Late Holocene landscape evolution in the Dazzler Range: New evidence

Abstract

Radiocarbon dating of a wood sample from the upper part of a sequence of coarse fluvial gravels at Branchs Creek has confirmed that accumulation of coarse fluvial gravels continued into the late Mid Holocene, prior to an influx of up to 3 m of sand during the last two millenia. Ongoing erosion at Branchs Creek has revealed that clay previously interpreted as a separate unit beneath the gravels is merely a clay lens and that the gravel/clay sequence is over 3.5 m thick. Investigation ofa site at Saxons Creek, at the southern end of the Dazzler Range, has revealed a similar stratigraphy and confirms widespread catchment instability during the Mid to Late Holocene. The upper gravels are again rich in logs and smaller wood fragments, and two samples have returned radiocarbon ages of -4.1 and 2.2 ka BP. At least 3 m of sand has accumulated since deposition of the gravels ceased, with at least 1 m of sand deposited over the last several centuries. As at Branchs Creek and elsewhere in the Dazzler Range, pronounced incision into alluvial sediments has been triggered by artificial straightening of the Saxons Creek channel.