The geology of the area around Lampeter, Llangybi and Llanfair Clydogau

Sheppard, T. Huw. 2004 The geology of the area around Lampeter, Llangybi and Llanfair Clydogau. Nottingham, UK, British Geological Survey, 24pp. (IR/04/064) (Unpublished)

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The country around Lampeter, Llangybi and Llanfair Clydogau comprises late Ordovician Ashgill to Silurian Llandovery-age bedrock overlain by a widely distributed cover of superficial deposits. The bedrock strata largely comprises sandstones, siltstones and mudstones deposited by turbiditic flows in the deep waters of the Welsh Basin. The major units recognized are the Yr Allt Formation, comprising dark pelagic mudstones and disturbed or dewatered sandstones, the Mottled Mudstone Member of the Cwmere Formation, the sandstone-dominant Rhyddlan Formation, the mudstone-dominant Clarewen Group, the rhythmitic Devil’s Bridge Formation, the mudrock-dominant Blaen Myherin Mudstones Formation and the generally coarse-grained rocks of the Cwmystwyth Grits Group. Outliers of the Borth Mudstone Formation are also recorded. The bedrock is deformed by a series of anastamosing faults which trend south-west to north-east. Major faults include the Rhysgog Fault, the Teifi Escarpment Fault, and the Falcondale Lake Fault. Fold axes follow the same trend, the folds dominantly having a vergence to the south-east with the eastern limbs of anticlines frequently overturned and fold closures sheared out by faults. Superficial deposits are dominated by tills, which form fans soliflucted from upland sheets down into the main river valleys of the region. Other drift deposits are largely confined to these trunk valleys. The geomorphology of the area reflects the glacial sculpting and exaggeration of bedrock structural lineaments.

Item Type: Publication - Report
Programmes: BGS Programmes > Geology and Landscape Southern
Funders/Sponsors: British Geological Survey, Wales Assembly Government
Additional Information. Not used in RCUK Gateway to Research.: This item has been internally reviewed but not externally peer-reviewed
Date made live: 09 Jan 2015 11:33 +0 (UTC)

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