TY - JOUR
T1 - Late paleo-mesoproterozoic plate margin deformation in the southern Gawler Craton: insights from structural and aeromagnetic analysis
AU - Stewart, John
AU - Betts, Peter
PY - 2010
Y1 - 2010
N2 - Abstract: The integration of structural analysis of outcrop and aeromagnetic interpretation has revealed a complex tectonic evolution for the southern Gawler Craton that reflects the regional tectonic signal during the late Paleo- to early Mesoproterozoic. Results suggest that exposures at Yarlbrinda Hill comprise the margin of a highly deformed St Peter Suite pluton emplaced within the southwestern Gawler Craton at ca. 1611 Ma. D, at outcrop records east- to northeast-directed ductile thrusting. Regionally, this deformation overprints north-south trending dextral Yarlbrinda Shear Zone fabrics within ca. 1622 Ma St Peter Suite granite and ca. 1690-1670 Ma Tunkillia Suite granite. Progressive east to northeast directed thrust movements led to exhumation of the deformed ca. 1611 Ma granite. D-2 deformation is recorded by the brittle reactivation of first generation mylonitic fabrics, accompanied by cataclasis, alteration and pseuclotachylite development. D-3 records a switch to similar to northwest-southeast shortening, which led to the folding and tear faulting of the D1-2 shear zone. A switch to extension and subsequent rotations of the principle stress axes led to Hiltaba Suite granite emplacement and contemporaneous faulting under similar to east-west extension during D-4 and west-northwest-east-southeast extension during D-5.
AB - Abstract: The integration of structural analysis of outcrop and aeromagnetic interpretation has revealed a complex tectonic evolution for the southern Gawler Craton that reflects the regional tectonic signal during the late Paleo- to early Mesoproterozoic. Results suggest that exposures at Yarlbrinda Hill comprise the margin of a highly deformed St Peter Suite pluton emplaced within the southwestern Gawler Craton at ca. 1611 Ma. D, at outcrop records east- to northeast-directed ductile thrusting. Regionally, this deformation overprints north-south trending dextral Yarlbrinda Shear Zone fabrics within ca. 1622 Ma St Peter Suite granite and ca. 1690-1670 Ma Tunkillia Suite granite. Progressive east to northeast directed thrust movements led to exhumation of the deformed ca. 1611 Ma granite. D-2 deformation is recorded by the brittle reactivation of first generation mylonitic fabrics, accompanied by cataclasis, alteration and pseuclotachylite development. D-3 records a switch to similar to northwest-southeast shortening, which led to the folding and tear faulting of the D1-2 shear zone. A switch to extension and subsequent rotations of the principle stress axes led to Hiltaba Suite granite emplacement and contemporaneous faulting under similar to east-west extension during D-4 and west-northwest-east-southeast extension during D-5.
UR - http://linkinghub.elsevier.com/retrieve/pii/S0301926809002307
U2 - 10.1016/j.precamres.2009.11.004
DO - 10.1016/j.precamres.2009.11.004
M3 - Article
SN - 0301-9268
VL - 177
SP - 55
EP - 72
JO - Precambrian Research
JF - Precambrian Research
IS - 1-2
ER -