Mudstones/rocks

The age of Kuroko mineralization can be estimated from (1) K-Ar ages of igneous rocks associated with Kuroko deposits and (2) foraminiferal assemblages in mudstone directly overlying Kuroko deposits. 

Figure 1.13. Distribution of three different sub-types of the Kuroko deposits in the Hanaoka district. The top of M mudstone is also shown to visualize the structure of country rocks (Horikoshi and Shikazono, 1978).

As already noted, most epithermal Au-Ag vein-type deposits are hosted by young (late Miocene-Pliocene) volcanic rocks and by sedimentary rocks, but dominant host and country rocks for base-metal vein-type deposits are submarine sedimentary and volcanic rocks. Submarine felsic tuff, tuff breccia, dacite lava, intrusive rocks and mudstone are dominant host and country rocks of Kuroko deposits. 

Tertiary rocks are distributed widely. They are composed of alternations of sandstone, mudstone, andesitic and dacitic tuff, tuff breccia and lava. These rocks are intensively and extensively altered and are called as Green tuff. Tertiary volcanic rocks are variable in composition. Andesite, dacite and basalt are found. Quaternary volcanic rocks are dominantly andesite lava and are abundantly distributed in the northern part of the province (Fig. 1.148). 

The Nishikurosawa Formation is composed of siltstone, mudstone, conglomerate and sandstone. Siltstone and mudstone contain foraminiferal fossil such as Globorotalia birnageae, and G. denseconnexa, indicating Zone N. 9 by Blow (1969). The upper part is characterized by glauconite-bearing sedimentary rock. The total thickness is about 150 m. 

The area consists of Quaternary late Pliocene pyroclastics and sedimentary rocks. Marine mudstone and sandstone of Mesozoic-lower Tertiary Shimanto Supergroup are overlain by these rocks. Thick (more than 1,000 m) dacitic tuffs interbedded with marine sedimentary rocks of late Pliocene-early Pleistocene age occur. These rocks overlie altered andesite lava and dacitic pyroclastics of Miocene-late Pliocene (Yoshimura et al., 1988). 

Central and Eastern England is almost entirely underlain by sedimentary rocks that young from west to east. Four major geological sub-divisions are presented in Figure 1. Permian and Triassic mudstone and sandstone dominate the East Midlands and parts of Yorkshire Jurassic clays crop out within the centre of the study area and Cretaceous chalk underlies most of Central East Anglia. 

The Otway Project is using a multilevel completion with three U-tubes to sample above and below the gas-water contact of a depleted gas reservoir, while C02 is injected in a well located 300 meters downdip. The uppermost U-tube was installed just below the mudstone cap rock and is sampling predominantly supercritical CH4, while the lower two U-tubes initially produced water, but transitioned to predominantly C02 and CH4 as the gas-water contact was pushed down by the increasing volumes of C02. 

China-clay rack is a kaolinized granite made up chiefly of quartz and kaolin, with sometimes tire presence of muscovite and tourmaline. The rock crumbles easily in the lingers. China stone is 11) a partially kaolinized granite, which contains quartz, kaolin, and sometimes mica and fluorite, is harder than china-clay rock and is used as a glaze in the production ol china or (2i a fine-grained, compact mudstone or limestone found in England and Wales... 

Shales are very fine-grained sedimentary rocks consisting of 67 % or more clay-sized (<4 pm) particles. Unlike mudstones, siltstones, and claystones, shales are very laminar and fissile that is, they readily split into thin, closely spaced, and parallel layers (Boggs, 1995), 181. Along with clay minerals, shales may have abundant microscopic quartz, feldspars, pyrite, hematite, calcite, dolomite, and/or organic matter (Boggs, 1995), 178. 

Claystone A clastic nonfissile sedimentary rock composed of clay-sized particles (<0.004 mm in diameter) (compare with mudstone, shale, and siltstone). 

Shale A very fine-grained, laminar, and fissile clastic sedimentary rock consisting of 67 % or more clay-sized (<4 pm in diameter) particles (compare with claystone, mudstone, and siltstone). 

Siltstone A clastic sedimentary rock primarily consisting of. v/7/-sized particles (0.004-0.063 mm in diameter) (compare with claystone, mudstone, and shale). 

From an agricultural viewpoint the sedimentary rocks are far more important than the igneous rocks since, although they represent only 15% of the crustal volume they occur spread over the igneous basement and amount to approximately 75% of the earth s surface. The most common sedimentary rocks are shales and mudstones (80%) sandstones, conglomerates and limestones account for the remaining 20%. 

Mechanical sediments are composed of particles or grains worn from other, pre-existing rocks. They are described by composition and/or particle size (see Table 2.IS). The individual sediment grains can be made of anything, including minerals or other rocks. So technically there could be a sandstone made entirely of diamonds Shale, claystone and mudstone form from very fine particles, while other mechanical sediments are mixtures of different grain sizes. Conglomerate, for example, consists of well-rounded... 

Finer-grained sediments may form massive rocks, such as siltstone, mudstone, argillite, or claystone. If a fine-grained rock has a platy texture, it is called shale. 

Phosphorus-rich sedimentary rocks (limestones, mudstones, siltstones) Groundwater from porous rock or from karst features (limestone, dolomite and calcrete) Mainly arid F, U, Rn Irrigated agriculture Mo, Pb... 

Rankama (1957) wrote that finely divided carbon in crystalhne schists of mudstone origin is much more widespread in Precambrian rocks than previously believed. The origin of this carbon probably is organic. 

In the order of increasing pressure and temperature, the metamorphic rocks formed from the sedimentary rocks shale and/or mudstones are slate, phyllite, schist and gneiss from volcanic tuff (ash turned to rock), various types of schist and amphibolite, a dark rock containing hornblende and feldspar from sandy limestone or dolomite, marble, tremohte marble, and diopside marble the latter two being coarse-grained, impure forms of marble. 

Hydrocarbons are generated from finely disseminated organic matter in fine-grained sedimentary rocks, such as shales, mudstones and fine-grained carbonates. 

The Phosphoria Formation was deposited in a foreland basin between the Continental margin and the North American cratonic shelf. This foreland basin, which is here defined by the area of deposition of the two organic-ncarbon-rich mudstone members of the Phosphoria (fig. 1), has been named the Sublett basin (8)5 and it covers an extensive area of approximately 400,000 knr (about 700 km by 600 km). The basin has a northwest-southeast-trending axis and seems to have been deepest in central Idaho where deep-water sedimentary rocks equivalent to the Phosphoria Formation are exceptionally thick. The depth decreased toward the shelves and land areas indicated in figure 1. The deepest part of the Sublett... 

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