Earth Sciences 1022A/B Lecture Notes - Lecture 6: Chert, Feldspar, Arkose
7 Dec 2015
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Earth sciences 1022a lecture 6 sedimentary rocks. How sediment gets deposited by various agents and turns into sedimentary rocks. They are important because they form 75% of rocks that we see on continents. Sedimentary: derived from latin sediment (meaning to settle) Part of the term diogenisis (group of chemical, biological, and physical changes that happen to sediment that turn into rock) Compaction: sediment compressed, into smaller volume, thinner o o. Cementation: minerals precipitate in pore spaces - mainly calcite, silica, iron oxides o o. Mainly settled rock fragments, clay form the weathering of plutonic rocks, and quartz. There are three main types of these rocks (and an additional fourth one) o. Shale: from settling of fine particles in quiet water - good cap rock for oil and gas. These particles rain down from a water column, and settle as mud. Over millions of years, it turns into solid rock called shale.
