Image: 3 stages of geological development at Croft Quarry. - geograph.org.uk - 1136369

Description: 3 stages of geological development at Croft Quarry.. The rock being quarried is granite, so the lowest levels are relatively early igneous formations. The slightly redder patch just to the right of the strong near-vertical shadow just right of centre shows tightly curved strata (not clearly visible at this scale) indicative of a rising stream of magma. The second stage is the clear evidence of glacial erosion of the granite shown by the smoothly curved boundary between the granite and the overlying sedimentary formations. A noticeable feature of the latter is the way they have been deposited preferentially into the hollows of the underlying granite so that the successive layers show less and less curvature, ending with an essentially horizontal top layer. The sedimentary deposits are mainly red mudstone with some thin intermediate layers of lighter coloured deposits. A more detailed view of part of this formation can be seen in 1136362.
Title: 3 stages of geological development at Croft Quarry. - geograph.org.uk - 1136369
Credit: From geograph.org.uk
Author: Alan Murray-Rust
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License: CC BY-SA 2.0
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