Geochronology and Petrogenesis of the Pillow Basalts in Western Karamay from West Junggar, NW China

<正>Recently,we carried out the National Nature Science Foundation of China(No.41303027)and focused on pillow basalts in western Karamay from West Junggar.The detailed geological survey at a scale of 1:500 distinguished an assemblage of accretionary complex in western Karamay.The accretionary complex consists of     

Petrogenesis of Early and Late Carboniferous Volcanic Rocks in theYining Block: Constraints from Sr-Nd Isotope

<正>The Yining Block is located in the southwestern part of the Central Asian Orogenic Belt(CAOB),which is characterized by widespread Carboniferous volcanic rocks.Recently,we carried out the National Nature Science Foundation of China(No.41273033)and Special Fund for Basic Scientific Research of Central Colleges(No.     

Accration and Subduction of Seamounts in West Junggar

<正>Recently,through implementation of the National Nature Science Foundation of China(No.41303027)and Special Fund for Basic Scientific Research of Central Colleges(310827153506,310827153407,2014G1271058),we focused on basalts in Darbut and Karamay ophiolitic mélanges in West Junggar which is a part of the Central Asian Orogenic Belt,and made some advances as follows.     

青藏高原东南缘金沙江下游新生代构造与地貌演化

青藏高原东南缘发育数十万平方千米的广阔地貌过渡带与大面积低起伏地貌面,独特的地貌提供了解读高原构造拓展与地表隆升时间、过程以及机制的理想窗口。为揭示青藏高原东南缘新生代构造变形响应和地貌演化过程,通过构造解析、构造地貌以及低温热年代学数据分析对金沙江下游流域进行综合研究。结果表明青藏高原东南缘早在始新世即已处于北西向为主的区域性挤压条件下而发生广泛褶皱变形。尽管始新世存在区域性变形响应,但青藏高原东南缘金沙江下游地区在古近纪为低海拔丘陵地貌,地表隆升幅度极为有限。晚渐新世—早中新世研究区总体处于长期的低剥蚀速率环境,促进了低海拔平缓地貌的形成。晚新近纪以来,青藏高原东南缘发生区域性缩短变形与显著地表隆升,大型水系同步下蚀,共同塑造形成现今较高海拔的低起伏地貌面与深切峡谷并存的特征性地貌。研究结果支持青藏高原东南缘晚新近纪以来的隆升与地壳构造缩短及增厚密切相关,而中下地壳塑性流动增厚机制并非必不可少。     

新太古界Campbellrand亚群白云岩岩溶系统对南非Postmasburg锰矿田的影响

为分析新太古界Campbellrand亚群白云岩基底形成的岩溶系统对南非Postmasburg锰矿田发育和分布的影响,笔者等利用XRF和偏光显微镜鉴定技术,结合野外地质调查和岩芯钻探,对矿石的矿物成分、矿体中的Mn、Fe空间分布、Doornfontein砾岩的结构特征、白云岩容矿构造的形态进行了研究。结果表明：Maremane穹隆上的Campbellrand亚群白云岩遭受了两次大规模的溶蚀。溶蚀构造引起沉积物分异,沉积建造底部Mn质最为富集,向外、向上逐渐由Fe质主导,形成褐锰矿—方铁锰矿—赤铁矿的序列,顶部则演变为铝土质岩。沉积序列中Mn+Fe质和Al质含量呈现出较强的负相关性。溶坑的特殊形态导致矿体受层控,但并不呈现规则的层状形态。东矿带的Wolhaarkop硅质角砾岩与白云岩中的燧石和硅质白云岩密切相关,而混合带和西矿带普遍发育的Doornfontein砾岩则是岩溶作用影响下锰质的成岩作用被推迟所形成,它们都是成矿期岩溶系统发育的间接产物。溶坑底部的锰土混合物揭示了成矿后期溶蚀作用的发生和沉积序列的坍塌破碎,小型的断层也造成了矿体的严重破碎和顶板地层的褶曲。Gamagara低山脊...     

Oceanic Island Basalts within the West Junggar Ophiolitic Mélanges: Petrogenetic and Tectonic Implications

<正>Recently,we focused on the Darbut and Karamay ophiolitic mélanges in West Junggar of the Central Asian Orogenic Belt(CAOB,?engr et al.,1993;Windley et al.,2007;Xiao and Santosh,2014),and made much progress.This study was supported by the National Nature Science Foundation of China(No.41303027)and Special Fund for Basic Scientific Research of Central Colleges Project(No.2014G1271058).The achievements are illustrated as follows.     

Petrogenesis of the Paleozoic and Mesozoic Volcanic Rocks in Northwest China

<正>Recently,we carried out the National Nature Science Foundation of China(No.41273033)and Special Fund for Basic Scientific Research of Central Colleges(No.310827153407)and made some advances as follows.The main research achievements of the Paleozoic volcanic rocks in northwest China include two aspects:     

引水工程出水路线的优化对太湖总磷格局的影响——基于新孟河工程的思考

“新孟河引水”作为“二引三排”格局的关键组成,将长江水直接引入太湖的竺山湖区,在新的引排格局下,“新孟河引水”对太湖水环境尤其是总磷会有怎样的影响？针对“新孟河引水”工程,如何设计出水路线才能趋利避弊,改善太湖总磷？本文实测并收集了2007—2020年太湖的水文水质数据为基础,模拟了不同路线对太湖分湖区总磷的影响,力求将“新孟河引水”对太湖的影响进行一个清晰的分析,并为形成最为合理的出水路线提供支撑.结果表明:太湖不同湖区对出水路线的响应不同.从单一出水路线的角度来看,新孟河引水后,太浦闸增加出水会使得太湖西北部浊水加快来到太湖东南部,对太湖东南部有不利的影响.而梁溪河或新沟河出水的西北小循环是“新孟河引水”工程优化出水路线,在降低竺山湖、梅梁湖总磷的同时,没有恶化太湖东南部水质,对太湖总磷也有降低的效果.在应用中可以组合各种出水路线,形成联动方案.从物料平衡的角度看,太湖底泥目前仍是磷汇.引水后4种出水路线年均滞留量为1435 t,其中出水河道设置在东太湖(太浦闸)磷滞留量最大,年滞留1513 t;出水河道设置在梅梁湖(新沟河、梁溪河)磷滞留量最小,年滞留1404 t左右.     

太湖水体交换周期变化(1986-2018年)及对水质空间格局的影响

针对太湖水体交换周期近十余年发生的变化,本文收集整理了1986-2018年太湖水文巡测、汛期水文巡测数据以及太湖流域沿江城市引水量、流域降雨量变化数据,基于太湖出入湖水量的变化研究了太湖水体交换周期的变化及原因,并对交换周期变化对水质空间格局的影响进行分析.结果 表明:太湖入湖水量有显著上升,2007年以来平均每年入湖...