Geology of Pembrokeshire

Pembrokeshire Geology Field Trip CAMBRIAN The Cambrian totters in the ara of Pembrokeshire can be divided into 3 stratigraphic ranges. These re flummox of Lower, Middle and Upper Cambrian. each(prenominal) originates from oceanic conditions, mainly of shallow marine sediments deposited on the grey ledge margin of the Welsh Basin. The Lingula Flags Formation, Menevian conclave, Solva Group and Caerfai Group wreak the Cambrian ranges of Pembrokeshire (in the order of youngest first). Caerfai Group (Lower-Cambrian) This concourse consists of Basal Conglomerate, St Nons Sandstone, Caerfai quest Shales and Caerbwdy Sandstone. The Basal Conglomerate is a inflameddish saturnine aqueous shudder that has clear joints and bedclothes planes. in that location argon large clasts that atomic number 18 hive away in the rock music which be approximately 1 20cm in diameter. These argon quartz, feldspar and rhyolite layover of time bands. The rock is classed as a conglomerate as the clasts are held in a finer matrix. Calcite mineral veins were to a fault gross on the rock face. Larger clasts were present at the poll of the rock and small clasts at the bottom f ashioning it a transgressive sequence. The Caerfai shale has a red/pink colour collectable to the charge of oxidised iron. It is a fine-grained sedimentary rock with both(prenominal) mineral veins present.

The mineral veins are approximately 3cm thick. Crystaline tuff is present through with(predicate) let on the rock, which is consolidated volcanic ash in which lechatelierites and crystal fragments predominate. The shale consists of 90 percent mud and 10 percent silt. Organisms strike outside sedimentary structures, as the rock is bioturbated. Laminations, flame structures, accuse structures and round-backed ripples were present throughout the shale. Finally, surveil fossils in the unionise of upended burrows were present running through the ash. The Caerbwdy Sandstone is present on a fault surrounded by St Nons Sandstone and Caerfai Shale. There are multiple planes of faulting and it is quite rocky to make out the bedding. The massive...If you desire to get a unspoilt essay, order it on our website: Orderessay

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