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Geological and biological evidence for drainage reorientation during uplift of alluvial basins, central Otago, New Zealand
Citation
Craw, D and Burridge, CP and Waters, J, Geological and biological evidence for drainage reorientation during uplift of alluvial basins, central Otago, New Zealand , New Zealand Journal of Geology & Geophysics, 50, (4) pp. 367-376. ISSN 0028-8306 (2007) [Refereed Article]
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Copyright Statement
© The Royal Society of New Zealand 2007
Official URL: http://www.royalsociety.org.nz
DOI: doi:10.1080/00288300709509844
Abstract
Three contiguous sedimentary basins at the foot
of the Hawkdun Range, central Otago, show evidence for
Pleistocene river capture events. The basins formed near the
intersection of NNW-trending and northeast-trending active
structures, along the NNW-striking Hawkdun Fault zone. The
basins are synclinal and have developed between northeasttrending
antiformal ridges. Continuing uplift of two adjacent
basins in the late Pleistocene has caused lowering of stream
gradients, which encouraged diversion of one river in each
basin to the northwest, to lower altitude in the adjacent basin.
These reoriented rivers have now cut gorges through growing
antiformal ridges, and new low-relief drainage divides have
formed in the basins. These river capture events are notable
because they involve basin uplift, not mountain range uplift.
We suggest that diversion of one of these rivers, the Ida Burn,
into the adjacent basin facilitated interchange of galaxiid fish
across the Taieri-Clutha catchment divide. Spontaneous mutations
of mitochondrial DNA (mtDNA) have accumulated
in populations of G. anomalus that are now separated by a
new drainage divide to the east of the Ida Burn. There has
been 1.1% divergence of mtDNA in fish on either side of this
new divide, and an empirical calibration of divergence rates
implies that the divide developed c. 60 thousand years (kyr)
ago. In contrast, flathead galaxiid species (G. depressiceps
and relatives) exhibit 3.5% mtDNA divergence between the
Clutha and Taieri catchments, implying separation of these
species for c. 500 kyr. Growth and impingement of mountain
ranges of the Rough Ridge antiformal complex during
the middle Pleistocene may have contributed to isolation of
these flathead galaxiid species. Populations of the fish species
Galaxias paucispondylus occur in the Hawkdun Basin
(Clutha catchment), to the northwest of the other two basins,
but not elsewhere in central Otago. A drainage link may have
existed between the Hawkdun Basin and the Waitaki valley to
the north, where G. paucispondylus is widespread. There is
c. 4.2% divergence in mtDNA of G. paucispondylus between
these catchments, and an empirical calibration of divergence
rates implies that isolation occurred c. 800 kyr ago.
Item Details
Item Type: | Refereed Article |
---|---|
Keywords: | river capture; geomorphology; tectonics; genetics; DNA |
Research Division: | Earth Sciences |
Research Group: | Geology |
Research Field: | Geochronology |
Objective Division: | Expanding Knowledge |
Objective Group: | Expanding knowledge |
Objective Field: | Expanding knowledge in the earth sciences |
UTAS Author: | Burridge, CP (Associate Professor Christopher Burridge) |
ID Code: | 59324 |
Year Published: | 2007 |
Web of Science® Times Cited: | 13 |
Deposited By: | Zoology |
Deposited On: | 2009-11-27 |
Last Modified: | 2009-12-01 |
Downloads: | 1 View Download Statistics |
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