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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 55 (1971)

Issue: 2. (February)

First Page: 344

Last Page: 344

Title: Production of Reef-Margin Breccias by Submarine Cementation and Slumping of Carbonate Sands, Miette Reef Complex: ABSTRACT

Author(s): John C. Hopkins

Article Type: Meeting abstract

Abstract:

Carbonate breccias in beds up to 1-2 m thick interbedded with coarse, reef-derived, carbonate sands and fine, basinal, terrigenous and carbonate muds are present seaward of the southeastern margin of the Devonian Miette Reef Complex of the Canadian Rocky Mountains.

The majority of the breccia fragments are cemented carbonate sand set in a matrix of noncemented sand. The allochems of both the fragments and the matrix are very similar in composition. The associated beds of carbonate sand that are intercalated with the breccias show similar textures. Within the latter, both boudinage-cemented layers and nodules with tension cracks, as well as slumped sequences of cemented sand in a noncemented matrix are seen. The breccia beds are therefore considered to have formed by differential submarine cementation of fore-reef carbonate sands coupled with downslope creep and slumping.

Breccias of this type do not record a profound break within the reef complex but correspond to times of maximum supply of sand to the forereef slope. Slumping is the direct result of instability of the sand accumulation on the slope during periods of more rapid sedimentation.

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