Quaternary Sedimentation on the Amazon Continental Margin: A Model

Research Article| May 01, 1975 Quaternary Sedimentation on the Amazon Continental Margin: A Model JOHN D. MILLIMAN; JOHN D. MILLIMAN 1Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543 Search for other works by this author on: GSW Google Scholar COLIN P. SUMMERHAYES; COLIN P. SUMMERHAYES 1Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543 Search for other works by this author on: GSW Google Scholar HENYO T. BARRETTO HENYO T. BARRETTO 2Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, Brasil Search for other works by this author on: GSW Google Scholar GSA Bulletin (1975) 86 (5): 610–614. https://doi.org/10.1130/0016-7606(1975)86<610:QSOTAC>2.0.CO;2 Article history first online: 01 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 JOHN D. MILLIMAN, COLIN P. SUMMERHAYES, HENYO T. BARRETTO; Quaternary Sedimentation on the Amazon Continental Margin: A Model. GSA Bulletin 1975;; 86 (5): 610–614. doi: https://doi.org/10.1130/0016-7606(1975)86<610:QSOTAC>2.0.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 SocietyGSA Bulletin Search Advanced Search Abstract Sedimentation on the Amazon continental margin occurred in two distinct patterns during the Quaternary Period. During interglacials, when sea level was high (as at present), most of the sediment contributed by the Amazon River was deposited near the river mouth, then transported northwest along the innermost shelf by longshore currents. Apparently, little Amazon sediment escaped the nearshore environment. As sea level fell in response to glacial advance, the sedimentation pattern remained roughly similar, resulting in construction of an extensive prograding shoreline. Once the sea fell more than −60 to −80 m relative to present sea level, however, most Amazon sediment was channeled directly to the deep sea. Shoreline accretion stopped, but prograded sediments were preserved as a mud wedge that presently occupies the inner shelf seaward of the Amazon River.This model also explains the accumulation of large quantities of arkosic sands throughout the western Equatorial Atlantic deep sea during Pleistocene glacial epochs. These arkosic sediments appear to have been derived mostly from the Andes Mountains via the Amazon River. 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.