Central Fujian Research Articles

Geology, ore-forming fluid and genesis of the Qiucun gold deposit: Implication for mineral exploration at Dehua prospecting region, SE China

The Qiucun gold deposit, located in the central Fujian Province, is one of the most important gold producers at the Dehua prospecting region. The deposit is hosted in the Nanyuan Formation consisting of continental arc volcanic rocks, which belong to the Mesozoic coastal volcanic belt of south China. Gold ore bodies are controlled by a group of NE-NEE trending faults. Wall rock alteration shows that gold mineralization is closely associated with quartz (chalcedony)-illite-pyrite-calcite assemblages, in which pyrite is the dominate sulfides (>90%). Petrographic study of ore minerals shows that gold occurs as electrum grains of 2–65 μm in diameter, interstitially or in fractures within pyrite. EPMA analysis of electrum yielded compositions of 62–69 wt% Au and 28–33 wt% Ag. Fluid inclusions petrographic and microthermometric studies were carried out on auriferous quartz veins from three different elevations, i.e. 712 m, 742 m and 820 m above sea level. Two types of fluid inclusion were observed, namely two-phase liquid-rich (type I) and two-phase vapor-rich (type II) fluid inclusions. There inclusions are predominately aqueous inclusions but can sometimes contain minor CO2 and N2 as revealed by laser Raman analysis. Type I inclusions show homogenization temperatures (Th) of 181–248 °C, with salinities of 0.5–2.6 wt% NaCl equivalent. Type II inclusions display Th of 208–249 °C, with salinities of 0.5–0.9 wt% NaCl equivalent. The occurrence of platy calcite and hydrothermal breccias, together with coexisting type I and type II inclusions which shows similar homogenization temperatures but contrasting salinities, all indicate that fluid boiling is a crucial mechanism for ore deposition at the Qiucun gold deposit. Combining the geological settings, alteration, mineralization and fluid inclusion characteristics, we propose that the Qiucun gold deposit is a low-sulfidation epithermal deposit. The estimated pressure calculated by fluid inclusion boiling assemblages corresponds to a formation depth of 200 to 260 m below paleo-surface, which is slightly deeper than the current depth. Accordingly, the denudation thickness of the overlying Nanyuan volcanic rocks is supposed to be approximately 100 m since ore deposition, which is conductive to the preservation of epithermal ore deposit. It is therefore suggested that the large area of the Daiyunshan Volcanic Basin at Dehua district is of great potential for epithermal ore exploration.

Focus on Industrial Needs and Serve Local Economy Teaching Design of the “Design Sketch” Course of Clothing in Fujian Province

Clothing fabrics, clothing styles, clothing structure design, material texture re-creation need the innovation and re-creation ability of designers. Design sketch is the "window" of designer's personal style, is a special symbol and form of expression and is the basic approach of modeling and the form aesthetic training. In order to better serve the clothing and textile industry in Fujian Province, in this paper, taking the requirement of the clothing industry development in Fujian Province on the designer’s ability as the background, the application and promotion of design sketch in the cultivation of the ability of fashion designers are explored. Fujian Province is located in the hinterland of the economic zone on the west side of the strait and is known for light industry. Its southern Xiamen, Shishi, Jinjiang, Quanzhou, Zhangzhou, its central Putian, Fuzhou, Changle, its northern Sanming, Nanping and other places have large-scale clothing and textile industry which occupies a pivotal position in the local economy. Textile and clothing industry as the traditional processing industry of advantage in Fujian Province, has now formed a complete range of textile industry system involving the categories of chemical fiber, cotton, clothing, printing and dyeing, knitting, industrial textiles, home textiles and so on. Its textile economy is in the forefront in regional economic ranking. For example, in Shishi and Jinjiang which are the national textile industry leaders, the textile industry has become the pillar industry of local economy; Quanzhou in southern Fujian and Changle in central Fujian have built a relatively complete textile industry chain covering the cotton and chemical fiber, weaving and dyeing, clothing and accessories, etc. They occupy a large proportion in the local economy and have become the key of the local economic development.Â

A tree‐ring width based drought reconstruction for southeastern China: links to Pacific Ocean climate variability

We present a drought reconstruction for southeastern China based on a tree‐ring width chronology of Cryptomeria fortunei developed from two sampling sites in central Fujian. A reconstruction of July–February drought variability, spanning AD 1855–2011, was developed by calibrating total tree‐ring width data with the self‐calibrating Palmer drought severity index (scPDSI). The reconstruction was verified against an independent data set, and accounts for 36% of the actual scPDSI variance during the period 1955–2011. Relatively dry intervals were reconstructed between AD 1859–1880, 1899–1911, 1927–1933, 1946–1959, 1964–1970 and 1987–1997. Relatively wet conditions prevailed during 1855–1858, 1881–1898, 1912–1926, 1934–1945, 1960–1963, 1971–1986 and 1998–2011. Comparisons between our scPDSI reconstruction and a moisture‐sensitive tree‐ring width record from Vietnam revealed consistencies between the two data sets, suggesting similar drought regimes. Spectral peaks of 2.2–6.4 years may be indicative of El Niño‐Southern Oscillation (ENSO) activity, as also suggested by the significant correlations with sea surface temperatures (SSTs) in the eastern equatorial and southeastern Pacific Ocean and an extreme event analysis. The analysis of links between our scPDSI reconstruction and the large‐scale regional climatic variation shows that there is a relationship between regional drought variation and East Asian summer monsoon (EASM) intensity.

Crustal structures from the Wuyi-Yunkai orogen to the Taiwan orogen: The onshore-offshore wide-angle seismic experiments of the TAIGER and ATSEE projects

Knowledge of the crustal structure is important for understanding the tectonic framework and geological evolution of southeastern China and adjacent areas. In this study, we integrated the datasets from the TAIGER (TAiwan Integrated GEodynamic Research) and ATSEE (Across Taiwan Strait Explosion Experiment) projects to resolve onshore-offshore deep crustal seismic profiles from the Wuyi-Yunkai orogen to the Taiwan orogen in southeastern China. Three seismic profiles were resolved, and the longest profile was 850km. Unlike 2D and 3D first arrival travel-time tomography from previous studies, we used both refracted and reflected phases (Pg, Pn, PcP, and PmP) to model the crustal structures and the crustal reflectors. In total, data from 40 shots, 2 earthquakes, and approximately 1,950 stations were used; 15,612 arrivals were selected among three transects. Using these data, we determined the complex crustal evolution since the Paleozoic era , involving the closed Paleozoic rift basin in central Fujian, the Cenozoic extension due to the South China Sea opening beneath the coastline of southern Fujian, and the on-going collision of the Taiwan orogen. The shape of the Moho, which also reflects the crustal evolution, can be summarized as follows: ~30km deep to the west of Fujian, deepening toward central Fujian (~35km), becoming shallower toward the Taiwan Strait (~28km), deepening again toward the mountain belt of Taiwan (~42km), and becoming shallower toward the Pacific Ocean (~10km).

Elemental and Sr-Nd-Hf isotopic constraints on the origin of Late Jurassic adakitic granodiorite in central Fujian province, southeast China

This paper presents the first detailed SHRIMP or LA-ICP-MS zircon U–Pb dating, major and trace element geochemical and Sr–Nd–Hf isotopic data of an adakitic pluton (Tangquan pluton) and an I-type granitic pluton (Xiadao pluton) in central Fujian. SHRIMP and LA-ICP-MS zircon U–Pb dating indicates that the Tangquan and Xiadao plutons were emplaced in the Late Jurassic (~160 Ma) and Early Cretaceous (~143 Ma), respectively. The Tangquan pluton is mainly composed of high-K calc-alkaline granodiorite. The rocks show adakitic affinities, characterized by high Sr and low Y and Yb contents, with high Sr/Y ratios, and by high Mg#. They have initial 87Sr/86Sr of 0.7084–0.7087, eNd (T) of −8.8 to −9.0 and eHf (T) (in-situ zircon) of −11.2. Detailed elemental and isotopic data suggest that the Tangquan adakitic granodiorite was formed by partial melting of Paleoproterozoic metamorphic basement at a depth of ~40 km (P ~12.5 kbar) plus additional input from coeval basaltic magma. The Xiadao pluton consists of monzogranite, syenogranite and alkali-feldspar granite. These granites are high-K calc-alkaline and belong to I-type. They have relatively low Sr and high Y and Yb contents and show similar Mg# to pure crustal melts. The Xiadao granites have slightly higher initial 87Sr/86Sr (0.7095–0.7102) and lower eNd (T) (−9.0 to −9.4) and eHf (T) (−14.4; in-situ zircon) than the Tangquan granitoids. Detailed elemental and isotopic data suggest that the Xiadao I-type granites were formed by partial melting of Paleoproterozoic metamorphic basement at a depth of ~30 km (P ~10 kbar).

Origin of Silurian gabbros and I-type granites in central Fujian, SE China: Implications for the evolution of the early Paleozoic orogen of South China

The early Paleozoic orogen of South China is possibly one of the few examples of intraplate orogeny in the world. It is characterized by an angular unconformity between post-Silurian cover and pre-Devonian strata and by the intensive and extensive early Paleozoic granitic plutonism. However, synchronous mafic–ultramafic rocks have not been well-studied, but they are crucial for understanding the nature and evolution of the orogen. In this paper, we present the first detailed LA-ICP-MS zircon U–Pb dating, major and trace element geochemical and Sr–Nd–Hf isotopic data for a Silurian gabbroic pluton (Dakang) and a coeval granitic pluton (Guiyang), that have recently been identified in central Fujian, in the southeastern part of the orogen. We assess the origin of these mafic and granitic rocks and their relationship to the evolution of the early Paleozoic orogen in South China. LA-ICP-MS zircon U–Pb dating shows that the Dakang and Guiyang plutons were emplaced at 441–438Ma and 431Ma, respectively. The Dakang pluton consists of gabbros and minor intermediate rocks (diorite, monzodiorite and monzonite). These rocks are all metaluminous and potassic, and are enriched in large ion lithophile elements (LILE) and depleted in high field strength elements (HFSE). They have initial 87Sr/86Sr of 0.7066–0.7098, εNd (T) of −7.0 to −3.3 and εHf (T) (in-situ zircon) of −5.2 to −4.4. Geochemical data suggest that the Dakang gabbroic magmas were derived by partial melting of previously subduction-modified lithospheric mantle in the spinel–garnet transition zone at a high temperature (~1300°C). These primary magmas underwent fractionation crystallization of clinopyroxene and amphibole, forming the evolved gabbros and intermediate rocks. The Guiyang pluton consists of weakly peraluminous granites, which show low Ga/Al ratios (10,000*Ga/Al<2.6) and so can be classed as I-type granites. They have initial 87Sr/86Sr of 0.7095–0.7113, εNd (T) of −6.7 to −5.9 and εHf (T) (in-situ zircon) of −7.7 to −0.8. Geochemical data suggest that the Guiyang granites were generated by partial melting of a mixed source of Paleoproterozoic metaigneous and metasedimentary rocks in the lower crust. Our new data, together with published data, confirm that lithospheric delamination occurred along the metamorphic core of the early Paleozoic orogen of South China during the Silurian (442–420Ma), and that this represents a post-orogenic tectonic regime in the orogen core.

福建中部近海浮游动物数量分布与水团变化的关系

根据2009—2010年在福建中部近海24°55'—25°13'N、119°11'—119°32'E水域冬、春、夏3个季节的调查资料,探讨了该水域浮游动物总丰度与生物量的平面分布、季节变化及其与台湾海峡水团变化的关系。结果表明,调查水域浮游动物的数量在冬、春之交变化较大,而在春、夏季变化较小。浮游动物冬、春两季的平均丰度分别为8.90 个/m³和245.65 个/m³,夏季为236.82 个/m³。冬、春两季,该水域浮游动物的分布特征相近。其数量在近岸较高,向外侧水域逐渐降低。冬季浮游动物的丰度最高为31.56 个/m³,春季最高达到831.67 个/m³。中华哲水蚤(<em>Calanus sinicus</em>)是冬、春季影响总丰度变化最主要的种类。与冬、春季不同,夏季浮游动物的数量在离岸水域较高,丰度最高达1053.13 个/m³,而在近岸较低,最低值仅19.17 个/m³。汉森莹虾(<em>Lucifer hanseni</em>)、双生水母(<em>Diphyes chamissonis</em>)是影响总丰度变化最主要的种类。浮游动物在各季的不同分布特征与台湾海峡的季节性水团变化有关。受季风转换影响,从冬季到夏季,海峡内沿岸流势力逐渐减弱,台湾暖流水势力逐渐增强,并影响到沿岸的水文环境。这导致调查水域内浮游动物的优势种类由暖温种向暖水种演替。由于冬、春季的重要优势种类中华哲水蚤与夏季的汉森莹虾、双生水母具有不同的温度适应性,受不同性质水团的影响,在近岸和离岸水域各自呈现出不同的数量高低。从而进一步影响到各季浮游动物总数量的分布。;In three oceanographic surveys conducted in the coastal waters of central Fujian Province (24°55'-25°13' N, 119°11'-119°32' E) in December 2009 and April and August 2010, the abundance, biomass, horizontal distribution, and seasonal variation of zooplankton were investigated, and their relation to the seasonal variation of water masses in the Taiwan Strait was examined. The results showed that the numbers of zooplankton changed between winter and spring, but remained steady between spring and summer. In winter and spring, the zooplankton showed similar patterns of distribution, though the distribution pattern was different in summer. The average number of zooplankton was 8.90 ind./m³ in winter and 245.65 ind./m³ in spring. In these two seasons, the zooplankton were most abundant in nearshore waters and gradually diminished offshore. In summer, the average number of zooplankton was 236.82 ind./m³. The zooplankton abundance in nearshore waters was low, but the zooplankton were abundant in offshore waters. To ascertain which species made the greatest contribution to these distribution patterns, the regression contribution of each dominant species' abundance was computed. In winter and spring, <em>Calanus sinicus</em> was the species whose distribution determined the distribution of zooplankton abundance. In summer, <em>Lucifer hanseni</em> and <em>Diphyes chamissonis</em> exerted the greatest influence on the distribution of zooplankton abundance. As a warm-temperate species, <em>Calanus sinicus</em> usually prospers in low-temperature waters. By contrast, <em>Lucifer hanseni</em> and <em>Diphyes chamissonis</em> are warm-water species; they are usually abundant in high-temperature waters. The adaptability of these three species to water temperature is an important factor in determining the distribution patterns of zooplankton abundance in each season. However, the most important factor is the seasonal variation of the water masses in the Taiwan Strait. This variation leads to the seasonal alternation of the dominant species. In winter, the west side of the Taiwan Strait is controlled by China's coastal water, which has a low temperature. The dominant species in the investigated waters in winter were warm-temperate species like <em>Calanus sinicus</em>. In spring, as the northeast monsoon weakens, China's coastal water wanes and the Taiwan Warm Current becomes stronger. However, the west side of the Taiwan Strait is still controlled by China's coastal water so warm-temperate species are still dominant. In winter and spring, the offshore water has a relatively high temperature because of the Taiwan Warm Current. Correspondingly, in the offshore water <em>Calanus sinicus</em> had a low abundance. The greatest abundance of <em>Calanus sinicus</em> was in the nearshore water. In summer, the southwest monsoon begins and the Taiwan Warm Current dominates. The major species were mainly warm-water species, such as <em>Lucifer hanseni</em> and <em>Diphyes chamissonis</em>. In summer, the water is heavily stratified, and there is an upwelling of bottom water in the nearshore region of the western side of the strait. As a result, the water temperature in this region was the lowest. Accordingly, warm-water species such as <em>Lucifer hanseni</em> and <em>Diphyes chamissonis</em>, were less abundant in the nearshore water. The different distribution patterns of these important zooplankton species further influenced the total abundance and overall distribution patterns in different seasons.

Note sur la systématique et la répartition des Amphibiens Anoures de Chine et des régions avoisinantes. I. Rana exilispinosa Liu &amp; Hu, 1975 et Rana (Paa ) paraspinosa Dubois, 1975

This is the first of a series of papers dealing with the systematics and the distribution of the Anuran Amphibians of China and of neighbouring regions. Rana (Paa ) paraspinosa Dubois, 1975, from Hong Kong, is shown to be synonymous of Rana exilispinosa Liu &amp; Hu, 1975, from central Fujian. This species was also found in ancient collection from northern Fujian. A map is given showing the localities where this species has been collected as yet.