Which Of The Characteristics Of Sedimentary Rocks Deals With The Grains Being The Same Size?

Rounding - During the transportation process, grains may be reduced in size due to abrasion.  Random abrasion results in the eventual rounding off of the sharp corners and edges of grains.  Thus, rounding of grains gives us clues to the amount of time a sediment has been in the transportation cycle.  Rounding is classified on relative terms as well.

Sediment Maturity

Sediment Maturity refers to the length of time that the sediment has been in the sedimentary cycle.   Texturally mature sediment is sediment that is well rounded, (as rounding increases with ship distance and time) and well sorted (as sorting gets ameliorate as larger clasts are left behind and smaller clasts are carried abroad.  Because the weathering processes continues during sediment transport, mineral grains that are unstable about the surface get less common equally the distance of transport or fourth dimension in the bike increases.  Thus compositionally mature sediment is equanimous of merely the most stable minerals.

For example a poorly sediment containing glassy angular volcanic fragments, olivine crystals and plagioclase is texturally immature because the fragments are angular, indicating they have not been transported very far and the sediment is poorly sorted, indicating that little time has been involved in separating larger fragments from smaller fragments. It is compositionally immature because it contains unstable glass along with minerals that are non very stable near the surface - olivine and plagioclase.

On the other paw a well sorted beach sand consisting mainly of well rounded quartz grains is texturally mature because the grains are rounded, indicating a long time in the transportation cycle, and the sediment is well sorted, as well indicative of the long fourth dimension required to divide the coarser grained fabric and finer grained fabric from the sand.  The beach sand is compositionally mature because information technology is made upwardly simply of quartz which is very stable at the earth's surface.

Types of Clastic Sedimentary Rocks

We next look at various clastic sedimentary rocks that result from lithification of sediment.

Conglomerates and Breccias

Conglomerate and Breccia are rocks that comprise an abundance of coarse grained clasts (pebbles, cobbles, or boulders). In a conglomerate, the coarse grained clasts are well rounded, indicating that they spent considerable time in the transportation process and were ultimately deposited in a high energy surroundings capable of conveying the large clasts. In a breccia, the coarse grained clasts are very angular, indicating the the clasts spent little fourth dimension in the transportation cycle.

Sandstones

A Sandstone is fabricated of sand-sized particles and forms in many unlike depositional settings.
Texture and composition permit historic interpretation of the ship and depositional cycle and sometimes allows determination of the source. Quartz is, by far, the dominant mineral in sandstones. Nonetheless at that place are other varieties.  A Quartz arenite – is nearly 100% quartz grains.   An Arkose contains abundant feldspar.  In a lithic sandstone, the grains are by and large small rock fragments.  A Wacke is a sandstone that contains more than 15% mud (silt and clay sized grains).. Sandstones are one of the nearly common types of sedimentary rocks.

Mudrocks

Mudrocks are made of fine grained clasts (silt and clay sized) .  A siltstone is one diversity that consists of silt-sized fragments.  A shale is composed of clay sized particles and is a rock that tends to interruption into thin apartment fragments (See effigy 7.6e in your text).  A mudstone is similar to a shale, just does not break into thin flat fragments. Organic-rich shales are the source of petroleum.

Fine grained clastics are deposited in not-agitated h2o, at-home water, where there is little energy to continue to ship the modest grains.   Thus mudrocks course in deep water ocean basins and lakes.

Which Of The Characteristics Of Sedimentary Rocks Deals With The Grains Being The Same Size?,

Source: https://www.tulane.edu/~sanelson/eens1110/sedrx.htm

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