Geological formation of the Bight
The fragments of land that are now called Australia have gone through plenty of periods of amalgamation and fragmentation throughout the last few billion years due to constant tectonic action. But it wasnt until the breakup of Gondwana that Australia as we know it began to take form. Between the Early Permian and the Late Jurassic (280-160 million years ago), a rift valley began to form between what is now Australia and Antarctica, with the Bight representing the edge of that division.
Australia and Antarctica had been together for about a billion years, but only took about 100 million years to completely separate from each other. The break-up commenced as a result of sea-floor spreading of the Bight Basin, proceeding from west to east. The break-up isnt thought to have been accompanied by much magmatism, and thus the margin has been classified as a magma poor (or non-volcanic) rifted margin.
The sea-floor spreading was slow in the beginning, but by the mid-Eocene (45 million years ago) a widening seaway appeared between the two continents. About 10 million years later, the Bight Basin had become a well-developed distal ocean-continent transition zone, which only widened as Australia continued on its northward path.
After Australia and Antarctica severed their final connection along the Tasman Fracture Zone, and the current that circumnavigates Antarctica was established, the sea in the Bight Basin began evolving into the form its in today.
The fragments of land that are now called Australia have gone through plenty of periods of amalgamation and fragmentation throughout the last few billion years due to constant tectonic action. But it wasnt until the breakup of Gondwana that Australia as we know it began to take form. Between the Early Permian and the Late Jurassic (280-160 million years ago), a rift valley began to form between what is now Australia and Antarctica, with the Bight representing the edge of that division.
Australia and Antarctica had been together for about a billion years, but only took about 100 million years to completely separate from each other. The break-up commenced as a result of sea-floor spreading of the Bight Basin, proceeding from west to east. The break-up isnt thought to have been accompanied by much magmatism, and thus the margin has been classified as a magma poor (or non-volcanic) rifted margin.
The sea-floor spreading was slow in the beginning, but by the mid-Eocene (45 million years ago) a widening seaway appeared between the two continents. About 10 million years later, the Bight Basin had become a well-developed distal ocean-continent transition zone, which only widened as Australia continued on its northward path.
After Australia and Antarctica severed their final connection along the Tasman Fracture Zone, and the current that circumnavigates Antarctica was established, the sea in the Bight Basin began evolving into the form its in today.
