- sed rx are those which form by lithification of unconsolidated sediments.
- lithification is a process of compaction
Silicate clastics:
Shale: dark, quiet water, lagoon, lake, has layers (sheet structure)
Siltstone: also can't see grains, feels slightly gritty
Arkose: can see grains, near outcrop of grainite, dirty red, high feldspar content
Qtz sandstone: beach environment
Graywacke: dirty gray, a mix of stuff, formed in turbidity currents, can be fine on top and coarse on bottom.
Conglomerate: Mt. streams, rivers, round
Breccia: base of Mt. Slope, angular grains
Biogenic Sediments:
Limestones: CaCO3, fizzes when reacts with HCl
Chalk: warm, oceanic water, white, soft, made up of shells of microscopic organisms
Fossiliferrous Limestone: visible fossils, can be any color, also a warm shallow oceanic environment. Well consolidated frags well glued together.
Coquina: Formed in the surf zozne, poorly consolidated fragments loosely glued together.
Coal: black, shiny, light weight, forms in swamps, bogs.
Chemical Sedimentary Rx:
Limestone: No fossils, harder than chalk
Rock Gypsum: Evaporite, arid climate - basins, flats, out west, soft, light colored, not salty.
Rock Salt: Salty taste, evaporite
Chert: Jasper- red, flint- black, microcrystalline, deep ocean environment where CaCO3 from critters at shallow depths dissolve, but Silica precipitaties and settles to bottom of ocean.
-Sedimentary rx have several unique features:
- sorting:
- strata or beds:
- bedding planes:
- mud cracks, ripple marks, and cross-bedding
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