Coastal headlands - a natural history - Part lll

4 Jan 2012 6:30 AMSusan Guthrie
Coastal headlands - a natural history - Part lll

PART 3 The Burleigh headland and ridge 

 

Read the final part in Ian Black's, of Geo-Nature Walks and Tours, fascinating account of the formation of local Gold Coast headlands. 

 

The top of Burleigh headland, like Currumbin, Point Danger and the Banora ridge, was once the bottom of an old river valley that made its way to the coast around 23 MYA (Million Years Ago) before being filled in by the first flows of basalt from the Tweed Volcano (see part 1 & 2).

 

Burleigh Headland offers a great opportunity to view what must have been a very thick flow. Photo 1 shows the basalt columns above the metasediments of the Neranleigh-Fernvale beds at the front of the headland. Basalt erupts at temperatures in excess of 950’C. When the hot basalt flow is exposed to a cold valley floor and even the air above, the bottom and top of the flow cool quickly leaving in its wake large vertical cooling columns (photo 2).

 

 

Due to the very thick Burleigh flow, the middle section cooled slower causing the columns to crack horizontally and this section can be seen just below the Tumgun lookout (photo 3). As the hill either side of the flow eroded away, the basalt columns tumbled down the hill and are now protecting the base of the hill from wave erosion.

 

 

Photo 4 shows the smaller broken columns and the larger middle sections that came from below Tumgun lookout.

 

Interested in learning more about the area?  Contact Ian Black of Geo-Nature Walks and Tours for a copy of the latest full colour edition ‘Rocks and Landscapes of the Gold Coast and Hinterland’ by Warwick Willmott of the Geological Society of Australia, Queensland Division. Available for $15 plus postage.

 

Or better still, join one of Geo-Nature’s guided walks for a fascinating and informative introduction to the Gold Coast and surrounds.
 

Contact us today!

 

 

I really enjoyed your series on the coastal area. I liked the level of detail you went into.

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