scholarly journals Geochronological Study of the Jiashengpan Zn–Pb Deposit in Northern China: Implications for Base Metal Mineralization in Collisional Orogens

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 622
Author(s):  
Yu ◽  
Zhong ◽  
Xie ◽  
Li
Keyword(s):  
Shear Zone ◽  
Base Metal ◽  
North China ◽  
Northern China ◽  
Ore Formation ◽  
The North ◽  
Geochronological Study ◽  
Orogenic Belts ◽  
Collisional Orogens ◽  
Base Metal Mineralization

The Jiashengpan Zn–Pb deposit is located in the Langshan-Zhaertai region of the North China Craton. Zinc-lead mineralization at the Jiashengpan shows characteristics of shear-zone controlled syn-metamorphic mineralization. The 39Ar/40Ar ages of syn-ore hydrothermal muscovite averages at ~380 Ma, suggesting that the Zn–Pb mineralization took place in the Devonian. These results agree with zircon U–Pb ages of post-ore granite, which constrain the ore formation to be older than 277 ± 2 Ma. Ore formation was coeval with the emplacement of regional orogenic belts that formed as result of subduction associated with the closure of the eastern Paleo-Asian Ocean (~400 Ma). The Jiashengpan deposit provides evidence for base metal mineralization associated with metamorphogenic and shear-zone controlled characteristics during continental-continental collision, stressing the significance of orogenic activities for enrichment of base metals.

Hydrologic and Climatic Responses to Global Anthropogenic Groundwater Extraction

2017 ◽  
Vol 30 (1) ◽  
pp. 71-90 ◽  
Author(s):  
Yujin Zeng ◽  
Zhenghui Xie ◽  
Jing Zou
Keyword(s):  
North China Plain ◽  
North China ◽  
Supply And Demand ◽  
Northern China ◽  
Large Area ◽  
Deep Soil ◽  
Northern India ◽  
The North ◽  
The North China Plain ◽  
Climatic Responses

In this study, a groundwater (GW) extraction scheme was incorporated into the Community Earth System Model, version 1.2.0 (CESM1.2.0), to create a new version called CESM1.2_GW, which was used to investigate hydrologic and climatic responses to anthropogenic GW extraction on a global scale. An ensemble of 41-yr simulations with and without GW extraction (estimated based on local water supply and demand) was conducted and analyzed. The results revealed that GW extraction and water consumption caused drying in deep soil layers but wetting in upper layers, along with a rapidly declining GW table in areas with the most severe GW extraction, including the central United States, the north China plain, and northern India and Pakistan. The atmosphere also responded to GW extraction, with cooling at the 850-hPa level over northern India and Pakistan and a large area in northern China and central Russia. Increased precipitation occurred in the north China plain due to increased evapotranspiration from irrigation. Decreased precipitation occurred in northern India because the Indian monsoon and its transport of water vapor were weaker as a result of cooling induced by GW use. Additionally, the background climate change may complicate the precipitation responses to the GW use. Local terrestrial water storage was shown to be unsustainable at the current high GW extraction rate. Thus, a balance between reduced GW withdrawal and rapid economic development must be achieved in order to maintain a sustainable GW resource, especially in regions where GW is being overexploited.

scholarly journals Three-Dimensional Circulation Structure of Summer Heavy Rainfall in Central North China

2015 ◽  
Vol 30 (1) ◽  
pp. 238-250 ◽  
Author(s):  
Wei Sun ◽  
Rucong Yu ◽  
Jian Li ◽  
Weihua Yuan
Keyword(s):  
Heavy Rainfall ◽  
North China ◽  
Three Dimensional ◽  
Lower Troposphere ◽  
Northern China ◽  
Front Side ◽  
The North ◽  
Westerly Jet ◽  
High Level ◽  
Circulation Structure

Abstract Based on daily rainfall observations and Japanese 25-year Reanalysis Project data during ~1981–2010, a three-dimensional circulation structure that formed before heavy summer rainfall in central north China (CNC) is revealed in this study. Composite analyses of circulation in advance of 225 heavy rain days show that the circulation structure is characterized by a remarkable upper-tropospheric warm anomaly (UTWA), which covers most of northern China with a center at ~300 hPa. Under hydrostatic and geostrophic equilibriums, the UTWA contributes to the generation of an anticyclonic (cyclonic) anomaly above (below). The anticyclonic anomaly strengthens (weakens) westerly winds to the north (south) of the warm center and pushes the high-level westerly jet to the north. The cyclonic anomaly deepens the trough upstream of CNC and intensifies lower southwesterly winds to the mideast of the warm center. As a result, the northerly stretched high-level jet produces upper divergence in its right-front side and the intensified southwesterly winds induce lower moisture convergence in its left-front side, causing heavy rainfall in CNC. Correlation analyses further confirm the close connections between UTWA and circulation in the upper and lower troposphere. The correlation coefficients between UTWA and the upper geopotential height, upper westerly jet, and lower southerly flow reach 0.95, 0.70, and 0.39, implying that the two critical factors leading to intense rainfall in CNC, the high-level jet and the low-level southerly flow, are closely connected with the UTWA. Consequently, in the future analyses and forecasts of heavy rainfall over northern China, more attention should be paid to the temperature in the upper troposphere.

Enigma of the Jurassic monster shift of the North China block

2020 ◽  
Author(s):  
Shihong Zhang ◽  
Yangjun Gao ◽  
Qiang Ren
Keyword(s):  
North China ◽  
Rotation Axis ◽  
Eastern Asia ◽  
North China Block ◽  
Polar Wander ◽  
Plate Convergence ◽  
True Polar Wander ◽  
The North ◽  
Geochronological Study ◽  
Oceanic Plates

<p>Accumulation of the global paleomagnetic data, from both continental and oceanic plates, may suggest a true polar wander (TPW) event in Jurassic, with a rotation axis located in the present northwestern Africa, but no consensus has been reached regarding to the initiation, duration and velocity of the TPW. As one of the eastern Asian blocks, the north China block (NCB) is then located far from the rotation axis of the TPW and the plate convergence between Siberia and the Amur-NCB, known as the subduction in the Mesozoic Okhotsk-Baikal ocean, did exist. Paleogeographic changes observed of the eastern Asian blocks in Jurassic thus should contain the TPW component and plate moving component. To better estimate the influence of the TPW in the Eastern Asia blocks, we carried out a new paleomagnetic and precision U-Pb geochronological study on the middle Jurassic lavas in the NCB. Being profoundly different to the recent paleogeographic model (Yi et al., 2019, https://doi .org/10.1130/G46641.1) that suggest that the NCB experienced a large latitudinal displacement (monster-shift) responding to the TPW event between ~174 and ~157 Ma, we suggest that the NCB, as well as other blocks already connected with it, do not record any monster-shift between ~170 and ~160 Ma. The strata, ranging from 160 to 145 Ma, however, yield considerable paleomagnetic variations and need further investigation.</p>

scholarly journals Correcting model biases of CO in East Asia: impact on oxidant distributions during KORUS-AQ

2020 ◽  
Author(s):  
Benjamin Gaubert ◽  
Louisa K. Emmons ◽  
Kevin Raeder ◽  
Simone Tilmes ◽  
Kazuyuki Miyazaki ◽  
...  
Keyword(s):  
East Asia ◽  
North China ◽  
Climate Models ◽  
Northern China ◽  
Liaoning Province ◽  
Late Winter ◽  
Model Errors ◽  
Chemical Production ◽  
The North ◽  
Chemistry Research

Abstract. Global coupled chemistry-climate models underestimate carbon monoxide (CO) in the Northern Hemisphere, exhibiting a pervasive, negative bias against measurements peaking in late winter and early spring. While this bias has been commonly attributed to underestimation of direct anthropogenic and biomass burning emissions, chemical production and loss via OH reaction from emissions of anthropogenic and biogenic VOCs play an important role. Here we investigate the reasons for this underestimation using aircraft measurements taken in May and June 2016 from the Korea United States Air Quality (KORUS‐AQ) experiment in South Korea and the Air chemistry Research In Asia (ARIAs) in the North China Plain (NCP). For reference, multispectral CO retrievals (V8J) from the Measurements of Pollution in the Troposphere (MOPITT) are jointly assimilated with meteorological observations using an Ensemble Adjustment Kalman Filter (EAKF) within the global Community Atmosphere Model with Chemistry (CAM-chem) and the Data Assimilation Research Testbed (DART). With regard to KORUS-AQ data, CO is underestimated by 42 % in the Control-Run and by 12 % with the MOPITT assimilation run. The inversion suggests an underestimation of anthropogenic CO sources in many regions, by up to 80 % for Northern China, with large increments over the Liaoning province and the North China Plains (NCP). Yet, an often-overlooked aspect of these inversions is that correcting the underestimation in anthropogenic CO emissions also improves the comparison with observational O3 datasets, and observationally constrained box model simulations of OH and HO2. Running a CAM-chem simulation with the updated emissions of anthropogenic CO reduces the bias by 29 % for CO, 18 % for ozone, 11 % for HO2 and 27 % for OH. Longer lived anthropogenic VOCs whose model errors are correlated with CO are also improved while short-lived VOCs, including formaldehyde, are difficult to constrain solely by assimilating satellite retrievals of CO. During an anticyclonic episode, better simulation of O3, with an average underestimation of 5.5 ppbv and a reduction in the bias of surface formaldehyde and oxygenated VOCs can be achieved by separately increasing by a factor of two the modeled biogenic emissions for the plant functional types found in Korea. Results also suggest that controlling VOC and CO emissions, in addition to wide spread NOx controls, can improve pollution ozone over East Asia.

scholarly journals Characteristics of trace gaseous pollutants at a regional background station in Northern China

2009 ◽  
Vol 9 (3) ◽  
pp. 927-936 ◽  
Author(s):  
Z. Y. Meng ◽  
X. B. Xu ◽  
P. Yan ◽  
G. A. Ding ◽  
J. Tang ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Trace Gases ◽  
Northern China ◽  
Diurnal Variations ◽  
Gaseous Pollutants ◽  
The North ◽  
The North China Plain ◽  
Plain Region ◽  
Co Concentrations

Abstract. Measurements of trace gaseous pollutants were taken at the Shangdianzi site, a WMO Global Atmosphere Watch (GAW) background station in Northern China. The results are presented for the period from September 2003 to December 2006. Seasonal and diurnal variations of the O3, NOx, SO2, and CO concentration are characterized and possible causes for them are discussed. The observed levels of the trace gases are comparable to those at some other background sites in polluted regions inside and outside of China. It was shown that the seasonal variation of O3 can change slightly from year to year due to the year-to-year alternation in the meteorological conditions. Higher CO concentrations were observed in some warmer months, particularly in June and July, 2006. Intensive biomass burning in the North China Plain region, in combination with the transport of regional pollution by more frequent southwesterly winds, is believed to be responsible for the elevated CO concentrations. The diurnal variation of O3, with delayed peaking times, suggests that the transport of photochemical aged plume is an important source for O3 at Shangdianzi. The diurnal variations of SO2 in all seasons show higher values during daytime, contradicting the common view. An explanation for this unusual phenomenon is hypothesized. To gain an insight into the impact of transport on the trace gases levels at Shangdianzi, air mass backward trajectories were calculated and analyzed in combination with corresponding pollutant concentrations. The results indicate that the transport of air masses from the North China Plain region and from the major coal mining regions west of Shangdianzi is responsible for the high concentrations of the gaseous pollutants.

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