Rift basin evolution and the growth of normal faults

Conference · Wed Jan 01 04:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5934965

Schlische, R W ^[1]

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1. Rutgers, The State Univ. of New Jersey, Piscataway, NJ (United States). Dept. of Geological Sciences

The three-dimensional displacement geometry associated with micro-normal faults in sedimentary strata closely resembles the pattern of subsidence and uplift following earthquakes on parts of normal fault systems. Both are similar to the large-scale geometry of half-graben sedimentary basins and their uplifted footwall blocks. These observations suggest that (1) half-graben evolve as a consequence of repeated slip events on basin-bounding normal faults and (2) normal fault systems grow in length through time as displacement accumulates. Furthermore, details of the evolution of basins and their border fault systems (BFS) should be recorded in the basin fill. Indeed, Triassic synrift strata progressively onlap basement along the margins of many eastern North American rift basins, implying that these basins grew in length and width. A progressive decrease in accumulation rates through the Triassic section is also consistent with basin growth. Forward modeling involving basin growth, however, indicates that both features need not always occur. On the largest scale, a typical Mesozoic rift basin approximates a large syncline plunging toward its associated BFS. This geometry suggests that cumulative fault displacement and associated basin subsidence were highest near the center of the map trace of the BFS. On a smaller scale, transverse growth folds in the hanging wall of the BFS are associated with a segmentation of the BFS: synclines formed where fault segment displacement was highest; anticlines formed where displacement was lower, generally at the boundaries of fault segments. Thus, along-strike variations in fault displacement occur on a variety of scales. In addition, the map trace of the basement-sediment contact is apparently unaffected by the transverse folds and the segmentation of the BFS, implying some form of regional linkage among the segments of the BFs and perhaps other faults within the basin.

• OSTI ID: 5934965
• Report Number(s): CONF-921058--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 24:7
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CRACK PROPAGATION
DISPLACEMENT RATES
FRACTURED RESERVOIRS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GROUND SUBSIDENCE
ORIGIN
SEDIMENTARY BASINS