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Bloody Bridge River OutwashDown
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Summary Full report
Site Type: Inland exposure
Site Status:
District:
Grid Reference: J378269, J376269
Rocks
Rock Age: Quaternary (Late Midlandian)
Interest
Other interest: No data, No Data, cross-valley moraine, outwash

Summary of site:

There are two small exposures around the 230m contour in the Bloody Bridge valley that give a good indication of conditions here during the final melt-back of glaciers at the end of the Midlandian (the last Irish ice age).

Both exposures consist largely of mixed grain size glacial deposits (diamicts), 8-10m thick, with varying amounts of sand and some glacially faceted boulders. Both sets of deposits (probably originally continuous) show clear evidence of filled channels, up to 4m deep, cut across their surfaces. All these sediments appear to originate from the glacier that occupied the valley at the end of the Midlandian. They were probably released from the glacier snout as it retreated and their appearance suggests that the westerly deposits were closer to the ice front than those downstream. The coarser and heavier particles were dropped first while the sands were carried further downstream in the rushing meltwater, although some caution in interpretation is needed because it is possible to read too much into such limited exposures. As with all glaciers, seasonal variations and constantly shifting sub-glacial water flows were quite capable of cutting channels into recently released debris and the nature of the debris was likely to fluctuate widely, depending on the solid content of the ice melting at any given time.


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