Hull Pot EarthCache
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HULL POT
Was formed on limestone terrain, most rainwater soaks straight into cracks in the bedrock and surface channels rarely develop. The difference on the moor north-west of Pen-y-ghent is that the Lower Hawes limestone bench is coated by a layer of less-permeable glacial boulder clay (drift), which has allowed a small stream network to develop, centred on Hull Pot Beck. That has eroded through the drift down to bedrock, so the beck usually vanishes underground well upstream of this point. However, during periods of heavy rainfall, the infiltration capacity is exceeded and the stream enters Hull Pot over this ~20 m high waterfall.
During extreme sustained rainfall, water can't drain out quick enough either, and the whole basin has been known to flood.
For those keeping count, the streambed and upper walls are of Lower Hawes limestone, the base of the Yoredale series, whereas the lower walls are part of the Malham formation, the uppermost layer of the Great Scar limestone series, which is particularly popular with cavers for its ability to support networks of passages.
LIMESTONE
Limestone is a sedimentary rock composed largely of the mineral calcite (calcium carbonate: CaCO3). The deposition of limestone strata is often a by-product and indicator of biological activity in the geologic record. Calcium (along with nitrogen, phosphorus, and potassium) is a key mineral to plant nutrition: soils overlying limestone bedrock tend to be pre-fertilized with calcium. Limestone is an important stone for masonry and architecture, vying with only granite and sandstone to be the most commonly used architectural stone. Limestone is a key ingredient of quicklime, mortar, cement, and concrete. The solubility of limestone in water and weak acid solutions leads to important phenomena. Regions overlying limestone bedrock tend to have fewer visible groundwater sources (ponds and streams), as surface water easily drains downward through cracks in the limestone. While draining, water slowly (over thousands or millions of years) enlarges these cracks; dissolving the calcium-carbonate and carrying it away in solution. Most well-known natural cave systems are through limestone bedrock.
To log the cache please answer the following questions
1) Estimate the height of the pot from the top of where the water would flow to the floor
2) From which period is Limestone from
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