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101.
近年来,水产养殖用地分布广泛,但由于其在影像上所表现的复杂性和不均匀性,造成该用地类型提取中的困难,尤其针对中分辨率遥感影像。对此,本文提出了一种基于纹理和空间特征的养殖用地提取方法,该方法主要包括3个步骤:首先,利用纹理熵和归一化差异水体指数NDWI实现水产养殖用地的粗提取;然后,依据相邻地物间的关系实现同类型地物合并;最后,本文构建一种相对宽度作为地物的近似宽度,再次利用NDWI实现水产养殖用地的准确识别。本文以越南万丰湾为研究区域,以Landat-8融合影像(融合后的像元大小为15 m)的目视解译结果为标准,对本文方法与最小距离法分类结果进行比较。实验结果表明,该方法的精度可达91.13%,远高于传统的面向对象方法,并且所提方法的错误率和虚假率分别为0.09%和8.87%,表明了该方法可靠性,因而该方法可为基于中分辨率影像的地物类型提取提供一种有效手段。 相似文献
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S. Grassmann B. Cramer G. Delisle T. Hantschel J. Messner J. Winsemann 《Marine and Petroleum Geology》2010
During the past two million years low surface temperatures as well as episodically advancing ice sheets from Scandinavia acted on the subsurface pT-regime of northern Germany. Their likely effects on the petroleum system of Schleswig-Holstein were investigated. For the entire Quaternary mean annual ground temperature (MAGT) was reconstructed at a resolution of 1000 years by calibrating oxygen isotope records from ODP-site 659 to the climate of northern Germany of the past 120 kyr. The resulting MAGT trend served as input to an ice sheet model and a permafrost model along a 2D section crossing the petroleum bearing south-western part of Schleswig-Holstein. Here advances and retreats of the Scandinavian ice sheet during Saalian and Elsterian glaciation Stages were reconstructed. Maximum ice thicknesses of up to 1700 m and up to 20 periods of regional permafrost in northern Germany were reconstructed for the past 1.25 million years. Based on a basal heat flow of 50 mW/m2 permafrost thicknesses exceeded 100 m during most of these periods, temporarily extending down to depths of more than 300 m. Favourable surface temperatures and long durations of cold periods provided favourable conditions for onshore gas hydrate stability zones at Mittelplate. Implementing these glacial dynamics into 2D basin modelling (PetroMod, IES, Aachen, Germany) of the Mittelplate oil field reveals five phases of gas hydrate stability at depths down to 750 m. The latest of these events occurred during the Weichselian about 20 kyr ago. The effect of the ice sheets on pore pressure in the subsurface strongly depends on the hydraulic boundary conditions at the ice base (e.g. frozen vs. temperate ice sheet base). Excess pore pressure in the reservoir of more than 10 MPa during ice overriding is possible and probable. The calculated temperature effect of the Pleistocene cooling on the Mittelplate reservoir is in the range of 3–7 °C. Even today temperature in the reservoir is still lowered by about 4 °C in comparison to pre-Pleistocene times. Despite the fact that a significant influence of glacial effects on petroleum generation can be ruled out at Mittelplate, we state that pT-effects in reservoirs related to glacial processes in formerly glaciated areas have been underestimated in the past. 相似文献
104.
江南造山带位于扬子和华夏地块中间,受华南陆块及其周缘多期次的碰撞、裂解及再造过程影响,经历了复杂的构造运动和变形,于中生代期间受区域构造-岩浆事件影响,发生成矿“大爆发”,是研究陆内深部过程、成矿作用的关键地区。受沉积覆盖、出露较少等因素影响,江南造山带中段地壳结构、深部过程及其边界范围等还存在争议。为进一步提高对江南造山带中段中生代深部构造背景、动力学过程及成矿作用的认识,本文利用武宁—吉安深反射地震数据,进行随机介质参数的计算,获得了相关长度剖面。结果发现江南造山带中段地壳厚度沿剖面由北向南逐渐减薄,结合前人研究推测研究区受控于燕山期晚期伸展构造体制,在伸展构造背景下,导致地壳减薄,诱发幔源物质上涌,受地幔上涌影响由南往北逐渐减弱。同时揭示了宜丰—景德镇断裂深大断裂极性,进一步证明了萍乡—广丰断裂为江南造山带中段与华夏地块的边界。最后综合分析了中生代区域构造对成矿的影响,认为在伸展构造背景下,幔源物质沿断裂上涌控制了该区金、钨等矿床的形成。 相似文献
105.
内蒙古自治区中东部满克头鄂博组以流纹质火山碎屑岩为主夹山间湖盆相陆相碎屑岩及少量流纹岩或英安岩.沉积岩中产叶肢介Magumbonia paramecia,Nestoria reticulate,N.xishunjingensis,N.cf.pissoui,Lioestheria sp.;双壳类Ferganoconcha... 相似文献
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107.
LIU Jianqiu WU Cairong WANG Shaohong CHEN Binghua FANG Yulin YU Mingtong 《《地质学报》英文版》2007,81(5):722-726
The paleoforest remains studied are distributed within a range of 18000 m^2 in the intertidal zone of the Qianhu Bay, Fujian Province. Eighty-nine ancient tree stumps can be clearly recognized in the paleoforest remains. Microscopic studies of 10 relatively low-carbonized stump samples definitely showed four species: Glyptostrobus pensUi (Staunt) Kouch, Schima superba Gardn., Cinnamomum Schaeffer, and Litsea Lam. The 14^C dating of some samples yielded the ages of 42560±350 to 〉43000 a B. P., corresponding to the late Late Pleistocene. 相似文献
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109.
Chronostratigraphic constraints on Middle Pleistocene faunal assemblages and Acheulian industries from the Cretone lacustrine basin,central Italy
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110.
James Goff Catherine Chagué‐Goff Michael Archer Dale Dominey‐Howes Chris Turney 《第四纪科学杂志》2012,27(7):660-670
Large asteroid impacts are rare, and those into the deep ocean are rarer still. The Eltanin asteroid impact around 2.51 ± 0.07 Ma occurred at a time of great climatic and geological change associated with the Pliocene–Pleistocene boundary. Numerical models of the event indicate that a megatsunami was generated, although there is debate concerning its magnitude and the region‐wide extent of its influence. We summarise the existing evidence for possible Eltanin megatsunami deposits in Antarctica, Chile and New Zealand, while also examining other potential sites from several locations, mainly around the South Pacific region. In reviewing these data we note that these events were unfolding at the same time as those associated with the Pliocene–Pleistocene boundary and, as such, most of the geological evidence from that time has a climatic interpretation. The potential climatic and geological ramifications of the Eltanin asteroid impact, however, have failed to be considered by most researchers studying this time period. Although we are not advocating that all geological activity at that time is connected with the Eltanin asteroid impact, it raises interesting questions about the role potentially played by such catastrophic events in contributing to or even triggering epochal transitions. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献