Chemical weathering of fractured Eocene chalks in the Negev, Israel

A. Avigour, D. Bahat

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Ba, Ca, Fe, K, Mg, Mn, Sr and insoluble residue (I.R.) contents of Eocene chalks and of vein-filled derivative matter from the northern Negev, Israel, were analyzed. The Eocene chalk country rock weathered physically and chemically, and the eroded material has filled the fault planes and some of the joints. Two types of filling material were found: calcite crystals and soft fine carbonate material. The latter, as the chalk, are sometimes associated with Fe- and Mn-oxides. I.R./Ca, Mg/Ca, Sr/Ca and K/Ca values decrease from the country rock chalk to the fine carbonates and are lower in the calcite minerals. The Ba/Ca values are low in the soft fine carbonates and high in the calcite minerals. Barite was found in places in the chalk. Fe/Ca and Mn/Ca values are higher in the soft fine carbonate. Based on KD-values, the expected Ba/Ca, Mg/Ca and Sr/Ca values in the vein carbonates are lower and the expected Fe/Ca and Mn/Ca are higher than the actual values. The analysis of the soft fine carbonates from the various joints and faults shows that chemical precipitation was unaffected by these structures. This possibly suggests that the soft fine carbonates are younger and not contemporaneous with the structures.

Original languageEnglish
Pages (from-to)149-156
Number of pages8
JournalChemical Geology
Volume89
Issue number1-2
DOIs
StatePublished - 5 Dec 1990

ASJC Scopus subject areas

  • Geology
  • Geochemistry and Petrology

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