Tectonic affinity of the west Qinling terrane (central China): North China or Yangtze?

The Laodou gold deposit, located in the West Qinling Orogen of central China, is a newly recognized intrusion-related gold deposit. It consists of auriferous quartz-sulfide-tourmaline and minor quartz-stibnite veins that are structurally controlled by fault zones transecting the host quartz diorite porphyry. Two types of tourmaline were identified in this study: Type 1 tourmaline occurs as quartz-tourmaline nodules within the quartz diorite porphyry, whereas type 2 tourmaline occurs as quartz-sulfide-tourmaline veins in auriferous lodes. Here, we present a major and trace element analysis by electron microprobe and laser ablation inductively coupled plasma mass spectrometry on these two types of tourmaline. Both tourmaline types fall into the alkali group, and are classified under the schorl-dravite solid solution series. The substitutions of FeMg–1, FeAl–1, AlO((Fe, Mg)(OH)) –1, and X-site vacancyCa–1 are inferred by the variations of their major element compositions. Field and mineralogy observations suggest that type 1 tourmaline is a product of the late crystallization process of the quartz diorite porphyry, whereas type 2 tourmaline coexists with Au-bearing arsenopyrite and is crystallized from the ore-forming fluids. Their rare earth element compositions record the related magmatic hydrothermal evolution. The Co and Ni concentrations of the coexisting type 2 tourmaline and arsenopyrite define a regression line (correlation coefficient = 0.93) with an angular coefficient of 0.66, which represents the Co/Ni ratio of the tourmaline and arsenopyrite-precipitating fluids. This value is close to the Co/Ni ratios of the host quartz diorite porphyry, indicating a magma origin of the ore-forming fluids. The substitution of Al3+ by Fe3+ in both tourmaline types shows that type 1 tourmaline approaches the end member of povondraite whereas type 2 tourmaline occurs in opposite plots near the end member of Oxy-dravite, reflecting a more oxidizing environment for type 2 tourmaline formation. Moreover, the redox-sensitive V and Cr values of type 2 tourmaline are commonly 1–2 orders of magnitude higher than those of type 1 tourmaline, which also suggests that type 2 tourmaline forms from more oxidizing fluids. Combined with gold occurrence and fluid properties, we propose that the increasing of oxygen fugacity in the ore-forming fluids is a trigger of gold precipitation.

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Spatiotemporal pattern mining of drought in the last 40 years in China based on the SPEI index and space-time cube

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-21-0049.1 ◽

2021 ◽

Author(s):

Dehe Xu ◽

Qi Zhang ◽

Yan Ding ◽

De Zhang

Keyword(s):

North China ◽

Pattern Mining ◽

Space Time ◽

Central China ◽

Spatiotemporal Pattern ◽

Severe Drought ◽

Monthly Precipitation ◽

Hotspot Analysis ◽

The Past ◽

Significant Difference

AbstractDrought is a common natural disaster that greatly affects the crop yield and water supply in China. However, the spatiotemporal characteristics of drought in China are not well understood. This paper explores the spatial and temporal distributions of droughts in China over the past 40 years using multiscale standardized precipitation evapotranspiration index (SPEI) values calculated by monthly precipitation and temperature data from 612 meteorological stations in China from 1980 to 2019 and combines the space-time cube (STC), Mann-Kendall (M-K) test, emerging spatiotemporal hotspot analysis, spatiotemporal clustering and local outliers for the analysis. The results were as follows: 1) the drought frequency and STC show that there is a significant difference in the spatiotemporal distribution of drought in China, with the most severe drought in Northwest China, followed by the western part of Southwest China and the northern part of North China. 2) The emerging spatiotemporal hotspot analysis of SPEI6 over the past 40 years reveals two cold spots in subregion 4, indicating that future droughts in the region will be more severe. 3) A local outlier analysis of the multiscale SPEI yields a low-low outlier in western North China, indicating relatively more severe year-round drought in this area than in other areas. The low-high outlier in central China indicates that this region was not dry in the past and that drought will become more severe in this region in the future.

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Wars and Rumours of War, 1918-1945: Japan, the West and Asia Pacific

10.5117/9781898823636 ◽

2017 ◽

Author(s):

Roger Buckley

Keyword(s):

East Asia ◽

General Public ◽

British Literature ◽

North China ◽

Contextual Analysis ◽

Asia Pacific ◽

The West

Supported by an in-depth Introduction and contextual analysis, this six-volume set complements Series I (1918-1937 – From Armistice to North China), addressing the history between 1938 and1945. Despite the widespread operation of war-time censorship and surveillance, publishers in the West and, to a lesser degree in East Asia, put out a range of material that remains of considerable value to later generations. Some of the texts selected are undeniably partisan but the quantity of the published material (and to some extent its quality) left the general public with a vast and varied archive of printed matter that deserves to be consulted and debated by today's researchers and students. Greater attention is given to American and British literature rather than Chinese or Japanese simply by virtue of the practical realities.

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