Cody Carman

Year

2019

Degree Name

Bachelor of Science Honours

Department

School of Earth & Environmental Sciences

Advisor(s)

Colin Murray-Wallace

Abstract

Although the subject of previous investigations, there is a paucity of high-resolution stratigraphical analyses that have been undertaken on the Snapper Point Formation especially with regards to the glacially-related conglomerate beds, with many studies focusing on a broad-scale description of the formation. Therefore, the focus of this thesis is to produce a higher resolution facies analysis of the Snapper Point Formation and the inferred glacially-related facies found throughout the formation and their relation to the shallow marine sediments and depositional processes. Additionally, due to the higher cliff faces of the formations outcrop, many have not been adequately described. Thus a secondary focus is to map the previously inaccessible glacially-related facies and sedimentary units within the Snapper Point Formation. The fieldwork for this thesis project was conducted at the Snapper Point coastal outcrop at Kioloa, NSW. In addition to standard geological fieldwork practices, a drone was used for photographing the upper-most, inaccessible cliff exposures present, showing that drones are valuable fieldwork tools. These photographs would later be turned into several 3D models using the 3D photogrammetry modelling software, Agisoft PhotoScan. Two highly detailed stratigraphic logs were produced over an 80 m stratigraphic log of the southern portion and a 45 m stratigraphic log depicting the northern part. Over 430 individual sedimentary beds were recorded within these logs, with 224 discrete dropstone beds documented at the outcrop, providing a more detailed and quantitative analysis of the dropstone facies. A large 40 m laterally extensive Soft-Sediment Deformation Structure was observed in the cliffs of the outcrop. The palaeoenvironment is interpreted as a shallow marine setting above storm weather wave base, likely located in the inner to middle continental shelf environment. The environment is characterised by prolonged periods of calm, low energy deposition, that was continually being interrupted by rapid high energy storm events. The dropstone facies indicate that this environment was showered with ice-rafted debris, likely from the Permo-Carboniferous Ice Sheet over Gondwana at the time. Using the connection between Heinrich events and reported Dansgaard and Oeschger cycles occurring during the Permo-Carboniferous glaciation, this paper strengthens the hypothesis that the dropstone facies are the result of Heinrich-like events active during the Permian. Inquiries into the various theories and ideas surrounding the soft-sediment deformation structure at Snapper Point were performed, with the iceberg scour structure being highlighted as the likely cause.

FoR codes (2008)

040311 Stratigraphy (incl. Biostratigraphy and Sequence Stratigraphy), 040310 Sedimentology

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Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.