ERTH 209-02 Earth Sedimentary Rocks Part 2 Fall 2024 PDF
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Uploaded by HealthfulGeometry
University of Calgary
2024
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Summary
This document details sedimentary rocks, specifically focusing on lithification processes and classifications based on grain size, with examples like conglomerate, sandstone, and mudstone. Diagrams and tables explain the characteristics of different types of sedimentary rocks.
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ERTH 209-02 EARTH Fall 2024 Sedimentary rocks_part 2 Lithification Lithification is the conversion of sediment into rock. The following processes may be involved: Compaction: reduction in volume of sediments resulting from weight of newly deposited sediments above....
ERTH 209-02 EARTH Fall 2024 Sedimentary rocks_part 2 Lithification Lithification is the conversion of sediment into rock. The following processes may be involved: Compaction: reduction in volume of sediments resulting from weight of newly deposited sediments above. Cementation: precipitated minerals bind together the grains of a sediment, converting it into a sedimentary rock. Recrystallization: formation of new crystalline mineral grains in a rock. Depositional environment Clastic sedimentary rock classifications There are more than 50 classifications of the clastic sedimentary rocks. Classification according to grain size; Classification according to particle roundness; Classification according to particle sphericity; Classification according to sorting; Classification according to presence/absence of the matrix. Classification according to grain size There are three major categories: GRAVEL; SAND; MUD. Gravel According to the size of the particles: Boulder > 256 mm; Cobble 64 – 256 mm; Pebble 4 – 64 mm; Granule 2 -4 mm. Clastic rocks: breccia (angular fragments) and conglomerates (rounded fragments). Conglomerate (1) and breccia (2) Sand According to the size of the particles: coarse 0.5 – 2 mm; medium 0.25 – 0.5 mm; fine 0. 125 – 0.25 mm; very fine 0.063-0.125 mm. Sandstone (detrital rock consisting primarily of sand held together by a cementing agent). Sand class Microconglomerate Coarse sandstone Fine sandstone Mud According to the size of the particles: Silt 0.004 – 0.063 mm; Clay < 0.004 mm. The rocks are: mudstone (silt or clay, not layered), siltstone, claystone and shale (silt or clay, layered). Mud class It is layered so it is siltstone, claystone or shale.
