Geological Magazine; January 2008; v. 145; no. 1;
p. 105-147; DOI: 10.1017/S0016756807003925
© Cambridge University Press (CUP)
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Figure 16. Palaeoenvironmental model of the Tytherington reptile-bearing fissures during their Rhaetian infilling. The cross-section runs N–W to S–E and includes fissures 2, 13 and 14. The occurrence of seasonal rainfall is predicted from the presence of Euestheria minuta, the palaeolatitude, the dolomitization of the calcite layers in the Rhaetian laminated sediments and general climatic indicators in the region at the time. The vegetation cover (not shown) would be expected to be fairly dense, especially around the entrances to the fissures, as the freshwater lens that was supported by the saline waters of the Rhaetian sea would maintain fresh water very near the limestone surface. Modern islands below about 10 ha can lack a permanent freshwater lens (Whittaker, 1998), but the field relationship of local Rhaetic deposits suggest that the Tytherington paleo-island would have been much larger than this, perhaps about 700 ha.
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