by this author on: GSW Google Scholar Geology (1998) 26 (6): 487–490. https://doi.org/10.1130/0091-7613(1998)026<0487:LSRITB>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 H.-U. Worm, A. M. M. Ahmed, N. U. Ahmed, H. O. Islam, M. M. Huq, U. Hambach, J. Lietz; Large sedimentation rate in the Bengal delta: Magnetostratigraphic dating of Cenozoic sediments from northeastern Bangladesh. Geology 1998;; 26 (6): 487–490. doi: https://doi.org/10.1130/0091-7613(1998)026<0487:LSRITB>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 A 4.3-km-thick section of clastic sediments of the Surma basin, northeastern Bangladesh, that is exposed along the Shari River was sampled for a magnetostratigraphic study. Miocene through Pleistocene ages have been discussed previously; however, there has been no firm dating through biostratigraphy, or radiometric or other methods. Primary paleomagnetic remanent magnetizations of normal or reversed polarity were determined for most of the 300 collected samples. On the basis of assumptions of (1) constant sedimentation rates, on average, throughout the deposition of the sedimentary sequence, (2) no major gaps in sedimentation, and (3) a fairly young (< 2 Ma) age for the topmost Dupi Tila deposits, we find good agreement between the measured profile and the geomagnetic polarity time scale if the entire sedimentary sequence is between 4.9 and 1.4 Ma in age. The Upper Marine Shales, an important seismic marker horizon, are dated as 3.5 Ma and are therefore ∼1.5 m.y. younger than previously assigned by biostratigraphic results. The Upper Marine Shales presumably correspond to the last pre-Pleistocene sea-level highstand. The dating of rock units below the Upper Marine Shales is tentative because of a large gap in exposure. The inferred sedimentation rate—and thus the rate of delta subsidence—of 1.2 m/k.y. is much larger than previously assumed; it appears to be one of the highest sedimentation rates in Earth history that was sustained for millions of years. 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.