19 10 264 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/a2dca59737eb2c3d29333e3962ec3b2c.png 3ba4d8fd1792ea4b1f901fd6231abc77 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/ce333ef152dcc34b5bb15d92b0d8a85e.png b659a0b06a3b027e8a5add24e3407d70 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 Fossils Description An account of the resource <p>Welcome to the fossils section of the website. This is designed to help you learn the different characteristics of each major fossil group so that you are able to distinguish between them.</p> <p>First year students, please refer to the specimens housed in the first year teaching laboratory. There is no substitute for handling the specimens themselves; this website is just an accessory to help you along the way.</p> <p>Animals occupy different environments, have different life habits and lived through different periods in geological time. It is good to be aware of these differences in lifestyle and timing, within and between phyla, classes, orders and families.</p> 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>Graptolite</h2> Description An account of the resource <h2>Taxonomy</h2> <p>Phylum: Hemichordata</p> <p>Class: Graptolithina</p> <h2>Diagnostic features</h2> <p>Stick-shape (often branched)</p> <p>One or both edges may appear serrated</p> <p>Thecae</p> <p>Rhabdosome</p> <p>Stipes</p> <h2>Stratigraphic range</h2> <p>Cambrian to Carboniferous (Dendroids)</p> <p>Ordovician to Middle Devonian (Graptoloids)</p> <h2>Way of life</h2> <p>Colonial</p> <p>Planktonic (mostly, although some dendroids were sessile benthonic)</p> <p>Suspension feeders</p> <h2>Typical preservation</h2> <p>Flattened along bedding planes, normally in shales</p> <p>Carbonization or pyritization of the animal</p> <p><a href="https://www.digitalatlasofancientlife.org/learn/nature-fossil-record/types-of-fossil-preservation/">Learn about types of preservation</a></p> <h2>Advanced notes</h2> <p>Graptolites, because of their abundance and variation in morphology are very good index fossils. At a very basic level the angle between the stipes and number of stipes can be used to give a rough age for the fossil, with Early Ordovician graptolites having two stipes with the 'sawtooth' facing each other (pendent), later Ordovician graptolites having a more open oblique or reflex angle between the 'sawtooth' faces, and Siluran graptolites having the 'sawtooth' faces back to back (scandent) or having lost one stipe altogether (for example monograptids).</p> <h2>Specimens</h2> <p><a href="/p1acollections/exhibits/show/graptolites">Browse graptolites</a></p> colonial jaw stick 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/. Description An account of the resource This glossary describes a number of geological terms with which the 1A students should become familiar.<span> It is by no means an exhaustive list, but is aimed to help you understand the material within the first year course.</span> Title A name given to the resource Glossary 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>Groundmass</h2> Subject The topic of the resource Rapidly cooled magmas are largely made-up of many tiny crystals. These make up the groundmass. https://wserv3.esc.cam.ac.uk/p1acollections/files/original/8f405f64623521e108d34b8ac6e9ef2b.jpg ad850366799f011921773473d420f89e https://wserv3.esc.cam.ac.uk/p1acollections/files/original/1a88452109e13e7129392147bb5e03ad.jpg c6e415aec066d49603afe47dc94cf415 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/050bc4eadcb75a778ba3577c7c3d4bd9.jpg e9a8dfa44409f9b288ff980f4b434275 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>Gypsum</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text"> <p>CaSO₄∙2H₂0</p> </div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Non-silicate</p> </div> </div> <div class="element"> <h3>Crystal System</h3> <div class="element-text"> <p><em>Crystal system:</em><span> </span>monoclinic (+)</p> </div> </div> <div class="element"> <h3>Physical Properties</h3> <div class="element-text"> <p><em>Colour in hand specimen:</em><span> </span>usually white or colourless<br /><em>Cleavage:</em><span> </span>rhombohedral, one perfect, two distinct<br /><em>Hardness:</em><span> </span>2</p> </div> </div> <div class="element"> <h3>Mineral Specimens</h3> <div class="element-text"> <p class="NoSpacing"><strong><span>M530 Gypsum</span></strong><span> </span><br class="NoSpacing" /><strong>Shotover, Oxford</strong><strong><span> </span></strong><br class="NoSpacing" />Single euhedral crystal<span> </span><br class="NoSpacing" />Colourless, transparent<span> </span><br class="NoSpacing" />Hardness 2; Soft – scratched with your fingernail</p> <p class="NoSpacing"><strong><span>M531 Massive gypsum</span></strong><span> </span><br class="NoSpacing" /><strong>Nottingham</strong><strong></strong><span> </span><br class="NoSpacing" />Fibrous habit – many fine crystals<span> </span><br class="NoSpacing" />White-cream colour<span> </span><br class="NoSpacing" />Translucent<span> </span><br class="NoSpacing" />Pearly lustre</p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">gypsum</div> </div> fingernail sulfur 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/. Description An account of the resource This glossary describes a number of geological terms with which the 1A students should become familiar.<span> It is by no means an exhaustive list, but is aimed to help you understand the material within the first year course.</span> Title A name given to the resource Glossary 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>Habit (or form)</h2> Subject The topic of the resource The three dimensional shape of a crystal. The crystal structure of a mineral influences the characteristic habit(s) which it displays. For example, biotite mica tends to display a platy or tabular habit because its crystal lattice is made up of sheets. https://wserv3.esc.cam.ac.uk/p1acollections/files/original/807cc48ab93cd8cad76b2bb06a578b0a.jpg 6aac8ea3562c60bfeff5bb94c7f347ff 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>Halite</h2> Subject The topic of the resource <span>This mineral is commonly known as rock salt.</span> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text"> <p>NaCl</p> </div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Non-silicate</p> </div> </div> <div class="element"> <h3>Crystal System</h3> <div class="element-text"> <p><em>Crystal system:</em><span> </span>cubic</p> </div> </div> <div class="element"> <h3>Physical Properties</h3> <div class="element-text"> <p><em>Colour in hand specimen:</em><span> </span>colourless or white when pure, more typically orange or red due to inclusions of iron compounds, and may also be grey, yellow or blue<span> </span><br class="NoSpacing" /><em><span>Cleavage:</span></em><span> perfect cubic, three planes intersect at 90°</span><span> </span><br class="NoSpacing" /><em><span>Hardness:</span></em><span> 2.5</span></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">halite</div> </div> cubic evaporite 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/. Description An account of the resource This glossary describes a number of geological terms with which the 1A students should become familiar.<span> It is by no means an exhaustive list, but is aimed to help you understand the material within the first year course.</span> Title A name given to the resource Glossary 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>Hardness</h2> Subject The topic of the resource Hardness is measured on the Mohs scale. A hard mineral is rigid, resistant to pressure and is not easily scratched. Determining the hardness (or relative hardness) of a mineral in hand specimen can aid your identification of the mineral. https://wserv3.esc.cam.ac.uk/p1acollections/files/original/7b2be47bf331c3137fab55b54dd00400.jpg 4df92e4c361bdf836240b34aa1def201 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/a9feaa0d7b228322ef58f10eabce759a.jpg 2b6715ada6c2fb263e952153d2c695a1 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>Hematite</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text"> <p>Fe₂O₃</p> </div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Non-silicate</p> </div> </div> <div class="element"> <h3>Crystal System</h3> <div class="element-text"> <p><em>Crystal system:</em><span> </span>trigonal (-)</p> </div> </div> <div class="element"> <h3>Physical Properties</h3> <div class="element-text"> <p class="NoSpacing"><em><span>Colour in hand specimen: </span></em><span>black, steel-grey and bright to dull red</span><span> </span><br class="NoSpacing" /><em><span>Streak:</span></em><span> cherry-red</span><span> </span><br class="NoSpacing" /><em><span>Cleavage:</span></em><span> none</span><span> </span><br class="NoSpacing" /><em><span>Hardness:</span></em><span> 5-6</span></p> </div> </div> <div class="element"> <h3>Optical Properties</h3> <div class="element-text"> <p class="NoSpacing"><em><span>Colour in plane polarised light:</span></em><span> opaque; blood-red in very thin splinter</span><span> </span><br class="NoSpacing" /><em><span>Pleochroism:</span></em><span> none</span><span> </span><br class="NoSpacing" /><em><span>Relief:</span></em><span> high</span></p> </div> </div> <div class="element"> <h3>Mineral Specimens</h3> <div class="element-text"> <p class="NoSpacing"><strong><span>M500 Hematite</span></strong><span> </span><br class="NoSpacing" /><strong>Cumberland</strong><strong></strong><span> </span><br class="NoSpacing" />A concretionary mass showing concentric and radial structure<span> </span><br class="NoSpacing" />Silvery black with a red streak<span> </span><br class="NoSpacing" />Oxidised to dark brown-red in places<span> </span><br />Metallic lustre</p> </div> </div> <div class="element"> <h3>Rock Specimens</h3> <div class="element-text"> <p><a href="/p1acollections/exhibits/show/sedimentary-rocks/l310">L310 Breccia</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l311">L311 Conglomerate</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l324">L324 Sandstone, feldspathic arenite</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l326">L326 Sandstone, ferruginous arenite</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l340">L340 Mudstone</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l354">L354 Limestone, shelly</a><br /><a href="/p1acollections/exhibits/show/metamorphic-rocks/l500">L500 Slate</a></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">hematite<br />iron oxide<br />opaques</div> </div> oxidation sedimentary 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/. Description An account of the resource This glossary describes a number of geological terms with which the 1A students should become familiar.<span> It is by no means an exhaustive list, but is aimed to help you understand the material within the first year course.</span> Title A name given to the resource Glossary 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>Hypabyssal</h2> Subject The topic of the resource Hypabyssal rocks and textures are those associated with very shallow magmatic intrusions, where cooling is moderately rapid. This term is restricted to relatively small intrusive bodies centimetres to tens of metres in diameter. 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/. Description An account of the resource This glossary describes a number of geological terms with which the 1A students should become familiar.<span> It is by no means an exhaustive list, but is aimed to help you understand the material within the first year course.</span> Title A name given to the resource Glossary 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>Hypermelanic</h2> Subject The topic of the resource <span>Hypermelanic rocks have a very high colour index. That is to say that &gt;90 vol% of the rock is made up of ferromagnesian minerals.</span> 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/. Description An account of the resource This glossary describes a number of geological terms with which the 1A students should become familiar.<span> It is by no means an exhaustive list, but is aimed to help you understand the material within the first year course.</span> Title A name given to the resource Glossary 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>Inclusion</h2> Subject The topic of the resource As a crystal grows in a magma, tiny blobs of melt can become trapped in its structure. These are melt inclusions. Small crystals of other minerals can also become trapped. These are mineral inclusions. Description An account of the resource Have a look at the <strong>alkali basalt (<a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/1">L100</a>)</strong>, the <strong>porphyritic rhyolite (<a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/5">L110</a>)</strong> and the <strong>garnet schist (<a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/38">L504</a>)</strong> in the 1A Reference Series.