Abstract

Miocene calcarenites of Menorca exhibit abundant terrigenous dolomite, both as rock fragements and as individual abraded crystals. Petrographically, this detritus looks both like neighboring Jurassic dolostones and like Triassic Muschelkalk dolostones. To determine which stratigraphic unit(s) provide this terrigenous dolomite, the iron contents of Triassic and Jurassic dolostones were analyzed. Jurassic dolostones proved to be the principal source. The Triassic dolomite detritus is proportionate to the small area of Triassic exposure relative to the Jurassic. Diagenetic dolomite in Miocene calcarenites occurs as 1) pervasive crystals and 2) overgrowths on the terrigenous dolomite crystals. These two varieties commonly occur together, but overgrowths occur in some samples in the absence of the pervasive variety, which indicates that "seeding" by terrigenous dolomite promoted diagenetic dolomitization. Calcitization of Miocene dolomite favored centers of the pervasive dolomite crystals and the inner margins of dolomite overgrowths. These patterns of dedolomite indicate that the two varieties of dolomite are behaviorly correlative, which suggests that they are temporally correlative as well.--Modified journal abstract.

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