The distribution and discrimination of shallow, authigenic carbonate in the Pliocene-Pleistocene Palomas Basin, southern Rio Grande rift

Abstract

Research Article| May 01, 2000 The distribution and discrimination of shallow, authigenic carbonate in the Pliocene–Pleistocene Palomas Basin, southern Rio Grande rift Greg H. Mack; Greg H. Mack 1Department of Geological Sciences, New Mexico State University, Las Cruces, New Mexico 88003, USA Search for other works by this author on: GSW Google Scholar David R. Cole; David R. Cole 2Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA Search for other works by this author on: GSW Google Scholar Leandro Treviño Leandro Treviño 1Department of Geological Sciences, New Mexico State University, Las Cruces, New Mexico 88003, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Greg H. Mack 1Department of Geological Sciences, New Mexico State University, Las Cruces, New Mexico 88003, USA David R. Cole 2Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA Leandro Treviño 1Department of Geological Sciences, New Mexico State University, Las Cruces, New Mexico 88003, USA Publisher: Geological Society of America Received: 16 Nov 1998 Revision Received: 15 Jun 1999 Accepted: 30 Jul 1999 First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2000) 112 (5): 643–656. https://doi.org/10.1130/0016-7606(2000)112<643:TDADOS>2.0.CO;2 Article history Received: 16 Nov 1998 Revision Received: 15 Jun 1999 Accepted: 30 Jul 1999 First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Greg H. Mack, David R. Cole, Leandro Treviño; The distribution and discrimination of shallow, authigenic carbonate in the Pliocene–Pleistocene Palomas Basin, southern Rio Grande rift. GSA Bulletin 2000;; 112 (5): 643–656. doi: https://doi.org/10.1130/0016-7606(2000)112<643:TDADOS>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 Nine types of authigenic carbonate are present in the Pliocene–Pleistocene alluvial-fan and axial-fluvial sediment of the Palomas half graben in the southern Rio Grande rift. Pedogenic and other vadose carbonate includes (1) pedogenic carbonate of stage II and stage III morphology underlying Bw and Bt horizons, (2) mudstones in which the carbonate nodules may be pedogenic or the result of shallow groundwater invasion of the vadose zone, (3) pedogenic calcic nodules and tubules in eolian sand, and (4) gully-bed cement of proximal-fan conglomerates formed by infiltration and evaporation of surface runoff. Shallow groundwater carbonate exists as (5) thin (30–50 cm), massive beds with an upper fringe of nodules and tubules precipitated at the water table and in the capillary fringe, (6) thick (1.5–3 m), massive beds deposited by lateral flow of groundwater or at springs, and (7) thin (30 cm), calcified root mats associated with near-surface, water-saturated sediment or springs. Phreatic spar cements (8) occupy the interstices of conglomerates and sandstones and locally exist as (9) oriented concretions.Groundwater carbonates are best developed near the toes of the large, hanging-wall–derived alluvial fans, whereas phreatic cement preferentially exists in footwall-derived, alluvial-fan conglomerates. Pedogenic carbonate is distinguished from groundwater carbonate by the association with other diagnostic paleosol horizons, a predominantly vertical arrangement of root traces, peds, desiccation cracks, and calcic tubules, and by gradational contacts. The δ13C and δ18O values are similar among pedogenic and shallow groundwater carbonate, although locally nodules in eolian sand and gully-bed cement have higher δ18O values, perhaps due to the effects of evaporation. Some phreatic cements may be distinguished from pedogenic and shallow groundwater carbonate by lower values of δ13C and δ18O. Authigenic carbonate in footwall-derived, alluvial-fan sediment has consistently higher values of δ13C than that in hanging-wall–derived sediment, which may reflect differences in vegetative type and/or density on either side of the basin. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.