Geology Reference
In-Depth Information
Recent research is focused on the question of how fos-
sil contourites can be recognized. Many inferred fossil
'contourites' are now interpreted as bottom-reworked
turbidites.
Basics: Deepmarine pelagic carbonates
Bandel, K. (1974): Deep-water limestones from the Devo-
nian-Carboniferous of the Carnic Alps, Austria. - Inter-
national Association of Sedimentologists, Special Publi-
cations,
1
, 93-115
Bernoulli, D., Jenkyns, H.C. (1974): Alpine, Mediterranean
and Central Atlantic Mesozoic facies in relation to the
early evolution of the Tethys. - In: Dott, R.H., Shaver,
R.M. (eds.): Modern and ancient geosynclinal sedimen-
tation. - Society of Economic Paleontologists and Miner-
alogists, Special Publications,
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, 129-160
Böhm, F. (1992): Mikrofazies und Ablagerungsmilieu des
Lias und Doggers der Nördlichen Kalkalpen. - Erlanger
Geologische Abhandlungen,
121
, 57-217
Cook, H.E., Enos, P. (eds., 1977): Deep-water carbonate en-
vironments. - Society of Economic Paleontologists and
Mineralogists, Special Publications,
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, 336 pp.
Farinacci, A. and Elmi, S. (eds., 1981): Rosso Ammonitico
Symposium 1980. - 602 pp., Roma (Tecnoscienza)
Garrison, R.E. (1972): Inter- and intrapillow limestones of
the Olympic Peninsula, Washington. - Journal of Geol-
ogy,
80
, 310-322
Garrison, R.E., Fischer, A.G. (1969): Deep-water limestones
and radiolarites of the Alpine Jurassic. - In: Friedman,
G.M. (ed.): Depositional environments in carbonate rocks.
A symposium. - Society of Economic Paleontologists and
Mineralogists, Special Publications,
14
, 20-56
Jenkyns, H.C. (1986): Pelagic environments. - In: Reading,
H.G. (ed.): Sedimentary environments and facies. - 343-
390, Oxford (Blackwell)
Leggett, J.K. (1985): Deep-sea pelagic sediments and palae-
ocenography: a review of recent processes. - In: Brenchley,
P.J., Wulliams, B.O.J. (eds.): Sedimentology: Recent de-
velopments and developments and applied aspects. - Geo-
logical Society of London, Special Publication,
18
, 95-
121
Santantonio, M. (1993); Facies associations and evolution
of pelagic carbonate platform/basin systems: examples
from the Italian Jurassic. - Sedimentology,
40
, 1039-1068
Scholle, P.J., Arthur, M.A., Ekdale, A.A. (1983): Pelagic en-
vironments. - In: Scholle, P.A., Bebout, D.G., Moore,
C.G. (eds.): Carbonate depositional environments. -
American Association of Petroleum Geologists, Memoir,
33
, 620-691
Stow, D.A.V., Faugères, J.-C., Viana, A., Gonthier, E. (1998):
Fossil contourites: a critical review. - Sedimentary Geol-
ogy,
115
, 3-31
Stow, D.A.V. (ed., 1991): Deep-water turbidite systems. -
IAS Reprint Series, 3, 488 pp.
Tucker, M. (1974): Sedimentology of Palaeozoic pelagic
limestones: the Devonian Griotte (Southern France) and
Cephalopodenkalk (Germany). - International Associa-
tion of Sedimentologists, Special Publications,
1
, 71-
92
Wendt, J., Aigner, T. (1985): Facies patterns and depositional
environments of Palaeozoic cephalopod limestones. -
Sedimentary Geology,
44
, 263-300
Wilson, J.L. (1969): Microfacies and sedimentary structures
in 'deeper water' lime mudstones. - In: Friedman G.M.
(ed.): Depositional environments in carbonate rocks. A
symposium. - Society of Economic Paleontologists and
Mineralogists, Special Publications,
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, 4-19
Further reading:
K022, K181; see also Basics: Platform
margins and carbonate slopes.
Examples of ancient carbonate contourites have been
described from the Ordovician Jiuxi Drift in Hunan,
China (Duan et al. 1993), the Late Cretaceous Couches
Rouges and Couches de Wang in the Swiss and French
Alps (Villars 1991), the Cretaceous Talme Yafw For-
mation in Israel (Bein and Weiler 1976), the Paleogene
Lefkara Formation in Cyprus (Kahler 1994), and the
Neogene Mishaki Formation in Honshu, Japan (Stow
and Faugéres 1990). These examples exhibit the fol-
lowing common criteria:
•
Location: along the slope or base-of-slope.
•
Prism shape of the sediment body, mound shape
(several hundreds of meters in size).
•
Distinct contourite sequences.
•
Intensive bioturbation, continuous with deposition.
Main contourite facies are bioturbated calcisiltite and
burrow-mottled calcisiltites.
•
The sediment consists of calcilaminite, calcilutite,
calcarenite, calcirudite and marls transported to the
basin margin by downslope resedimentation of epi-
continental platform carbonates. The coarse-grained
facies is interpreted as being deposited by turbidity
currents and debris flows; the fine-grained facies as
having been dispersed along the slope by bottom
currents and deposited as calcareous muddy con-
tourites.
•
Contourites occur within a range of resedimented
facies, pelagites, hemipelagites associated with
cherts and micrites; or hemipelagites with pyroclas-
tic sediments and concentrations of volcaniclastics.
•
The association with macrofossils and trace fossils
is characteristic of deep-marine environments.
•
Calcareous contourites occur in regions of dominant
pelagic biogenic input. Bedding indistinct, primary
lamination may be preserved, mean grain size is most
commonly silty clay or clayey.
•
The dominant biota are nannofossils and foramin-
ifera. Many biogenic particles are stained and frag-
mented.
Stow et al. (1998) suggested a three-stage approach
to investigating of contourites, consisting of small scale
(field, borehole or lab), medium-scale (formation and
region) and large scale (system or continent) studies.
Most of the questions summarized by the authors and
related to the occurrence, structure, texture, fabric,
structure and sequence of supposed contourites can be
answered by combining microfacies data and outcrop
observations.
