Abstract:The Qinghu monzonite was formed by the cooling and crystallization of the magma derived from the lower crust layer. It belongs to the intermediate rocks of the alkaline series, having 87Sr/esSr (apatite) of 0.70472±1 0.0004, and U-Pb (Zircon) isotope age of 158·4 Ma. Its REE abundance is 284.69 ppm, ∑Ce/ ∑Y=6.40, δEu=0.88. The majority of the REE of the rock body come from the deep-seated sourse, i. e. the lower crust layer, although a small preportion from surrounding rocks. As magma was crystallized and differentiated, REE in it were mainly deposited as RED mineral orthite, and REE-bearing amphibole, plagioclase and apatite, whdch are main REE carrier in the rocks,and play an impdstant role in REE immigrating and gathering in the weathering crust during the weathering and decdmposition of the rocks.

Abstract:A zone of eclogite-garnet lherzolite-spinel lherzolite complex occurs in the Archean basement, running from the east seacoast in Shandong through northern Jiangsu into the Dabie Mountains for about 1200 km. The complex suite has a sequence consisting of garnet lherzolite, spinel lherzolite and dunite in the lower part, and eclogite and garnet pyroxenite in the upper part. The garret lhezzolite, spinel lherzolite and dunite are of interbedded layer. Over 1000 of the complex blocks are exposed as boudins resulting from stretching and shearing, which have formed a specific 'melange' with their country rocks including gneiss, amphibolite and granulite. The garnet lherzolite is similar in main chemical composition to the xenoliths from the basalts in eastern China, is characterized by a high content of Mg0 for the olivine,. clinopyroxene, orthopyroxene and garnet. The fresh garnet Iherzolite has a total REE content of 2.41一14.23 ppm, a.nd shows much the same REE patterns which are similar to those of pyro- lite. The equilibrium temperatures and the pressures of the minerals range from 800 to 1371℃.and from 35 to 49.8 ×108 Pa respectively. The.paleo- geotherm is essentially coincident with the continental geotherm. The age of the garnet lherzalite deter mined by Sm-Nd method is 925± 53 Ma. The authors suggest that the garnet lherzolite represents essezltially paleo- pyrolite of South China.

Abstract:The Niangniangshan alkaliue series occurs in the Niangniaugshan caldera, which is located in the centre of the Ningwu volcanic basin, and surrounded by ring fractures. The volcanic rocks in the caldera are getting younger from outer to inner, The major rock types include trachyte, high-potassium phonolite, hail- ynite phonolite and subvolcanicintrusive rocks. This series is high alkaline, silica-undersaturated and very rich in LREE. The initial ratios of 87Sr/86Sr and ∈Nd range from 0.7070 to 0.7073 and-3.4, 一3.3 respectively. The quantitative modelling shows that;(1 )the source rocks of hailynite phonolite and aegirine augite syenite are the mixtures of upper crust and depleted mantle, being 41% and 59 % or 42% and 58% respectively;(2) the primary magma of the alkaline series was formed by partial melting of source rocks, the degrees of partial melting being 6.4%and 6.6%.The modelling provides probable quantitative geachemical model for diagenetic process of the alkaline series.

Abstract:The zircon was dated by using the technique of single-zircon stepwise evaporation-deposition with a thermal ion mass spectrometry (Bernd Kober, 1986 and 1987). The zircon ages are 2.60-2.54 Ga for biotite-leptynite (BL), 3.36-2.62 for mimatized leptite (ML), and 3.53-3.08 Ga for quartzite(Q) from the iron formation. Combined with available data, it is comidered that the sourcerock of biotite--leptynite might be intermediate-acid volcanic material of ca.2.7 Ga, and that of migmatized leptite and quartzite might come from granitic crust older than 3.0 Ga. The iron formation was formed on the continental crust base at about 2.7 Ga, and was immediately metamorphosed for the first time.

Abstract:Myrmekite, an intergrowth between vermicular quartz and sodic plagioclase,often occurs in minor amounts in felsic intermediate-acidic intrusive and gneissic rocks. Several hypotheses for myrmekite genesis are briefly reviewed. The proportionality relationship between the amount of vermicular quartz and the composition of plagioclase in myrmekite or the Ca content of the rocks is consistent with hypotheses of replacement, solid-state exsolution, and recrystalli-zation of primary plagioclase. The presence of perthitic albite and even K-feldspar relicts in the myrmekite obviously indicates that the myrmekite is formed by replacement of Ca-bearting sodic solution or emanation after K-feldspar.Therefore, myrmekites of different morphology and spatial distribution are of the same metasomatic origin. The myrmekite formed during the deformation period should be later than that formed during the pre-deformation period.

Abstract:Thin section petrography, differedtial thermal analysis, infrared spectroscopy,electronic microscopy and X-ray diffraction have been used in the study of pyrophyllite and pyrophylitites from Liyang, Jiangsu. The difference in meaning is known between the pyrophyllite and pyrophyllitite. Two kinds of pyro-Phyllite have been found from the pyrophyllitites in this area. It is clear thatthe previously so-called pyrophyllite is referred to"pyrophyllitite" indeed. A preliminary classification for pyrophyllitites has been made by the author.

Abstract:Mineraiogical studies of; the ;Duchuantou ".illite" in Zhejiang province indi- cate that the mineral formerly called "illite" is actually sericite. Its XRD, IR, DTA, SEM and TEM data and, es-pecially, chemical composition exhibit chara- cteristics .of the typical sexioite mineral. The Duchuantou sericite is characterized by Mg0<0.25%，K20>9%, Si/Al< 1.2, octahedral Mg less than 0.03, and octahedral electric charges -0.052- + 0.048/ O10(OH)2, whereas illite is noted for Mg0>2.0%，K20 some 8%，Si/Al> 1.5, octahedral Mg 0.2-0.4, and octahedral electric charges -0.17一-0.40/O10(OH)2. The Duchuantou sericite.has high crystallinity, flaky form, grain size smaller than 5μm, sharp and symmetric 9.95A, (002) peak, and 2 M polytype, while illite generally has low crystallinity, 1 M polytype and gentle (001) peal. In addition, the Duchuantou sericite displays characteristic 3624, 3450, 930, 825 and 799 cm-1 infrared absorptions, 45-111.2℃ weak endqthermic valley and 600- 700℃strong endothermic valley; in contrast, illite does not show apparent 825, 799 cm-1 infrared absorption, but exhibits 100℃ strong endothermal valley and 5000℃ and 9000℃ endothermal valley.

Abstract:The Xiyuantou rare metal granite pegmatite of Fujian province is a rare metal deposit dominated by Ta and containing various soxts of associated ele- meets. The pegmatite were found into mica-plagioclase granulite and quartzmica schist of Sinian metamorphic series. Micas from different assemblage zones of pegmatitic veins all belong to 2M1 type Rb-bearing muscovite, which has quite stable chemical composition at the positions of tetrahedxa arnd octahedra, varying within the compositiohal range of normal muscovite .Micas contain Rb (Rb2O=0.45-1.78%)and Cs (Cs2O= 0.02%-0.06%)but are deficient in Li and F.The variation in Rb2O and Cs2O content of different assemblage zones is connected to certain extent with modes of occurrence, mineral assemblages, grain sizes and colors of micas. Ferriferous muscovite in mica-plagioclase leptynite differs from Rb-bearing muscovite in that the former is a bit higher in Ti, Mg and Fe content and specific gravity (G= 2.83-2.88)，but contains extremely low Li2O, Rb2O and Cs2O. The site occupancy of cations (Li1+ +R2+ +R2+ +Ti4+=4.372) in the octahe- drop of 3T type alumo-protolithionite from quartz-mica schist is between the dioctahedron and the trioctahedron, belonging to the transitional type. Besides conitaining abundant Ti, Mg and Fe, this mica is characterized by rich rare alkali elements (Rb2O=1.42, Cs2O=1.36% and Li2O=1.90%)and volatiles (F- =3.34%).Data of infrared absorption spectrum and differential thermal ana- lyses also suggest the transitional characteristics of this mica. Its unit cell parameters are as follows: a0=5.19A，bo=5.19A c0=30.05A，β=90º，a=90º，γ= 120º，Nm=Ng=1.601, 2V= 0一3º，and G= 2.91. Chemical composition and species of micas reflect ge}logi-cal environments for their formation, thus playing an indicating role in prospecting for minerali- zation. Mica rich in rare alkali formed in pegmatite and quartz-mica schist is related to properties of wall rocks and rich rare alkali elements in pegmatite melt-solution. It is therefore kniown that mica can serve as a typomorphic mine- ral in the rare metal pegmatite deposit.

Abstract:Pyrupc, generally ix1 the form of single crystals, is a common mineral in such mantle source rocks as kimherlites, and also serves as one of the important indicator minerals in placer prospecting for diamond.. It is found through recent studies that(1)pyrope is not a typical. dry phase nesosilicate mineral, with minor amounts of constitutional water contairxed in its lattice, and(2)the content of trace element Ni in pyrope sensitively indicates the formation temperature of pyrope. Ln this paper, the author has looked into content characteristics of some trace elements in pyrope such as Ni, Zn, Y and Zr, made a comparative study of formation temperature ranges of pyrvpes . from kimberlites of different ore potentialities, tentatively discussed the elationship between water content a.nd formation temperature of pyro'pe. and, on such a basis, dealt with the origin of constitutional water and its geological significan- ce. 25 typical coarse-crystalline pyropesamples were selectively collected from the No. 50 Icimberlite pipe in Liaoning Province. After flattening and polishing both faces, we performed proton probe trace element analysis and infrared spec- tral analysis. It has been found that pyrope from this rock body contains Ni 10-95 ppm, Zn 4-20 ppm, Ga 7-30 ppm, Sr 0-3 and Y 3-56 ppm. Accord- ing to geotlzermometer calculations of trace element Ni, 84% of pyropes were for- med above 1000℃, mainly iii the range of 1050-1150℃. The temperature-pre- ssure variations of the continental shield area suggest that these pyropes were formed in the diamond stable area of the upper mantle, thus indicating the exis- tence of diamond in the rock body. Kimberlite body in Shexian County of Hebei Province is a barren rock body, and analyses of samples from this rock body all demonstrate that the formation temperature is below 1000℃. Infrared spectral analysis of all samples shows that for six samples there exists an obvious absorption peak in the range of 3700一3500 cm-1，implying that these samples contain minor amour6ts of constitutional water. Calculations show that the temperature for the formation of hydrous pyrope varies from 1050 to 1250℃，higher than the stable boundary of 1000℃，hence demonstrating the close connection between the constitutional water and the formation of diamond.. Py- ropes containing constitutional water are all rich in Zr. The enrichment of incom- patible element suggests that the formation of constitutional wator might be cloesly related to the mantle metasomatism.

Abstract:The Dongshengmiao large-sized polymetallic pyrite deposit in Langshan area of Inuei Mongolia is located in the western part of northern North Ghina platform and occurs within Langshan-Zhaertai faulted trough. The ore-bearing rock series of Middle Froterozoic Langshan Group is a set of fine elastic rocks- carbonate rocks which have undergone epimetamorphism. This ore deposit bears resemblance to gigantic Proterozoic pyrite type deposits, in the world in many aspects .In this paper, the author has made a special discussion on the major ore mineral in the deposit-sphalerite, looking into the relationship between the typomorphic characterstics of sphalerite and genesis of the ore deposit. Sphalerite of this deposit was formed irr two stages, with the early sphale- rite related to submarine hot-water exhaled deposition whexeas the late spha- lerite to late stage regional metamorphism, being the product of local mobiliza- tion, accumulation and recrystallization. The author has further investigated the formation conditions of sphalerite .FeS molecules in sphalerite increase obviously from early stage to late, and the Zn/Fe ratio decreases from 8.64 to 4.06.The unit cell parameter of sphalerite grows with the increasing FeS content. Co content gradually decreases from early to late stage.Temperature for the for- mation of sphalerite tends to rise from early to late.Sphalerite formed in the process of late metamorphic transformation contains more iron than the originally sedimentogenicsp halerite, thus constituting a mineral sequence from sphalerite to marmatite. Typomorphic characteristics of sphalerite indicate undoubtedly that the Dongshengmiao pdlymetallic pyrite deposit is genetically of submarine hot-water exhaled deposition-weak reformation type.