Showing papers in "Journal of Geochemical Exploration in 1993"

TL;DR: In this paper, immobility in hydrothermal alteration and metamorphism provides useful lithogeochemical parameters for mineral exploration in greenstone terranes, which are illustrated on maps and diagrams, and otherwise used in exploration.

TL;DR: Semi-conformable alteration zones are present within the footwall stratigraphy of base metal horizons hosted within various volcanic environments as mentioned in this paper, where chemical gradients present across these zones indicate that their formation is a result of a series of simultaneous and consecutive metasomatic reactions between seawater and the volcanic pile that take place at progressively higher temperatures with depth in the stratigraphys, with the isotherms controlling the reactions are parallel to the subhorizontal upper contact of the underlying synvolcanic intrusion.

TL;DR: In this article, the authors summarize the hierarchy of geochemical patterns from local, regional, provincial, megaprovincial to global, using examples obtained in China and classify them according to their sizes.

TL;DR: For example, rare earth element (REE) patterns of hydrothermally altered rhyolite from geothermal systems located in the Taupo Volcanic Zone in the North Island of New Zealand provide evidence of REE mobility as mentioned in this paper.

TL;DR: A major gold province of the world exists in the Proterozoic Birimian and Tarkwaian supracrustal rocks of West Africa, and the bulk of the gold comes from the primary lode occurrences of the Birimians of Ghana as discussed by the authors.

TL;DR: Two types of visibly hydrothermally altered rocks are present in the Cambro-Ordovician Balcooma volcanic-hosted massive sulfide (VHMS) district of northeast Queensland: (1) quartz-chlorite ± biotite schist, and (2) pyritic quartz-muscovite schists as discussed by the authors.

TL;DR: The Delbridge mine as mentioned in this paper is a massive porphyritic-to-aphyric massive rhyolite and breccia mine with an irregular chloritic alteration pipe with mineralization is subvertical to the ore lens.

TL;DR: In this paper, a regional geochemical reconnaissance, based upon the minus 150 micron fraction of active stream sediment, has been conducted by the Geological Survey of Ireland (GSI) over Irish Caledonian terrains.

TL;DR: In this article, the authors used principal component analysis (PCA) to identify geochemical anomalies using the combined application of data analysis and geostatistical methods, using data from a local multi-element geochemical prospecting soil survey in NW Spain.

TL;DR: In this paper, a survey of the halogen geochemistry of apatite in layered intrusions, including new data from four intrusions from the Yilgarn block of Western Australia (the Jimberlana Intrusion, the Windimurra complex and the Mount Thirsty and Ora Banda Sills) and the Duluth Complex in Minnesota, was presented.

TL;DR: In this article, the chemistry of stream sediments is used to quantify natural geochemical baselines and anthropogenic effects, which is less effective in establishing baselines because of additional factors such as modifications of the Eh-pH conditions with varied landscape type and rainfall amounts.

TL;DR: In this paper, the Pt content of surficial media associated with Pt-rich chromitites in the dunite core of the Tulameen ultramafic complex was determined by fire assay-inductively coupled plasma spectroscopy.

TL;DR: The stream water hydrogeochemical database, prepared by the British Geological Survey's Geochemical Survey Programme, in conjunction with databases for stream sediments, soil samples and mineral concentrates, has recently been enhanced for a range of economic and environmental objectives as mentioned in this paper.

TL;DR: A fluid inclusion study of pegmatitic intrusions in amphibolite facies metamorphic rocks is conducted in this article to model fluid evolution along the shear zone at different crustal levels.

TL;DR: The Regional Geochemistry-National Reconnaissance (RGNR) Project of China as mentioned in this paper was initiated in 1978 to sample systematically various types of surface materials, determine the contents of 39 elements in the samples by multi-element, multi-method analytical systems and present the spatial variation of the elements as geochemical maps of different scales.

TL;DR: In this paper, rare-earth elements (REE) mineralization related to aluminum phosphates in Ti-rich surface laterites (iron crusts and lateritic soils) containing anatase over the Maicuru Complex is discussed.

TL;DR: In this article, major and trace element petrochemistry has been determined for forty-six Late Triassic-Early Jurassic rocks representing the Mt Milligan and Chuchi porphyry Cu-Au deposits, marginal phases of the Hogem Batholith, and Takla Group volcanic rocks.

TL;DR: In this article, the authors used the metamorphic AFM phase diagram to map the massive sulphide alteration in the Snow Lake area of Manitoba to identify the conformable and conformable synvolcanic alteration zones.

TL;DR: In this article, Gold distribution in non-truncated laterites tends to be sigmoidal in distribution, which can be cut off, strongly modified, or concealed by tropical weathering.

TL;DR: The CHIM electrogeochemical exploration technique was developed in the former Soviet Union about 20 years ago and is claimed to be effective in exploration for concealed mineral deposits that are not detectable by other geochemical or geophysical techniques as discussed by the authors.

TL;DR: In this article, trace element analysis of conifer tissues demonstrates the application of biogeochemistry to mineral exploration for gold and other metals hosted by lower Paleozoic metasediments in eastern Nova Scotia.

TL;DR: In this article, the authors used fire assay-atomic absorption to detect gold anomalies in a stream in northeastern Thailand and found that heavy mineral concentrates from pavement and other high energy sites are more reliable than conventional sediment samples for detecting gold anomalies.

TL;DR: In this article, the authors applied two methods of computational data reduction simulating low density sampling to the British Geological Survey's high precision, high resolution ( 1 sample per 1.5 km 2) stream sediment datasets for Northern Britain, exemplified by Ni and B.

TL;DR: In this paper, the solubility of chlorargyrite probably controls the silver contents of shallow groundwaters near oxidized gold and silver veins at the Sleeper mine in Humboldt County, Nevada.

TL;DR: In this paper, a factor analysis (FA) rendered robust using the minimum volume ellipsoid (MVE) estimator was carried out on geochemical till data consisting of 622 observations on 21 variables (Al, Ba, Ca, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Ni, P, Sc, Sr, Th, Ti, V, Y, Zn) from Outokumpu, Finland.

TL;DR: In this paper, the distribution of gold between different size and density fractions was determined by instrumental neutron activation and fire assay-atomic absorption, respectively, and selected samples were examined in detail.