CGRG Bibliography of Canadian Geomorphology
Search Results
Author : Duk-Rodkin, A.; and Barendregt, R.W.
Date : 1997.
Title : Mid-Pliocene to mid Pleistocene glaciations in the Tintina Trench, Dawson Area, Yukon Territory
Publication : Beringia Paleoenvironments Workshop Sept., 1997: Abstracts and Program. Edited by: Scott Elias and Julie Brigham-Grette . Workshop sponsored by the U.S. National Science Foundation.
Issue :
Page(s) : 35.
Abstract
Stratigraphic work following regional Quaternary mapping in the Dawson area has revealed a series of glacial and interglacial events of late Gauss to late Matuyama age. These events are represented by outwash, till and loess sequences with paleosols. Of the many sites studied two main sites are described here to which other sites are correlated, Eastfifteenmile Site and Rock Creek Site. These two sites are located along the north side of the Tintina Trench about 30km from each other. Stratigraphic work at both sites indicate that the glacial sequence overlies pre-glacial fluvial Tertiary strata. The glacial strata is conformably overlain pre-glacial Pliocene gravel deposits but is unconformably overlaying older deposits most likely Miocene in age. Preliminary paleomagnetic determination of the glacial sequence at Eastfifteen Mile Site has revealed a normal-reverse-normal-reverse sequence. The base of the sequence has gravel and sand deposits (normal), most likely distal outwash deposits, followed by three tills (reverse-normal-reverse), each of them capped by a pale-osol of one to 3 metre thick. The top of the exposure has two reverse loess deposits. This exposure has about 12 metres covered at top. The paleosols are atypical wounded moose paleosols. Preliminary paleomagnetism at Rock Creek Site shows also a normal-reverse-normal-reverse glacial sequence. The basal deposit is a normal outwash overlain by a reverse till with a paleosol which underlies another till with a paleosol of unknown age. The unknown till is overlain by a normal outwash and till with a paleosol which is subsequently overlain by a reversed outwash sequence. A composite stratigraphy of these two sites includes a basal outwash sequence of Gauss age (normal) which is overlaying by a reversed (early Matuyama) - normal (Olduvai ) - reversed (mid and late Matuyama) tills, out-wash and loess deposits. The main reason for assigning these ages are based on the fact that the Olduvai sub-chron included cold periods for glaciers development and interglacial periods long enough to developed thick paleosols unlikely the Jaramillo subchron. Also, elsewhere in the region outwash deposits associated with the first glaciation in the region have yielded Gauss normal polarity. Furthermore, pre-glacial gravel deposits of Pliocene in age have yielded the same age associated with the first glaciation in the region. This record represents at least seven glacial events from late Pliocene to Mid Pleistocene, the oldest and longest record in Canada.
Bibliography of Canadian Geomorphology