Trace elements and stable isotopic geochemistry of an Early Cambrian chert-phosphorite unit from the lower Yurtus Formation of the Sugetbrak section in the Tarim Basin

A chert-phosphorite unit from the Sugetbrak section in the Tarim Basin was analyzed for rare earth elements (Ce, Eu), redox sensitive proxies, and carbon isotopic compositions (δ¹³C_carb and δ ¹³C_org) in the lower Yurtus Formation of the Early Cambrian period. Redox sensitive element ratios (Th/U, V/Cr, Ni/Co, and V/Sc) were employed to determine the palaeoenvironmental conditions during this period. The ratios indicated that the depositional environment of the chert-phosphorite-black shale unit ranged from suboxic to anoxic. Negative Ce and positive Eu anomalies in the chert-phosphorite assemblages of the studied Yurtus Formation indicated the existence of a redox-stratified ocean, similar to that of South China. Overturn or upward expansion of the deep water-mass probably reached the shallow marine zone after the formation of the Yurtus phosphorites. The characteristics of the negative Ce anomaly may be due to phosphoritic inheritance from the Ce-depleted signature of the overlying water column. Subsequent hydrothermal inputs and reduced detrital supplies of the deep water caused by the upwelling affected certain redox sensitive elements in the sedimentary basin. δ ¹³C_carb and δ¹³C_org negative excursions in the Yurtus chert-phosphorite unit may be related to a transgression phase when episodic basinal upwelling moved ¹²C- and P-rich waters from the pelagic basin floor to the continental shelf. Although carbon isotopic compositions in the Yurtus chert-phosphorite assemblages may have suffered from diagenetic alteration, they can be used to probe diagenetic conditions. Multi-proxy geochemical studies indicated that the δ ¹³C_carb values of the Yurtus chert-phosphorite assemblages might be considered reflections of a predominantly suboxic environment that was subsequently affected by hydrothermal inputs due to the upwelling.     

纬度圈上的大地震带

根据Ms≥6.0大地震活动的空间分布,有地震带和地震区之分.中国境内既有纵贯南北缘经度分布并把我国地震活动分隔成东西两部分的南北地震带,也有横穿北纬40左右呈东西向分布的阴山、燕山地震带,以及呈片状展布的东北深震区等.     

Hydrachemical Characteristics at the Seismic Stations in Songyuan District,Jilin Province

The hydrochemical types and origins of underground water in Songyuan and vicinity, Liaoning Province were discussed based on the hydrochemical composition, δD and δ¹⁸O. The water samples from eight wells were collected 4 times during 2014 to 2015. The main ion concentrations of water were analyzed with an Ion Chromatography. Isotopic compositions of hydrogen and oxygen were analyzed with the Liquid Water Isotope Analyzer. The mineralization (TDS) of the water ranged from 125.4 mg/L to 19 350.9 mg/L. Values of δD and δ¹⁸O ranged from -71.7‰ to -98.1‰ and from -9.0‰ to -12.5‰, respectively. The isotopic data indicated that the water originated from meteorological precipitation. The chemical compositions of Taolaizhao phreatic water were influenced by the human activity while the other water samples collected from artesian well were less affected by the human activity. Water in Changling, Dongdashi, Taohaotai, Qianan and Ningjiang were characterized by HCO₃-Na with low TDS values. Such chemical types of water with fluctuations of Na⁺, SO42- and δ¹⁸O drift were resulted from dissolving silicate minerals and adding surfactant during oil exploitation. Fresh water in Fuyu well was Cl-Na type, which was influenced by acid injection during oil exploitation. Water in Qianguo well was characterized by Cl-Na type with TDS up to 19 350.9 mg/L, the obvious fluctuations of hydrogen and oxygen isotopes and increasing ion concentrations in the Qianguo well may be caused by the earthquakes that occurred in the sampling duration. The results will provide the background of hydrochemistry, and will be of benefit to monitoring earthquake and certificating seismic-chemical anomalies in the future.     

Kinetics of hydrocarbon generation for Well Yingnan 2 gas reservoir,Tarim Basin,China

Well Yingnan 2, an important exploratory well in the east of Tarim Basin, yields high commercial oil and gas flow in Jurassic. Natural gas components and carbon isotopic composition indicate that it belongs to sapropel type gas. Because this region presents many suits of hydrocarbon source rocks, there are some controversies that natural gases were generated from kerogen gas or crude oil cracking gas at present. By using the kinetics of hydrocarbon generation and carbon isotope, natural gas of Well Yingnan 2 is composed mainly of crude oil cracking gas, about 72%, it is generated from secondary kerogen gas of Cambrian-Lower Ordovician source rock and crude oil cracking gas of Mid-Upper Ordovician oil reservoir. The main oil and gas filling time is 65 Ma later in the Jurassic gas reservoir of Well Yingnan 2, so the gas reservoir belongs to late accumulation and continuous filling type.     

2019年12月26日湖北应城M4.9地震震源参数及余震活动性研究

2019年12月26日湖北应城发生M4.9有感地震,其震感波及武汉大部分地区。为了分析该地震的发震构造及余震活动性,本文利用波形拟合方法测定了不同速度模型下该地震的震源机制解和矩心深度,并用Bootstrapping抽样反演技术评价反演结果;此外,利用模板匹配技术匹配主震和目录余震波形,获取了更为完整的余震目录。结果显示,应城地震以走滑为主,矩心深度7.5km左右,矩震级M_W4.67;应城地震有1个前震和17个余震,余震序列缺少M2~4事件,表明应城地震为孤立型地震,M2以下地震的b值为0.8。     

哀牢山过山气流的气候效应

本文研讨哀牢山脉北段西南季风与东北季风的过山气候效应。     

Understanding geographical patterns of a city’s diurnal rhythm from aggregate data of location‐aware services

Do collective behaviors of the daily routine of a city's inhabitants form the periodical cycling of human activity at the city level (here termed the “city's diurnal rhythm”)? If the answer is yes, do there exist geographical patterns in the city's diurnal rhythm? Using a nationwide dataset of observed uses of location‐aware services in the largest Chinese social media platform, we first confirm the significant periodicity in city‐level human activity from the perspective of the aggregate degree of social media uses over a day. We then investigate geographical changes in the diurnal rhythm of human activity and its local variations in different parts of the city, and between weekdays and weekend days, over 340 Chinese cities. Our results show that a city's diurnal rhythm across the whole country exhibits both regular, nationally conspicuous shifts along geographical gradients and locally distinct spatiotemporal changes within the city. Our findings could provide insights into the characterization of the daily routine of city‐level human activity and its geographical patterns, and have potential for several issues in terms of planning, management, and decision‐making related to human population dynamics.     

不同上覆水氟浓度对湖泊沉积物氟释放与微生物群落的影响

通过模拟沙湖沉积物-水系统,以沙湖原水氟离子（F^-）浓度为1倍浓度（0.69 mg/L）,设置0.5倍浓度、1倍浓度、1倍浓度灭菌、2倍浓度和4倍浓度共5个实验组,探究不同上覆水F^-浓度背景下沙湖沉积物中F^-的迁移.结果表明,沉积物F^-的释放量随上覆水F^-浓度的增加而呈下降的趋势,其中2倍和4倍浓度组的沉积物由释放F^-转变为吸附F^-.碱性水体有利于沉积物F^-的释放,即随着pH增大,F^-释放量也会增加.微生物的Beta多样性层次聚类分析表明,F^-会抑制Paenisporosarcina与Thiobacillus的相对丰度,但对Fusibacter的生命活动具有促进作用.根据各浓度组间优势菌属相对丰度与环境因子的冗余分析可得,Acinetobacter、Thiobacillus相对丰度与pH呈负相关;Fusibacter相对丰度与F^-浓度呈显著正相关,而Thiobacillus的相对丰度则与F^-表现出弱负相关.通过对各浓度组中重要离子的分析发现,0.5倍组和4倍组中F^-的迁移受Ca²⁺、HCO₃^-和SO₄^2-浓度影响较大;相关性分析表明0.5倍浓度组的Ca²⁺、HCO₃^-浓度与F^-浓度呈极显著正相关,而4倍组中F^-浓度和Ca²⁺、HCO₃^-浓度呈负相关,SO₄^2-浓度和F^-浓度的相关性则是0.5倍组呈负相关,4倍组呈极显著正相关.本文在不同上覆水F^-浓度背景下全面探究了沙湖沉积物中F^-释放和迁移机理,为沙湖及其他含氟地表水的氟污染防治提供理论支持.     

高温高压实验弹性波速研究及其地球动力学意义

本文在收集，整理国内外有关高温高压实验岩石，矿物弹性波速研究资料的基础上，对高温高压实验弹性波速研究的目的，内容进行了概述，并对国内外这一领域研究的历史，现状及有关实验技术方法进行了综述，其中重点介绍了我国在高温高压岩石波速研究方面的进展及所取得的成就，并对高温高压弹性波速研究的地球动力学意义进行了讨论。     

云南测震台网地震监测能力分析

2018年1月云南省测震台网示范工程20个新增测震台建设完成,选取原有48个台以及新增20个台连续48小时数据记录,基于近震震级公式,计算并网前后云南省测震台网的地震监测能力,对比测震台增加前后的地震监测能力,发现:云南省地震监测能力由ML 2.2提升到ML 1.6,局部地区由ML1.4提升到ML0.8。