Ichnofabric and siliciclastic depositional systems: Integration for sequence stratigraphic analysis

Conference · Fri Mar 01 00:00:00 EST 1991 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:5694137

Bottjer, D J ^[1]; Droser, M L ^[2]

---

1. Univ. of Southern California, Los Angeles (United States)
2. Univ. of California, Riverside (United States)

Much previous research on biogenic sedimentary structures has established how ichnofacies (assemblages of discrete trace fossils) vary within marine depositional systems. However, studies aimed at understanding the distribution of ichnofabric (sedimentary rock fabric resulting from biogenic reworking) have only recently been attempted. Because ichnofabric can be recorded using a semi-quantitative series of ichnofabric indices (ii), its distribution in marine sedimentary rocks can be easily recorded through vertical sequence analysis. Thicknesses of strata recording different ichnofabric indices can be logged from stratigraphic sections or cores. These data are best displayed in histograms as percent of ii recorded from the total thickness measured. These ichnofabric histograms (ichnograms) show variable but distinctive distributions for genetic units such as facies within systems tracts of siliciclastic depositional sequences. An average ichnofabric index for any genetic sedimentary unit can also be computed from the data used to construct ichnograms. Because skeletal fossils are typically much less commonly preserved in siliciclastic than carbonate depositional systems, such ichnofabric analyses have the potential of providing an important new line of evidence for depositional systems and sequence stratigraphic analysis of siliciclastic strata. In petroleum exploration results from completing analyses of ichnofabric distribution could provide important information including: (1) systems tracts with fine-grained facies that have relatively low ichnofabric values are potential source beds; and (2) petroleum reservoirs that occur in coarse episodically deposited beds are more likely to from in systems tracts with facies that have low rather than high ichnofabric values.

• OSTI ID: 5694137
• Report Number(s): CONF-910403-; CODEN: AABUD
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 75:3; Conference: Annual meeting of the American Association of Petroleum Geologists (AAPG), Dallas, TX (United States), 7-10 Apr 1991; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
02 PETROLEUM
PETROLEUM DEPOSITS
RESERVOIR ROCK
SOURCE ROCKS
LITHOLOGY
STRATIGRAPHY
COMPARATIVE EVALUATIONS
CORRELATIONS
EXPLORATION
FOSSILS
GEOLOGIC MODELS
PALEONTOLOGY
EVALUATION
GEOLOGIC DEPOSITS
GEOLOGY
MINERAL RESOURCES
RESOURCES
580000* - Geosciences
020200 - Petroleum- Reserves
Geology
& Exploration