FLINDERS RANGES: Matthew Flinders & the Coastal Landforms of SE Australia

The expedition's chief naturalist [scientist] Mr Brown led a group to 'mountain X', while Flinders continued his charting of the head of the gulf. 'The land on both sides is moderately high ... especially on the eastern side where the mountains form a sharp-topped ridge nearly parallel to the shore ... In the morning, Messrs. Brown, Bauer & Westal, with attendants, set off with the intention of ascending for the highest peak X of the ridge of mountains on the east side of the river [channel at head of Gulf] ... 'The excursion of the party up the mountains proved to be a most laborious one; the mountain X [later called Mt Brown], the object at which they aimed, being proving to be not less than 15 miles distant from where they landed distant, although it appeared to be abreast of the ship, they did not reach its top until 5 in the evening, and were obliged to pass the night without water, or fire: which was not found until the following day in their walk down, however, on the following day water was found, and a spot of tolerably good ground around it. ' - Journal of Matthew Flinders [Fri 10 & 12 Mar 1802]
The Flinders Ranges are a significant set of mainly north-south aligned mountain ranges. In the south they merge with the Mt Lofty Ranges (see Spencer Gulf - Adelaide Info Page). The Southern Flinders are well moderately well vegetated. In the north, the ranges are largely lacking trees, with many bare rocky surfaces visible. The Northern Flinders are particularly suited to the study of rocks of different geological eras. This has been recognised with the establishment of various educational geological trails.	Photo 1: Part of Southern Flinders, east of Spencer Gulf, near Port Augusta
The 'mountain X' of Flinders 1802 Journal was later named Mt Brown, in honour of the expedition's naturalist (scientist), who led a group to the summit. From there the party gained a view of the surrounding country. The view did not inspire them greatly... ' ... The view from the summit did not furnish any lakes or bays to the westward, but a dead uninteresting flat country every where presented itself.' - from Journal of Matthew Flinders [12 Mar 1802]	Flinders' chart, Mt Brown Extract from Flinders' chart - portion of Flinders Ranges east of Spencer Gulf
While Robert Brown's group climbed Mt Brown, Flinders took the ship's boat to the extreme end of the gulf, proving once-and-for all that it ended at that location . From the head of the gulf, views of surrounding hills and ranges were be obtained (the Flinders Ranges run north-south just to the east of the gulf). Expedition artist William Westall's sketch of the mountains from the 'head of Spencer's Gulph'
The Flinders Ranges are minly formed from sedimentary rocks that formed over a considerable period of time. The sediments piled up within a trough from about 1,000 million years ago. About 700 m.y. ago rocks from icebergs were incorporated into the sediment. Some strata show evidence of early lifeforms, including clearly observed stromatolite formations (algal mats) in ancient limestone and dolomite and fossils of the earliest multi-celled animals (the Ediacara fauna - jellyfish, worms and other soft-bodied animals - of about 600 m.y. ago). Later Cambrian animals (about 500 m.y.) include trilobites, molluscs and corals. Folding occurs when compressional pressure is exerted upon a rock mass. The pressure is released through rock bending, with portions being uplifted. The folding began about 500 million years ago. Over the past 450 million years the present landscape has been etched out. The higher peaks are mainly of Rawnsley quartzite (white when fresh); the somewhat softer Bonney sandstone (red) lies below the quartzite. Interestingly, rocks of similar ages and compositions have been found in Antarctica. This is part of the evidence supporting the theory that Australia and Antarctica were once joined.	Photo 2: Rawnsley Bluff, Wilpena Pound - looking over the ridges and wide valleys Photo 3: Educational signboard (by Tourism SA) showing formation of Flinders Ranges
Wilpena Pound The best known feature of the Flinders Ranges is Wilpena Pound (see Photo 4). It is an elevated 'dish' or depression, surrounded by steep, hard cliffs whose walls face outwards. Its interior size is about 14 by 7 kms. The depression (ie. syncline) is the lowest part of a former, gigantic folded system, the upper parts of which have been removed by erosion (see Photo 5). This topography can thus be considered as 'inverted', as the highest land today was originally the bottom (ie. lowest part) of fold systems. The tops (ie. higher parts) of the original folds have been eroded away, and now form the lowest areas of the present landscape.	Photo 4: Wilpena Pound, looking north from near Rawnsley Bluff Photo 5: Cross-section of Wilpena Pound (softer limestone and shales are below the layers shown)
The higher parts of the Flinders Ranges are made of sandstones and quartzites. The quartzites of the Flinders Ranges are highly resistant to weathering. The rock sample (quartzite) shown has been broken, having fallen from a high ledge. The freshly exposed face is white, with fragments of quartz visible. The rock surface, when weathered, becomes orange in colour. This rock is a sedimentary quartzite (in contrast with metamorphic quartzite). In contrast, the lower elevation parts of the Flinders Ranges are composed of softer, more easily weathered rocks such as shale and siltstone.	Sedimentary quartzite Photo 6: Quartzite, freshly broken by a rock fall, Wilpena Pound
Flinders and his men, while coming across evidence (fires, huts, and possibly voices) of human occupation, did not directly encounter any Aborigines, much to Flinders' disappointment. Aboriginal occupation of the area goes back at least 15,000 years. Aboriginal stories involving the landforms of the Flinders' Ranges are of considerable interest: see Yurlu's Story
During 1851 and a number of following years, good rains fell. However, 1864 saw the start of the Great Drought. The grazing lands north of Mt Remarkable were devastated, as they had already been over-grazed; the bodies of sheep lay everywhere. This prompted the government to send Surveyor-General G.W.Goyder to define areas of reliable rain. He defined a line, the Goyder Line, north of which drought was likely. Grazing, combined with the ravages of drought and introduced pests (rabbit, cat, fox and goat), caused the extinction of many species in the Flinders. These included the Bettong and the Sticknest Rat.	Photo 7: Abandoned building, farming area near Hawker
The local aborigines fared poorly during the drought as their food supply, native animals, were gone. They could only try to beg food from squatters, or to steal the squatters' animals - both were unhappy options. Some official efforts were made to help them. In the 1870s and early 1880s, after a series of good rainfall years, wheat farmers replaced pastoralists in much of the area north of Adelaide. Wheat growing crossed the Goyder Line. In this time of optimism, the saying was 'rain would follow the plough' (ie. areas that were farmed would receive more rain). Towns sprung up and the railways expanded. However, the rains were not to last; the rainfall of the area around the Flinders Ranges returned to its 'normal' (i.e. drier) state. Many properties (and towns) were abandoned, and agricultural practices eventually changed in response. Today, the Flinders Ranges region has found an identity as a vital conservation zone and a prime tourist mecca. Agriculture continues in parts of the ranges in a more sustainable manner than previously.