Cornwall Flashcards
What is the age of the Lizard Ophiolite, and where will you observe it?
The Lizard Ophiolite is ~400–370 million years old (Devonian). You will observe it at Lizard Head and Kynance Cove on Day 1.
Example sentence: The Lizard Ophiolite is a key feature of the field trip.
During which geological event was the Lizard Ophiolite emplaced onto the continental crust?
The Lizard Ophiolite was emplaced during the Variscan Orogeny, which occurred ~370–290 million years ago.
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What structural features are characteristic of chevron folds at Millook Haven and Hartland Quay?
Chevron folds exhibit sharp fold hinges, bedding-parallel faults, and flexural slip, all caused by compressional forces during the Variscan Orogeny.
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What is the tectonic significance of the Lizard Boundary Fault (LBF)?
The LBF marks the boundary between ophiolitic material and continental rocks in the Meneage melange, formed during the Variscan Orogeny.
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What geological period followed the Variscan Orogeny and saw the formation of igneous dykes at Godrevey Cove?
The Permian to Triassic period (~290–200 million years ago) saw post-Variscan rifting and the formation of igneous dykes at Godrevey Cove.
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What sedimentary structures will you observe in the Westphalian turbidites at Millook Haven and Maer Cliff?
The Westphalian turbidites (~315–305 million years ago) display sharp boundaries between sandstone and shale, with features such as chevron folding and bedding-parallel faults.
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How did Westphalian turbidites form, and during which geological period?
Westphalian turbidites formed in foreland basins from the erosion of the Variscan mountains during the Late Carboniferous (~315–305 million years ago).
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What is the age of the sedimentary formations you will observe at Kennack Sands, and how are they related to the Lizard Ophiolite?
The sedimentary formations at Kennack Sands were deposited during the Variscan Orogeny and were deformed by high-pressure metamorphism, linked to the tectonic processes of the Lizard Ophiolite.
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What environmental issue is significant at Restronguet Creek, and what period’s mining activities caused it?
Heavy metal contamination from historical mining activities (dating back to the Industrial Revolution) is a significant issue at Restronguet Creek.
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What geochemical measurements will you take at Restronguet Creek, and why are they important?
You will measure pH and redox potential (Eh) in sediment cores to assess the mobility of contaminants like heavy metals in the salt marshes.
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What is the historical significance of Upton Towans Nature Reserve, and what environmental issue will you assess there?
Upton Towans was the site of an explosives factory, and you will assess soil and water contamination from industrial activities.
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How did mining affect the estuarine sediments at Restronguet Creek, and what type of pollution is present?
Mining led to heavy metal pollution, including lead and cadmium, which accumulated in estuarine sediments and affected local ecosystems.
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What is the time range of the Variscan Orogeny, and what types of structural features does it produce?
The Variscan Orogeny occurred between ~370–290 million years ago and produced features such as chevron folds, thrust faults, and fold-and-thrust belts.
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How will you use radiometric dating techniques during the field trip?
Radiometric dating helps place field observations of rock formations into a chronological framework, particularly for events like the Variscan Orogeny.
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What types of rocks will you observe at Lizard Head and Kynance Cove on Day 1?
You will observe ultramafic lithologies such as serpentinite and gabbro, as well as basaltic dykes, all part of the Lizard Ophiolite.
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