Open AccessPatterns of Late Cenozoic exhumation deduced from apatite and zircon U‐He ages from Fiordland, New Zealand
Author(s) -
House M. A.,
Gurnis M.,
Sutherland R.,
Kamp P. J. J.
Publication year - 2005
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2005gc000968
Subject(s) - zircon , geology , cenozoic , subduction , provenance , thermochronology , geochemistry , basement , apatite , fission track dating , paleontology , tectonics , archaeology , geography , structural basin
New apatite and zircon (U‐Th)/He ages from the Fiordland region of New Zealand's South Island expand on earlier results and provide new constraints on patterns of Late Cenozoic exhumation and cooling across this region. Zircon (U‐Th)/He cooling ages, in combination with increased density of apatite ages, show that in addition to a gradual northward decrease in cooling ages that was seen during an earlier phase of this study, there is also a trend toward younger cooling ages to the east. Distinct breaks in cooling age patterns on southwestern Fiordland appear to be correlated to the location of previously mapped faults. The northward decrease in ages may reflect asynchronous cooling related to migration in the locus of exhumation driven by subduction initiation, or it may reflect synchronous regional exhumation that exposed different structural levels across Fiordland, or some combination of these effects. In either case, differential exhumation accommodated by major and minor faults that dissect Fiordland basement rocks apparently played an important role in producing the resulting age patterns.