Abstract:The extensive development of tourmalinites is a major feature that distingui- shes the northern Guangxi tin polymetallic metallogenic province of China from the other similar metallogenic provinces (belts). There are two types of tourmalinite in the province. The first type, occurring in the lower part of the Lower Proterozoic Sibao Group, is bedded, stratoid or lenticular tourmalinite. The laminated structure and gel and degel structures are well developed in this type of tourmalinite. Its mineral composition is very simple and the grain size of the minerals ranges from 2 to 8 μm. Tourmaline is rich in Mg, with a Fe0/(Fe0+Mg0+Mn0) ratio of 0.191-0.653. The second type of tourmaliinte occurs as lodes and is strictly controlled by faults. It is distrbuted in the exocontact zone of Late Proterozoic biotite granite. Its mineral composition is relatively complex; the minerals are present in euhedral or subhedral crystals ranging in grain size from 0.1 to 3.5mm, mostly from 0.5 to 1 mm. Tourmaline usually exhibits radiating and zoned structures, with a Fe0/(Fe0+Mg0+Mn0) ratio of 0.639-0.849. On the basis of the above-mentioned features coupled with geochemical studies and an extensive correlation of research results of tourmalinites from various parts of the world, it is suggested that bedded tourmalinite was formed by exhalation in an Early Proterozoic continental-margin depression, while lode tourmalinite was formed in a plate conergence environment and was genetically associated with Late Proterozoic biotite granite. As tourmalinites themselves are orebodies or mineralized rocs in the study region, the origin of the tosrma in tes and their evolution in the geological history also reflect the form ation ana evolution of tin polymetallic deposits.

Abstract:All of the chondrite-normalized REE patterns of kimberlites from Shandong and Liaoning, incline to the right, the (La/Yb)N,ratios changed from 22.7 to 357.9 and the LREE/HREE ratios from 12.4 to 61.3, belonging to LREE-rich type (Fig.l and 2). This characteristic may be related with the LREE´s strong alkalinity and easily getting into the alkaline kimbPrlite. Moreover, the above kimberlites shave the following REE geochemical chara- cteristies: the (La/Sm)N ratios changed from 3.8 to 11.5, the (Gd/Yb)N ratios from 4.1 to 18.6. The δEu values changed from 0.75 to 1.22, but most of them are between 0.80 to 0.99. The ∑REE ranges of diamond-rich kimberlites are smaller: between 300 and 600 ppm, for instance, ranging from 361.6 to 544.7 ppm in Shengli I`No.l pipe,Shandong province; from 378.9 to 511.9 ppm in No.50, 51，42 and 30 pipes, Liaoning province. The FREE ranges of diamond-poor or -free kimberlites are larger, and the ∑REE contents are either less than 300 ppm or more than 600 ppm (Table 2).Therefore ∑REE of kimberlite is an important parameter in diamond exploration. The ∑REE contents of xenoliths in kimberlites are: himberlite xenolith 237. 6 ppm, eclogue 55.2 to 73. 3 ppm, dunite 10.6 ppm, they are all much lower than those of diamond-rich kimberlites (Table 1). The REE patterns for kimberlites are apparently different from those of eclogue and dunite xenoliths (Fig. 4).

Abstract:The paper has calculated magma density of basaltic rocks from various tectonic settings. It firstly suggested that two types of magma density: I density type of primary basaltic magmas in Arc Regions; Ⅱ density type of primary basaltic magmas in Within Plate and Mid-Ocean-Ridge. The paper points out that Ⅱ magma type concern with the pressure and temperature conditions on which magmas formed, and Ⅰ magma density is controlled by fO2 and fH20 in source of basaltic magmas. So, the density of primary basaltic magmas is a important criteria to distinguish geodynamics settings in which magmas formed. Considing the relationship of density with pressure, the paper suggests that density of primary basaltic magmas controls on the depth of magma chamber and condition of temperature-pressure on which magma crystallized, on the some extent, and make effect on intrusion-eruption of magmas. In the regions of island-arc, magma density and the crust thickness control on time-space evolution of rock series(Ih-CA-Sh) and decide the crystallization condition and evolution path of magmas. Using data about magma density, "two-layer" model of crust structure in Yidun Island-Arc regions，westhern Sichuan Province，has been established.

Abstract:Someof the most remarkaLle rocks, especially in texture and genesis, are undou- btedlv the komatiites, which together with komatiitics basalts and/or tholeiites constitute the komatiitic suites. However. there are differences in geochemistry between komatiites from different areas and/or ages, providing a direct evidence of the physical and chemical changes of the mantle.Nesbitt and Sun (1979) recognized two kinds of komatiites: aluminum-undepleted komatiites (Group I) and alnum-depleted komatiites(Group II)discriminated by the hediagrams of Al2O23 vs. TiO2 and CaO vs.Al2O3.The typical examples are from Abitibi, Canada and Barberton. South Africa, respectively. Recently,Ohtani et al. (1989) identified a new kind of komatiites: alumium-enriched komatiites (Group III).The authhor documents that the Group III komatiites not only exist, but also have high Al2O3/TiO2 ratios caused by depletion of Ti instead of enrichment of alnminum. Although most of komatiites or komatiitic suites are of Archean ages and occur in greenstone belts, some also occur in Phanerozoic ophiolitic suites, such as the Cape Smith belt (Early Proterozoic)，Canada; Betts Cove (Ordovician)，Newfoundland, Canada; Othris Mountains (Triassic)，Greece and Gorgona Island (Tertiary)，Columbia. So far, the relationships between the various kinds of komatiites, komatiitic hasalts and tholeiites and their evolution throughout the geological time are not well-known, although that might be a key problem in the understanding of Archean and Phanerozoic crust-mantle evolution，This paper attempts to discuss these problems on the basis of the petroehemistry of over 500 samples selected from a database established by the author.

Abstract:The kinetics is one of the important subjects on the petrology. In this paper the theory and method of the crystal size distribution(CSD)and its characteristics in some simple geological processes are intrudu}ed..And an appraisal was raised for CSD according to a) theoretically and the practical application，b) the natural geological processes, c) the calculating results of two to three dimensions in some rocks, and d) the geochronology. It is suggested that 1) the natural geological processes are very }omplirated and have some effects to CSD, 2) the errors of calculating from two to three dimensions in some minerals with the]ow-grade symmetric crystal system could be easy eliminated by the orientated measure, and 3) the crystal growth time has ageochronological significance under some conditions.

Abstract:Using natural olivine pyroxenite and crystalline limestone or biotite-quartz schist and dolomitic marble as starting materials, the authors performed metasomatic experimentation in 0.5M KCl+0.5M NaF solution with pH 6.0-8.0 at 450-700℃ and under (500-1400) × lO5Pa; as a result, humite group minerals were formed. Humite group minerals formed by metasomatism are colorless (some with light yellotv tone) and transparent. Crystal morphology is perfectly developed with crystal sizes being generally 0.005-0.02mm; biaxial positive. Their optical properties such as refractive indices and their X-ray diffraction patterns indicate that they are chondrodite, humite and clinohumite. The principal conditions for the formation of humite group materials are that the mole number ratio between Mg and Si must be higher than 3:1 in the starting materials which, in addition, should contain saturated H20. Under suitable temperature and pressure, neutral-weakly alkaline solution of K, Na halogenides and oxidation environment are favorable for their growth and development With topologic graphical method. the authors have reached the conclusion that,at constant chemical potential of SiO2. the formation of clinohumite (one of the humite group minerals) and its major paragenetic minera-s-forsterite, brucite and antigorite is dependent on fairly high μMgO and μHO.It is also proved that the coexistence of these minerals is an inherent law in their interaction.

Abstract:Melnikovite, one of the most important ore minerals in the South China type massive sulfide deposits, was originally a sedimentary product of submarine volcanic hydrothermal fluids and has been annealed remarkably in the subsequent geological history. Based upon microscopic studies on ore textures, the annealing process of melnikovite in these deposits might be divided into three stages: primary crystallization, seriateblastic growth and adjustment of grain boundaries. Ores of these three stages usually occupy positions progressively closer to the Yanshanian intrusives in the above sequence, indicating the predominant role played by the thermal effect of these intrusives on the annealing of melnikovite. Accompanying the recrystallization of sulfides, the annealing process has also resulted in a redistribution of minor elements between melnikovite and pyrite.

Abstract:The Yixian maifanlite (YMS), a biotite-quartz monzouite, is a newly found mineral resource for food industry. It possesses the following characteristics: (1) existence of varied trace elements which are beneficial to human health; (2) fairly good functions of leaching, ion absorption and exchange, adjusting of pH and hardness of water and bacteria-inhibition; (3) Unique role in medical treatment and health care. It has thus been widely used in such aspects as medicine and health care, food and beverage, and environment protection. For the first time the author has noticed that a large quantity of zeolite occurs in cleavages, openings and cavities of feldspar, a dominant mineral of the rock. In addition, the author has also named the densely-distributed secondary cavities of the feldspar filled with specific porous zeolite and clay minerals as secondary microspongy texture, which, on the basis of its secondary mineral composition, shapes and sizes of mineral aggregates and its modes of occurrence, can be further divided into bladed, veinlike, spotted, ringlike and pockety types. The author holds that the secondary microspongy texture isa distinctive character of maifanlite, by which maifanlite is distinguished from common intermediateacidity igneous rocks. This texture might be a major factor responsible for the beneficial physicochemical effects of maifanlite as well as its medicohealth care function. It can also be taken as an important geological diseriminant criterion of maifanlite.

Abstract:On the basis of sulfide phase equilibria of the systems Ag2S-PbS，Ag2S-PbS-Sb2S3 and Ag2S-PbS-Bi2S3.and electron microprobe analyses of galena from various mineral assemblages in some deposits of Inner Mongolia，the authors discuss the occurrence state of silver and its enrichment pattern in galena in relation to Sb and/or Bi contents. In Sb-bearing geochemical environments and under low temperature conditions (<350`C)，silver tends to form fine-grained,independent Ag-Sb-sulfosalt minerals in galena which m uch favors the recovery of silver in the course of ore-processing. In Bi-bearing geoche mical environ m ents and under low temperature conditions，however，silver tends to be disseminated in galena as an isomorphous substitute for Pb, which renders its recovery from the ore difficult or even impossible. In the Baiyinno deposit where native bismuth and Bi-sulfosalts were formed under hydrothermal conditions，silver exists independent sulfosalts in the galena matrix and as an isomorphous substitute for Pb in galena. The recovery of silver in these deposits is therefore low. Electron microprobe analysis of galena from these deposits indicate low silver content of galena coexisting with Sb-sulfosalts but high silver content of galena coexisting with native bismuth and Bi-sulfosalts.

Abstract:A fairly complete medium-pressure Barrovian type progressive regional metamorphic belt can be recognized in the Caohe Group, which includes chlorite, Liotite, almandine, staurolite, kyanite and sillimanite zones. The regional metamorphism of the Caohe Group shows a series of special characteristics in such aspects as mineral ass0mblages, rock types, chemical and physical properties of minerals, which are consistent with the features of various metamorphic zones of the region. During the regional metamorphism, the A1z03, Fe0+Fez03 and Mg0 contents of almandine increased but the Ca0 and Mn0 contents decreased with the heigh- tening of the grade of metamorphism. Using the garnet-biotite mineral pair as a geothermometer, the author has determined the formation temperatures of the metamorphosed argillaceous rocks:the almandine zone is below 450℃, the staurolite-kyanite zone 450-600℃, and the sillimanite zone 600-620℃.