Technical Analysis and Identification of a Glass Inlaid Sui-Tang Dynasty Woman’s Crown

A woman’s crown made of fine gilt bronze with refined glass inlay work was excavated in 2007 from the Sui-Tang tomb called Kunlun M2 in Xi’an. Many questions surround this mysterious crown which was found buried without context. This study uses nondestructive analysis of the crown to determine its significance, when was it made, and the status of the woman for whom was it made. Optical microscopy (OM), optical coherence tomography (OCT), micro X-ray fluorescence imagery (XRF), and Raman spectroscopy were applied, and identified the crown’s inlays as potash-lime glass, composed mainly of the raw materials include vein quartz or quartzite with potassium nitrate as flux. The inlays were sintered before embedding into gilt copper wire filigree. Compared with existing research on other crowns and their inlays, it is speculated that the crown dates from the Sui dynasty (581-618) or early Tang dynasty (618-649), was made locally by Chinese craftsmen and belonged to the wife of an official.

Facies Architecture and Sedimentary Structures in the drill cores of Uranium Bearing Sediments of Banganapalle Formation of Palnad Sub-basin, Guntur District, Andhra Pradesh

The Banganapalle Formation, the lowest member of the Neoproterozoic Kurnool Group of rocks, resting over the basement granites, has been identified as the host rock for uranium in Koppunuru area in the western part of Palnad sub-basin. The uppermost arenite facies of the Banganapalle Formation is exposed on surface and shows only few bedform indicators like ripple marks, planer laminations etc. Down-hole lithological examinations on course of core drilling in Koppunuru and adjoining areas identified five recognizable lithofacies of Banganapalle Formation, viz. basal conglomerate unit, quartzite-shale intercalated facies, and two quartz arenite facies separated by a grey shale dominated argillaceous facies. The polymictic conglomerate, with unsorted grit to pebble size clasts of granite, shale, quartzite, vein quartz and dolerite indicate short distance transportation and derivation from nearby granitoids traversed by quartz reef/dolerite dykes. Cyclic repetitions of arenaceous and argillaceous sediments in Banganapalle lithocolumn above the basal conglomerates point to alternate rhythmic marine transgression and regression regimes. These units can also be discriminated based on their sedimentary texture, bedforms and several soft-sedimentary penecontemporaneous deformational structures (PCD) like load structure, convolute bedding/laminations, and slump structures such as micro-slips, gravity faults and folds. These syn-sedimentary structures clearly indicate perturbation and submergence of the basin contemporaneous to deposition. Cross-beds suggests change in current direction/intensity while bi-directional symmetrical ripples in outcrops of upper arenite facies suggests that the Banganapalle sediments are derived from the basement granitoids exposed to the north as well as upper Cuddapah sediments to its west. Overall, the sedimentary structures, textural and composition variation of the lithounits suggest deposition of these sediments in marginal marine, inter- to supra-tidal flat environment. The porous and permeable nature of the quartz arenite and the basal conglomerates and the presence of available reductants in the form of sulphides and carbonaceous matter make them the best suited loci for fluid movement and precipitation of uranium.

Mineralogie křemenných žil ložiska cínových rud Hřebečná u Abertam v Krušných horách (Česká republika)

An extraordinary rich mineral assemblage (more than 35 determined mineral species) has been discovered in quartz greisen mineralization found at dump material of the abandoned Mauritius mine. This mine is situated about 1 km N of the Hřebečná village, 16 km N of Karlovy Vary, Krušné hory Mountains, Czech Republic. The studied mineralization with its textural and mineralogical character differs significantly from the usual fine-grained greisens mined in this area. The primary mineralization is represented by coarse-grained quartz and fluorapatite with sporadic zircon, monazite-(Ce), xenotime-(Y) and very rare cassiterite. Besides common sulphides (arsenopyrite, chalcopyrite, pyrite, sphalerite, tetrahedrite-group minerals), Bi-sulphosalts (aikinite, bismuthinite, berryite, cuprobismutite, emplectite, wittichenite) were determined. Members of the tetrahedrite group also contain increased amounts of Bi - in addition to Bi-rich tennantite-(Zn) and tennantite-(Fe), microscopic zones represented by the not approved Bi-dominant analogue of tennantite („annivite-(Zn)“) were also found. The primary mineralization was intensively affected by supergene processes. Chalcopyrite and sphalerite are replaced by Cu sulphides - especially anilite and digenite, and more rarely by geerite, spionkopite and covellite. Some of the fluorapatite grains in the vein quartz were decomposed and mrázekite, mixite, libethenite, pseudomalachite, hydroxylpyromorphite, metatorbernite as well as rare dzhalindite crystallized in the resulting cavities. However, the most abundant supergene phases are the minerals of the alunite supergroup - crandallite, goyazite, plumbogummite, svanbergite and waylandite. The detailed descriptions, X-ray powder diffraction data, refined unit-cell parameters and quantitative chemical composition of individual studied mineral phases are presented.

Gold and Porphyry Cu–Mo Mineralization of the Bumbat Ore Cluster and Its Relationship with the Early Paleozoic Magmatism of the Lake Zone (Western Mongolia)

––Geological, mineralogical, and geochemical studies of copper and gold mineralization in the Bumbat ore district of Mongolia have shown its association with igneous rocks of different ages formed under different geodynamic, geologic, and geochemical conditions. Copper ore occurrences (site 98 and Altan Gadas site) with an age of 518.0 ± 4.9 Ma have similar mineralogical and geochemical features and seem to be related to plagiogranite-porphyry stocks formed at the late island arc stage (524.5 Ma). The ores were deposited from weakly concentrated solutions with a low content of СО2 at 240–230 °С under subsurface conditions. The association of mineralization with plagiogranites, its localization predominantly in veins, and its essentially copper composition, with high contents of Zn, Mn, Ba, and, in some samples, Ag and Bi, permit us to assign this mineralization to the vein quartz–sulfide type. Its commercial value has yet to be assessed. Gold mineralization of the Three Hills and Darvi sites formed later (455.9 ± 4.3 Ma), during the formation of the final granitoid phases at the accretion–collision stage (511–465 Ma). These sites are mineralized crushing zones composed of hydrothermally altered rocks of sericite–quartz composition with veinlet and disseminated (stockwork) sulfide mineralization and gold-bearing quartz veins. The content of gold in the ores varies from tenths to tens of ppm, and its fineness varies from 700 to 1000‰. The ores of both sites have high contents of Cu, Zn, Mn, Ba, and, in places, Mo. Mineralization formed from hydrothermal solutions with TDS = 9.5–12.0 wt.% NaCl eq. at medium temperatures (230–300 °C) under subsurface conditions. The above specific features of gold mineralization are typical of the flank zones of porphyry Cu–(Mo) deposits.

Microstructure of Vein Quartz Aggregates as an Indicator of Their Deformation History: An Example of Vein Systems from Western Transbaikalia (Russia)

We investigated the microstructural and crystallographic features of quartz from complex vein systems associated with the development of thrust and shear deformations in Western Transbaikalia using electron back scatter diffraction (EBSD) and optical microscopy. Vein quartz systems were studied to obtain insights on the mechanisms and localization of strains in quartz, in plastic and semibrittle conditions close to the brittle–ductile transition, and their relationship to the processes of regional deformations. Five types of microstructures of vein quartz were distinguished. We established that the preferred mechanisms of deformation of the studied quartz were dislocation glide and creep at average deformation rates and temperatures of 300–400 °C with subsequent heating and dynamic and static recrystallization. The formation of special boundaries of the Dauphiné twinning type and multiple boundaries with angles of misorientation of 30° and 90° were noted. The distribution of the selected types in the differently oriented veins was analyzed. The presence of three generations of vein quartz was established. Microstructural and crystallographic features of vein quartz aggregates allow us to mark the territory’s multi-stage development (with the formation of syntectonic and post-deformation quartz).