Mass-production of Cambro-Ordovician quartz-rich sandstone as a consequence of chemical weathering of Pan-African terranes: Environmental implications

D. Avigad*, A. Sandler, K. Kolodner, R. J. Stern, M. McWilliams, N. Miller, M. Beyth

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

193 Scopus citations

Abstract

A vast sheet of mature quartz sand blanketed north Africa and Arabia from the Atlantic coast to the Persian Gulf in Cambro-Ordovician times. U-Pb geochronology of a representative section of Cambrian sandstone in southern Israel shows that these sediments are dominated by 550-650 Ma detrital zircons derived from Neoproterozoic Pan-African basement. The short time lag between magmatic consolidation of a Pan-African source and deposition of its erosional products indicates that, despite their significant mineralogical maturity, the voluminous quartz-rich sandstones on the northern margin of Gondwana are essentially first-cycle sediments. Mass production of these voluminous first-cycle quartz-rich sandstones resulted from widespread chemical weathering of the Pan-African continental basement. We suggest that conditions favoring silicate weathering, particularly a warm and humid climate, low relief and low sedimentation rates prevailed over large tracts of Gondwana in the aftermath of the Pan-African orogeny. An unusually corrosive Cambro-Ordovician atmosphere and humid climate enhanced chemical weathering on the vegetation-free landscape. We infer that late Neoproterozoic-Cambro-Ordovician atmospheric pCO2 rose as a consequence of widespread late Neoproterozoic volcanism, followed by an uptake of CO2 by chemical weathering to produce the Cambro-Ordovician sandstone as a negative feedback.

Original languageAmerican English
Pages (from-to)818-826
Number of pages9
JournalEarth and Planetary Science Letters
Volume240
Issue number3-4
DOIs
StatePublished - 15 Dec 2005

Bibliographical note

Funding Information:
Supported by USA–Israel Binational Science Foundation (BSF) and by the Israel Ministry of Infrastructure. We thank Y. Erel and Z. Garfunkel for discussions, and R.H. Dott, K. Burke and T. Prave for reviews and stimulating comments.

Keywords

  • Cambro-Ordovician
  • Chemical weathering
  • Gondwana
  • Sandstone

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