Home > Quaternary coastal evolution adjacent to southern Ningaloo Reef, Western Australia: Implications for land use planning

Quaternary coastal evolution adjacent to southern Ningaloo Reef, Western Australia: Implications for land use planning

Posted on 24 August 2011

TitleQuaternary coastal evolution adjacent to southern Ningaloo Reef, Western Australia: Implications for land use planning
Publication TypeThesis
Year of Publication2003
AuthorsLeeden, CL
AdvisorCollins, L
Academic DepartmentApplied Geology
DegreeBachelor of Science (Honours)
Number of Pages1-135
Date Published2003
UniversityCurtin University of Technology
Keywordsgeology, Ningaloo, terrestrial
AbstractThe 290 km long segmented, fringing Ningaloo Reef of Western Australia lies between latitudes 21°47’ and 24°S along longitude 113°30’E. Nearshore currents, controlled by the reef, dictate both marine and terrestrial sedimentary systems and provide a modern analogue for the adjacent uplifted and preserved paleo-reefs. The present day reef records Holocene and Last Interglacial phases of reef growth in a tectonically stable environment, overlying uplifted Tertiary carbonates of the Cape Range, which is flanked by raised Plio-Pleistocene terraces and reefs. The coastal plain adjacent to Ningaloo Reef and the Cape Range region, provides evidence of coastal evolution, tectonic uplift, global sea-level changes, coastal aeolian processes, desert aeolian processes and karstic processes. Interactions between these processes have determined the geomorphology and stratigraphy of the region. The Holocene evolution of the coastal plain adjacent to Ningaloo Reef records five depositional stages; shelf erosion and shore face retreat, transgressive deposits, highstand deposits, regressive deposits, and modern beach and foredune development. As a reflection of these influences, large parabolic dune fields were deposited during the transgression and highstand, relic coastal features generated during highstand, and beach ridge plains formed during the regression. The regional geomorphology varies from rugged Tertiary limestone cliff coasts adjacent to the southern extent of Ningaloo Reef, to Holocene sandy active beaches on the coast adjacent to the northern extent of the reef. The pre-existing topography has largely dictated Holocene depositional regimes. An expansive Pleistocene desert dune plain dominates the regional inland geomorphology and is indicative of past aridity. The coastal plain in mapped areas is typically characterised by a narrow coastal strip of Holocene dunes, including rocky and sandy shorelines, modern foredunes and relic foredunes, beach ridges and parabolic dune fields. However, sections of coast adjacent to the southern extent of Ningaloo Reef have no Holocene deposition where high Tertiary cliff coasts abut the waters edge. The coast adjacent to Ningaloo Reef is rapidly increasing in popularity as a preferred tourist destination and this has led to increasing degradation of the fragile coastal environment. This degradation is primarily related to nodes of activity, in the forms of uncontrolled proliferation of access tracks and clearing vegetation for camping sites. Geomorphological mapping of the coastal zone, integrated with a land classification scheme based on substrate capacity, provides a regional data base that enables natural and anthropogenic coastal environmental impacts to be assessed. The development of a land classification scheme based on substrate capacity was incorporated with land system units (geological units, further defined by environmental characteristics) to assist in future land management and environmental monitoring. Land system units with low substrate capacity are unconsolidated, have little to no vegetation, are commonly mobile units that take form in steep slopes and undulating topography, making them prone to sediment remobilisation and hence degradation. Land system units with a medium to high substrate capacity consist of consolidated limestone with a thin to non existent cover of colluvial material and significant vegetation cover. Based on GIS analysis, risk zones were delineated, and areas which are particularly at risk of degradation due to a combination of the level of land use and substrate characteristics were highlighted. This study is of direct benefit for land management and planning purposes as it quantifies the impacts on the coastal zone and allows for the development of more effective management strategies. It is expected that the geological, environmental and geographic information system (GIS) data produced in this study will form the platform for further research work in this area.
Refereed DesignationRefereed
Leeden Honours thesis 2003.pdf9.76 MB