The Granada ignimbrite: A compound pyroclastic unit and its relationship with Upper Miocene caldera volcanism in the northern Puna

The Granada ignimbrite, an Upper Miocene volcanic unit from the northern Puna, previously has been interpreted as an extensive ignimbrite (>2300 km²) associated with eruptions from the Vilama caldera (trap-door event). On the basis of new data, we revise its correlation and redefine the unit as a compound, high aspect ratio ignimbrite, erupted at approximately 9.8 Ma. Calculated volumes (100 km³) are only moderate in comparison with other large volume (>1000 km³) ignimbrites that erupted approximately 2–6 m.y. later in the region (e.g. Vilama, Panizos, Atana). Six new volcanic units are recognized from sequences previously correlated with Granada (only one sourced from the same center). Consequently, the area ascribed to the Granada ignimbrite is substantially reduced (630 km²), and links to the Vilama caldera are not supported. Transport directions suggest the volcanic source for the Granada ignimbrite corresponds to vents buried under younger (7.9–5 Ma) volcanic rocks of the Abra Granada volcanic complex. Episodes of caldera collapse at some stage of eruption are likely, though their nature and timing cannot be defined from available data. The eruption of the Granada ignimbrite marks the onset of a phase of large volume (caldera-sourced) volcanism in the northern Puna.     

斑节对虾高密度养殖配合饲料的研制

为了适应斑节对虾高密度养殖业迅猛发展的需要,研制了粤海牌斑节对虾饲料。该饲料配方合理,工艺先进,不加粘结剂,能达到水中稳定性的要求。试验结果表明：饵料系数1．39～2．18,饲养79～126d,产量6870～9240kg／hm2,收虾规格54～72尾／kg;饲养的斑节对虾肌肉饱满,活力强。     

辽东半岛南部张夏组中上部高频率旋回层序及复合海平面变化

辽南地区张夏组中上部高频率旋回地层特征明显,反映高频旋回特点。根据岩性、岩相及界面特征,对其进行划分。其中复州地区划分出４个四级旋回层序,２１个五级旋回层序,７０～８０个六级旋回层序;大连地区共划分出４个四级旋回层序,１９个五级旋回层序及７４个六级旋回层序。各级别旋回层均由相应的次一级旋回层序向上变浅、变厚、变粗的序列组成,其底部均以相应级别的间断—加深面为界。三、四级旋回层序具有区域对比意义。该期海平面具有高频振荡特点,为一复合海平面变化旋回。     

Geology and mineralization of the Pulang supergiant porphyry copper deposit (5.11 Mt) in Shangri-la,Yunnan Province,China: A review

The porphyry copper belt in the Geza island arc in southwestern China is the only Indosinian porphyry copper metallogenic belt that has been discovered and evaluated so far. The Pulang porphyry copper deposit (also referred to as the Pulang deposit) in this area has proven copper reserves of 5.11×10⁶ t. This deposit has been exploited on a large scale using advanced mining methods, exhibiting substantial economic benefit. Based on many research results of previous researchers and the authors’ team, this study proposed the following key insights. (1) The Geza island arc was once regarded as an immature island arc with only andesites and quartz diorite porphyrites occurring. This understanding was overturned in this study. Acidic endmember components such as quartz monzonite porphyries and quartz monzonite porphyries have been identified in the Geza island arc, and the mineralization is mainly related to the magmatism of quartz monzonite porphyries. (2) Complete porphyry orebodies and large vein orebodies have developed in the Pulang deposit. Main orebody KT1 occurs in the transition area between the potassium silicate alteration zone of quartz monzonite porphyries and the sericite-quartz alteration zone. Most of them have developed in the potassium silicate alteration zone. The main orebody occurs as large lenses at the top of the hanging wall of rock bodies, with an engineering-controlled length of 1920 m and thickness of 32.5‒630.29 m (average: 187.07 m). It has a copper grade of 0.21%‒1.56% (average: 0.42%) and proven copper resources of 5.11×10⁶ t, which are associated with 113 t of gold, 1459 t of silver, and 170×10³ t of molybdenum. (3) Many studies on diagenetic and metallogenic chronology, isotopes, and fluid inclusions have been carried out for the Pulang deposit, including K-Ar/Ar-Ar dating of monominerals (e.g., potassium feldspars, biotites, and amphiboles), zircon U-Pb dating, and molybdenite Re-Os dating. The results show that the porphyries in the Pulang deposit are composite plutons and can be classified into pre-mineralization quartz diorite porphyrites, quartz monzonite porphyries formed during the mineralization, and post-mineralization granite porphyries, which were formed at 223±3.7 Ma, 218±4 Ma, and 207±3.9 Ma, respectively. The metallogenic age of the Pulang deposit is 213‒216 Ma. (4) The petrogeochemical characteristics show that the Pulang deposit has the characteristics of volcanic arc granites. The calculation results of trace element contents in zircons show that quartz monzonite porphyries and granite porphyries have higher oxygen fugacity. The isotopic tracing results show that the diagenetic and metallogenic materials were derived from mixed crust- and mantle-derived magmas.©2022 China Geology Editorial Office.     

面向资源环境行业需求的多层次复合型地理信息人才培养模式

随着资源环境行业对地理信息人才需求的增加,结合目前地理信息系统专业在人才培养模式上的不足,如培养目标不清晰、课程体系与行业需求不协调、学生实践能力不足和缺乏特色专业教材等,本文提出了面向资源环境行业需求的多层次复合型地理信息人才培养模式,并从课程体系与教学方法、实践教学环节、开放式办学模式、特色专业建设和教师队伍建设等5个方面途径来阐述这一培养模式。     

Numerical calculation for bed variation in compound-meandering channel using depth integrated model without assumption of shallow water flow

In a compound meandering channel, patterns of flow structures and bed variations change with increasing water depth owing to complex momentum exchange between high-velocity flow in a main channel and low-velocity flows in flood plains. We have developed a new quasi-three-dimensional model without the shallow water assumption, i.e., hydrostatic pressure distribution; our method is known as the general bottom velocity computation (BVC) method. In this method, a set of depth-integrated equations, including depth-integrated momentum and vorticity equations, are prepared for evaluating bottom velocity and vertical velocity distributions. The objective of this study is to develop a bed variation calculation method for both single and compound meandering channels by using the BVC method coupled with a sediment transport model. This paper shows that the BVC method can reproduce the pattern change of bed variation in a compound meandering channel flow with increasing relative depth. The variation in sediment transport rate due to overbank flow is explained by experimental and computational results.     

兴趣点的检查算法研究与实现

软件检查是提升地图数据质量的重要手段,本文通过对兴趣点名称和代码间关系的分析研究,提出了兴趣点的自动检查算法并编程实现,为城市兴趣点数据库的大规模生产提供了质量保证;文中提出的重复点检查算法,部分解决了兴趣点简称和全称匹配问题,可为互联网上中文搜索引擎、地图网站查询搜索工具提供借鉴。     

腾冲地洼区—一个复合型地洼区

腾冲地区是由元古代的地槽褶皱带,经古生代—三叠纪的地台体制,至侏罗纪开始构造-岩浆活化作用形成的地洼区。该区地洼阶段的演化及成因机制分为二个阶段。早期(侏罗纪-早第三纪)以花岗岩多次侵入为特征。这些花岗岩的主元素、微量元素及同位素特征均可与中国东部地洼花岗岩相对比。此阶段的地台活化作用源自该区的深部活动过程。晚第三世纪开始,该区的大地构造演化机制发生重大转折。巽他陆块与印度陆地的碰撞控制着该区的活化作用,形成广泛的中—基性火山岩喷发,这些火山岩的地球化学研究证明其构造背最及成因均与火山弧岩石相似。因此,从成因机制角度,腾冲地区属一个复合型地洼区。     

Typhoon disaster in China: prediction,prevention, and mitigation

Typhoon-induced disaster is one of the most important factors influencing the economic development and more than 250 million in China. In view of the existing state of typhoon disaster prediction, prevention, and mitigation, this paper proposes a new probability model, Multivariate Compound Extreme Value Distribution (MCEVD), to predict typhoon-induced extreme disaster events. This model establishes prevention criteria for coastal areas, offshore structures, and estuarine cities, and provides an appropriate mitigation scheme for disaster risk management and decision-making.     

Molecular and stable carbon isotopic characterization of PAH contaminants at McMurdo Station, Antarctica

The molecular and stable carbon isotopic compositions of contaminant polycyclic aromatic hydrocarbons (PAHs) at McMurdo Station, Antarctica were analyzed in samples collected from land and sub-tidal area. PAHs in the study areas were characterized by high amounts of naphthalene and alkylated naphthalenes from petroleum products introduced by human activities in the area. Principal component analysis (PCA) of PAH composition data identified multiple sources of PAH contamination in the study area. Compositional assignments of origins were confirmed using compound specific stable carbon isotopic analysis.