Search

BACKGROUND The main types of copper deposits are porphyry and skarn types. Dacite porphyry is a rock type commonly developed in the porphyry Cu-Mo-Au system. The rock can be used as a marker clue for ore prospecting and ore-forming rock when there is well-developed hydrothermal alteration. The Dabaoshan deposit is currently the largest copper polymetallic deposit in the South China Block. Previous studies have shown that the dacite porphyry of the mining area is not only the ore-forming parent rock, but also a favorable ore-bearing wall rock. However, there are some debates about the relationship between dacite porphyry and mineralization in this mining area. With the breakthrough of prospecting for medium and large dacite porphyry ore bodies in recent years, the relationship between dacite porphyry and mineralization has once again become a concern. OBJECTIVES To understand the relationship between dacite porphyry alteration and mineralization of the Dabaoshan deposit. METHODS Based on field work and indoor analysis, X-ray fluorescence spectroscopy (XRF) and inductively coupled plasma-mass spectrometry (ICP-MS) were used to determine copper, tungsten, silicon, aluminum and calcium in Dabaoshan dacite porphyry samples. The isotope composition, metal element contents and alteration characteristics of the dacite porphyry in the mining area were used to discuss the relationship between alteration and prospecting direction. RESULTS The copper content ranged from 107 to 6909μg/g, which was consistent with the copper ore grade of 0.3%-0.5% in the mining area. The LOI and other geochemical indicators that can represent the degree of alteration were positively correlated with copper. Hydrothermal alteration was widely developed in dacite porphyry, including potassium, prophyliticition and quartz-sericitization from early to late stage. Among different stages of alterations, the copper content of quartz-sericitization was 2 to 5 times higher than other alteration types, indicating that quartz-sericitization was closely related to copper mineralization and was an important prospecting marker clue. CONCLUSIONS The deep alteration intensity of the dacite porphyry (below the 270m elevation) has not been weakened, suggesting a great prospecting potential. In addition, the contact zone between dacite porphyry and the Jurassic strata, and the xenoliths in the dacite porphyry are also important prospecting directions, which may host skarn-type copper-rich deposits.

BACKGROUND A new deposit type with a scheelite-beryl-molybdenite assemblage was first discovered in the Zhen'an area of Shaanxi Province. BAOBJECTIVES The research on chromatic mechanism and genetic mechanism of emerald was carried out. METHODS Combined with the geological survey, Electron Microprobe and in-situ Micro X-ray Diffractomer were used to conduct mineral research. RESULTS The emerald mainly occurs in the quartz (calcite) veins as euhedral crystal and is associated with scheelite. Both the core and rim of the emerald with high V2O3 contents of 0.64%-0.98% and 1.04%-1.42%, respectively, show an increased V2O3 trend from core to rim. Diffraction data show that the emerald is normal beryl and has two kinds of isomorphous substitution mechanism, Al↔Me2+ and Be↔Li. Vanadium is the main coloring element of emerald and was mainly derived from carbonaceous slate, mica schist, and dolomitic marble, whereas Be, Si and Al were derived from deep acidic igneous rocks. CONCLUSIONS The discovery provides basic geological data for the comprehensive development and utilization of tungsten and antimony mineral resources in the deposit, and indicates new prospecting directions for continued searching for rare metal deposits in the region and deep areas of the South Qinling.

Tourmaline is an efficient tracer during diagenesis and metallogenesis. Chemical composition of tourmaline can not only be used to give information about environment of diagenesis and metallogenesis, but can also be useful in prospecting. Prospecting work of pegmatite-type rare metal deposits in Southern and Western China has seen a big breakthrough, however, there has been no obvious advance in prospecting in Northern China. Therefore, it is necessary to carry out systematical and detailed prospecting work. There are a lot of grey black idiomorphic tourmalines in pegmatite veins in Quyang County, Hebei Province, which makes it suitable for carrying out systematical mineralogy research. Samples based on detailed field work were systematically collected and are described in this paper. Microscopic identification, Powder X-ray Diffraction and Electron Microprobe were used to determine the chemical composition of tourmaline, in order to investigate the types, and diagenetic and metallogenic environment of tourmaline. Electronic Probe and Powder X-ray Diffraction show that tourmaline in Zhongzuo pegmatite belongs to dravite but is close to that of schorl. The Ca-Fe-Mg ternary diagram indicates that the diagenetic environment is poor Ca metamorphic pelite, metamorphic arenite and quartz-tourmaline rock. The chemical composition of tourmaline is closely related to the types of surrounding rock. The dravite in pegmatite veins was formed by assimilation blending between magmatic melt and surrounding rock at a temperature of 700-600℃ where Mg and Fe in surrounding rock provide the necessary sources for the formation of tourmaline. The systematical study of chemical composition of tourmaline in Zhongzuo pegmatite veins provides fundamental geological data and a prospecting direction for pegmatite-type deposits.

Zhuxi W-Cu deposit in northern Jiangxi Province is a recently found super large skarn W deposit. The formation of this deposit is closely related to granitic intrusions. The mining area is located in the central Jiangxi Taqian-Fuchun ore belt in Qin(zhou)-Hang(zhou) joint zone. The discovery of this deposit is further evidence for the model of the Southern tungsten North expansion. However, due to the lack of systematic geochemistry and geochronology of ore-related intrusions, the knowledge of this model is limited. Ore-related fine-grained muscovite granite was chosen as the research object for the study reported on in this paper. LA-ICP-MS zircon U-Pb dating of granite yielded a 206Pb/238U weighted average age of 146.90±0.97 Ma (MSWD=0.55). These granitic rocks have high silicon, alkali and potassium, and are strongly peraluminous, which belongs to the typical S-type granite. This study has indicated that ore-related magmatism occurred at the late Jurassic in Jiangnan uplift and provides new evidence for the genesis of Zhuxi W-Cu deposit and metallogenic regularity of the Taqian-Fuchun metallogenic belt.

The Zhuxi ultra-large type copper-tungsten deposit in the Northeast Jiangxi province located in Taqian -Fuchun metallogenic belt which belongs to Jiangnan ancient island-arc, the discovery of the deposit has verified Southern Tungsten North Expansion perspective and challenge the viewpoint that Tungsten located in the south but the copper located in the north of Jiangxi provience, but the previous lack of accurate chronology study related to Zhuxi copper-tungsten mineralization of granite not enough, resulting in the geodynamic background of understanding. In this study, on the basis of detailed field investigation, core logging and petrology studies on the granodioritic porphyries which had intruded into the Middle Proterozoic Shuangqiaoshan group and with copper mineralization alteration, using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U-Pb dating, we obtained the granodioritic porphyries zircon 206Pb/238U weighted mean age of 847.2±9.4Ma (MSWD=0.111), which can represent the granodiorite porphyry magma emplacement and crystallization age, belonging to the neoproterozoic. The results reveal that the granodioritic porphyries of Zhuxi copper-tungsten mine is a product of the early Neoproterozoic Southern China ancient oceanic crust subduction and Yangtze and Cathaysian continental blocks collisional magmatism, the magmatic activity provides the basis for the metallogenic Qinzhou-Hangzhou metallogenic belt, and the magma event is close related to the Taqian-Fuchun ore belt mineralization, it also provides new evidence for the study of Zhuxi ultra-large type copper-tungsten deposit.

A new tungsten-copper deposit with large-super mineralization potential was recently discovered in the Zhuxi area, Jingdezhen city of Jiangxi Province. The primary halo research plays a very important guiding role in further exploration work. By using Polarized Energy Dispersive X-ray Fluorescence Spectrometry, Inductively Coupled Plasma-Mass Spectrometry/Atomic Emission Spectrometry, large amounts of sample analyses have been conducted. According to the contents of elements W, Sn, Bi, Mo, Pb, Zn, Cu, As, Sb and Ag, these are served as the indicators of the primary halo. The primary halo of Zhuxi tungsten-copper deposit shows that Cu, Zn, Ag and Pb have good correlation as well as W, Bi, Sn and Mo. W is also correlated with Cu. The ore-forming elements have some characteristics in space. In the same section, high temperature elements such as W are more enriched at the northwest, whereas in the plane, this performance appeared at the southwest. Overall, W-oriented high-temperature elements are more enriched at lower depths. By comparison, Cu-oriented middle-temperature elements are shallower than W. This study indicates that the Cu deposit is distributed in the medium deep part (-1400--1500 m), W deposit in the deep part (-1400--1900 m) and Ag, As, Sb at the surface (-1100--1200 m). This study provides a theoretical basis for mineralization forecast and further exploration.

Accompanied by the crucial breakthrough of prospecting for skarn-type Cu-W deposit in Zhuxi of Jiangxi Province, the previously established model of ore distribution was incorrect in that the W and Cu deposits distribution was in the south and north regions respectively. A new model is presented, indicating that the south W deposit might occur in the north region. To verify the new hypothesis, the crystallizing ages and tectonic attributes of ore-related igneous rocks become a critical issue. Furthermore, there are several lamprophyre veins in the study area that might have some temporal and spatial relationships to the Cu-W deposit. Consequently, after extensive field surveying, core logging recording and thin section observation, the veins were dated accurately by zircon U-Pb isotopic method of LA-ICP-MS. Two groups of 206Pb/238U weighted ages of crystallization were yielded, one being (856 ± 10) Ma (MSWD=0.22), and the other is (160.3 ± 2.1) Ma (MSWD=0.17). Considering overall proofs, it is suggested here that the former group of age might represents a magmatism event during the period of subduction for South China ancient oceanic crust in early Neoproterozoic and of collision between the Yangtze and the Cathaysia continental blocks, while the latter one might indicate a magma intrusion event in the early period of Late Jurassic, which produced re-melting of previous rocks triggered by subduction from the Pacific to the Eura-asia plates in Early Jurassic, in accordance with the metallogenic age of the Taqian-Fuchun metallogenic belt in Zhuxi area. The lamprophyre geochronological study in the paper provides a sound theory basis for the metallogenesis of Zhuxi Cu-W deposits.

It is a fatal challenge to the traditional cognition, which the W and Cu deposits distribute in the south and north regions of Jiangxi Province respectively, when the super Cu-W deposit in Zhuxi area was discovered recently, which attracts domestic researchers' attention and their interests in restudying geology of Taqian-Fuchun metallogenic belt in Zhuxi area that provides pivotal proofs for phenomenon of the south W deposit extends to the north region of the area. The recent discovery of the super Cu-W deposit in the Zhuxi area of northeast Jiangxi has challenged the belief that W and Cu deposits are distributed in the south and north regions of the province respectively and has led to a renewed interest in analyzing these areas again. The metallogenesis types in the Taqian-Fuchun metallogenic belt are complicated with multiple ores. For instance, Cu, W, Mo and Au are related to various igneous rocks, with some diagenesis. To address geological issues, such as the tectonic evolutional setting and ore material origins, which need to be solved urgently, the zircon U-Pb isotopic method of LA-ICP-MS was utilized and is reported in this paper in order to date the ore-related magmatic rocks. The results show that there were at least three periods of magmatism and two stages of metallogenesis in the belt. The three periods of magmatism include 850 Ma and 160 Ma granodiorites and for the lamprophyre veins, 146 Ma granites. Two stages of metallogenesis are the Taqian skarn-type W-Mo deposit and the Yuexing skarn-type Cu polymetallic deposit related to the 160 Ma granites, and the Zhuxi skarn-type Cu-W deposit related to the 146 Ma granites. Thus, considering previous regional data, the hypothesis from this study is that the ore-related magmas of Neoproterozoic and Jurassic in the belt were derived from the same magma chamber and the latter was inherited from the former. The porphyry granite and aplite veins formed in 145 Ma are the indicators of Cu-W deposit.

The Zhuxi deposit is a new discovery of copper-tungsten dominated large-super-large ore deposit with great mineralization potential situated in the Zhuxi Area, Jingdezhen City, Jiangxi Province. However, present research is somewhat limited for some of the geological characteristics. Further study on genetic types and geochemical characteristics for this deposit is necessary. A bench-top type Polarized Energy Dispersive X-Ray Fluorescence Spectrometer, coupled with directly pressed powder samples has been used to analyze drill core samples of the Cu-W ore body. The instrument used in the experiments has a high detection ability for measuring major elements (SiO2, CaO and MgO) and trace elements (Cu, W, Zn and Ag), compositions with low detection limit, small error, good stability and other characteristics. The experimental results show that the major elements of SiO2, CaO and MgO have strong metasomatism characteristics. The SiO2 and CaO have a negative correlation. Trace elements Cu, W, Zn and Ag also exhibit symbiotic features, and Cu, W contents are high in the middle and low on both sides spatially. All evidence explains the metasomatism characteristics controlled by structures. The element variations and related mineral compositions also indicate that ore-forming materials were derived from granodiorite, porphyry, granite porphyry and diorite. These results provide a theoretical basis for mineralization forecast and further exploration goals.

In a multi-bubble system, the bubble behavior is modulated by the primary acoustic field and the secondary acoustic field. To explore the translational motion of bubbles in cavitation liquids containing high-concentration cavitation nuclei, evolutions of bubbles are recorded by a high-speed camera, and translational trajectories of several representative bubbles are traced. It is found that translational motion of bubbles is always accompanied by the fragmentation and coalescence of bubbles, and for bubbles smaller than 10 μm, the possibility of bubble coalescence is enhanced when the spacing of bubbles is less than 30 μm. The measured signals and their spectra show the presence of strong negative pressure, broadband noise, and various harmonics, which implies that multiple interactions of bubbles appear in the region of high-intensity cavitation. Due to the strong coupling effect, the interaction between bubbles is random. A simplified triple-bubble model is developed to explore the interaction patterns of bubbles affected by the surrounding bubbles. Patterns of bubble interaction, such as attraction, repulsion, stable spacing, and rebound of bubbles, can be predicted by the theoretical analysis, and the obtained results are in good agreement with experimental observations. Mass exchange between the liquid and bubbles as well as absorption in the cavitation nuclei also plays an important role in multi-bubble cavitation, which may account for the weakening of the radial oscillations of bubbles. [ABSTRACT FROM AUTHOR]

Fluorescent carbon quantum dots (CQDs) were synthesized from cucurbit[7]uril (Q[7]) and 2,2-bis(hydroxymethyl)propionic (DMPA) by a hydrothermal method. The Q[7]–DMPA complex was confirmed by X-ray crystallography. The CQDs showed blue fluorescence, photostability, and ionic strength stability. They were used to detect histamine with a low limit of 2.33 × 10−6 M. [ABSTRACT FROM AUTHOR]

More and more countries have become greying societies along with the burgeoning of digital devices. The older generation suffers from a sharp digital divide. Although the information infrastructure is fully developed, the elderly, not having grown up with it, tend to lack digital literacy and hold less intention to learn to use digital technologies. In the past, it was cable TV which pervaded the market and because of its long history of development became indispensable in the lives of the elderly. Recently, the maturity of Smart TV, provides us with an appropriate digital learning tool to assist seniors in Taiwan to improve their digital literacy. This is done utilising a digital remote control, designed to be a mixture of new and old technologies that offers seniors a high degree of familiarity. The study explore the effects of technology anxiety, digital feedback, and familiar technological skills on the adoption of digital devices by the elderly. In addition, a learning strategy compatible with the existing living environment of the elderly is proposed. The findings and recommendations for an effective approach to this problem are discussed as well as limitations and future research directions. [ABSTRACT FROM AUTHOR]