Bound for Botany Bay: the human and environmental history of the Botany Basin to the point of European contact

Abstract

This thesis reconstructs the physical and human environment of the Botany Basin of southeast Australia as it was encountered by European colonists in 1788. It outlines the evolution of the environment from the initiation of the Basin in the Oligo-Miocene, with basement sagging after this time focussing regional drainage on Botany Bay and resulting in the accumulation in the Basin of a sedimentary record spanning 30 million years. The main focus of the thesis, however, is the environmental history of the Quaternary. For much of this time the landscape of the Basin formed an inhospitable world of mobile desert dunes lacking surface drainage and accessible groundwater. During the protracted cold stages of this period, low sea-levels exposed the inner continental shelf, uncovering a massive supply of sediment that was carried onshore by easterly winds developed on the northern edge of the glacial-stage anticyclone located over the continent.

Aeolian deposition ceased abruptly after 11 000 years ago, when rising sea-levels sequestered the offshore sources of sediment, rising water tables permitted the development of groundwater-supported swamplands and soils developed to stabilise the lands of the Botany Desert. These events set the scene for the earliest human presence in the Basin. The rise in sea-levels also drowned the extensive glacial-stage offshore landscape, although the resultant loss of great tracts of country must have been offset to some extent by the stabilisation of the Desert and its colonisation by complex heathland and swampland vegetation.

Similar environmental constraints operated to determine the location of the new colony, although many physical limitations were ignored and overridden by mercantile and strategic consideration. These resulted in the near-failure of the enterprise in its early days and saw the rapid expansion of the settlement west into environments in which northwest European agrarian practices could be more successfully deployed.