Cretaceous

For example, the many deepwater fields located in the Gulf of Mexico are of Tertiary age and are comprised of complex sand bodies which were deposited in a deepwater turbidite sequence. The BP Prudhoe Bay sandstone reservoir in Alaska is of Triassic/ Cretaceous age and was deposited by a large shallow water fluvial-alluvial fan delta system. The Saudi Arabian Ghawar limestone reservoir is of Jurassic age and was deposited in a warm, shallow marine sea. Although these reservoirs were deposited in very different depositional environments they all contain producible accumulations of hydrocarbons, though the fraction of recoverable oil varies. In fact, these three fields are some of the largest in the world, containing over 12 billion barrels of oil each ... 

Northwestern Ohio Niagaian dolomitic stone 6 = New York magnesian stone 7 = Virginia high calcium stone and 8 = Kansas Cretaceous high calcium stone (chalk). 

Values given relative to the universal standard PDB (Belemnitella amencana from the Cretaceous Pedee foraiation, South California, USA). 

Kreide-papier, n. enameled paper, art paper, -paste,/, a cement of chalk and glue, -piilver, n. chalk powder, -stein, m. chalkstone. -stift, m. crayon, kreldlg, a. chalky, cretaceous. 

Unter kom, n. undersize (grain), -korrektur, /. undercorrection, undercompensation, -kreide, /. (Geol.) Lower Cretaceous, imter-kriechen, v.i, crawl under, -kriegen, v.t. get the better of. -kritisch, a. below-critical (temperature, speed, etc.), -kiiblent v.t. supercool, undercool. 

Cretaceous 138 Myr Gondwana begins to break up. Continued radiation of flowering plants mammals begin diversifying. Meteorite strikes Yucatan Peninsula at end of period causing mass extinction (ca. 75% of all species disappear)... 

Hsii, J. 1983. Late cretaceous and Cenozoic vegetation in China, emphasizing their connections with North America. Ann. Missouri Bot. Gard. 70 490-508. 

Wolfe, J. A. 1975. Some aspects of plant geography of the Northern Hemisphere during the late Cretaceous and Tertiary. Ann. Missouri Bot. Gard. 62 264-279. 

Important metallic ore deposits include Besshi (Kieslager)-type (strata-bound cupriferous pyritic deposits), strata-bound Mn-Fe-type, skam-type, Kuroko-type and vein-type. Dominant non-metallic deposits are limestone, clay, native sulfur, zeolite, silica and gypsum deposits. The deposits are divisible into three groups, based on their ages of formation Carboniferous-Jurassic, Cretaceous-Paleogene and Tertiary-present. 

Jurassic—Cretaceous Besshi-type and Mn-Fe strata-bound deposits are present in Hidaka, Hokkaido (Fig. 1.2). Geochemical data and geological evidence all point to a midoceanic ridge environment of ore formation. values of Shimokawa Besshi-type... 

Ore deposits associated with volcanic rocks generally exhibit polymetallic (Cu, Pb, Zn, Sn, W, Au, Ag, Mo, Bi, Sb, As and In) mineralization. Sulfur isotopic values of sulfides from these deposits are close to 0%o, suggesting a deep-seated origin of the sulfide sulfur. Clay deposits (pyrophyllite, sericite and kaolinite) are associated with both felsic volcanic rocks and ilmenite-series granitic rocks of late Cretaceous age in the San-yo Belt. 

S C and 8 0 of carbonates from southern Kyushu (Hokusatsu gold district) have been studied in detail (Matsuhisa et al., 1985 Morishita, 1993). Morishita (1993) found that the S C values of hydrothermal solution in the district during the mineralization stages were low (—ll%c), compared with that of average crustal carbon (—7%o), suggesting that of hydrothermal solution is controlled by organic carbon in widely distributed sedimentay rocks of the Cretaceous Shimanto Supergroup basement. 

As shown in Fig. 1.117, Se-type and Te-type epithermal Au-Ag vein-type deposits are located in the Cretaceous-Quaternary volcanic terrane of Japan (e.g., northeast and southwest Hokkaido, middle Honshu, south Kyushu). Some Te-type deposits are located in regions similar to the Se-type deposits. Sometimes, Te mineralization is associated with the Se-type deposits, though Te minerals usually do not coexist with Se minerals. However, rarely, Te minerals coexist with Se minerals in the Te-type deposits (e.g., Teine, Suzaki, Kawazu, Iriki) on a polished section scale. For example, coexistence of native Te and Se-bearing tetrahedrite is found at Teine. Generally, Te mineralization occurs at... 

Age of mineralization Late Cretaceous-Quaternary Miocene-Present... 

The district is composed of sedimentary rocks of the pre-Paleogene Shimanto Supergroup (dominantly shale and sandstone) and Quaternary andesitic and dacitic volcanic rocks. The Shimanto Supergroup is comprised of shale, sandstone and their alternations. Although no fossil data are available, the age of sedimentation is thought to be middle to upper Cretaceous age from its lithology (Izawa et al., 1990). The Shimanto... 

Figure 1.166. Distribution or initial Sr/ Sr (r, ) for the Cretaceous-Paleogene plutonic rocks. Open squares gabbros open circles granites. Numbers indicate the last two or three digits of r, values. Solid squares and solid circles imply the magnetite-series open squares and open circles the ilmenite-series. (Shibata and Ishihara, 1979).

The chemical compositions of coexisting sphalerite and tennantite-tetrahedrite from the mines were determined. Except the Ashio polymetallic deposits, the other deposits have been formed at late Cretaceous related to felsic magmatism. 

Gold-quartz vein-type (mesothermal-type and hypothermal-type deposits in the sense of Lindgren (1928)) occur in sedimentary terrane associated with Cretaceous felsic... 

Ages of mineralization in the Hidaka and Kitakami regions may be Cretaceous, considering the ages of associated granitic rocks. 

Utada, M. (1980) Hydrothermal alterations related to igneous activities in Cretaceous and Neogene formations of Japan. Mining Geology Special Issue, 8, 67-83. 

Arima hot springs are located at middle Honshu. The geology of this area is composed of upper Cretaceous, and Paleogene granitic rocks. 

The Beppu hot springs are located at the eastern end of the Beppu-Shimabara Graben, Kyushu. The basement rocks are composed of Paleozoic crystalline schists and Cretaceous granitic rocks. Miocene to early Pleistocene andesitic rocks occur mainly in the southern part of the area, while lava domes of hornblende andesite which are younger than 100,000 years occur in the western part. 

Fig. 2.36. Tectonic setting of Kyushu, Japan, showing location of (north) Hishikari and Nansatsu (south) deposits in Kirishima arc. Triangle volcanoes younger than Middle Pleistocene stipple accretionary prism of Cretaceous and Tertiary age W-B zone isobath of deep Wadati-Benioff seismic zone MTL Median Tectonic Line BTL Butsuzo Tectonic Line K-P Ridge Kyushu-Palau Ridge (Mitchell and Leach, 1991).

Age of formation of Group B of Besshi-subtype are variable, early Cretaceous (Shimokawa), late Early Cretaceous to early Late Cretaceous (Makimine) and Triassic to Jurassic (Minenosawa, Kune). 

Host rocks in the Hitachi area suffered regional metamorphism, contact metamorphism by Cretaceous granitic rocks and hydrothermal alteration associated with sulfide mineralization. 

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