多源数据与机载LiDAR数据的DTM提取算法     

刘沛  李英成  薛艳丽  丁晓波  罗祥勇  李见阳 《测绘科学》2010,35(6):147-150

本文提出了基于坡度因子的概念、利用已知DEM辅助信息、针对LIDAR点云迭代进行DTM提取的新方法。主要介绍了多源数据配准、激光点云滤波算法的原理,并在山地、居民、水域等地区进行了实验,同时应用两种精度验证方法对实验数据进行运算和评价。实验证明该算法不依赖初始坡度设定,自适应性较好。  相似文献   

Thermal conductivity of dense hcp iron:Direct measurements using laser heated diamond anvil cell     

《地学前缘(英文版)》2020,11(5):1755-1761

Thermal conductivity(k) of iron is measured up to about 134 GPa.The measurements are carried out using the single sided laser heated diamond anvil cell,where the power absorbed by a Fe metal foil at hotspot is calculated using a novel thermodynamical method.Thermal conductivity of fee(γ)-Fe increases up to a pressure of about46 GPa.We find thermal conductivity values in the range of 70-80 Wm~(-1)K~(-1)(with an uncertainty of 40%),almost constant with pressure,in the hcp(e) phase of Fe.We attribute the pressure independent k above 46 GPa to the strong electronic correlation effects driven by the electronic topological transition(ETT).We predict a value of thermal conductivity of ε-Fe of about 40±16 Wm~(-1)K~(-1) at the outer core of Earth.  相似文献   

Paleo- and Mesoarchean TTG-sanukitoid to high-K granite cycles in the southern São Francisco craton,SE Brazil     

《地学前缘(英文版)》2022,13(5):101372

The generation of the continental crust is widely accepted to have taken place predominantly in the Archean, when TTG magmatism associated with greenstone-belt supracrustal succession development was typically followed by emplacement of high-K granites before crustal stabilization. This study focuses on the Campos Gerais complex (CGC), which is an Archean granite-greenstone belt lithological association in a tectonic window located in the southwesternmost portion of the São Francisco craton (SFC). The CGC is an important segment of Paleo- to Mesoarchean continental crust to be integrated into paleogeographic reconstructions prior to the transition into the Paleoproterozoic. This investigation reports field relationships, 28 major and trace element compositions, U–Pb (zircon) geochronological results, and Hf and Sm–Nd isotope data for orthogneiss and amphibolite samples. The results indicate that the CGC records a complex Archean crustal evolution, where voluminous 2.97 Ga TTG tonalites and trondhjemites (ε_Nd(t) =  ? 4.7; T_DM = 3.24 Ga) were followed by 2.89 Ga sanukitoid tonalite production (ε_Nd(t) =  ? 1.9; T_DM = 3.02 Ga), broadly coeval with the development of the Fortaleza de Minas and Pitangui greenstone-belts. These events are interpreted to represent the initial stage of an important subduction-accretion tectonic cycle, which ended with the emplacement of 2.82–2.81 Ga high-K leucogranites and migmatization of the TTG-sanukitoid crust, with hybrid and two-mica, peraluminous compositions (ε_Nd(t) =  ? 8.0 to ? 8.6; T_DM = 3.57 – 3.34 Ga). The presence of inherited zircons with ²⁰⁷Pb/²⁰⁶Pb ages of 3.08 Ga, 3.29 Ga, 3.55 Ga and 3.62 Ga indicates that the Mesoarchean tectonic processes involved reworking of Meso- to Eo-archean crust. Renewed TTG magmatism took place at ca. 2.77 Ga represented by juvenile tonalite stocks (ε_Nd(t) = +1.0 to ? 1.5; T_DM = 2.80 – 2.88 Ga) which intrude the TTG-greenstone belt association. Crustal stabilization was attained by 2.67 Ga, allowing for the emplacement of within-plate tholeiitic amphibolites (ε_Nd(t) =  ? 3.1; T_DM = 2.87 Ga). The CGC shows important tectonic diachronism with respect to other Archean terrains in the southern São Francisco craton, including an independent Meso- to Neoarchean crustal evolution.  相似文献