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Calcite cement in an ooid-rich limestone; Carmel Formation, Jurassic of Utah. Minerals bond grains of sediment together by growing around them. This process is called cementation and is a part of the rock cycle. Cementation involves ions carried in groundwater chemically precipitating to form new crystalline material between sedimentary grains ...
Microbial induced calcium carbonate precipitation has been proposed as an alternative cementation technique to improve the properties of potentially liquefiable sand. [ 1 ] [ 18 ] [ 20 ] [ 21 ] [ 22 ] The increase in shear strength, confined compressive strength, stiffness and liquefaction resistance was reported due to calcium carbonate ...
Whether the initial cementation was concentric or pervasive, there is considerable evidence that it occurred quickly and at shallow depth of burial. [45] [46] [47] [38] In many cases, there is clear evidence that the initial concretion formed around some kind of organic nucleus. [48] The origin of the carbonate-rich septaria is still debated.
The exponent has been observed near 1.3 for unconsolidated sands, and is believed to increase with cementation. Common values for this cementation exponent for consolidated sandstones are 1.8 < < 2.0. In carbonate rocks, the cementation exponent shows higher variance due to strong diagenetic affinity and complex pore structures.
Carmelo Formation (conglomerate) at Point Lobos Nagdong Formation at Sangju. Conglomerate (/ k ən ˈ ɡ l ɒ m ər ɪ t /) is a sedimentary rock made up of rounded gravel-sized pieces of rock surrounded by finer-grained sediments (such as sand, silt, or clay).
In sandstones, framework grains are often cemented by silica or carbonate. The extent of cementation is dependent on the composition of the sediment. For example, in lithic sandstones, cementation is less extensive because pore space between framework grains is filled with a muddy matrix that leaves little space for precipitation to occur.
Soil sieve nests with dry soil aggregates after removal from a laboratory drying oven. Soil aggregate stability is a measure of the ability of soil aggregates—soil particles that bind together—to resist breaking apart when exposed to external forces such as water erosion and wind erosion, shrinking and swelling processes, and tillage.
Folk's carbonate rock classification details the relative proportions of allochems in the rock and the type of matrix. The classification scheme covers most common carbonate rocks, however the more inclusive although less precise alternative, Dunham classification, may be preferred in some instances. Folk classification consists of one or two ...