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On the number and spacing of faults
Author(s) -
Morellato Chiara,
Redini Francesco,
Doglioni Carlo
Publication year - 2003
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1046/j.1365-3121.2003.00501.x
Subject(s) - décollement , geology , rift , basement , seismology , thrust fault , sedimentary rock , thrust , extensional definition , petrology , paleontology , tectonics , civil engineering , physics , engineering , thermodynamics
Orogens and rift zones have a finite number of regional faults. The accretionary prisms analysed here have a number of thrusts < 50, whereas extensional areas have a number of normal faults ranging between six and 44. The average spacing of thrusts is between 5 and 25 km; spacing of normal faults is more restricted into two peaks, at 25–29 km and 4–6 km, in which the latter is the most common. The number and spacing of faults appear to be mainly controlled by the depth of the decollement plane, which seems to be more variable in compressive settings with respect to rift zones. Basement‐involved orogens present fewer and more spaced thrusts; by contrast, a greater number of thrusts with shorter spacing characterize thin‐skinned thrust belts. The shallower the decollement is, the stronger it appears to control the palaeogeography, in the sense of rheological lateral variations in the sedimentary cover.