Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
Provenance of Jurassic sandstones in the Rakaia Terrane, Canterbury, New Zealand
Ist Teil von
New Zealand journal of geology and geophysics, 2018-04, Vol.61 (2), p.136-144
Ort / Verlag
Abingdon: Taylor & Francis
Erscheinungsjahr
2018
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
Detrital zircon U-Pb and muscovite
39
Ar/
40
Ar ages from sandstones in the fluviatile to shallow marine mid-Jurassic Clent Hills Group and Wakaepa Formation of mid-Canterbury, South Island, New Zealand, show characteristic patterns that demonstrate a derivation from local Permian (and possibly Triassic) basement rocks of the Rakaia Terrane (Torlesse Composite Terrane). In the Clent Hills and Wakaepa age data sets, Permian to Triassic zircons form the major age groups, 34% and 58% respectively, but early Paleozoic (20% and 10%) and Precambrian (32% and 28%) zircons also form minor groups. The Precambrian zircons are mainly late Mesoproterozoic and late Neoproterozoic. The muscovite
39
Ar/
40
Ar age patterns reveal no Precambrian ages and the majority (48%) again fall in the Permian-Triassic age range. We postulate a local sediment source in the predominantly Permian Rakaia Terrane basement during Jurassic time, when the terrane was a deformed and stabilised upland block extending principally to the east. This was thus a convergent plate margin against which contemporary marine sedimentary basins developed and consolidated as the Kaweka Terrane (Torlesse Composite Terrane). The provenance of the Canterbury Jurassic cover rocks contrasts markedly with Jurassic-age cover rocks in the Brook Street Terrane. The latter show an almost unimodal pattern reflecting a volcaniclastic environment well-removed from continental sediment sources.