The Coorong: Murray-Darling river basin (Australia)

The Coorong is a long, narrow back-barrier lagoon near the mouth of the River Murray, Australia. It was accorded the status of a Wetland of International Importance under the Ramsar Convention in 1985 when it was described as a shallow, brackish-to-hypersaline lagoon. Historically the lagoon has played an important role as habitat for waterbird and fish populations, in particular migratory wading bird species covered under international agreements, underpinned by extensive seagrass beds. Evidence of long term change reveals the Coorong to have been a highly tidal system for several thousand years but was substantially affected by water diversions in the catchment and the construction of end-ofsystem barrages in 1940. These changes have seen declines in seagrass cover and associated birds and fish, exacerbated by an extended dry period in recent years with the Coorong experiencing extreme hypersalinity and consequent change in its perceived natural ecological character. The extended record of change reveals the Coorong to be outside its historical range of variability and the challenge to restore its condition is considerable. © Springer Science+Business Media B.V., part of Springer Nature 2018. All rights reserved

Is Australia a tectonically stable continent? Analysis of a myth and suggested morphological evidence of tectonism

Occasional references to the relative tectonic instability of the Australian continent have been published over the last hundred years or so. Youthful tectonic forms were described from various parts of the continent throughout that period. Despite this, it was repeatedly claimed that the shield lands in particular were tectonically stable, and as recently as this century reference has been made to a concept embracing a tectonically inert continent. However, some 60 years ago, the accumulated evidence convinced E.S. Hills that in Australia all land surfaces, including the shield lands, and even recent alluvial plains, were tectonically disturbed. This conclusion was reinforced by analyses of seismicity and faulting; by regional geological mapping that revealed widely distributed tectonic forms and especially fault-related features, many of them of neotectonic age; by technological advances that allow faulting episodes to be closely dated; by the recognition of underprinting; and by the realization that many minor forms, previously unrecognized or attributed to other mechanisms or processes, are associated with crustal stress and are of tectonic origin. Thus, while Australia is a relatively stable continent, it is subject to widespread small-magnitude earth movements. Ironically, in view of earlier thinking, neotectonic forms may be better developed and preserved on the shields than elsewhere.C. R. Twidal