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Geochronology and provenance of the Late Devonian Canowindra fish bed, Lachlan Orogen

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posted on 28.03.2022, 12:27 authored by Lou-Andrea Gennatas
Placoderms, armoured fish, are recognised as the most diverse group of fish in the Devonian period and were found throughout the world in marine and freshwater environments. Fossil records show placoderms occur from Early Silurian to the Late Devonian, and completely disappear from the fossil record at the Devonian to Carboniferous boundary. The Canowindra fish bed of the Mandagery Formation, is a remarkable Lagerstätte of placoderm fish, first discovered in 1956. The timing and cause of death, however, also remains uncertain. This study suggests the Canowindra fish bed was deposited in a shallow marine environment, as opposed to the previously suggested fluviatile environment. Field observations suggest that the fish assemblage lies within the lower rather than the upper part of the Mandagery Formation. Zircon U/Pb radiometric dating presents a maximum depositional age of 363 ± 3.1Ma for the Canowindra fish bed. Finally, using these new findings, a new timescale of the Hervey Group is introduced, as well as a new model for the cause of death of the Canowindra fish fauna. The new model suggests the timing and cause of death may be associated with the Frasnian-Famennian mass-extinction event -- abstract.

History

Table of Contents

1. Introduction -- 2. Previous work -- 3. Methods -- 4. Results -- 5. Discussion -- 6. Conclusion -- References -- Supplementary material.

Notes

Theoretical thesis. Bibliography: pages 50-54

Awarding Institution

Macquarie University

Degree Type

Thesis MRes

Degree

MRes, Macquarie University, Faculty of Science and Engineering, Department of Earth and Environmental Sciences

Department, Centre or School

Department of Earth and Environmental Sciences

Year of Award

2019

Principal Supervisor

Elena Belousova

Additional Supervisor 1

Richard Glen

Rights

Copyright Lou-Andrea Gennatas 2019. Copyright disclaimer: http://mq.edu.au/library/copyright

Language

English

Extent

1 online resource (v, 63 pages) illustrations

Former Identifiers

mq:71358 http://hdl.handle.net/1959.14/1273549