夏商周年表的制订与14C测年

夏商周断代工程的总目标是制订有科学依据的年表。研究途径主要有两条：1)根据古代天象记录,通过现代天文计算推定其年代;2)根据考古提供的系列样品作14c年龄测定,转换成误差较小的、有考古内涵的历法年。天文推算可以得出年龄定点,14c测年可以覆盖全面,建立起夏商周的年龄框架。两者结果互证,再同历史文献、考古研究等多学科综合研究,制订出夏商周三代年表。同过去相比,这应当是最有科学依据的。     

广西金牙金矿有机包裹体激光拉曼光谱研究

金牙金矿是桂西北微细粒浸染型金矿床具有代表意义的典型矿床。其赋矿层位为三叠系中统百蓬组的富有机碳的浊积岩系。通过对成矿过程中有机包裹体的激光拉曼分子微探针研究认为:(1)有机质在成矿过程中会发生热降解,其降解产物烃的量可衡量热的程度;(2)无机组分和CO2/CH4 参数可用于研究热液的地球化学环境。     

A Coastal Air-Ocean Coupled System (CAOCS) Evaluated Using an Airborne Expendable Bathythermograph (AXBT) Data Set

A coastal atmosphere-ocean coupled system (CAOCS) is developed with Princeton Ocean Model (POM) as the oceanic component, and with National Center for Atmospheric Research (NCAR) regional climate model (RegCM2) as the atmospheric component. The model domain (98.84°–121.16°E, 3.06°S–25.07°N) covers the whole SCS and surrounding land and islands. The surface fluxes of water, heat (excluding solar radiation), and momentum are applied synchronously with opposite signs in the atmosphere and ocean. Flux adjustments are not used. The CAOCS model was verified using an intensive airborne expendable bathythermograph (AXBT) survey between 14–25 May 1995 over the majority of the SCS down to about 300-m depth.     

桶形基础负压沉贯特性分析

介绍了桶形基础负压沉贯的室内试验,中间现场试验,应用有限元法对负压沉贯的渗流场分析,负压对桶形基础沉贯阻力的影响,对土壤特性的影响,负压大小对桶形基础沉深,沉速的影响,研究了桶形基础在海上的可行性。     

广东惠州燕山期以来地质构造演化:对华南构造的新启示

为揭示广东惠州燕山期以来的地质构造演化,以惠州石坝-黄沙洞地区为例,并综合基础地质调查、大地电磁学、岩石地球化学、年代学等方法来分析研究.大地电磁结果显示研究区深部存在连为一体厚超5 km的燕山期花岗岩体岩床,并被新生代断裂切割;丹霞组底砾岩矿物磨圆较差显示出近源沉积特征;谐和年龄及年龄谱图揭示底砾岩年龄约160 Ma...     

A buried submarine canyon in the northwest South China Sea:architecture,development processes and implications for hydrocarbon exploration

High-resolution multichannel seismic data enables the discovery of a previous, undocumented submarine canyon(Huaguang Canyon) in the Qiongdongnan Basin, northwest South China Sea. The Huaguang Canyon with a NW orientation is 140 km in length, and 2.5 km to 5 km in width in its upper reach and 4.6 km to 9.5 km in width in its lower reach. The head of the Huaguang Canyon is close to the Xisha carbonate platform and its tail is adjacent to the central canyon. This buried submarine canyon is formed by gravity flows from the Xisha carbonate platform when the sea level dropped in the early stage of the late Miocene(～10.5 Ma). The internal architecture of the Huaguang Canyon is mainly characterized by high amplitude reflections, indicating that this ancient submarine canyon was filled with coarse-grained sediments. The sediment was principally scourced from the Xisha carbonate platform. In contrast to other buried large-scale submarine canyons(central canyon and Zhongjian Canyon) in the Qiongdongnan Basin, the Huaguang Canyon displays later formation time, smaller width and length, and single sediment supply. The coarse-grained deposits within Huaguang Canyon provide a good environment for reserving oil and gas, and the muddy fillings in Huaguang Canyon have been identified as regional caps. Therefore, Huaguang Canyon is potential area for future hydrocarbon exploration in the northwest South China Sea. Our results may contribute to a better understanding of the evolution of submarine canyons formed in carbonate environment.     

CO2 flux of soil respiration in natural recovering karst abandoned farmland in Southwest China

Acta Geochimica - To estimate carbon sequestration potential in the karst area, soil respiration in a natural recovering karst abandoned farmland in Shawan, Puding, Guizhou, southwest China was...     

基于大数据分析的地热勘探潜力区预测方法的新进展

地质、地球物理、地球化学等数据信息资料是预测地热系统的关键。热源、流体或热量的运移途径、地热储层、盖层和保温条件对一个有效的地热系统的形成和保存至关重要。同时,地热勘探应考虑地形、地震活动、野生动物保护、环境敏感区和基础设施等因素。全球地热数据库调研分析表明:目前只有以美国为代表的少数国家整合了不同的地热数据库中历史积累的数据,能够初步用于地热勘探潜力区预测。大多数其他国家和地区的地热数据库数据缺乏统一的数据组织方式,查询和分析功能不完善,无法进行深层次的数据挖潜及有效使用。地理信息系统工具和数学方法的引入,有可能是解决这一问题的途径,可以整合不同属性的数据,运用模糊逻辑方法或机器学习方法方法,叠加潜力区带分析思想,从而预测隐藏式地热系统。     

Autumn daily characteristics of land surface heat and water exchange over the Loess Plateau mesa in China

The Loess Plateau, located in northern China, has a significant impact on the climate and ecosystem evolvement over the East Asian continent. In this paper, the preliminary autumn daily characteristics of land surface energy and water exchange over the Chinese Loess Plateau mesa region are evaluated by using data collected during the Loess Plateau land-atmosphere interaction pilot experiment （LOPEX04）, which was conducted from 25 August to 12 September 2004 near Pingliang city, Gansu Province of China. The experiment was carried out in a region with a typical landscape of the Chinese Loess Plateau, known as ＂loess mesa＂. The experiment＇s field land utilizations were cornfield and fallow farmland, with the fallow field later used for rotating winter wheat. The autumn daily characteristics of heat and water exchange evidently differed between the mesa cornfield and fallow, and the imbalance term of the surface energy was large. This is discussed in terms of sampling errors in the flux observations-footprint; energy storage terms of soil and vegetation layers; contribution from air advections; and low and high frequency loss of turbulent fluxes and instruments bias. Comparison of energy components between the mesa cornfield and the lowland cornfield did not reveal any obvious difference. Inadequacies of the field observation equipment and experimental design emerged during the study, and some new research topics have emerged from this pilot experiment for future investigation.     

The impact of natural vegetation restoration on surface soil moisture of secondary forests and shrubs in the karst region of southwest China

Soil moisture is crucial to vegetation restoration in karst areas, and climate factors and vegetation restoration are key factors affecting changes in soil moisture. However, there is still much controversy over the long-term changes in soil moisture during vegetation restoration. In order to reveal the changes in soil moisture during vegetation restoration, we conducted long-term positioning monitoring of soil moisture at 0–10 and 10–20 cm on secondary forests sample plot (SF, tree land) and shrubs sample plot (SH, shrub land) in karst areas from 2013 to 2020. The results showed that the aboveground biomass of SF and SH increased by 50% and 240%, respectively, and the soil moisture of the SF and SH showed an increasing trend. When shrubs are restored to trees in karst areas, the soil moisture becomes more stable. However, the correlation coefficients (R²) between the annual rainfall and the annual average soil moisture of SF and SH are 0.84 and 0.55, respectively, indicating that soil moistures in tree land are more affected by rainfall. The soil moisture of shrubs and trees are relatively low during the months of alternating rainy and dry seasons. Rainfall has a very significant impact on the soil moisture of tree land, while air temperature and wind speed have a significant impact on the soil moisture of tree land, but the soil moistures of shrub land are very significantly affected by rainfall and relative humidity. Therefore, during the process of vegetation restoration from shrubs to trees, the main meteorological factors that affect soil moisture changes will change. The results are important for understanding the hydrological processes in the ecological restoration process of different vegetation types in karst areas.