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Información del Artículo

Stratigraphy of the Bluff Formation (Miocene-Pliocene) and the newly defined Brac Formation (Oligocene), Cayman Brac, British West Indies.
En: CARIBBEAN JOURNAL OF SCIENCE, 30 (1-2) June 1994: 30-51. bibl. foto(s). tabla.
Revista: Caribbean journal of science, vol. 30, núm. 1-2; June 1994
Resumen: The core of Cayman Brac is formed of Tertiary strata that dip at about 0.5 to the southwest. The basal 33m of the succession, formed of Lepidocyclina-rich limestones and dolostones, are assigned to the newly named Brac Formation.
Resumen: The overlaying Bluff Formation is divided into the Cayman and Pedro Castle members. The Cayman Member, about 100m thick, is formed of fabric-retentive dolostones with a diverse fauna of corals, bivalves, gastropods, foraminifera, red algae, and Halimeda.Rhodolites are locally common.
Resumen: The Pedro Castle Member, 15 to 20 m thick, is formed of dolostone, dolomitic limestone, and limestone with a fauna similar to that in the underlying Cayman Member. The Brac Formation, Cayman Member and Pedro Castle Member are unconformity-bounded packages. Each records a period of prolonged deposition whereas the unconformities represent periods of emergence and erosion.
Resumen: The foraminifera faunas and 87 Sr/86Sr isotope ratios from the limestones in the Brac Formation and the Pedro Castle Member, indicate that the former was deposited during the late early Oligocene (Rupelian), whereas the latter was deposited during the Pliocene. A middle Miocene age is tentatively assigned to the Cayman Member, but these strata are devoid of age-diagnostic fossiland dolomitization has reset the 87Sr/86Sr isotope ratios.
Resumen: The disconformity between the Brac and Bluff formations developed during late Oligocene and lower Miocene times whereas the disconformity between the Cayman and Pedro Castle members of the Bluff Formation developed during late Miocene and possibly early Pliocene times.
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