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This paper presents the relics of rock joints caulked with lead strips, unearthed by the authors in 2007 and 2008. The relics were in ancient quarry caverns in Shepan Island, Zhejiang Province, eastern China. The quarry activities were mainly carried out for production of regular tuff stone plates about 800 years ago. Each of the lead strips was sealed into a rock joint by punching manually and carefully. At present, the lead strips still contact tightly with the rock joints and new mineral cerussite is found to have formed at the contact surfaces between the lead strip and its caulked rock joint. The use of lead strips caulking rock joints in quarry caverns is found for prevention of water from seeping out of the country rocks into quarry cavern bases, where all of the in-situ intact tuff rock was manually and near-horizontally split into thin rock sheets one by one for production of regular tuff plates. Furthermore, it is found that the tensile splitting of tuff sheets at the cavern base required the intact rocks at the cavern base had to be dry. Through this horizontal base splitting for tuff sheets from the top to the bottom, a dome-shape interior space was formed for each rock cavern with the near horizontal imprints of thin sheet layers permanently on the sidewalls.

The Dong Ujimqin Qi mesosiderite is the first recorded fall of a stony-iron meteorite in China. According to silicate textures and metal composition, this meteorite is classified as a member of subgroup IB. Instrumental neutron activation analyses (INAA) of metals show that the matrix metal has lower concentrations of Os, Ir, Re, and Pt, but higher concentrations of Ni and Au than the 7.5 cm metal nodule present in the meteorite. We attribute these compositional differences to fractional crystallization of molten metal. Studies of olivine clasts show that FeO contents are uniform in individual olivine crystals but are variable for different olivine clasts. Although concentrations of rare earth elements (REEs) change within olivine clasts, they all exhibit a vee-shaped pattern relative to CI chondrites. The relatively high concentrations of REEs in olivine and the shape of REE patterns require a liquid high in REEs and especially in light REEs. As such a liquid was absent from the region where basaltic and gabbroic clasts formed, mesosiderite olivine must have formed in a part of the differentiated asteroid that is different from the location where other mesosiderite silicate clasts formed.

The No31 pegmatite group is the largest pegmatite cluster of the Nanping pegmatite field and represents one of the most important Ta-Nb deposits in China. The columbite-tantalite occurring in No31 pegmatites showed faint oscillatory zonation and complex patchy zonation patterns in back-scattered electron images. Microprobe analyses revealed that columbite-tantalite in the pegmatites has a wide range of composition. Neither Mn/(Mn + Fe) nor Ta/(Ta + Nb) atomic ratio has obvious trend of compositional variation along the profile of a single pegmatite dike. However, in the quadrilateral diagrams the compositional trend in columbite-tantalite varies front ferrocolumbite to tantocolumbite, then to manganotantalite. The features of zonation and composition in columbite-tantalite imply that the formation of Nanping pegmatites underwent original differentiation stage and later metasomatism stage.

The aeschynite-group minerals occurring in an aegirine-fluorite-dolomite- aeschynite vein in the Bayan Obo Nb-REE-Fe deposit show complex compositional zoning in BSE images. Microprobe analyses revealed that the concentrations of REE2O3 are globally high in aeschynite-group minerals, ranging from 36.72 to 40.32 wt.%. Four species were identified in the same sample, these being aeschynite-(Ce), aeschynite-(Nd), nioboaeschynite-(Ce) and nioboaeschynite-(Nd). The correlations among cations suggest two special coupled substitutions with charge-balanced described by the exchange vectors as CaNb(Nd,Sm,Pr)-1 Ti-1 and LaNbTh-1 Ti-1. The chondrite-normalized REE patterns are hump-shaped with the maximum at Pr or Nd. The chondrite-nomalized La/Nd ratios vary in the range ∼0.15 to 0.40. It indicates that at Bayan Obo aeschynite minerals are relatively strongly La-depleted and Nd-enriched. The compositional variations in aeschynite-group minerals were controlled by the crystal chemistry and affected by fluid composition.

Ba-REE fluorcarbonate minerals from a carbonatite dyke at Bayan Obo, Inner Mongolia, North China, are first reported in this contribution, in which chemical composition, rare earth element (REE) patterns, and intergrowth relationships for these minerals have been investigated. Syntactic intergrowth or syntaxy between cebaite and cordylite, as well as cordylite and huanghoite were observed. This syntactic texture resulted from the variation of chemical composition of crystallizing agents for those minerals that crystallized directly from carbonatite magmas. It is worth noting that REE patterns of the Ba-REE fluorcarbonate minerals in the dyke are similar to those of the corresponding minerals from the ore hosted dolomite marble of the Bayan Obo giant REE-Nb-Fe mineral deposit, which implies their relation in origin.

Rare earth element fluorocarbonate minerals such as bastnaesite and parisite are firstly discovered in carbonatite dykes from Bayan Obo, Inner Mongolia, China. Bastnaesite rarely occurs as homogeneously single crystal, but contains microfine phase of parisite. They form regular intergrowth along (0001) plane net, which is identified as epitaxy. This eptactic texture results from the variation of chemical composition of crystallizing agents of those minerals that crystallize directly from carbonatite magma.

Chemical composition and crystal structure of natural non-metamict Fe-rich chevkinite-(Ce) from the aegirine-alkali granite, Mianning, Sichuan Province, China, were investigated. Microprobe analyses indicated that FeO (total iron) content in Fe-rich chevkinite(Ce) ranges from 10.97 % to 11.59 % (wt.) and Ce 2 O 3 from 23 % to 25 %. There are deficient A - and ( B + C )-type cations in the formula. The crystal structure of Fe-rich chevkinite-(Ce) was refined from CCD data in the space-group type C 2/ m ( R = 2.41 %). Cell parameters are a = 13.456(3) A, b = 5.728(1) A, c = 11.083(2) A, β = 100.60(3)°, V = 839.7(3) A 3 , Z = 2. The structure of Fe-rich chevkinite-(Ce) is made up of two kinds of sheets, one is a sheet of Si 2 O 7 groups and B -octahedra, and the other is a sheet of C -octahedra, both parallel to the ab plane. The two kinds of sheets alternate along c axis and form a three dimensional framework. The rare earth ions lie between the disilicate groups and the sheets of octahedra to form (8+3)-coordinated A 1-polyhedra and 10-coordinated A 2-polyhedra. The Fe and Ti are partially ordered among the octahedral sites of B , C 1, C 2A and C 2B. The Charge Distribution analysis confirms Fe 3+ /ΣFe = 0.61 and a mixture of Fe 2+ and Fe 3+ in the B site. The chemical formula for the natural Fe-rich chevkinite-(Ce) is (Ce 3+ 1.76 La 0.89 Ca 0.46 Nd 0.22 Pr 0.18 Sm 0.04 Gd 0.04 Th 0.03 Ba 0.01 □ 0.37 )Σ 4.00 (Fe 3+ 0.29 Ti 0.21 Fe 2+ 0.18 Mn 2+ 0.13 Mg 0.18 □ 0.11 ) Σ1.00 (Ti 2.16 Fe 3+ 0.81 Fe 2+ 0.52 Nb 0.16 Al 0.06 □ 0.08 ) Σ4.00 Si 4 O 20.72 (OH) 1.28. .