The La Gorce Formation is a sequence of alternating metagraywacke, phyllite, and metapelite. Three bedding associations are recognized. The predominant type consists of massive or laminated graywacke beds in delayed graded contact with overlying thin mudstones. Of secondary importance are beds with characteristics of Bouma's model turbidite, mainly A, C, and E divisions. Beds of laminated sandy siltstones are of minor importance. The graywackes are matrix rich (54-76%). Petrographic examination shows no rock fragments that are diagnostic of provenance but does show a suite of detrital minerals that are indicative of a fairly high-grade metamorphic source. We interpret the environment of deposition to have been middle-fan, depositional lobe, in a particularly broad shelf-rise setting.

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