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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 923

Last Page: 923

Title: Environmental Adaptations of Elphidium subarcticum: ABSTRACT

Author(s): Dorothy J. Echols, Mary Ann Rafle

Article Type: Meeting abstract


Elphidium subarcticum Cushman, a free, benthic, hyaline foraminifer, has been observed in several localities encrusted with extraneous material and adapted to an attached mode of life. The protozoan appears to secrete an organic sheath upon which foreign material is either agglutinated or precipitated. Several forms were acidized and one that was heavily encrusted and firmly attached on its side to a quartz grain left an internal residue of an organic matrix and a cyst-like sheath of flexible organic material. This sheath is composed of loosely interlocked, silt-sized quartz particles. Scanning-scope photos of the unacidized encrusted form reveals a random arrangement of carbonate particles of various sizes.

E. subarcticum may be strengthening its test in response to stresses in the environment. The attachment of the foraminifer on rock fragments is interpreted as an adaption in a high-energy environment.

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Copyright 1997 American Association of Petroleum Geologists