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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 47 (1963)

Issue: 2. (February)

First Page: 356

Last Page: 356

Title: Early Vadose Silt in Townsend Mound (Reef), New Mexico: ABSTRACT

Author(s): Robert J. Dunham

Article Type: Meeting abstract


Vugs, fractures, interstices, and other voids in the Townsend carbonate mound (reef) are floored with internal sediment composed of well sorted calcite silt. Internal sedimentation predates precipitation of blocky cement, and post-dates both precipitation of early drusy cement and early internal erosion. The crystal silt differs from associated marine sediment in its scarcity of clay-size particles, sand-size particles, and recognizable skeletal debris.

The age relationships and texture of crystal silt seem best explained by sedimentation inside pre-existing crumbly rock in the vadose zone during early emergence. If the explanation is valid, similar internal sediment might be a valuable clue to previously unrecognized subaerial stages in other carbonate mounds.

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Copyright 1997 American Association of Petroleum Geologists