24 10 264 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/f6e898cd01802fb7acdebb33ce327862.jpg 63ab96468652d4ce048e01dc652b190f https://wserv3.esc.cam.ac.uk/p1acollections/files/original/dded11a8e088fb9744260bddcb9b5015.jpg cbf87a0795d18f9b11a03ab73acf8183 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/0a7fda527a98690dcee575c19b33a611.jpg 6edb633111e026da117eb2b2b9d0ee41 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>L500<br /></strong></h2> <h2>Slate</h2> Subject The topic of the resource <h3>Age</h3> <div class="element-text"> <p>Lower Cambrian</p> <h3>Location</h3> <div class="element-text"> <p>Llanberis, North Wales</p> </div> </div> Description An account of the resource <div class="element"> <h3>Hand Specimen</h3> <div class="element-text"> <p>Very fine-grained rock with a prominent, well-developed<span> </span><a href="/p1acollections/items/show/180">cleavage</a>. The dark red-purple colour is due to<span> </span><span>iron-staining</span>. The light green smudge is a<span> </span><span>reduction spot</span>.</p> </div> </div> <div class="element"> <h3>Thin-section</h3> <div class="element-text"> <p>Mud size grains.<br />Mainly indistinguishable clay minerals.<br />Some quartz, muscovite, opaques.</p> </div> </div> <div class="element"> <h3>Rock History</h3> <div class="element-text"> <p>The protolith of this rock was a pelite (mudstone). Under low-grade, regional metamorphic conditions, crystals within the pelite were aligned, producing the slaty cleavage.</p> </div> </div> <div class="element"> <h3>Advanced Notes</h3> <div class="element-text"> <p><span>Iron staining</span><span> </span><br />Hematite(Fe₂O₃) → red (blood-red, cherry-red, brown-red) iron-staining<span> </span><br />Limonite (FeO(OH)·nH₂O) → yellow or brown iron-staining<span> </span><br />The red-purple colour of this rock is probably produced by hematite.</p> <p><span>Reduction spot</span><span> </span><br />The dark red-purple of the majority of this rock is due to the presence of iron in the 3+ oxidation state (Fe³⁺). The light green colour of the reduction spot is instead due to the presence of iron in the 2+ oxidation state (Fe²⁺). Hence,<span> </span><em>reduction</em><span> </span>of the iron ions from Fe³⁺<span> </span>to Fe²⁺<span> </span>has taken place in the reduction spot.</p> </div> </div> <div class="element"></div> <div class="element"></div> <div class="element"> <h3>Rock Name</h3> <div class="element-text">slate</div> </div> Date A point or period of time associated with an event in the lifecycle of the resource Lower Cambrian metapelite reduction https://wserv3.esc.cam.ac.uk/p1acollections/files/original/ffadc04ed9e3124d98272e135fd7da8f.jpg db59789e6e6fd0e709090ca690e32786 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/6947dd2e59661db1bf837d372feb2120.jpg 4d91339ce17b1bc0e945ae3d1d434b1c https://wserv3.esc.cam.ac.uk/p1acollections/files/original/df18c0e4e2bcbbcf532dd5fe47d3863e.jpg ca894e8b7bbf20601e7e6765893c3be6 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>L371<br /></strong></h2> <h2>Chert, bedded</h2> Subject The topic of the resource <h3>Age</h3> <div class="element-text"> <p>Early Carboniferous</p> <h3>Location</h3> <div class="element-text"> <p>Carboniferous Limestone<br />Skyes, Bowland, Yorkshire</p> </div> </div> Description An account of the resource <div class="element"> <h3>Hand Specimen</h3> <div class="element-text"> <p>Two rock types, with an irregular contact between them.</p> <p>1 – Very dark brown,<span> </span><a href="/p1acollections/items/show/227">microcrystalline</a><span> </span>rock. This fizzes with acid. It is a limestone.</p> <p>2 – Grey and black, intermingled, microcrystalline silica. Brittle and well jointed. Some medium grained white quartz vein material.</p> </div> </div> <div class="element"> <h3>Thin-section</h3> <div class="element-text"> <p>1 – A fine to medium grained mosaic of calcite with cross-sections of foraminifera and other shell material.</p> <p>2 – Microcrystalline silica, quartz forming a uniform mosaic texture, slightly coarser in some places than others. Scattered with grains of calcite and<span> </span><span>opaques</span>, both typically 0.1 mm across. Criss-crossing calcite veins, some dark red-brown discolouration.</p> </div> </div> <div class="element"> <h3>Rock History</h3> <div class="element-text">This rock has a complicated history. In essence the chert (2) has replaced the limestone (1). The irregular patches of limestone within the chert are probably relics of pre-existing limestone, but the calcite rhombs are related to the calcite veining and therefore later than the chert. Similarly the opaques, which cut across the structure of the chert, formed later than the chert.</div> </div> <div class="element"> <h3>Advanced Notes</h3> <div class="element-text"> <p>The cubic<span> </span><a href="/p1acollections/items/show/206">form</a><span> </span>of the<span> </span><span>opaques</span><span> </span>is suggestive of pyrite, but we cannot be sure.</p> </div> </div> <div class="element"></div> <div class="element"> <h3>Rock Name</h3> <div class="element-text">bedded chert</div> </div> conchoidal microcrystalline replacement https://wserv3.esc.cam.ac.uk/p1acollections/files/original/a208f3e1a4d5b13c2f81d3ec49b5b314.jpg a620047d874c5f7b4353192625ce8f7b https://wserv3.esc.cam.ac.uk/p1acollections/files/original/e237c8cfeee6fc635fea026faf549f99.jpg 081148ca95653367a2ff3adf38dcbe74 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/b5fed400782b1050357184726a850f88.jpg 0f078f721ecc91609d3d3ea52ced6444 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>L370<br /></strong></h2> <h2>Chert, flint nodule</h2> Subject The topic of the resource <h3>Age</h3> <div class="element-text"> <p>Cretaceous</p> <h3>Location</h3> <div class="element-text"> <p>Upper Chalk, Cambridgeshire</p> </div> </div> Description An account of the resource <div class="element"> <div class="element"> <h3>Hand Specimen</h3> <div class="element-text"> <p>This rock is made up of<span> </span><a href="/p1acollections/items/show/184">cryptocrystalline</a><span> </span>silica (quartz), black to brown. Being made up of silica, it is hard and displays<span> </span><a href="/p1acollections/items/show/182">conchoidal fracture</a>.</p> <p>This is a flint nodule, which comes from a chalk bed – notice the thin shell of white chalk. Flints are irregular silica concretions characteristic of the upper Chalk.</p> </div> </div> <div class="element"> <h3>Thin-section</h3> <div class="element-text"> <p>Cryptocrystalline silica (quartz)<span> </span><br /><a href="/p1acollections/items/show/171">Amorphous</a>, not grains. Partially devitrified<span> </span><br />Uniform texture<span> </span><br />Rare larger quartz crystals</p> <p>Occasional elliptical strips of greater than average grain size probably represent cross-sections of shells now replaced by silica.</p> </div> </div> <div class="element"> <h3>Rock History</h3> <div class="element-text"> <p>Flint nodules are produced by the digenetic<span> </span><a href="/p1acollections/items/show/248">replacement</a><span> </span>of chalk. A silica gel, formed by the dissolution of sponge spicules, precipitates silica in nodules. Chert deposits are more common in organic-rich regions of the chalk, and there is a hypothesis that the silica precipitates in burrows.</p> </div> </div> <div class="element"></div> <div class="element"></div> <div class="element"> <h3>Rock Name</h3> <div class="element-text">chert<br />flint nodule</div> </div> </div> diagenesis sponge https://wserv3.esc.cam.ac.uk/p1acollections/files/original/cd0887d0796095eddd0dc41b3db1e1dc.jpg 8e4939397352f33d03d66ea841e757b9 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/8299c6ff44bb9caa79c67702c74cb2c5.jpg 656cbb57478c378eff753a41a68050dd https://wserv3.esc.cam.ac.uk/p1acollections/files/original/6c4bb513fcf8f9af3b246a26e3b77ab6.jpg 4fcf5efddbe66c008e446fbb8eee5448 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>L361<br /></strong></h2> <h2>Oolitic ironstone</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>Inferior oolite<br />Thrapston, Northamptonshire</p> </div> </div> Description An account of the resource <div class="element"> <h3>Hand Specimen</h3> <div class="element-text"> <p>This rock is made up of light grey sub-spherical<span> </span><a href="/p1acollections/items/show/230">ooids</a>.<span> </span><br />Fine to medium sand grain size.<span> </span><br />A few lithic/biogenic fragments.<span> </span><br />Dark grey cement.<span> </span><br />Small hair-line white veins run through this rock.</p> </div> </div> <div class="element"> <h3>Thin-section</h3> <div class="element-text"> <p>Ooids made up of a greenish sheet silicate mineral called<span> </span><span>chamosite</span>, partially altered to<span> </span><span>siderite</span><span> </span>and<span> </span><span>limonite</span>. Concentric structure. Central cores of fine-grained material.</p> <p>A layer formed of brown, transparent crystals, sometimes with rhombic cross-sections surrounds the peripheries of many ooids. This is<span> </span><span>siderite</span>.</p> <p>Some quartz grains.</p> <p>The cement is made up mainly of carbonate (<span>siderite</span>), with a small quantity of a green-brown material, which has anomalous interference colours.</p> <p>This rock is a grainstone (Dunham naming system) or oo-sparite (Folk naming system).</p> </div> </div> <div class="element"> <h3>Rock History</h3> <div class="element-text">Deposited in a moderate energy, marine energy.</div> </div> <div class="element"> <h3>Advanced Notes</h3> <div class="element-text"> <p><span>Chamosite</span><span> </span>is an Fe-rich chlorite, often greenish. It is a sheet silicate.</p> <p><span>Limonite</span><span> </span>is amorphous or cryptocrystalline, and yellow-brown to brownish-black in colour. It comprises hydrated iron (III) oxides with a range of compositions.</p> <p><span>Siderite</span><span> </span>is iron carbonate (FeCO₃). It is often difficult to distinguish siderite from calcite and dolomite optically.</p> </div> </div> <div class="element"></div> <div class="element"></div> <div class="element"> <h3>Rock Name</h3> <div class="element-text">oolitic ironstone<br />oolite</div> </div> marine moderate energy ooid https://wserv3.esc.cam.ac.uk/p1acollections/files/original/7291e86760176da9f97a80315239a4a3.jpg 641053d2ac38252bfbfcd017132bdd7b https://wserv3.esc.cam.ac.uk/p1acollections/files/original/0c9848580f19fe22471cc47ec1ac97a1.jpg 17e9b388b24cd606bbd2c17dac3f4921 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/8401006c872fbdb728f5a6be5b55c412.jpg 2ea13c93c494e2bd17ea8d20b0c4ceed 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>L354<br /></strong></h2> <h2>Limestone, shelly</h2> Subject The topic of the resource <h3>Age</h3> <div class="element-text">Middle Jurassic<br /><h3>Location</h3> <div class="element-text">Forest Marble<br />Near Weymouth</div> </div> Description An account of the resource <div class="element"> <h3>Hand Specimen</h3> <div class="element-text">This rock is made up of well cemented bioclasts. The bioclasts (mainly shell fragments) are poorly sorted, ranging from &lt;1mm up to a few 10s of mm.<span> </span><br />Fine-grained cement fizzes with acid, indicating that it is carbonate. It has weathered to a pale yellow-grey.</div> </div> <div class="element"> <h3>Thin-section</h3> <div class="element-text">Carbonate fossil fragment in a carbonate cement (sparite). The laminated structure of the shells is visible in places.<span> </span><br />Cement contains some hematite (brown regions).<span> </span><br />There are a few epidote grains and some opaque areas.<br />This is a rudstone (Dunham naming system) or biosparite (Folk naming system).</div> </div> <div class="element"> <h3>Rock History</h3> <div class="element-text">The shells are not in life position – they have been transported.<span> </span><br />Deposited in moderate to high energy environment.<span> </span></div> </div> <div class="element"></div> <div class="element"></div> <div class="element"> <h3>Rock Name</h3> <div class="element-text">shelly limestone</div> </div> bioclastic biosparite high energy https://wserv3.esc.cam.ac.uk/p1acollections/files/original/a8ebb735837d9956e575a80998326557.jpg fc76384c38e5cf0159e6f5d5cf29780a https://wserv3.esc.cam.ac.uk/p1acollections/files/original/095bede3faf77aba6437db18c5ea8c3d.jpg 081910d957d523c1ed6d58000288e9fd https://wserv3.esc.cam.ac.uk/p1acollections/files/original/264fccd8895162f27b1c45f528f49833.jpg 7c6514d9b3c13ca2538b98b74b1faae5 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>L353<br /></strong></h2> <h2>Limestone, oolitic, packstone</h2> Subject The topic of the resource <h3>Age</h3> <div class="element-text"> <p>Upper Jurasssic</p> <h3>Location</h3> <div class="element-text"> <p>Corallian, Weymouth</p> </div> </div> Description An account of the resource <div class="element"> <div class="element"> <h3>Hand Specimen</h3> <div class="element-text"> <p>Grey-buff colour rock made up of<span> </span><a href="/p1acollections/items/show/230">ooids</a>, mainly medium grained and spherical.<span> </span><br />Some shell and lithic fragments.<span> </span><br />Well compacted and cemented by calcite, which fizzes with acid.</p> </div> </div> <div class="element"> <h3>Thin-section</h3> <div class="element-text">The ooids look brown. They are made up of calcite grains much smaller than the thickness of the slide (which is 30μm). These small grains refract, diffract and reflect light travelling through the slide producing the brown appearance of the ooids. Most of the ooids were formed around a central nucleus (usually an angular quartz grain, sometimes a shell fragment).The calcite forming the ooids is mostly too fine-grained to distinguish individual crystals.<span> </span><br />Only some of the ooids appear to be touching in thin-section, but taking account of their 3D relationships, the rock is probably clast supported.<br />Rounded shell fragments including aragonite bivalve moulds and silicified brachiopods.<span> </span><br />Occasional quartz grains.<br />Clean, colourless calcite cement.<br /><br />This is a packstone (Dunham naming system) or oo-biosparite (Folk naming system).</div> </div> <div class="element"> <h3>Rock History</h3> <div class="element-text">Deposited in a moderate energy, marine environment.</div> </div> <div class="element"></div> <div class="element"></div> <div class="element"> <h3>Rock Name</h3> <div class="element-text">oolitic limestone<br />packstone<br />oo-biosparite<br />oolite</div> </div> </div> marine moderate energy https://wserv3.esc.cam.ac.uk/p1acollections/files/original/5eeedf6cef3678833d999dbc34eb9f04.jpg fb5db93c68e1a218f556059b62c702b8 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/e9913f8533b76352e685256738d581d0.jpg 6b88bde6e4c3b3bae18f5133f63d0c5f https://wserv3.esc.cam.ac.uk/p1acollections/files/original/8bc15411d7f18659c4c19c47f51aaed0.jpg 323e29f678447040745639d5408595c0 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>L352<br /></strong></h2> <h2>Limestone, dolomitic</h2> Subject The topic of the resource <h3>Specimen Age</h3> <div class="element-text"> <p>Permian</p> <h3>Location</h3> <div class="element-text"> <p>Sunderland</p> </div> </div> Description An account of the resource <div class="element"> <div class="element"> <h3>Hand Specimen</h3> <div class="element-text"> <p>Pale buff coloured, crystalline rock.<span> </span><br />Numerous cavities, thought to have been formed by shrinkage during<span> </span><a href="/p1acollections/items/show/170">alteration</a><span> </span>of primary calcite (CaCO₃) to secondary dolomite (CaMg[CO₃]₂). There is a weak reaction to dilute acid, which suggests that there may be some calcite remaining.<span> </span><br />Colourless crystalline material infilling holes.</p> </div> </div> <div class="element"> <h3>Thin-section</h3> <div class="element-text">Almost entirely made up of very fine grains of dolomite (which tends to show more rhomb shaped crystals than calcite).<br />Irregular cavities into which well-developed rhomb crystals of dolomite have grown. Note that one should distinguish between the cavities in the rock (with rhombs of dolomite) and those due to the preparation of the sections.</div> </div> <div class="element"> <h3>Rock History</h3> <div class="element-text">It is thought that this rock was initially made-up of calcite. The alteration from calcite to dolomite, with its consequent increase in specific gravity and decrease in volume, accounts for the formation of the cavities.</div> </div> <div class="element"></div> <div class="element"></div> <div class="element"> <h3>Rock Name</h3> <div class="element-text">dolmitic limestone<br />dolomite<br />magnesian limestone</div> </div> </div> alteration https://wserv3.esc.cam.ac.uk/p1acollections/files/original/3a7bddff2255cc7a7dcc663122d87c71.jpg a3fb4b72c7044bc0cc533c326bf8b5a3 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/c4615e800cf68c2a0bbb58c4b83b8b72.jpg 421e357b5d8169f7569a910104c89132 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/894017ef7943543b9cb8f27555b5996b.jpg 2574889d189e18e9073f829a0ea8e2ab 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 &lt;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 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/525a241f1ce2f94ad242f5ec092f3c76.jpg cde1d2a26fd2c6910cebfd1899914898 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/689c24718bf255b4704657c58dcc5233.jpg 3c71ef349643240db6d58e500485eba3 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/d2711c16055d4ee6c63aeb3d711fcc80.jpg 166a017771d3f3e68a9511e71f97d465 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/bc9f99fb9db7ea2ca968f0e6a1eabe25.jpg 8873cd3567483ef43a551eb10aaafbca 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 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/2104f9a268fa0c07974391c7e5b42537.jpg 22683b5b280f6f7e52b127fa96a1c1b3 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/0d1b0055e9ce25409830de31afcc15e7.jpg d8ddf286bf56cf0325e01f494e811bac https://wserv3.esc.cam.ac.uk/p1acollections/files/original/f6f992805d2607a8fd41a0fc8b12aa41.jpg 5082c93831a75300cc00734390354bc0 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