Ichnology of pelagic carbonate in New Zealand and Denmark: Shelf Sea or Deep Sea
Conference
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· AAPG Bulletin (American Association of Petroleum Geologists); (USA)
OSTI ID:7061311
- Univ. of Utah, Salt Lake City (USA)
Today, pelagic carbonate ooze is an exclusive feature of deep-sea environments 1 km or more in depth. In contrast, the extensive epicratonic seas that characterized the Late Cretaceous and early Tertiary received great thicknesses of pelagic carbonate sediment in environments only a few hundred meters deep. Distinguishing between deep-sea and shelf-sea carbonate is not an easy task, but ichnologic investigation helps. Biogenic sedimentary structures, ichnofacies, and ichnofabrics in Cretaceous-Tertiary epicratonic pelagic deposits display many similarities to those in deep-sea sediment. Ichnologic features in shelf-sea chalk and limestone in both New Zealand and northern Europe reveal some interesting paleobathymetric trends. These trends include a general decrease in crustacean traces (Thalassinoides, etc.) and bioerosion traces (Trypanites, etc.) with increasing water depth, accompanied by a concomitant increase in worm burrows (Zoophycos, etc.). Maastrichtian-Oligocene pelaic limestone in New Zealand and Maastrichtian-Paleocene chalk in Denmark neither of which represent a truly deep-sea setting, exhibit similar ichnofacies and ichnofabrics. Some notable differences exist because the New Zealand platform was less extensive and more tectonically active than the northern European shelf. Pelagic strata in New Zealand are associated with shallow-water quartzose sandstone beneath and fossiliferous calcarenite above, as well as deep-water bedded chert within, the pelagic carbonate sequence. In New Zealand strata Zoophycos-rich facies dominate Thalassinoides-rich facies, and bored hardgrounds are uncommon; in Danish chalk sequences the opposite is true in both cases.
- OSTI ID:
- 7061311
- Report Number(s):
- CONF-900605--
- Conference Information:
- Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 74:5
- Country of Publication:
- United States
- Language:
- English
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Applications of Ichnology to petroleum exploration: A core workshop: SEPM core Workshop No. 17
Conference
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Tue May 01 00:00:00 EDT 1990
· AAPG Bulletin (American Association of Petroleum Geologists); (USA)
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OSTI ID:6713454
Cretaceous shelf-sea chalk deposits
Conference
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Thu Dec 31 23:00:00 EST 1987
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OSTI ID:6591783
Applications of Ichnology to petroleum exploration: A core workshop: SEPM core Workshop No. 17
Book
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Tue Dec 31 23:00:00 EST 1991
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OSTI ID:6299034