Chemical Weathering of Serpentinite in the Eastern Piedmont of Maryland

Abstract

Research Article| March 01, 1974 Chemical Weathering of Serpentinite in the Eastern Piedmont of Maryland EMERY T. CLEAVES; EMERY T. CLEAVES 1Maryland Geological Survey, Baltimore, Maryland 21218 Search for other works by this author on: GSW Google Scholar DONALD W. FISHER; DONALD W. FISHER 2U.S. Geological Survey, Washington, D.C. 20242 Search for other works by this author on: GSW Google Scholar OWEN P. BRICKER OWEN P. BRICKER 3Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, Maryland 21218 Search for other works by this author on: GSW Google Scholar Author and Article Information EMERY T. CLEAVES 1Maryland Geological Survey, Baltimore, Maryland 21218 DONALD W. FISHER 2U.S. Geological Survey, Washington, D.C. 20242 OWEN P. BRICKER 3Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, Maryland 21218 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1974) 85 (3): 437–444. https://doi.org/10.1130/0016-7606(1974)85<437:CWOSIT>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 Email Permissions Search Site Citation EMERY T. CLEAVES, DONALD W. FISHER, OWEN P. BRICKER; Chemical Weathering of Serpentinite in the Eastern Piedmont of Maryland. GSA Bulletin 1974;; 85 (3): 437–444. doi: https://doi.org/10.1130/0016-7606(1974)85<437:CWOSIT>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 Weathering processes in a small watershed (Soldiers Delight) underlain by Serpentinite in the Piedmont of Maryland were studied by means of a mass balance technique and were compared with the processes operative in a watershed uncertain by schist. The two terranes are downwasting at a rate of 2.4 m per m.y., but chemical weathering much more strongly affects the Serpentinite (2.2 m per m.y.) than the schist (1.2 m per m.y.).The serpentinite lacks a saprolite cover because resistate minerals are absent and alumina in the bedrock is scarce. In contrast, the schist contains both quartz and a source of alumina in the alumino-silicate minerals and, as a result, has a thick saprolite mantle. Relatively small amounts of secondary quartz, chalcedony, and 14Å clay minerals are synthesized in the serpentinite watershed, but relatively large amounts of gibbsite and clay minerals (kaolinite and vermiculite) are formed during the weathering of the schist. The hydrologic consequences in the serpentinite terrane compared with the schist watershed are increased flood-flow discharge, greater fluctuation in seasonal, instantaneous base-flow discharge, and pronounced seasonal fluctuations in total discharge. The serpentinite stream water averaged 205 ppm of total dissolved solids in the base flow compared to 25 ppm in the schist. Stream water from the serpentinite is of the magnesium bicarbonate type; that from the schist is sodium–calcium bicarbonate type.On the serpentinite, substantial land-surface reduction (denudation) is effected by chemical weathering; mechanical weathering is secondary. On the schist terrane, mechanical weathering is the primary agent that lowers the land surface, even though chemical weathering has reduced the rock mass ay almost one-half. 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.