Intrusive deposits

Intrusive Deposits. Deposits included in the intmsive deposit type are those associated with intmsive or anatectic rocks of different chemical composition, eg, alaskite, granite, monzonite, peralkaline syenite, carbonatite, and pegmatite. Examples include the uranium occurrences in the porphyry copper deposits such as Bingham Canyon and Twin Butte in the United States, the Rossing Deposit in Namibia, and Ilimaussaq deposit in Greenland, Palabora in South Africa, and the deposits in the Bancroft area, Canada (15). 

Intrusive deposits are associated with intrusive rocks, including alaskite, granite, pegmatite, and monzonites. Major world deposits include Rossing (Namibia) and Palabora (South Africa). 

V-Surficial, weakly coherent, alluvial deposits readily eroded by water. (Vj-<3 percent slope V2-<12 percent slope). I-Incompetent, or weakly coherent, bedrock such as shales and tuffs readily eroded by water and (or) prone to mass movement on steep slopes (li-<12 percent slope l2->12 percent slope). C-Competent, or strongly coherent, bedrock such as layered lava flow rocks and igneous intrusives not readily eroded by water, nor generally prone to mass movement except for rockslides and rockfalls from very steep slopes and cliffs (Ci-<12 percent slope). 

Figure 1.73. Distribution of epithermal Au-Ag vein-type deposits, propylitic and advanced argillic alterations and intrusive rocks of diorite prophyry (Shikazono, 1985a).

The Seigoshi and Toi deposits occur in the andesitic pyroclastic rocks of the upper horizon of the Yugashima Group and basic intrusive rocks. Distributions of the wallrock alteration minerals from underground in the Seigoshi mine and on the surface near the... 

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. 

Obira deposit is located at south Kyushu. It occurs in Shimanto Group rocks composed of shale, and limestone, associated with middle Miocene granitic intrusive rocks. Polyascendant zoning and mineralization are observed in the Obira deposit. From early- to late-stage mineralizations are ... 

The other opinion is that the mineralization is related to bimodal volcanism. For example, in west Izu Peninsula, epithermal Au-Ag vein type deposits (e.g., Seigoshi) are associated with basic intrusive rocks and acidic volcanic rocks. 

Shinozuka et al. (1999) analyzed the host volcanic and intrusive rocks in the Minamidani mine district in the Maizuru tectonic Belt and found that these rocks formed in an island arc back-arc system near Laurasia during late Paleozoic. Probably the Yanahara deposits, one of the representative Hitachi subtype deposits, were formed in an island arc back-arc system as same as the Minamidani. Sato and Kase (1996) thought that the Hitachi-subtype deposits formed in back-arc rift or continental rift (Table 2.21). 

Intrusive Rossing deposit in Nambia, uranium occurrences in porphyry copper deposits as Bingham Canyon and Twin Buttle in USA, the Palabora in South Africa, deposits in the Bancroft area, Canada. 

All soils contain soluble salts, but their concentration is low. The salt content of most arid soils is, however, much higher. Salts in desert soils are usually derived from three main sources (1) deposition of wind-blown salt spray or dust (2) in situ weathering of salt-containing rocks or sediments, and (3) upward movement with the capillary flow from a shallow salty groundwater. Along the coastline, some salinization may occur through intrusion and flooding by seawater. 

Mesozoic volcanic rocks and coeval intrusive complexes within the Quesnel geotectonic terrain of central British Columbia host several major porphyry copper-gold mines. Exploration for new deposits in this region has been met with limited success, because prospective bedrock is mantled by Late Pleistocene glacial sediment (e.g.,till) and Late Olig-ocene to Pleistocene plateau basalt. 

The geology of the study area comprises mainly limestones, shales, alluvial deposits and basic extrusive and intrusive rocks. 

The Ulsan carbonates (Fig. 1) have long been interpreted as limestone of Paleozoic age or "age unknown" and as the host of a skarn-type iron (magnetite) deposit due to the intrusion of Cretaceous granitic rocks (Park Park 1980 Choi et al. 1999). However, a Paleozoic marine limestone hypothesis fails to explain the spatial association or the relationship between carbonate and ultramafic rocks in a concentric, ellipsoidal shape surrounded by Cretaceous sedimentary, volcanic, and granitic rocks. The sedimentary hypothesis also fails to explain the isolated exposure of a funnel-shaped Paleozoic marine limestone where no marine limestone has been previously observed within the Mesozoic Kyongsang Basin. 

Bowman, J.R. 1998. Stable-isotope systematics of skarn. In Lentz, D.R. (ed.) Mineralized intrusion-related skarn systems, 99-145. Mineralalogical Association of Canada Short Course 26. Choi, S. 1983. Skarn evolution and iron-tungsten mineralization and the associated polymetallic mineralization at the Ulsan mine, Republic of Korea. Unpublished PhD. Dissertation, Waseda University, 271 p. Choi, S., So, C., Youm, S. Kim, M. 1999. Stable isotopeand fluid inclusion studies of iron-tungsten mineralization at Ulsan skarn deposit (Abstract). Economic and Environmental Geology, 32, 148-9. 

Another similar origin deposit is Lac des files in Canada. This complex is apparently contrary to a somewhat general rule in that of intrusion and is regarded as Archean age and may be therefore intruded prior to the Kenora origin into a technically unstable environment. 

Introns, 12 449 17 619 20 824 Intrusive uranium deposits, 17 520 Inulin, classification by structure, 4 723t In-use properties, of soap, 22 728, 730-731 Invention. See also Patents... 

At the scale of an individual deposit, 3D GIS can be used to visualize metal zonation patterns and their relationship to geological elements such as syn-volcanic intrusions (Fig. 4). 3D GIS also represents the tool of choice to examine the geometry of an ore body and to target drilling in areas of possible extensions. 

Thermally-driven convection in porous media has been simulated since Lapwood (1948) and has become increasingly complex and realistic. No models to our knowledge have systematically investigated the number and size of deposits that might form above a sill, nor have any modeled a system that would permit significant flow on the side and under the intrusive heat source. 

The footwall units below the ore horizon include the Watson Lake Rhyolite and the Bell River Complex intrusion. Both have U-Pb dates of 2724 Ma (Mortensen 1993), and the Bell River Complex is considered to the heat source which drove the hydrothermal circulation that created the ore deposits. 

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