Geology Reference
In-Depth Information
16.5.2.1 Late Eocene 'Whiskey Creek' Seep
Carbonates of Washington State, U.S.A.
Box 16.5.
Selected studies of ancient vent and seep com-
munities and carbonates. See Callender and Powell
(1999) for an extended list.
Carbonate deposits and invertebrate communities as-
sociated with areas where seepage fluids enriched in
reduced compounds reached the seafloor have a long
geologic record in marine strata along the Pacific slope
of North America (Campbell and Bottjer 1993). An-
cient methane-seep carbonates are widespread within
the marine strata of the Olympic Peninsula, western
side of Washington State. An example is the Whiskey
Creek limestone formed around a methane seep. The
limestone consists of micrite, carbonate cement and
densely-packed large bivalves (Goedert et al. 2003;
Peckmann et al. 2003). These carbonates occur as large
limestone boulders exhibiting a chaotic fabric (Fig.
16.17) produced by bioturbation, concretionary carbon-
ate formation, early in-situ brecciation and late frac-
turing. A nodular fabric is caused by pyritiferous mi-
crite aggregates induced by anaerobic oxidation of
methane and carbonate corrosion. Authigenic non-car-
bonate minerals are common constituents of the lime-
stone.
The biota comprises bivalves, worm tubes, benthic
foraminifera and some palynomorphs. Abundant bi-
valve mollusks are represented by six species comprised
solemyids, nuculanids, mytilids, lucinids, thyasirinids,
and vesicomyids. Lipid biomarkers extracted from the
Tertiary
: Aharon and Sengupty 1994; Campbell 1992;
Cavagna et al. 1999; Clari and Martire 2000; Clari
et al. 1988, 1994; Conti and Fontana 2001, 2002;
Goedert and Squires 1990; Goedert et al. 2003; Lutz
and Kennish 1993; Niitsuma et al. 1989; Peckmann
et al. 2001, 2003; Rigby and Goedert 1996; Squires
and Goedert 1991; Terzi 1993; Terzi et al. 1994
Cretaceous:
Beauchamp and Savard 1992; Beauchamp
et al. 1989a, 1989b; Campbell and Bottjer 1995;
Campbell et al. 1993; Kauffman et al. 1996; Lemoine
et al. 1982
Jurassic:
Campbell and Bottjer 1993; Campbell et al.
1993; Gaillard et al. 1992; Kelly et al. 1995; Lemoine
et al. 1982; Little et al. 1999; Rolin et al. 1990;
Carboniferous:
Bittner et al. 1990, 1992; Peckmann
et al. 2001
Devonian:
Belka 1998; Kuznetsov et al. 1990; Mounji
et al. 1998; Peckmann et al. 1999
Silurian:
Liljedahl 1991; Little et al. 1997
Ordovician:
Hovland 1989; Lavoie 1997; Steele-
Petrovich 1988.
the surrounding mound facies. Seep mound faunas ex-
hibit low species richness and high dominance; they
are autochthonous with little indication of disturbance.
Shell dissolution can be extreme owing to the high CO
2
or H
2
S content in interstitial waters.
Fig. 16.17.
Seep carbonates.
Typical chaotic fabric of a methane-derived limestone. White areas are authigenic carbonate
cements. Polished slab. Late Eocene: Washington State. After Peckmann et al. (2003).
