Subduction-related deformation and the Narooma anticlinorium, Eastern Lachlan Fold Belt, Southeastern New South Wales
Titel:
Subduction-related deformation and the Narooma anticlinorium, Eastern Lachlan Fold Belt, Southeastern New South Wales
Auteur:
Miller, J. McL. Gray, D. R.
Verschenen in:
Australian journal of earth sciences
Paginering:
Jaargang 44 (1997) nr. 2 pagina's 237-251
Jaar:
1997-04
Inhoud:
The Narooma anticlinorium is a north-plunging, apparent antiformal structure within imbricated turbidite, chert, basalt and melange of mid-Cambrian to Late Ordovician age. Younging in the turbidites and fold vergence in both chert and turbidite indicate that the anticlinorium is not a simple antiformal fold. Complexity relates to superposition of early structures (subduction underplating) by late structures (wedge shortening). Early Silurian? subduction was responsible for a bedding-parallel fabric (S*), isoclinal recumbent folding, imbrication and broken formation. Superimposed crenulation cleavages, refolding of early folds, late-stage high-strain zones and brittle faults are part of mid-Silurian to Middle Devonian subduction-related, progressive deformation responsible for shortening in the accretionary 'wedge'. At this time the Narooma anticlinorium developed progressively above a gently west-dipping, subduction-related detachment fault by a combination of fold-amplification above a splay fault, localised wrenching and backthrusting. The eastern Lachlan Fold Belt records structural evidence for subduction at the macro- and mesoscopic scales from at least the Early Silurian to possibly the Middle Devonian.
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