EARTH121 Lecture Notes - Lecture 6: Ooid, Anthracite, Microcrystalline
21 Dec 2017
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Document Summary
Sediment: broken particles due to deposition which is previously broken down from weathering and erosion. Re-crystallization: example of diagenetic change where development of more stable minerals form from less stable ones; ex. aragonite to calcium carbonate. Lithification: unconsolidated sediments are transferred into solid sedimentary rocks. Compaction: weight of overlying material compresses the deeper sediments after sediment accumulates; more compact the firmer it becomes; less pore space & loss of fluids. Pore space: the open space b/w rock particles or within rock fractures. Cementation: process where sediments are converted to sedimentary rock; chemical diagenetic change which involves precipitation of minerals among individual sediment grains; cementing materials are carried in soln by water going through pore space and filling it up over time. Calcite, silica and iron oxide are most common cements; orange-dark red means iron oxide. Some sed rx forms as solid masses of intergrown crystals rather than sep particles; some start as sep particles and form interlocking crystals.
