中国东南极地质考察20年进展与展望

在1998—2017年期间,我国组织了14次东南极地质考察,将考察的范围从中山站所在的拉斯曼丘陵向外扩展了约400 km,主要包括格罗夫山、埃默里冰架东缘-西南普里兹湾、北查尔斯王子山、布朗山、赖于尔群岛和西福尔丘陵等露岩区。通过大、中比例尺的地质编图和多学科综合研究,取得如下重要进展:(1)确定格罗夫山冰下高地为泛非期(~570—500 Ma)单相变质地体,发现镁铁质和泥质高压麻粒岩并刻画了泛非期造山的精细过程,为普里兹造山带的碰撞造山成因以及冈瓦纳超大陆的多陆块汇聚模型提供了岩石学支撑;(2)论证在印度克拉通与东南极陆块之间存在一个延长2 000 km的中元古代长寿命大陆岛弧,岛弧岩浆作用从~1 500 Ma一直持续到~1 000 Ma,提出雷纳造山带格林维尔期(~1 000—900 Ma)的构造演化可能经历了从弧陆碰撞到陆陆碰撞的过程;(3)在赖于尔群岛超高温变泥质岩中识别出早期蓝晶石的残留,确定了超高温变质作用顺时针演化的精细P-T轨迹;(4)在西福尔丘陵西南部基性岩墙群中发现了格林维尔期(~960—940 Ma)不均匀麻粒岩化,变质条件达820—870℃、0.84—0.97 GPa,认为西福尔陆块也卷入到印度克拉通与东南极陆块的碰撞造山过程;(5)在西福尔丘陵东南部浅变质冰川漂砾和松散砂中获得~3.5—3.3 Ga的古老锆石U-Pb年龄,推测在西福尔丘陵东南方向存在一个从前未知的古太古代冰下陆块。建议今后在东南极面向印度洋构造域的地质考察要进一步扩展到南查尔斯王子山、内皮尔杂岩和登曼冰川,研究工作的重点仍聚焦在南极大陆如何响应地质历史时期里超级大陆的聚散过程这一关键科学问题上,并可在以下几个方面展开:(1)太古宙古老地壳及陆核的识别与全球对比;(2)格林维尔期造山记录与罗迪尼亚超大陆汇聚;(3)泛非期造山记录与冈瓦纳超大陆汇聚;(4)显生宙冈瓦纳超大陆裂解及陆块分离。通过这些考察和研究工作,可以促使我国对南极地质科学的研究达到国际先进水平。     

REE/trace element characteristics of sandstone-type uranium deposits in the Ordos Basin

1 Introduction The Ordos Basin is the second largest sedimentary basin in China. During the last 10 years, a great progress has been achieved in the aspects of tectonic evolution, dynamics process, inner and outer geological processes during Mesozoic-Cen…     

双重介质中核素迁移模型的解析解及其应用

给出了具有单裂隙的双重介质中，裂隙一端有分时注入源情形下的迁移模型的解析解及一些简化条件下的解析解，并利用解析解研究了核素在双重介质中的迁移问题。     

A Laboratory Model for the Flow in Urban Street Canyons Induced by Bottom Heating

Water tank experiments are carried out to investigate the convection flow induced by bottom heating and the effects of the ambient wind on the flow in non-symmetrical urban street canyons based on the PIV (Particle Image Visualization) technique. Fluid experiments show that with calm ambient wind,the flows in the street canyon are completely driven by thermal force, and the convection can reach the upper atmosphere of the street canyon. Horizontal and vertical motions also appear above the roofs of the buildings. These are the conditions which favor the exchange of momentum and air mass between the street canyon and its environment. More than two vortices are induced by the convection, and the complex circulation pattern will vary with time in a wider street canyon. However， in a narrow street canyon， just one vortex appears. With a light ambient wind, the bottom heating and the associated convection result in just one main vortex. As the ambient wind speed increases, the vortex becomes more organized and its center shifts closer to the leeward building.     

沙尘暴数值预报技术取得新进展

（1）中国气象科学研究院自主开发的沙尘暴预报系统CUACE／Dusl与天气预报模式GRAPES实现了在线双向耦合运行。目前中国气象局业务运行的沙尘暴数值预报系统CUACE／Dust中的气象模式是MM5,大气成分中心利用我院自主开发的中尺度气象模式GRAPEs—Meso替换了MM5,建立了GRAPES_CUACE／Dust沙尘暴数值预报系统。同时把模式分辨率提高到0．5～0．5°,     

Tracking embodied carbon flows in the Belt and Road regions

In the past few decades, economic globalization has driven rapid growth of cross-border trade and a new international division of labor, leading to increasing inter- country embodied carbon flows. Multi-region input-output (MRIO) analysis is used to identify embodied carbon flows between major world regions, including seven regions along the Belt and Road (BR), and the spatial distribution of production- and consumption-based carbon intensities. The results show that current embodied carbon flows are virtually all from BR regions to developed countries, with more than 95% of world net embodied carbon exports coming from BR regions. Consumption in the United States and European Union countries induce about 30% of the carbon emissions in most BR regions, indicating that the former bear a high proportion of consumers’ responsibility for the carbon emitted in the latter. For this reason, measuring environmental responsibilities from consumption rather than a production- based perspective is more equitable, while developing countries should be given a louder voice in the construction through dialogue and cooperation, in part in the context of the Belt and Road Initiative, of an inclusive global climate governance system.     

桑沟湾不同形态锰的分布、季节变化及影响因素

利用催化动力学分光光度法和两步提取法对2011年4月（春）、8月（夏）、10月（秋）和2012年1月（冬）桑沟湾海域溶解态无机锰(DIMn)和表层沉积物中的锰的含量进行测定。结果表明,桑沟湾4个季节（春季至冬季,后同）DIMn浓度呈现出近岸高、远岸低的分布特点,其平均浓度分别为(60.5±43.1) nmol/L、(42.0±30.5) nmol/L、(23.4±11.2) nmol/L和(18.2±13.5) nmol/L,呈现出明显的季节变化,即春季最高,夏季、秋季次之,冬季最低;与相邻的俚岛湾和爱莲湾相比,桑沟湾春季、夏季DIMn的浓度较高,秋季、冬季则没有显著性差异。桑沟湾表层沉积物中总Mn在4个季节的含量分别为(861±308) mg/kg、(915±322) mg/kg、(589±108) mg/kg、(653±185) mg/kg,表层沉积物中醋酸提取态Mn在4个季节的含量分别为(500±272) mg/kg、(502±232) mg/kg、(322±81) mg/kg、(345±91) mg/kg,两者均表现出近岸高、远岸低的分布特点。醋酸提取态Mn的含量在春季、夏季要显著高于秋季、冬季。悬浮颗粒物的吸附和浮游生物的利用是影响桑沟湾DIMn浓度与分布的重要因素。桑沟湾DIMn的源主要包括河流及地下水输送、大气输送、沉积物−水界面释放;汇主要包括养殖生物的清除、向黄海的输送等。简单箱式模型收支计算结果显示,桑沟湾DIMn的源略大于汇,表明除了养殖生物的清除和向黄海的输送,桑沟湾DIMn还存在其他汇。本研究的结果为桑沟湾DIMn的生物地球化学循环的深入认识提供了基础数据。     

Homogeneity and mechanical behaviors of sands improved by a temperature-controlled one-phase MICP method

Acta Geotechnica - Microbially induced carbonate precipitation (MICP) has been actively investigated as a promising method to improve soil properties. A burning issue impeding its wide application...     

吉林省夹皮沟花岗岩—绿岩带成因模式探讨

通过对夹皮沟绿岩带层序、岩石成因以及叠加其上的变质变形作用特征的研究,认为绿岩带形成于硅铝壳的扩张环境;英云闪长岩—奥长花岗岩成分的花岗质片麻岩是在大陆或大陆边缘的挤压环境下,由变质镁铁质火山岩经部分熔融侵位的深成花岗质岩石。由此,提出夹皮沟花岗岩—绿岩带的裂谷成因模式。     

光栅栅距检测与线阵CCD细分技术研究

利用线阵CCD分辨率高、像素均匀等特点对光栅莫尔条纹进行细分是目前广泛采用的一种新技术。由于CCD具有自扫描能力，能将光强随空间分布的莫尔条纹信号转换成随时间变化的电信号，从而可以对光栅刻线的像的移动进行精确定位和直接数字化，改变传统莫尔条纹位相细分方法，实现对光栅栅距进行高倍数的细分。