The Adelaide Geosyncline
(also known as Adelaide Rift Complex
) is a major geological province in central South Australia
. It stretches from the northernmost parts of the Flinders Ranges
, narrowing at the Fleurieu Peninsula
and extending into Kangaroo Island, and composes the two major mountain ranges of the State: the Flinders Ranges
and the Mount Lofty Ranges
. The sediments in the rift complex were deposited between about 870 Ma (the middle Neoproterozoic
) to ~500 Ma (the end of the Cambrian
). They consist of a thick pile of sedimentary rocks and minor volcanic rocks that were deposited on the eastern margin of Australia during the time of break up of the supercontinent Rodinia
. A number of authors have noted the similarity in these sedimentary rocks with rocks found in western North America and have suggested that they were formerly adjacent to each other in Rodinia. This is one major correlation in the so-called SWEAT (SW USA against East Antarctica) reconstruction
of Rodinia (Moores 1991; Dalziel 1991).
The Adelaide Geosyncline is a great belt of sediments, deposited in a depression during a time of lithospheric stretching in an arc approximately a thousand kilometres long and several hundred kilometres wide. The thickest parts of the belt are approximately 24,000 m thick. Limestones
, and sandstones
indicate a predominantly marine environment.
This sedimentation ended towards the Cambrian, when plate movements changed and the area... Read More