Seawater and basalt-derived [sup 87]Sr/[sup 86]Sr in multiple dolomitization events, Seroe Domi Formation, Curacao, Netherlands Antilles

Conference · Wed Jan 01 04:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:6000031

Fouke, B W; Meyers, W J; Hanson, G N ^[1]; Beets, C J ^[2]

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1. State Univ. of New York, Stony Brook, NY (United States). Dept. of Earth and Space Sciences
2. Free Univ., Amsterdam (Netherlands). Geomarine Centre

The distribution, petrography and geochemistry of Seroe Domi Formation Dolomites I, I[prime] and II are consistent with precipitation from seawater and/or seawater-dominated mixed fluids. Stratigraphic distributions and secular variations in the Sr-87/86-Sr of neogene seawater suggests that Dolomite I precipitated from Late Miocene seawater, Dolomite I[prime] precipitated from early Pliocene seawater, and Dolomite II precipitated from Plio-Pleistocene seawater. However, while Dolomite I and I[prime] are more radiogenic than their host Middle Miocene limestones, Dolomite II is equal to or less radiogenic than its host Pliocene limestone. Dolomite II is also enriched in Zn and Cu relative to Dolomites I and I[prime]. Biomoldic porosity, skeletal diagenesis and calcite cementation suggest that the host Seroe Domi limestones were extensively leached and recrystallized in meteoric fluids prior to dolomitization. Therefore, the only viable source of the nonradiogenic Sr in Dolomite II was through low-temperature groundwater interaction with altered basalts of the Curacao basement. Less radiogenic Sr was not incorporated in Dolomite I and I[prime] because the basalt had not yet been adequately weathered, or was not in hydrologic contact with Seroe Domi carbonates until the Pliocene or Pleistocene due to the thousands of meters of tectonic uplift and erosion of the Curacao basement. The anomalously high Sr/Ca and HCO[sub 3] abundances and non-radiogenic Sr-87/Sr-86 of modern groundwaters within the Curacao Lava Formation further substantiate this interpretation. Modeling with REACT implies that these meteoric groundwaters are supersaturated with respect to both dolomite and calcite, and that less than 20% of this Curacao groundwater in a mixture with Pleistocene seawater could have created the Sr-87/Sr-86 observed in Dolomite II.

• OSTI ID: 6000031
• Report Number(s): CONF-921058--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 24:7
• Country of Publication: United States
• Language: English

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