天气现象露的判定之刍见

根据多年的工作经验,总结出4点观测、判断露的注意事项。     

影响人工站与自动站水汽压差值原因探究

为探究人工观测气象站与自动站水汽压差值产生原因,利用全国134个1年的基准气象观测站逐时气压、干球气温、湿球温度等资料,分别采用人工站和自动站水汽压计算公式,模拟了本站气压、干球温度、湿球温度、自动站气温、相对湿度等要素产生一增量时,水汽压所对应变化量随各要素的变化规律,并分析了影响水汽压差值与其主导因子定量关系。通过实际观测资料的数据模拟分析,气压和干球温度的系统误差对人工与自动观测站的水汽压差值影响很小,而自动站的相对湿度和气温对水汽压差值影响较大,其中相对湿度的影响最明显。当自动站的相对湿度或气温的系统误差为一固定值时,水汽压差值变化幅度随气温大小变化,气温越高,水汽压差值越大。     

A review on anthropogenic geomorphology

With the continuous development of man’s ability to reshape nature, human activities have become the third geomorphologic agent in the modern geomorphological process. Man-made landform is a landform unit characterized by human activities and is a result of synergizing human and nature geomorphologic agents under the physical geographical background. This article provides an overview on the major progresses in research on anthropogenic geomorphology from aspects like the origin of anthropogenic geomorphology, man-made landform agents and classification, man-made landform evolution and its influencing mechanism, map presentation of man-made landform, and environmental impact of man-made landforms. In addition, in the article, the future development of anthropogenic geomorphology is forecasted. It is pointed out that future studies on anthropogenic geomorphology should pay more attention to the following directions: construction of discipline system of anthropogenic geomorphology, material composition and morphological features of man-made landforms, spatial expansion process and development laws of man-made landforms, regional disparity and accumulative environmental effects of man-made landforms, and environmental management on man-made landforms and comparative analyses of relevant international management policies.     

重庆东部地区寒武系龙王庙组碳、氧同位素特征及其意义

在野外露头和镜下薄片观察分析的基础上,对重庆东部地区下寒武统龙王庙组83个碳酸盐岩样品的碳、氧同位素进行测试,并分析了其所保留的海水原始信息的有效性。结果表明,扣除无效数据后,重庆地区龙王庙组δ¹³C值分布在-4.300‰~2.694‰之间,平均值为-0.031‰;δ¹⁸O值分布在-9.880‰~-0.100‰之间,平均值为-7.396‰;纵向上,碳同位素值整体呈现先降低后升高的趋势,底部、中上部及顶部为正值且变化幅度小;中下部整体为负值且波动幅度大,正、负漂移事件频发。古环境恢复结果显示,龙王庙期重庆东部地区整体处于海相沉积环境,海水盐度在龙王庙组早期较低,晚期较高;海水温度主要介于20~30,℃之间,属温暖或炎热的亚热带气候;龙王庙期共经历3期海退—海侵作用,海平面上升、海洋生产力增加、有机碳快速埋藏使得海洋中¹³C含量升高,反之则使其降低。龙王庙组沉积中期与末期,δ¹³C值负偏,水体较浅,盐度较高,是白云岩发育的最有利阶段。     

The influence of seafloor hydrothermal activity on major and trace elements of the sediments from the South Mid-Atlantic Ridge

Sediment samples obtained from the South Mid-Atlantic Ridge were analyzed for the major and trace elements by inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry. Results revealed that the contents of elements (e.g., Fe, Mn, Cu, Zn, V, Co) were high in samples 22V-TVG10 and 26V-TVG05 from the sites near the hydrothermal areas, and low in sample 22V-TVG14, which was collected far from the hydrothermal areas. The contents of Ca, Sr and Ba in the samples showed opposite trends. A positive correlation between the concentrations of metallic elements (Cu, Zn, Co, Ni, Pb, V) and Fe in the samples were observed. These results are consistent with chemical evolution of the dispersing hydrothermal plume.     

Coastal Reclamation and Saltmarsh Carbon Budget: Advances and Prospects

As an important carbon pool and fragile eco-system of earth system, more and more coastal saltmarshes have been reclaimed for releasing population pressure and promoting food safety and economic development, especially in developing countries. During reclamation, original soil carbon cycling pattern and pathway in saltmarshs would be changed, which furthermore could change global carbon budget. In this study, a great amounts of literature and data were summerized to generalize the changes of soil organic carbon, carbon sequestration rate and carbon flux in three main kinds of saltmarshes (Mangrove saltmarsh, Estuary saltmarsh and coastal saltmarsh) during reclamation. The results are as shown: ①The conclusions collected from Europe and America are not suitable to eastern Asia’s coast and more attention should be paid to eastern Asia’s coastal reclamation; ②Mangrove saltmarshes have higher Soil Organic Carbon (SOC) and carbon sequestration rate, followed by estuary saltmarshes and coastal saltmarshes. Soil clay, aggregate, burial rate usually have positive effect on SOC sequestration in coastal areas. Flood frequency, salinity and underground water level generally have negative effect on it. After reclamation, coastal SOC first shows a decrease followed by an increase. Nearly 30 years of reclamation is the turning point where paddy fields can significantly promote SOC; ③CH₄ and CO₂ are the main ways of carbon emission in coastal areas of which CO₂ flux usually is the largest. Mangrove saltmarshes’ carbon emissions are the highest. In natural sites, the carbon emissions in Spartina alterniflora Loisel. and Phragmites australis are higher than those in bare flat areas. Carbon fluxes in flood tide usually are lower than those in other periods. Otherwise, carbon fluxes in natural saltmarshes are far lower than those in reclamation zones, especially upland tillage zones. The results acquired from field monitoring, saltmarshes are the carbon sinks and become the carbon sources when reclamation activities happen. Finally, three main aspects of coastal study were given as follows: much more attention should be paid to carbon budget inventory in saltmarshes; the effect of reclamation activity (i.e., anthropogenic activity, tillage practice, land use, etc.) on carbon cycling in ocean-inland system; the study of land use and reclamation process simulation and its impact on carbon cycling in coastal zone should be strengthened.     

准噶尔盆地石西地区侏罗系八道湾组储层特征及主控因素分析

通过岩心、录井、铸体薄片以及扫描电镜等分析手段,对准噶尔盆地石西地区侏罗系八道湾组储层进行分析,认为研究区储层以细粒沉积为主,岩石类型以长石岩屑砂岩、岩屑砂岩为主;储集空间主要由原生粒间孔、粒间溶孔、粒内溶孔和微裂缝组成,属于中低孔、中低渗储层。同时探讨了石西地区侏罗系八道湾组储层的主控因素,结果表明,岩性是优质储层形成的物质基础;沉积相是控制优质储层发育的主导因素;成岩作用和早期油气充注控制着储层孔隙的发育程度。研究区有利储层主要分布于八一段(J_1b~1)和八三段(J_1b~3)的辫状河扇三角洲前缘水下分流河道中。     

桃夭门大桥基岩长周期设计反应谱

文中结合舟山市桃夭门大桥抗震设计在长周期频段的需要,研究分析了桃夭门大桥场地基本地震地质环境特点和长周期地面运动谱的研究现状,从强震记录长周期分量信息特点出发,以强震记录为基础,选用了11个有代表性的M≥65的强震,共72条强震地面运动记录,参照核法规HAF0101(1)特定场地谱的确定方法,通过统计分析建立了以均值反应谱为基础的长周期反应谱     

皖东张八岭群主期变质温度评价及结构框架探究

皖东张八岭群处于郯庐断裂带南段,构造位置极为独特和和关键,其是大别造山带和苏鲁造山带之间最重要的变质块体之一。前人主要侧重于构造地质学、年代学及岩石地球化学等方面研究,而对张八岭群的峰期变质条件、岩石单元划分和构成以及时间序列并不明晰。故而,本文将通过对张八岭群的区域变质岩石学、岩相学、热力学及年代学等研究,进一步确定其峰期变质条件、岩性特征,并对其岩石单元划分和构成进行深入解析。本次主要对张八岭群应用了白云母温度计进行峰期变质温度评价,单元-Ⅰ和单元-Ⅱ的温度范围分别为：T = 368 ℃～494 ℃和T = 331 ℃～394 ℃,主要经历了绿片—绿帘角闪岩相变质。锆石U-Pb年代学分析表明单元-Ⅰ和单元-Ⅱ原岩结晶年龄分别为749±8 Ma～738±8 Ma和738±9 Ma,该结果与前人研究结果基本一致。单元-Ⅲ的碎屑年龄范围为908±29 Ma～685±30 Ma,最大沉积年龄为685±30 Ma,沉积时限应属于新元古代,沉积物源主要来自扬子板块。据野外特征、岩相学差异、热力学评价和年代学分析,本文将张八岭群自下而上划分为3个单元,其中,单元-Ⅰ主要由石英—长石片岩组成,单元-Ⅱ主要由云母石英片岩和少量变基性岩组成,单元-Ⅲ主要由千枚岩、大理岩及少量片岩组成。本文认识对于理解华北板块与扬子板块沿郯庐断裂汇聚提供一定的岩石学支撑,张八岭群并没有经历高压低温蓝片岩相变质。     

中新元古界原生白云岩: 以中国典型台地区为例*

基于对中国塔里木盆地新元古界上震旦统奇格布拉克组、四川盆地新元古界上震旦统灯影组以及华北盆地中元古界蓟县系雾迷山组野外露头及钻井岩心白云岩的系统观察,发现中国典型台地区中新元古界中厚层至块状白云岩异常发育,其中泥(粉)晶白云岩占岩层总厚度86%~97%,且大多为厚层至块状。这些中厚层至块状泥(粉)晶白云岩,无论是否含藻类与菌类等微生物,次生交代作用基本都不发育。沉积古地理特征分析结果表明: (1)中新元古界的白云岩几乎覆盖整个海盆,广泛沉积于潮上带、潮间带以及潮下的开阔或局限台地环境;(2)白云岩的亚类在平面上受古基底隆凹格局控制,低凹部位以泥晶白云岩为主,高部位以颗粒泥晶白云岩或丘状叠层石泥晶白云岩为主;(3)白云岩台地中发育较深水台盆。地震剖面显示,这些台盆的形成受控于中新元古代的同生深大断裂活动,大断裂可将深部的Mg²⁺通过热液输入到碳酸盐岩台地中,使得海水中的Mg²⁺浓度增加。地球化学分析结果与古气候特征指示,不同晶粒结构的白云岩,即泥晶白云岩与少量的粉晶及细晶白云岩,其碳氧同位素比值没有明显分异,整体上与全球中新元古代海水背景值吻合,表明粉晶及粉细晶白云岩与泥晶白云岩同为沉积成因,其结构加粗乃原生泥晶白云石晶粒重结晶自生加大而成,并非次生交代成因,即这些少量发育的粉晶—细晶白云岩与主体的泥晶白云岩为同一成因机制。整合岩石学、沉积环境及地球化学等分析结果,认为中国典型台地区中新元古界的白云岩乃较典型的原生沉积成因。