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Evolution of a Normal Fault System Along Eastern Gondwana, New Zealand
Author(s) -
Sahoo T. R.,
Nicol A.,
Browne G. H.,
Strogen D. P.
Publication year - 2020
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1029/2020tc006181
Subject(s) - geology , gondwana , fault (geology) , terrane , rift , seismology , paleontology , basement , cretaceous , tectonics , transform fault , civil engineering , engineering
The Great South Basin (GSB) developed in the Cretaceous from continental rifting at the southeastern margin of Gondwana. The basin contains a thick Cretaceous succession that is largely unaffected by Neogene compressional tectonics, with rift faults and associated growth strata imaged by good‐quality 2‐D and 3‐D seismic data tied to wells. These data show three distinct stages of normal faulting here referred to as fault system initiation (Stage 1), fault system growth (Stage 2), and fault system death (Stage 3). The different stages of fault system evolution comprise dominant NE trending faults (NW‐SE extension), and minor NW trending faults (NE‐SW extension). Fault initiation at ~105–101 Ma mainly occurred in the central GSB with rift depocenters mostly on, or close to, NW trending basement terrane boundaries. These preexisting basement boundaries represent zones of weakness that locally promoted early localization of NW faults and retarded the propagation of NE faults. With increasing regional extension and fault system growth from ~101 to 90 Ma the influence of the basement fabric gradually decreased, while NE trending faults increased in length, number, displacements, and spatial distribution. Finally, during the fault system death stage from ~90 to 83 Ma the length, number and displacements of faults decreased. Fault death coincided in time with Gondwana breakup and reflects the localization of extension along spreading centers distal to the GSB.