Unit5 Microfossils 0.0 / 5 ? GeologyOstracodsForaminiferaConodontsRadiolariaPollen & SporesA2/A-levelOCR Created by: Gabby-ACreated on: 19-05-16 13:35 Spores & Pollen Composed of sporopollenin Size ranges between 10 - 200 microns in diameter Produced in plants that either lived on land or in a marginal shallow water environment Spores Produced by plants (such as mosses and ferns) Earliest preserved terrestrial plants are from the late silurian Though spores were found earlier in the ordovician Pollen Product of seed bearing plants Earliest pollen producing plants were from the late devonian 1 of 5 Radiolaria Planktonic mode of life Size ranges from 30µm to 2mm Occupied niches near the surface to hundreds of metres deep Have a rich diversity of delicate silica skeletons Therefore preserved at depths below the carbon compensation depth (ccd) and are easy to recover Have been around since the late precambrian Great stratigraphic tool Great palaeo-envirionmental tool 2 of 5 Conodonts - Extinct The teeth of a soft-bodied creature thought to be similar to a hagfish Composed of calcium phosphate Size ranges from 200µm to 5mm Earliest are found in precambrian rocks Died out in the permo-triassic extinction event 3 of 5 Ostracods Complex crustaceans, related to trilobites and crabs They have similar morphological features to bivalves: Two valves A hinge with teeth and sockets aductor muscles to close the valves Usually less than 2mm in length Shell (carapace) made of chitin or calcium carbonate Range from cambrian to the present day Mainly a benthonic mode of life Good palaeo-environmental indicators As they have different forms in waters of the entire range of salinity 4 of 5 Foraminifera Mostly simple single-celled creatures with a protective shell (test) Composed of calcium carbonate They range in size from 1µm to around 110mm Modern foraminifera capture their food using thread-like structures Which extend through holes in the test Most forms are benthonic (sessile or vagrant) But a few are planktonic (such as globigerina) They range from early cambrian to the present day Although planktonic forms were not common untill the mesozoic Excellent stratigraphic tool (used extensively in the oil industry) 5 of 5
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