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https://wserv3.esc.cam.ac.uk/p1acollections/files/original/3a7bddff2255cc7a7dcc663122d87c71.jpg
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Physical Object
An inanimate, three-dimensional object or substance. Note that digital representations of, or surrogates for, these objects should use Moving Image, Still Image, Text or one of the other types.
Dublin Core
The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/.
Title
A name given to the resource
<h2><strong>L351<br /></strong></h2>
<h2>Limestone, mudstone, micrite, chalk</h2>
Subject
The topic of the resource
<h3>Age</h3>
<div class="element-text">Upper Cretaceous<br /><h3>Location</h3>
<div class="element-text">Melbourn, Cambridge</div>
</div>
Description
An account of the resource
<div class="element">
<h3>Hand Specimen</h3>
<div class="element-text">This white rock is virtually pure carbonate. It fizzes with acid. It is fine-grained and poorly cemented, making it soft and low density. It is commonly known as ‘chalk’.</div>
</div>
<div class="element">
<h3>Thin-section</h3>
<div class="element-text">
<p>Very uniform<span> </span><a href="/p1acollections/items/show/184">cryptocrystalline</a><span> </span>carbonate.<span> </span><br />Rare larger calcite crystals <0.5mm.</p>
</div>
</div>
<div class="element">
<h3>Rock History</h3>
<div class="element-text">Very fine-grained, so deposited in a very low energy environment.<span> </span><br />Such fine carbonate could have been produced in one of two ways:<br />1. Tests of calcitic plankton.<span> </span><br />2. Very finely ground shell fragments. Currents alone could not grind the shells this finely. This would require bioerosion – e.g. fish ingesting organisms with carbonate shells, and grinding the carbonate to a fine powder.</div>
</div>
<div class="element"></div>
<div class="element"></div>
<div class="element">
<h3>Rock Name</h3>
<div class="element-text">limestone<br />mustone<br />micrite<br />chalk</div>
</div>
low energy
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https://wserv3.esc.cam.ac.uk/p1acollections/files/original/525a241f1ce2f94ad242f5ec092f3c76.jpg
cde1d2a26fd2c6910cebfd1899914898
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https://wserv3.esc.cam.ac.uk/p1acollections/files/original/d2711c16055d4ee6c63aeb3d711fcc80.jpg
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https://wserv3.esc.cam.ac.uk/p1acollections/files/original/6ed13a674224bdc3c93b262cc6e97792.jpg
a7687b21c3602304b9ca9de2153202a4
https://wserv3.esc.cam.ac.uk/p1acollections/files/original/0b64b5226c627127a81eb64a3ee7a171.jpg
e32098b5ba06e5cd80f55eaefc43cf8b
https://wserv3.esc.cam.ac.uk/p1acollections/files/original/30f248264c6c30136e90aa83eac8eeef.jpg
9fca7631e1dbb5a6faa2dc37bd104852
Physical Object
An inanimate, three-dimensional object or substance. Note that digital representations of, or surrogates for, these objects should use Moving Image, Still Image, Text or one of the other types.
Dublin Core
The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/.
Title
A name given to the resource
<h2><strong>L350<br /></strong></h2>
<h2>Limestone, argillaceous</h2>
Subject
The topic of the resource
<h3>Age</h3>
<div class="element-text">
<p>Jurassic</p>
<h3>Location</h3>
<div class="element-text">
<p>Purbeck<br />Near Salisbury</p>
</div>
</div>
Description
An account of the resource
<div class="element">
<h3>Hand Specimen</h3>
<div class="element-text">
<p>Pale yellow-grey mudstone containing the fossil remains of a<span> </span><span>small arthropod with a segmented exoskeleton.</span><span> </span><br />The rock is banded and shows some surface discolouration due to weathering.<br />Rock fizzes with acid, so contains carbonate.<span> </span><br />This is a soft, though well consolidated limestone (the surface has been scratched).</p>
</div>
</div>
<div class="element">
<h3>Thin-section</h3>
<div class="element-text">
<p>Moving across the slide, perpendicular to the laminations, there are alternations (gradual transitions) between calcareous mudstone and<span> </span><a href="/p1acollections/items/show/176">argillaceous</a><span> </span>limestone. One band is rich in angular quartz grains (0.1 to 0.2 mm), and contains carbonate shell fragments.</p>
<p>Calcite mudstone – fine-grained mosaic of calcite, small proportion of transparent brown impurity and a few small grains of quartz.</p>
<p>Argillaceous limestone – even finer grained calcite mosaic, more abundant brown material (probably organic) than in the calcite mudstone.</p>
</div>
</div>
<div class="element">
<h3>Rock History</h3>
<div class="element-text">Low energy, aqueous environment.</div>
</div>
<div class="element">
<h3>Advanced Notes</h3>
<div class="element-text">The fossil remains are those of Archaeoniscus, a small crustacean (which belongs to the arthropods), of supposed freshwater origin. With this extra knowledge it may be inferred that the rock was deposited in fresh water.</div>
</div>
<div class="element"></div>
<div class="element"></div>
<div class="element">
<h3>Rock Name</h3>
<div class="element-text">argillaceous limestone</div>
</div>
aqueous
arthropod
fossil
low energy
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https://wserv3.esc.cam.ac.uk/p1acollections/files/original/2104f9a268fa0c07974391c7e5b42537.jpg
22683b5b280f6f7e52b127fa96a1c1b3
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https://wserv3.esc.cam.ac.uk/p1acollections/files/original/40665952add448e60dd592fd440b8865.jpg
7b6d78f1fce43703a587baebadc97de2
https://wserv3.esc.cam.ac.uk/p1acollections/files/original/5d38ba3667c7dc71e02797f7fd019b47.jpg
fa6341537d67035838ad15b76a87a4ec
Physical Object
An inanimate, three-dimensional object or substance. Note that digital representations of, or surrogates for, these objects should use Moving Image, Still Image, Text or one of the other types.
Dublin Core
The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/.
Title
A name given to the resource
<h2><strong>L341<br /></strong></h2>
<h2>Mudstone, calcareous</h2>
Subject
The topic of the resource
<h3>Age</h3>
<div class="element-text">
<p>Lower Carboniferous</p>
<h3>Location</h3>
<div class="element-text">
<p>Millstone Grit Series<br />Bowland, West Yorkshire</p>
</div>
</div>
Description
An account of the resource
<div class="element">
<h3>Hand Specimen</h3>
<div class="element-text">
<p>Very dark grey to black mudstone.<span> </span><br />Faint, fine-scale laminations visible on cut surface.<span> </span><br />Not<span> </span><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/196">fissile</a><span> </span>- does not readily split along bedding planes.<br />Contains fossils and fossil imprints.<span> </span><br />Some glinting flakes of mica.<span> </span><br />This rock fizzes gently with acid, indicating that it contains some carbonate.<span> </span><br />Weathered to light brown-grey in places.</p>
</div>
</div>
<div class="element">
<h3>Thin-section</h3>
<div class="element-text">Laminations are very clear when the thin-section is held up to the light. They are mainly planar, but some wrap around lighter regions in the rock.<br /><br />Under the microscope, the rock is brown, with fine dark brown streaks, laminated.<br />Mainly carbonate, some white mica, rare quartz.<br />Bioclasts, mainly along bedding surfaces, probably gastropods and bivalves. Some of the shells have been dissolved. The spaces left have been filled by secondary calcite.<br />Sparry carbonate cement.</div>
</div>
<div class="element">
<h3>Rock History</h3>
<div class="element-text">
<p>Fine-grained, so formed in a very low energy environment.<span> </span><br />Shells are too large to have been swept in by such low energy currents, so the shells are in life position.<span> </span><br />If the shells are indeed gastropods and bivalves the rock could be marine or non-marine. The presence of brachiopods<span> </span><em>would</em><span> </span>indicate a marine environment.</p>
</div>
</div>
<div class="element"></div>
<div class="element"></div>
<div class="element">
<h3>Rock Name</h3>
<div class="element-text">calcareous mudstone</div>
</div>
lamination
low energy