115. Pioneer Bay - Quaternary Stratigraphy

This information has been developed from one or more of these publications:

Sites of Geological and Geomorphological Significance in the Westernport Bay Catchment (1984) by Neville Rosengren.
Sites of Geological and Geomorphological Significance in the Western Region of Melbourne (1986) by Neville Rosengren
Sites of Geological and Geomorphological Significance on the Coast of Port Phillip Bay (1988) by Neville Rosengren.
Sites of Environmental Significance in the Flood Plain of the Upper Yarra Valley Region (1983) by Neville Rosengren, Douglas Frood and Kim Lowe (as part of a study of Sites of Environmental Significance by the University of Melbourne for the then Upper Yarra Valley and Dandenong Ranges Authority).

Geological heritage sites, including sites of geomorphological interest and volcanic heritage sites, are under regular revision by the Geological Society of Australia, especially in the assessment of significance and values. Reference should be made to the most recent reports. See the Earth Science Heritage section of the Geological Society of Australia website (external link) for details of geological heritage reports, and a bibliography.

Location:	Lang Lang - 715558. Two kilometres south-east of Red Bluff.	The multiple recurving spits that comprise Stockyard Point. Also shown are Lang Lang delta (A), tidal watershed (B), Red bluff (C), part of Pioneer Bay (D).
Access:	Jetty Lane.
Ownership:	Crown land and private land.
Geology/Geomorphology:	In Pioneer Bay a sequence of freshwater, marine and intertidal sediments record the late Quaternary sea level history of this part of Westernport Bay. Freshwater peats, organic muds, salt marsh clays and some sand and shells outcrop as low cliffs or can be recovered by shallow coring. Radiocarbon dating of the sediments has been used as a basis to interpret late Pleistocene sea level changes. The sequence has been described in detail and interpreted by Miles (1976). The present shoreline is an eroding low cliff backed by a degraded saltmarsh terrace. One hundred metres inland is an abandoned low cliff of similar form to the active one but cut into older freshwater swamp deposits.
Significance:	International. This is the best documented and dated site in the Westernport region to contribute to an understanding of late Quaternary sea level changes. It therefore constitutes a site of international significance as part of the growing network of such localities on the Australian coast. These sites are of interest to Quaternary scientists attempting to elucidate the nature of sea level changes on different continents.
Management:	Class 1. The surface and sub-surface sediments and the configuration of the present and former shorelines are the critical components of the site. Therefore no construction works or excavations of any kind should be permitted as these will interfere with the display of these elements of the site. Grazing animals should be excluded from the site as these cause deterioration of the land surface form.
References:	Miles, I. W. (1976). The morphology of northern Westernport Bay. M.Sc. thesis (unpub.) Dept. of Geog. Univ. of Melb.

Site 115, Pioneer Bay Quaternary sequence.

Geological section at Pioneer Bay showing details of the Late Quaternary materials. The dates are radio-carbon ages obtained on sediments from cores. (Diagram based on Miles, 1976)

Page top