EARLY MARITIME HERITAGE OF NORTHERN SPENCER GULF
From the beginning till 1862
Whyalla Maritime Museum
Northern Spencer Gulf.
Latitude: Top (Port Augusta) at 32° 29’ 06” S
Bottom (Point Riley) at 33° 52’ 04” S
A triangle defined by coastal cities of Port Augusta in the North, Whyalla and Cowell in the West and Port Pirie and Wallaroo in the East has an approximate length of 160 km with the widest point at circa 40 km.
(Source: Australia-South Coast, South Australia, Point Riley to Port Augusta, Chart, Australian Hydrographic Service, Wollongong, 1978)
The narrow northern end of the gulf ends in a desert landscape that leads to the great salt lakes.
West is defined by plains encountering a ridge running north – south from Port Augusta to Whyalla, known as Rebecca Plateau or Cultana Range with the highest point at 305 m above sea level. That ridge leads to much smaller adjacent plains ending with granitic inselberg landscape that borders the sea. The shore is predominantly formed by pebble beaches that are replaced by coastal flats between Whyalla and Cowell in the southern direction.
East is formed by flat coastal plains and dramatically elevated Flinders Ranges with the highest point at 967 m above sea level (Mount Brown).
The landscape West of northern Spencer Gulf is one of the most ancient areas on the Earth dating back 1600 millions years. It is believed that Spencer Gulf was part of a wide rift valley about 1 000 millions years ago which can be compared to the modern day rift valley in East Africa.
(Source: Satellite image of Northern Spencer Gulf, Landsat 7 ETM, Geoscience Australia, 1999. Natural History of Eyre Peninsula, Royal Society of SA, Adelaide, 1985. Freycinet Trail, An Ancient Rift Valley, sign, text by Greg Drew, Whyalla, 2004.)