Weathering experiments
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| Alexander at Eunos Earth Quarry, Singapore, c.1948-1950. (LDGSL/38). Click to enlarge. |
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Elizabeth Alexander’s particular interest was the effects that Singapore’s tropical climate had on its geology. The results could be spectacular as can be seen in this image, caused by wind and water erosion.
Before her forced departure from Singapore, Alexander had conducted experiments to determine the rate of tropical weathering, such as burying samples of rocks in a mangrove swamp which were to be compared against a control sample in her home laboratory.
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‘False Teeth’ beds of secondary quartz, Singapore, c.1948-1950. (LDGSL/38). Click to enlarge. |
After her return in 1948, she found her lab had been completely stripped and was initially unable to find her buried samples, as the hill she had used as a triangulation point had been bulldozed.
Alexander resurrected her weathering studies, finding that the speed of erosion could be quite rapid, but equally rapid was the development of concretionary structures formed from the iron, aluminium and silica which had leached out of the rocks.
The white seams in this photograph are quartz crystals precipitated from weathered silicate rocks. Their odd appearance gained the nickname ‘false teeth’ bed.
In 1951, Alexander was again to leave Singapore to follow her husband to his new post at University College Ibadan, Nigeria, but was still called upon to advise the Singapore government on geological matters until her sudden death in 1958.
Her final paper “Observations on Tropical Weathering: a study of the movement of iron, aluminium and silicon in weathering rocks at Singapore” was published posthumously in the Society’s Quarterly Journal in 1959.
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