Heterogeneous brittle deformation in the Devonian carbonate rocks of the Pillara Range, Canning Basin: Implications for the structural evolution of the Lennard Shelf

Litho-structural controls on mineralisation at the Pillara carbonatehosted Zn-Pb Deposit, Lennard Shelf District, Western Australia

“…Stylolites also define the margins of some highangle veins, suggesting that local compressive stresses continued to exist following mineralisation. This observation is consistent with the findings of Dörling et al (1996b) from outcrop in the Pillara Springs area indicating that horizontal stylolites and tensions gashes formed progressively during mineralisation.…”

“…Seismic data indicate that extensional faults directly north of the Limestone Billy Hills strike northeast-southwest and dip to the northwest or southeast, creating a horst and graben structure (Dörling et al, 1995;Kemp and Wilson, 1980). There are three main structural styles in nearby outcrop (Dörling et al, 1996b): dominant, north-trending, sinistral oblique-slip faults containing limestone clasts cemented by calcite spar and sulphides, interpreted as Riedel shears; west to northwest-trending dextral oblique faults, and; northwesttrending domino faults with minor offset but containing sulphide minerals. Tension gash orientations and tectonic stylolites in outcrop indicate that s1 was orientated northwestsoutheast, s3 northeast to southwest, and that s2 was near vertical.…”

“…Tension gash orientations and tectonic stylolites in outcrop indicate that s1 was orientated northwestsoutheast, s3 northeast to southwest, and that s2 was near vertical. The orientation of s1 is considered to have been subvertical outside of the accommodation zone (Dörling et al 1996b). The platform sequence is estimated to have been tilted between 10 and 20 o to the northeast following deposition (Murphy et al, 1986;Dörling et al 1996b).…”

“…The orientation of s1 is considered to have been subvertical outside of the accommodation zone (Dörling et al 1996b). The platform sequence is estimated to have been tilted between 10 and 20 o to the northeast following deposition (Murphy et al, 1986;Dörling et al 1996b). Symons and Arne (2005) conclude that most of the tilting of the sequence predated base metal deposition based on paleomagnetic studies.…”

Stratal architecture and platform evolution of an early Frasnian syn‐tectonic carbonate platform, Canning Basin, Australia

“…The north‐west‐trending Lennard Shelf represents the shallow northerly flanks of the Fitzroy Sub‐basin on which carbonate and siliciclastic sediment accumulated (Shaw et al ., ). Location and growth of platforms on faulted basement blocks at the margins of the Fitzroy Sub‐basin have been known for many years (Playford, ; Kemp & Wilson, ; Dörling et al ., ).…”