Redefinition and interpretation of late Miocene‐Pleistocene terrestrial stratigraphy, Central Otago, New Zealand

Youngson, J. H.; Craw, Dave; Landis, C. A.; Schmitt, K. R.

doi:10.1080/00288306.1998.9514790

Cited by 67 publications

(91 citation statements)

References 27 publications

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“…Many parts of the rectilinear pattern of normal faults were reactivated as reverse faults. The waihemo and Hawkdun Faults, in particular, developed new relief on the northeast (now upthrown) side, and shed sediments to the south on to the Otago Schist (Youngson et al 1998). Subsequently, in the Quaternary, the schist foliation and overlying sediments were folded into broad northeast-trending antiformal ridges with intervening synformal basins (Fig.…”

Section: Post-metamorphic Deformationmentioning

confidence: 99%

Structural and lithological controls on gold mineralisation at Oturehua on the northeastern margin of the Otago Schist, New Zealand

Mackie

MacKenzie

Craw³

2009

New Zealand Journal of Geology and Geophysics

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A set of more than 50 mineralised normal faults cuts lower greenschist facies rocks at the northeastern margin of the Otago Schist belt near Oturehua, central Otago. The faults strike northwest and dip steeply (>60°) northeast, and individual mineralised zones are traceable for up to 700 m along strike. The mineralised faults are closely associated with, and are generally parallel to, a swarm of northwest striking, steeply dipping extensional quartz ± ankerite veins (centimetre scale) that occur over an area of at least 25 km 2 in the host schist. Mineralised faults contain 10-100 cm thick quartz veins that are traceable as interlinked structures for tens of metres along strike. where faults cut massive quartz-feldspar-rich schist, the veins are planar, contain scattered sulfide minerals and visible gold, and there has been little alteration of essentially undeformed adjacent wall rock (centimetre scale). in contrast, muscovite-rich laminated schist host rock is extensively deformed and altered adjacent to mineralised faults (metre scale), with addition of quartz (silicification) and ankeritic replacement of metamorphic chlorite by kaolinite and/or sericitic muscovite. Veins adjacent to laminated (micaceous) schist contain abundant breccias with variably altered clasts. widespread addition of auriferous sulfide minerals, mainly arsenopyrite, has occurred in the laminated schist alteration zones and breccias. The mineralised faults formed in the hinge of a northwest-trending post-metamorphic antiform, and the faults may have been localised by zones of weakness associated with kink folding in the hinge of the antiform. Hydrothermal fluids responsible for mineralisation were channelled by the normal faults. These faults developed by coalescence of extensional fractures in the schist rock mass during middle Cretaceous regional extensional unroofing of the Otago Schist belt. The location of these mineralised faults near the margin of the Otago Schist belt suggests a genetic relationship between mineralisation and the regional northwest-striking normal fault systems that cut and define the schist margin.

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Section: Post-metamorphic Deformationmentioning

confidence: 99%

Structural and lithological controls on gold mineralisation at Oturehua on the northeastern margin of the Otago Schist, New Zealand

Mackie

MacKenzie

Craw³

2009

New Zealand Journal of Geology and Geophysics

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“…Late Miocene to Pliocene uplift of the Torlesse greywacke mountains along the northwest-striking faults on the northern margin of the schist belt yielded large volumes of greywacke detritus that at least partly filled Lake Manuherikia and formed extensive fan deposits: the Maniototo Conglomerate (Fig. 1B) in the northern part of Central Otago (Douglas 1986;Youngson et al 1998).…”

Section: Geological Settingmentioning

confidence: 99%

“…The basement ranges, uplifted sediments and intervening unconformity are currently rising on folds and faults and shedding debris to form a thin veneer of fan deposits in the intervening basins ( Fig. 1B; Youngson et al 1998;Forsyth 2001). …”

Section: Geological Settingmentioning

confidence: 99%

“…Fluvial sediments related to associated uplift were deposited on the low-relief surface and in channels cut into that surface, as the early to middle Miocene Dunstan Formation (Douglas 1986). The Dunstan Formation is dominated by quartz gravels, commonly with placer gold, and fluvial sands, silts, muds and lignite (Douglas 1986;Youngson et al 1998). This formation is overlain by, and locally interfingered with, lacustrine sediments of the middle to late Miocene Bannockburn Formation, which were deposited in the regionally extensive lake complex of Lake Manuherikia (Douglas 1986).…”

Section: Geological Settingmentioning

confidence: 99%

“…Parts of the section are overlain by Miocene sediments, and these sediments were deposited during active deformation along the Blue Lake Fault Zone. Some sedimentary facies are directly linked to fault activity (Lindqvist 1994;Youngson et al 1998), and some of these sediments contain important vertebrate fossils (Worthy et al 2006). This paper provides some additional structural context for the sediments which contain these significant fossils.…”

Section: Introductionmentioning

confidence: 99%

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Structure of the Blue Lake Fault Zone, Otago Schist, New Zealand

Henne

Craw

MacKenzie

2011

New Zealand Journal of Geology and Geophysics

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The Blue Lake Fault Zone occurs at a major crustal boundary between Otago Schist and Torlesse greywacke. This zone has been active since the middle Cretaceous (c. 112 Ma), when extensional exhumation of the Otago Schist belt was initiated. The Blue Lake Fault Zone is dominated by a set of normal faults that have caused juxtaposition of rocks of different metamorphic grade, from prehnite-pumpellyite facies turbidites to pervasively recrystallised greenschist facies schists. This metamorphic transition has been thinned from c. 15 km to c. 2 km by normal fault motion on the scale of kilometres. This condensed section is the narrowest such section on the Otago Schist margin. The faults in this condensed section are defined by gouge zones that are hundreds of metres wide and constitute about 30% of the section. Gouge zones were locally reactivated as thin Late Cenozoic reverse faults on the centimetre to metre scale.

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River drainage reorientation during placer gold accumulation, southern New Zealand

Craw

2013

Miner Deposita

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Redefinition and interpretation of late Miocene‐Pleistocene terrestrial stratigraphy, Central Otago, New Zealand

Cited by 67 publications

References 27 publications

Structural and lithological controls on gold mineralisation at Oturehua on the northeastern margin of the Otago Schist, New Zealand

Structural and lithological controls on gold mineralisation at Oturehua on the northeastern margin of the Otago Schist, New Zealand

Structure of the Blue Lake Fault Zone, Otago Schist, New Zealand

River drainage reorientation during placer gold accumulation, southern New Zealand

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