GEOL 3032 Chapter : Lec18 Ch13 Siliciclastic Rocks Part 1
Document Summary
How to study sedimentary rocks? (cid:149) texture (grain size, sorting) (cid:149) structure (beds, ripples) (cid:149) mineralogy (quartz, feldspar, micas, etc. ) (cid:149) chemistry (overall composition, sio2, al2o3 ) Sedimentary rock types (cid:149) siliciclastic (cid:149) carbonate (cid:149) other chemical/biochemical. Siliciclastic sedimentary rocks (cid:149) conglomerate (>2mm) (cid:149) sandstone (1/16 to 2 mm) (cid:149) mudrock (1/256 to 1/16mm), Sandstones (cid:149) sandstones comprise 20-25% of all sedimentary rocks (cid:149) framework sand-sized silicate grains (cid:149) mineral quartz (cid:149) mineral feldspar (cid:149) accessary minerals (cid:149) rock fragments (cid:149) matrix (cid:149) Sandstones mineralogy (cid:149) framework mineralogy (quartz & feldspar) (cid:149) quartz (sio2) dominant mineral (cid:149) (cid:149) Superior hardness and chemical stability (cid:149) can survive multiple recycling. Sandstones mineralogy (cid:149) framework mineralogy (quartz & feldspar) (cid:149) feldspars (cid:149) ~10-20% and are second most abundant (cid:149) chemically less stable, more susceptible to chemical destruction during weathering and diagenesis. (cid:149) easily rounded and shattered (as compared to quartz) (cid:149)
