Geology Reference
In-Depth Information
lithoclasts. Shell beds are common. Frequent micro-
facies types are
• Non-graded, poorly sorted skeletal packstones and
densely packed grainstones and rudstones, consisting
of coarse skeletal debris, e.g. shell accumulations (bi-
valves, brachiopods; Pl. 102/1) or accumulations of
crinoids (Pl. 95/2). The limestone is often dark-colored.
• Graded skeletal packstones, grainstones and rud-
stones consisting of skeletal debris including mollusks,
brachiopods and echinoderms.
• Biolithoclastic graded, densely packed floatstones
and rudstones with coarse fragments of mollusks and
echinoderms, together with centimeter-sized intraclasts.
• Lithoclastic packstones, rudstones and densely
packed floatstones. A common microfacies of proxi-
mal tempestites is characterized by angular micritic
clasts resulting from reworking of beds underlying the
storm bed.
• Thinly-laminated bioclastic mudstones and wacke-
stones, sometimes with pelsparite laminae and graded
fine shell debris (Pl. 102/2).
Box 12.3.
Selected case studies of storm deposits
in an-
cient carbonate environments. Most papers deal with
tempestites in ramp settings.
Tertiary:
Martin et al. 1993
Cretaceous:
Banerjee 1981; Chel and Leckie 1992;
Garcia-Ramos et al. 1989; Hunter and Clifton 1982;
James 1979, 1980; Valecka 1984
Jurassic
: Ager 1974; Badenas and Aurell 2001; Fürsich
and Oschmann 1986, 1993; Galli 1990; Ghosh et al.
1986; Hamblin and Walker 1979; Hüssner 1985; Molina
et al. 1997; Monaco 1992; Moore et al. 1992a, 1992b;
Specht and Brenner 1979
Triassic:
Aigner 1979, 1982, 1985; Aigner et al. 1978;
Aljinovic 1995; Blendinger and Blendinger 1989; Calvet
and Tucker 1988; Duringer 1984; Galli 1989; Hagdorn
1982; Hips 1998; Masetti et al. 1988; Michalik 1997;
Michalik et al. 1992; Perez-Lopez 2001; Röhl 1986;
Török 1993
Permian:
McKie 1994
Carboniferous:
Ball 1971; Buatois and Mangano 1994;
Engelbrecht 2000; Graham 1982; Handford 1986;
Kelling and Mullin 1975; Reynolds 1992; Simpson 1987;
Stevens 1971; Wright 1986; Wu 1982
Devonian:
Dreesen 1982; Gischler 1995; Hubmann
1999; Kazmierczak and Goldring 1978; Lavoie 1992;
Miller et al. 1988; Rehfeld 1986; Stel 1975
Silurian:
Brunton and Copper 1994; Cotter 1990; John-
son 1989; Sami and Descrochers 1992
Ordovician:
Bakush and Carozzi 1986; Brenchley and
Newall 1982; Brookfield and Brett 1988; Drummond
and Sheets 2001; Jennette and Pryor 1993; Kreisa 1981;
Lee 1988; Lee and Kim 1992; Lehman and Pope 1989;
Paik and Lee 1989
Cambrian:
Liang and Friedman 1993; Markello and
Read 1981; Mount 1982; Mount and Kidder 1993;
Sepkoski 1962
Some of the characteristic microfacies criteria of
tempestites are shown in Plate 102.
Phanerozoic storm patterns:
Indications of storm-
related sedimentation are abundant in Phanerozoic lime-
stones formed on ramps and in mixed carbonate-silici-
clastic environments (Box 12.3). Fluctuations in the
number and intensity of storms during the Phanerozoic
have been suggested, based on global paleogeographi-
cal distributional patterns of storm deposits (Marsaglia
and Klein 1983), paleoclimatic models (Parrish and
Curtis 1982; Barron 1989) and variations in the wave-
length of hummocky cross stratification (Ito 2001). Sur-
prisingly, the overlap between the spatial distribution
of ancient reefs with large amounts of fore-reef detri-
tus and inferred paleowind directions is rare for most
of the Phanerozoic except for the Late Triassic (Kiess-
ling 2002).
genetically unrelated processes, such as turbidity or
slump events. Turbidite sedimentation may be storm-
induced (Wu 1982). A table summarizing the distin-
guishing criteria of tempestites and turbidites (Einsele
and Seilacher 1991) as well as a discussion of diagnos-
tic thin-section criteria can be found in Sect. 15.7.2.5.
Erosional sole marks, gradation, lamination and ripple
bedding occur in both types of event beds, but differ in
their frequency. The main discriminating criteria of
proximal tempestites and proximal turbidites are bio-
facies, fossils and stratigraphic context.
Event Deposits and Eventstones
Tempestites are a class of event deposits.
Event de-
posits
include tempestites, turbidites, mass flow depos-
its, inundites (flood deposits) as well as seismites de-
scribed in Sect. 12.4 (see Seilacher 1991 for a discus-
sion of concepts). Event beds are the result of short-
term sedimentation processes that produce character-
istic sedimentary signatures. These signatures may bear
considerable similarities.
Eventstones:
The term designates carbonate sedi-
ments whose deposition took place in rapid short-term
events as compared to the long-term average back-
ground sedimentation (Hüssner 1985). Eventstones in-
clude tempestites and turbidites and imply the exist-
ence of a relief and gravitative sediment transport (tur-
bidites) or of episodically high water energy (e.g.
storms; tempestites).The important criteria of event-
Differentiation of tempestites and turbidites:
Storm
deposits are physically similar to deposits from other
