Tectonic settings of Archaean (3325-2775 Ma) crustal-supracrustal belts in the West Pilbara Block

Krapež, Bryan; Eisenlohr, B.N.

doi:10.1016/s0301-9268(97)00068-5

Cited by 58 publications

(33 citation statements)

References 21 publications

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“…Smithies et al . (2005a) outlined features of the Whundo Group that can be interpreted in terms of modern‐style plate tectonic processes, suggesting a convergent margin setting at 3.13 Ga. Krapez and Eisenlohr (1998), Smith et al . (1998), and Smith (2003) suggested a back‐arc setting for these rocks, but the lack of evidence for felsic basement, the presence of boninites, and low Th/La, La/Nb, and Ce/Yb ratios is more consistent an intra‐oceanic arc setting (Smithies et al .…”

Section: Pilbara Cratonmentioning

confidence: 97%

“…Crustal extension, related either to the last mantle plume event (Van Kranendonk et al . 2006a) or to a possible subduction zone about 200 km to the northwest (Krapez & Eisenlohr 1998), established a northeast‐trending zone of rifting and crustal thinning along the northwestern side of the East Pilbara Terrane. A similar zone of rifting was developed on the southeastern side of the terrane, and this eventually developed into the Mosquito Creek Basin (Fig.…”

Section: Pilbara Cratonmentioning

confidence: 99%

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Review of the Pilbara Craton and Fortescue Basin, Western Australia: Crustal evolution providing environments for early life

Hickman

2012

Island Arc

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The oldest part of the Pilbara Craton is 3.80–3.55 Ga crust. Between 3.53 and 3.22 Ga, mantle plume activity resulted in eight successive volcanic cycles forming the Pilbara Supergroup. Large volumes of granitic magma were intruded during the same period. By 3.22 Ga, a thick continental crust, the East Pilbara Terrane, had been established. Between 3.22 and 3.16 Ga, rifting of the East Pilbara Terrane separated off two additional terranes (Karratha and Kurrana), with intervening basins of oceanic crust. After 3.16 Ga, the three terranes began to converge, resulting in both obduction of oceanic crust (Regal Terrane) and, in another area, subduction to form a 3.13 Ga island arc (Sholl Terrane). At 3.07 Ga, the Karratha, Regal, and Sholl Terranes collided to form the West Pilbara Superterrane, and this collided with the East Pilbara Terrane. The 3.05–2.93 Ga De Grey Superbasin was deposited as a succession of basins: Gorge Creek, Whim Creek, Mallina, and Mosquito Creek. Eventual closure of the basins, between 2.94 and 2.93 Ga, formed two separate orogenic belts on either side of the East Pilbara Terrane. Post‐orogenic granites were intruded between 2.89 and 2.83 Ga. The 2.78–2.63 Ga Fortescue Basin developed in four stages: (i) rifting of the Pilbara Craton; (ii) folding and erosion; (iii) large igneous province (LIP) volcanism; and (iv) marine sedimentation on a passive margin. A review of all known evidence for early life in the Pilbara Craton is provided. In hydrothermal settings, most of the evidence occurs as filamentous and spheroidal microfossils, organic carbon, microbial mats, and rare stromatolites. By contrast, shallow‐water marine sedimentary rocks contain a diverse range of stromatolites, and microbial mats. Lacustrine and shallow‐water marine carbonate rocks in the Fortescue Basin contain abundant and morphologically diverse stromatolites, widespread microbial mats, and organic carbon.

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Section: Pilbara Cratonmentioning

confidence: 97%

Section: Pilbara Cratonmentioning

confidence: 99%

Review of the Pilbara Craton and Fortescue Basin, Western Australia: Crustal evolution providing environments for early life

Hickman

2012

Island Arc

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“…The coastal Pilbara terrane, which is equivalent to the Roebourne lithotectonic complex [ Krapez and Eisenlohr , 1998], is exposed for more than 200 km along the northwest coast of the Western Australia and for about 30 km inland (Figures 1 and 2). The southern boundary of this terrane is marked by an east‐west trending strike‐slip fault zone, the Sholl shear zone [ Kriewaldt , 1964; Smith et al , 1998], which separates the Whim Creek Group and the 3.1 Ga Sholl Belt [ Horwitz and Pidgeon , 1993; Barley et al , 1994].…”

Section: Geologic Setting Of the Coastal Pilbara Terranementioning

confidence: 99%

Structural evolution of the middle Archean coastal Pilbara terrane, Western Australia

Kiyokawa

Taira²,

Byrne

et al. 2002

Tectonics

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The middle Archean coastal Pilbara terrane is composed of two lithotectonic units: the Karratha and Cleaverville‐Roebourne supercomplexes. The Karratha supercomplex lies tectonically beneath the Cleaverville‐Roebourne supercomplex and consists of 3270 ∼ 3250 Ma granitic batholiths and metamorphosed terrigenous sediments. It is identified as a juvenile continental crust with tonalite‐trondhjemite‐granodiorite type granites. The Cleaverville‐Roebourne supercomplex is interpreted as a dismembered immature island arc which has a restored crustal thickness of ∼20 km. This supercomplex consists of 3195 Ma bimodal volcanic‐chemical sedimentary sequences, metabasite, low‐K granitic gneiss and peridotite. Regionally distributed granite‐porphyries (circa 3020 ∼ 3000 Ma) have intruded all of the coastal Pilbara terrane. Detailed structural analyses and zircon U/Pb dating suggest that the coastal Pilbara terrane records two phases of deformation. The first phase is an immature island arc and micro‐continental crust collision and is represented by top to the northwest thrusting (D1, circa 3100–3020 Ma). This phase of deformation (an arc‐continent collision) appears to represent an important transition in the formation of continental crust. The 3020 Ma granite‐porphyry event may be related to syn‐post collision igneous activity and may reflect a second crustal thickening associated with magmatic underplating. The second phase of deformation is characterized by regional‐scale left‐lateral strike‐slip faulting (D2, circa 3020–2925 Ma) and by more localized right‐lateral strike‐slip faulting (D3, circa 2925–2770 Ma). This phase of craton‐scale strike‐slip faulting may represent stabilization of the newly formed continental crust.

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“…1). This area, situated within the coastal Pilbara Terrane or West Pilbara Superterrane (Krapez & Eisenlohr 1998; Kiyokawa et al . 2002; Smithies et al .…”

Section: Introductionmentioning

confidence: 99%

Lateral variations in the lithology and organic chemistry of a black shale sequence on the Mesoarchean seafloor affected by hydrothermal processes: The Dixon Island Formation of the coastal Pilbara Terrane, Western Australia

et al. 2012

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The Dixon Island Formation of the coastal Pilbara Terrane, Western Australia is a 3.2 Ga volcanic–sedimentary sequence influenced by syndepositional hydrothermal activity formed in an island‐arc setting. We documented lateral variations in stratigraphy, hydrothermal alteration, and biological activity recorded in the sedimentary rocks (over several kilometers), with the aim of identifying areas of biological activity and related small‐scale structures. The Dixon Island Formation comprises volcaniclastics, black chert, and iron‐rich chert within seven tectonic blocks. Based on detailed geological mapping, stratigraphic columns, carbon isotope composition, and organic carbon (Corg) content, we found lateral (>5 km) variations in stratigraphy and carbon isotope compositions in a black chert sequence above the Mesoarchean seafloor with hydrothermal activity. Two felsic tuff layers are used as stratigraphic marker beds within a black chert sequence, which was deposited on altered volcanic rocks. The black chert sequence in each tectonic block is 10–20 m thick. Thickness variations reflect topographical undulations in the paleo‐ocean floor due to faulting. Early‐stage normal faults indicate extensional conditions after hydrothermal activity. Black chert beds in the topographically subsided area contain higher Corg contents (about 0.4 wt%) than in areas around the depression (<0.1 wt%). Carbon isotope compositions for the black chert vary from −40 to −25‰, which are similar to values obtained for a black chert vein within the komatiite–rhyolite tuff sequence (underlying the black chert sequence). Those for other rock types in the Dixon Island Formation are −33 to −15‰. Results indicate that deformation occurred soon after the final stages of hydrothermal activity. After this early‐stage deformation, organic‐rich sediments were deposited over an area several kilometers across. The organic‐rich sediments indicate stagnant anoxic conditions that resulted in the deposition of siliceous and organic matter from hydrothermal vein systems. When hydrothermal activity terminated, normal faulting occurred and organic matter was deposited from the sea surface and silica from the seafloor.

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Tectonic settings of Archaean (3325-2775 Ma) crustal-supracrustal belts in the West Pilbara Block

Cited by 58 publications

References 21 publications

Review of the Pilbara Craton and Fortescue Basin, Western Australia: Crustal evolution providing environments for early life

Review of the Pilbara Craton and Fortescue Basin, Western Australia: Crustal evolution providing environments for early life

Structural evolution of the middle Archean coastal Pilbara terrane, Western Australia

Lateral variations in the lithology and organic chemistry of a black shale sequence on the Mesoarchean seafloor affected by hydrothermal processes: The Dixon Island Formation of the coastal Pilbara Terrane, Western Australia

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