Northeastern Yunnan Research Articles

Tectono‐Chemistry for the Exploration of Concealed Orebodies of the Zhaotong Maoping Zn‐Pb‐(Ge‐Ag) Deposit in Northeastern Yunnan, China

Tectono‐Chemistry for the Exploration of Concealed Orebodies of the Zhaotong Maoping Zn‐Pb‐(Ge‐Ag) Deposit in Northeastern Yunnan, China

Geological and Geochemical Features of the Maoping Pb‐Zn Deposit, Northeastern Yunnan Province, China

Geological and Geochemical Features of the Maoping Pb‐Zn Deposit, Northeastern Yunnan Province, China

Metallogenic Geological Conditions and Prospecting Indicators of the Carbonate-Hosted Pb-Zn Deposits in Northeastern Yunnan Province, China

Based on large scale geological mapping, geological-section, tectonic and geochemical studies on the carbonate-hosted Pb-Zn deposits in NE Yunnan, the metallogenic geological conditions are discussed, and the ore-prospecting indicators are summarized. The Pb-Zn deposits have many common features, which are mainly controlled by the thrust fault-fold structures and lithological conditions. The ore-forming mechanism of them is similar to the MVT Pb-Zn deposit. The combination of thrust fault-fold structures and altered carbonate rocks with geochemical anomalies are good indicators for prospecting.

Composition and mode of occurrence of minerals in Late Permian coals from Zhenxiong County, northeastern Yunnan, China

AbstractMinerals in the Late Permian coals from the Niuchang-Yigu mining area, Zhenxiong County, northeastern Yunnan, China, were investigated using optical microscopy and low temperature ashing plus X-ray diffraction (LTA + XRD). The results showed that minerals in the coal LTAs are mainly quartz, kaolinite, chamosite, mixed-layer illite/smectite (I/S), pyrite, and calcite, with trace amounts of marcasite, dolomite, and bassanite. The authigenic quartz generally occurs in collodetrinite or as a filling in cleats or cell cavities. This silica was mainly derived from aqueous solutions produced by the weathering of basaltic rocks in the Kangdian Upland and from hydrothermal fluids. The presence of β-quartz paramorph grains in collodetrinite probably indicates that these grains were detrital and came from a volcanic ash. Clay minerals are generally embedded in collodetrinite and occur as cell-fillings. Pyrite occurs as framboidal, anhedral, and euhedral grains and a cell-filling. The coals are high in pyrite and the high pyrite content probably results from seawater invading during the stage of peat accumulation. Calcite generally occurs as vein-fillings, indicating an epigenetic origin.

Application of Audio-Magnetotelluric Method for Exploration the Concealed Ore-Bodies in Yuele Lead-Zinc Ore Feild, Daguan County, NE Yunnan Province, China

The results of recent mineral exploration in the Yuele lead-zinc mining area of Daguan County, northeastern Yunnan province, showed that there are much early Paleozoic strata under thick late Paleozoic strata in northeastern Yunnan province, where developed some hidden salt structures (SSs), often with lead-zinc polymetallic mineralization varying degrees along the tension torsional fault (belts) or fracture (joint). The ore-bodies belong to the epigenetic hydrothermal filling vein-type deposit, and the prospecting potential is great. In this area, the superficial mineralization information displayed clear, but the deep mineralization is unknown, so the exploration work is restricted. The audio-megnetotelluric (AMT) surveying is an advantageous method to characterize the size, resistivity and skin depth of the polarizable mineral deposit concealed beneath thick overburden. This paper presents the surveying results using AMT method to evaluate the concealed lead-zinc mineralization in Yuele lead-zinc ore field, Daguancounty, NE Yunnan province, China. After comparing the interpretation result of AMT surveying data with the geological data and the drilling data, it is found that there is some distinct difference in resistivity and polarizable between ore-bodies hosted strata, upper strata and gypsum strata. The results show that AMT method is helpful to identify lead-zinc mineralization under this geological condition.

Zoning and Exploration Significance of the Maoping Pb-Zn Deposit, Northeastern Yunnan Province, China

Based on the lithofacies mapping and petrographic studies, the mineralization-alteration zoning and mineralization process of the Maoping Pb-Zn deposit are discussed. Three ore body groups of the Maoping Pb-Zn deposit have similar transversal zoning, which is characterized by different mineral assemblages from the ore body center to outside. The mineralization-alteration can be divided into diagenetic stage, massive sulfide-carbonate stage, veined sulfide-carbonate stage, and supergene stage. The massive sulfide-carbonate stage is main Pb-Zn mineralization stage. The established zoning model and indicators can be used for ore prospecting.

Murine Typhus in Drug Detoxification Facility, Yunnan Province, China, 2010

Murine Typhus in Drug Detoxification Facility, Yunnan Province, China, 2010

New paleomagnetic investigations of the Emeishan basalts in NE Yunnan, southwestern China: Constraints on eruption history

Paleomagnetic and magnetostratigraphic investigations have been conducted on two consecutive sections of the Emeishan trap at Shuimo (SM) and Dadi (DD) in northeastern Yunnan province, southwestern China. Rock magnetic analysis indicates that the magnetic carrier of the basalts is dominantly low-Ti magnetite. Stepwise thermal demagnetization isolates a stable characteristic remanent magnetization (ChRM) at high temperatures (400–585°C). The ChRMs (301/323) at SM section are northeasterly upward of normal polarity, with a mean direction of Ds/Is=11.0/−5.2° (N=12, k=53.7, α95=6.0°). At DD section, the ChRMs are southwesterly downward of reversed polarity, with a mean direction of 205.9/10.0° (N=5, k=78.4, α95=8.7°). The ChRMs from the basaltic gravels from the overlying conglomerate layer in late Permian Xuanwei Formation at DD section pass the conglomerate test, suggesting the primary nature of magnetization. Together with other magnetostratigraphic studies (e.g., N–R pattern) of the Emeishan basalts and the known radiometric ages (ca 260Ma), it suggests that the eruption period of the Emeishan large igneous province is less than 3Myr.

Carbon and strontium isotope evolution of seawater across the Ediacaran–Cambrian transition: Evidence from the Xiaotan section, NE Yunnan, South China

This study reports a high-resolution carbon and strontium isotope profile for the Ediacaran–Cambrian Xiaotan section, situated in northeastern Yunnan, South China. Xiaotan section represents a more distal setting than the more condensed Meishucun section in eastern Yunnan, and is, biostratigraphically and chemostratigraphically, the best constrained section on the Yangtze platform covering the Ediacaran–Cambrian interval. The carbonate carbon isotopic ratios of the late Ediacaran, upper Dengying Formation to the early Cambrian, Zhujiaqing Formation, exhibit a large negative excursion (N1, −12.2‰) in the Daibu Member, just below the first appearance of small shelly fossils (SSF) at the base of the Zhongyicun Member, and a sustained pre-‘Tommotian’ positive excursion (P4, δ13C up to +7.3‰) which coincides with the occurrence of the Heraultipegma yunnanensis (=Watsonella crosbyi) Assemblage SSF in the Dahai Member. Least altered strontium isotope ratios, based on sequential acid leaching of limestones as well as dolostones and phosphorites following rigid petrographic and geochemical selection, reveal a systematic decreasing trend from 0.7085–6 in the latest Ediacaran (Daibu Member) to about 0.7082–3 by the FAD of Watsonella crosbyi in China (Dahai Member). The carbon and strontium isotope features of the Xiaotan section can be correlated with those from sections in Morocco, Mongolia and Siberia, and confirm a decrease in seawater 87Sr/86Sr during Cambrian Stage 1 accompanied by C-isotope oscillations, which together may assist global stratigraphic correlation of the early Cambrian. As previously intimated by C-isotopes and biostratigraphy, this new Sr-isotope evidence confirms a depositional gap during the pre-Tommotian in the Aldan River area of SE Siberia. The decreasing trend of 87Sr/86Sr in the Cambrian Stage 1 marks a temporary (∼16Myrs) reversal of the overall increasing trend during the Ediacaran and Cambrian periods, and potentially records a short-term decrease in continental weathering within a prolonged interval of generally increasing weathering rates. Other factors, such as increased submarine hydrothermal alteration, ocean spreading rates and/or chemical weathering of volcanic provinces and young carbonate dissolution might also have affected this decrease in seawater 87Sr/86Sr.

The ge of the Shizhaishan Cultural Complex

Ge was one of the most widely used weapons during the Bronze and early Iron Age of China. It was common from the later 2nd millennium BCE until the end of the pre-Christian era in northern China, and remained in use until the late Western Han Dynasty in southwestern China. This paper discusses the chronological distribution, functions and possible stylistic origin of ge from the Shizhaishan cultural complex, a Bronze-Iron Age culture distributed over central and northeastern Yunnan. The analysis indicates that this weapon was first adopted from the beginning of the Spring and Autumn period in northeastern Yunnan and then peaked during the late Warring States period and Western Han in the Lake Dian region. The ge of the Shizhaishan cultural complex possibly had more functions than their northern counterparts, and the Shizhaishan people possibly transformed them in size, shape and decoration in order to meet the local tastes. Furthermore, the typological evidence suggests that the stylistic origin of Shizhaishan ge was Sichuan.

Ligularia qiaojiaensis sp. nov. (Asteraceae) from Yunnan, China

Ligularia qiaojiaensisY. S. Chen & H. J. Dong sp. nov., known from two localities in northeastern Yunnan province of China, is described, illustrated and compared with similar species.

Calanthe yaoshanensis sp. nov. (Orchidaceae) from northeastern Yunnan, China

A new species of Orchidaceae, Calanthe yaoshanensis Z. X. Ren & H. Wang from northeastern Yunnan, China, is described and illustrated. It is morphologically similar to C. brevicornu Lindley, from which it differs by having a glabrous column and an elliptical middle lobe with three triangular lamellae. The morphological differences between C. yaoshanensis and related species are discussed. The habitat was investigated and its conservation status was assessed as a 'Critically Endangered' (CR).

Two Zosterophyll Plants from the Lower Devonian (Lochkovian) Xitun Formation of Northeastern Yunnan, China

Abstract:Two zosterophyll plants are described from the Lower Devonian (Lochkovian) Xitun Formation of Qujing, Yunnan, China. Xitunia spinitheca gen. et sp. nov. has stalked sporangia laterally attached on the axis in a helical arrangement. Sporangia are dorsoventrally flattened and composed of two unequal valves; the adaxial valve is round in face view, while the abaxial valve is larger than the former, triangular or wedge‐shaped, and radially bears long spiny appendages along the distal margin. Xitunia shows new variation of sporangial morphology within the zosterophylls. Zosterophyllum minorstachyum sp. nov. has K‐shaped branchings at the basal parts and small‐sized terminal spikes, which consist of round to elliptical sporangia arranged helically. This paper provides new data on the diversity of plant types during Lochkovian when rare vascular plants were reported. As for various species of Zosterophyllum in South China, their apparent evolutionary trend of features from the Late Silurian to Early Devonian (Emsian) is discussed.

Floristic Equilibrium Point and Its Biogeographic Significance

The floristic equilibrium point and its biogeographic significance are important for understanding the floristic origin, distribution, and spatial patterns of plant diversity. Based on field surveys, documented data and related case studies, the relationship between altitude and latitude at floristic equilibrium points, and its biogeographic significance are examined. The results showed a floristic equilibrium point at 2 050 m elevation on Mt. Yao, northeastern Yunnan, China. The elevation of the floristic equilibrium point decreases with an increase in latitude. Mean annual temperature at different floristic equilibrium points shows high consistency around 12.96±0.28℃, which hints that the floristic equilibrium point reflects certain energy requirements. Below the floristic equilibrium point, the majority of the flora contains tropical and subtropical elements; above that point temperate elements are dominant. According to the relationship between altitude and latitude at the floristic equilibrium point, the theoretical north-south dividing line between the vegetation in eastern China is around 36°N. According to the mean annual temperature at the floristic equilibrium point and spatial patterns of the isotherm in eastern China, the north-south boundary of vegetation is between 34 and 35°N, on the northern slope of the Qinling Mountains, which is consistent with previous case studies.

Rhododendron qiaojiaense(Ericaceae), a New Species from Yunnan, China

Rhododendron qiaojiaense L.M. Gao & D.Z. Li sp. nova (Ericaceae) is described from northeastern Yunnan, China, and illustrated. The new species is compared with the morphologically similar R. decorum and R. vernicosum.

The Most Complete Pistosauroid Skeleton from the Triassic of Yunnan, China

Abstract: A new specimen discovered from the Falang Formation in northeastern Yunnan represents the most complete skeleton of Triassic pistosauroids. The new specimen is referred to Yunguisaurus Cheng et al., 2006 on the basis of the skull features, such as the presence of a separated nasal entering the external naris, a large pineal foramen located at the frontal/parietal suture and an interpterygoid vacuity with a narrow anterior extension. The new specimen differs from the type species of Yunguisaurus liae Cheng et al., 2006 in some aspects. Most of these differences can be attributed to ontogenetic variations. The new specimen is provisionally considered as Yunguisaurus cf. liae although its relatively short snout of the skull and slenderer hyoid may not be explained ontogenetically. Whether or not the new specimen represents a different taxon has to wait for a detailed study of the whole skeleton.

Geochemistry and geochronology of native copper mineralization related to the Emeishan flood basalts, Yunnan Province, China

Native copper mineralization in northeastern Yunnan is related to the Emeishan flood basalts, which have high Cu background concentrations. The deposits are located in the Ludian, Maoling and Yiche synclines between the flood basalts and the overlying Xuanwei Formation. Evidence from REE and HSFE concentrations, oxygen isotope compositions, bitumen reflectance, and mineral paragenesis indicates that the high-grade copper orebodies were deposited from moderate to low temperature hydrothermal solutions (420 to 100 °C) in a reducing environment. 40Ar/ 39Ar spectra for the laumontites that coexist with native copper in the high-grade ores yield consistent plateau and isochron ages (226 to 228 Ma). These are interpreted to represent the age of the first stage of hydrothermal mineralization, which took place at temperatures of 200 to350 °C, concordant with that of Zn–Pb–Ag–Ge mineralization also occurring in the area. The heulandites yield a stable 40Ar/ 39Ar plateau age of 134.0 ± 1.7 Ma, consistent with isochron ages indicated by U–Th–Pb isotopic systematics, indicating a second stage of native copper mineralization at lower temperatures (100 to 200 °C) that took place during the Early Cretaceous.

CONTOURS OF AN ANTHROPOLOGY OF THE CHINESE STATE: POLITICAL STRUCTURE, AGENCY AND ECONOMIC DEVELOPMENT IN RURAL CHINA

Anthropologists have long been inclined to view China from the perspective of a state‐society dichotomy. In this model, the inevitable consequence of economic reform is that – especially at the local level – the state must yield more and more of its power to entrepreneurs, foreign investors, non‐state organizations, and local communities. Not only does this approach distort the role of the state in society, but by placing the state above and outside society it also excludes it from the anthropological gaze. This article proposes an anthropology of the Chinese state which does not merely view the state in society, but also investigates the state itself as society. Drawing on fieldwork in northeastern Yunnan province, I illustrate this general point by investigating the changing role of the local state in economic development. This agenda for an anthropology of the Chinese state resonates both with the recent ‘reinvention’ of the subfield of political anthropology with its focus on governmentality, policy, and rights, and with recent calls by political scientists for the development of an interdisciplinary anthropology of the developmental state.

Species composition and diversity of fig wasps and figs in Yunnan

Hymenoptera of the family Agaonidae (fig wasps) are the obligate pollinating insects of fig trees (Ficus spp.), and fig syconium is the only host of fig wasp. For the pollination of their flowers, fig trees are dependent upon fig wasps. For their reproduction and growth, fig wasps are dependent upon the gall (ovaries) of the figs, in which their larvae develop. Thus, the two groups share a symbiotic relationship. Species diversity and richness of fig and fig wasp are highest in Yunnan among all the provinces of China. Our study shows that the fig wasps collected from Yunnan include 50 species of 12 genera, which are mainly distributed in the tropics and south sub-tropics below an altitude of 1600 m. Both figs and fig wasps decrease in species number with increasing altitude. Above an altitude of 3700 m, no natural fig tress were found, except for cultivated species. Species diversity increased in the following order: northwestern Yunnan (H′= 0.6902), northeastern Yunnan (H′= 0.6976), central Yunnan (H′= 0.9211), southeastern Yunnan (H′= 1. 2164), western Yunnan (H′=1.5017), and southern Yunnan (H′=1.6441).

Strontium isotope geochemistry of the Lemachang independent silver ore deposit, northeastern Yunnan, China

Sr isotope geochemical studies (the87Sr/86Sr and δ18O-87Sr/86Sr systems) on the wall rocks and ores from the Lemachang independent Ag deposit in northeastern Yunnan provide strong evidence that the ore-forming fluids had flown through radiogenetically Sr-enriched rocks or strata prior to their entry into the locus of ore precipitation, and water-rock interaction is the main mechanism of Ag ore precipitation. The radiogenetically Sr-enriched source region may be the Proterozoic basement (the Kunyang and Hekou groups). Moreover, the theoretical modeling of the Sr isotopic system indicates that the ore-forming fluids contain as much as 3×10-6 Sr with isotopic composition of Sr being 0.750 and that of oxygen 7.0‰ The ore-forming temperatures were estimated at 150–250°C for the carbonate rock-type ores and at 200–260°C for the clastic rock-type.