New Late Eocene mollusks from localized limestone deposits formed by subduction-related methane seeps, southwestern Washington

The trochid archaeogastropod Margarites ( Pupillaria ) columbiana n. sp., the mytilid bivalve Modiolus ( Modiolus ) willapaensis n. sp., and the vesicomyid bivalve Calyptogena chinookensis n. sp. are described from the earliest known fossil communities associated with subduction-related methane seep...

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Bibliographic Details
Published in:Journal of Paleontology
Main Authors: Squires, Richard L., Goedert, James L.
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 1991
Subjects:
Online Access:http://dx.doi.org/10.1017/s0022336000030389
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022336000030389
Description
Summary:The trochid archaeogastropod Margarites ( Pupillaria ) columbiana n. sp., the mytilid bivalve Modiolus ( Modiolus ) willapaensis n. sp., and the vesicomyid bivalve Calyptogena chinookensis n. sp. are described from the earliest known fossil communities associated with subduction-related methane seeps. The communities are in very localized limestones of late middle to late Eocene age along the southwestern margin of Washington. These limestones contain large numbers of chemosynthetic bivalves and worm tubes, as well as other macrobenthos, that colonized around cool-temperature methane seeps along the landward slopes of an ancient subduction-zone complex. Calyptogena chinookensis n. sp.is the earliest known species of this genus, which was previously known from Miocene to Recent.