The Braided Stream Depositional Environment: Comparison of the Platte River with Some Silurian Clastic Rocks, North-Central Appalachians

Abstract

Research Article| October 01, 1970 The Braided Stream Depositional Environment: Comparison of the Platte River with Some Silurian Clastic Rocks, North-Central Appalachians NORMAN D SMITH NORMAN D SMITH Department of Geological Sciences, University of Illinois at Chicago Circle, P. O. Box 4348, Chicago, Illinois 60680 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1970) 81 (10): 2993–3014. https://doi.org/10.1130/0016-7606(1970)81[2993:TBSDEC]2.0.CO;2 Article history received: 20 Feb 1970 rev-recd: 15 May 1970 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation NORMAN D SMITH; The Braided Stream Depositional Environment: Comparison of the Platte River with Some Silurian Clastic Rocks, North-Central Appalachians. GSA Bulletin 1970;; 81 (10): 2993–3014. doi: https://doi.org/10.1130/0016-7606(1970)81[2993:TBSDEC]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 Studies of the South Platte-Platte River in Colorado and Nebraska substantiate Ore's (1964) conclusion that braided patterns in streams are created mainly by accretion of longitudinal bars and dissection of transverse bars. Distribution of bars in the South Platte-Platte River depends on texture of the bed load. Coarse, poorly sorted sediment favors formation of longitudinal bars, and finer grained, better sorted materials form transverse bars. The relative proportion of transverse to longitudinal bars increases downstream, following the river's tendency to fractionate its load into finer sizes downstream. This is accompanied by an increase in the ratio of planar cross-stratification to horizontal stratification and a decrease in cross-channel topographic relief expressed as a bed-relief index.Relative abundances of planar cross-stratification and horizontal stratification, as well as bed-relief indices were measured in sandstones and conglomerates of the Lower Silurian Shawangunk Conglomerate, Green Pond Conglomerate, and Tuscarora Sandstone in New Jersey and Pennsylvania. These formations display downslope trends similar to those of the South Platte and Platte Rivers, and, combined with paleocurrent, grain-size distribution, and other data, suggest that the coarse eastern facies (Green Pond, Shawangunk) represent proximal braided stream deposits with longitudinal bars that grade westward and northwestward into finer grained distal braided stream sediments (Tuscarora) characterized by transverse bars. 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.