New Zealand Journal of Geology and Geophysics abstracts

---

Change in direction of the Pelorus River, Marlborough, New Zealand: evidence from composition of Quaternary gravels

NICK MORTIMER

Institute of Geological & Nuclear Sciences
Private Bag 1930
Dunedin, New Zealand

PAUL WOPEREIS

Consultant Geologist
P.O. Box 963
Nelson, New Zealand

Abstract  Clasts in greenish subsurface gravels of presumed Quaternary age in the Kaituna valley comprise mainly metamorphosed and variably foliated volcanic litharenite of the Pelorus Group, but also contain some Dun Mountain Ophiolite Belt lithologies. These clast compositions are inconsistent with the gravel source being either the surrounding schist basement or the nearby Wairau River, but instead strongly suggest a source in the Pelorus River catchment. Thus, at some time in the Quaternary, the Pelorus River flowed south into the Wairau River instead of east and north into Pelorus Sound as it does now. The change in drainage direction since then was due either to non-tectonic river capture and/or northward regional tilting.

Keywords  Marlborough; gravels; river terraces; Quaternary; Pelorus Group; tectonics

New Zealand Journal of Geology and Geophysics, 1997, Vol. 40: 307-313

0028-8306/97/4003-0307 $7.00/0 (c) The Royal Society of New Zealand 1997

PDF file of entire paper: medium quality (1593K); (scanned from paper original: notes about this process)

---

This year's abstracts | Journal home page | All abstracts | Publishing home page