Strontium isotopes in discordant dolomite bodies of the Judea Group, Dead Sea basin

Mordechai Stein, Amotz Agnon, Amitai Katz, Abraham Starinsky*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

The dolomitization of the Upper Cretaceous limestones of the Judea Group by seawater of the Sedom lagoon is reflected by the chemical and 87Sr/86Sr isotope composition of discordant dolomite bodies, which are formed at the expense of the limestone. We have carried out a traverse through a discordant dolomite body in the Turonian limestone (Netzer Fm.), Nahal Boqeq. southern Judea Desert at the elevation of 80 m above MSL. The host limestone is characterized by 87Sr/86Sr ratios of 0.7074-0.7076 typical of the Cenomanian-Turonian ocean. The discordant dolomite exhibits significantly higher 87Sr/86Sr ratios, in the range of 0.7082 to 0.7086. Evaporitic minerals from the Sedom Fm. display 87Sr/86Sr ratios similar to those in the discordant dolomite. It is suggested that these minerals precipitated from Ca-chloride brines that were produced via dolomitization of the Cretaceous limestone by the Sedom lagoon water. The similarity between the 87Sr/86Sr ratios in the Sedom Fm. minerals and the discordant dolomite bodies supports earlier conclusions about the close relationship between the dolomite and the Sedom lagoon brines. The wide 87Sr/86Sr ratio range in the dolomite bodies studied, relative to its much narrower range in stratigraphic dolomite of the Sedom Fm., testifies that the Ca-chloride brines that were the late dolomitization agents did not return to the Rift Valley, but may have migrated further to the west.

Original languageAmerican English
Pages (from-to)219-224
Number of pages6
JournalIsrael Journal of Earth Sciences
Volume51
Issue number3-4
DOIs
StatePublished - 2002

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