CGRG Bibliography of Canadian Geomorphology
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Author : Aitken, A.E.; and Murray, J. P.
Date : 2002.
Title : Palaeoecology of holocene glaciomarine molluscan faunas, Axel Heiberg Island, Nunavut.
Publication : Geological Association of Canada and Mineralogical Association of Canada Joint Annual Meeting, May 27 - 29, 2002. Saskatoon, Saskatchewan.
Issue :
Page(s) :
Abstract
Holocene molluscan faunas are distributed along depth/energy gradients within nearshore glaciomarine sedimentary environments. Postglacial molluscan faunas observed on Axel Heiberg Island record an abrupt transition ca. ~8 ka BP from faunas dominated by the taxa Portlandia, Hiatella and Mya to faunas dominated by the taxa Astarte,Mya,Macoma and Serripes. Portlandia-Hiatella-Mya faunas have no direct counterpart in modern glaciomarine faunas. These faunas dominated fiord-head deltaic environments characterized by reduced salinities and rapid sedimentation of clastic sediments. The Astarte-Mya-Macoma faunas are directly comparable to modern shallow water faunas. These faunas dominated low-energy environments characterized by slow sedimentation and extensive ice-scouring. Taphofacies analysis was undertaken to identify patterns of preservation in the macrofossil assemblages. Paired, in situ shells are recovered infrequently from Early Holocene sediments, but occur commonly in sediments dated ca. 2-6 ka BP. The shells of Astarte, Hiatella and Portlandia exhibit excellent preseravtion being represented commonly as whole shells with attached periostracum. In contrast, the shells of Macoma, Mya and Serripes exhibit fair to poor preservation being represented commonly as variably fragmented shells. The fossil record preferentially preserves infaunal suspension-feeding taxa. The lack of preservation of deposit-feeding, browsing, and carnivorous molluscan taxa poses problems for the study of community trophic dynamics based on the trophic group composition of the macrofossil assemblages.
Bibliography of Canadian Geomorphology