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42.
Sébastien Nomade Giovanni Muttoni Hervé Guillou Eric Robin Giancarlo Scardia 《Quaternary Geochronology》2011,6(5):453-457
The Ceprano calvarium, found in 1994 in Italy and attributed to Homo cepranensis, is one of the most celebrated hominin remains of Europe. It was considered at least 700 ka-old until a recent investigation incorporating magnetostratigraphy and K-Ar ages from the literature assigned to the calvarium an age of ∼450 (+50, −100) ka. Here we pin down the age of the Ceprano calvarium to 353 ± 4 ka (±1σ external) by means of new 40Ar/39Ar dating on K-feldspars retrieved from the sediments that hosted the skull. In absence of evidence of reworking, this refined age sinks the conviction that H. cepranensis belonged to human evolution at the Brunhes–Matuyama boundary (c.a. 781 ka). Our refined age indicates that H. cepranensis lived in central Italy probably during the cold period of marine isotope stage (MIS) 10, and that despite his archaic morphology and lack of Neanderthal traits, he was contemporaneous with more advanced species such as H. heidelbergensis. 相似文献
43.
The character of mountain building processes in Palaeoproterozoic times is subject to much debate. Based on the discovery of high-pressure granulites in the Man Rise (Côte d'Ivoire), several authors have argued that Eburnean (Palaeoproterozoic) reworking of the Archean basement was achieved by modern-style thrust-dominated tectonics.
A mafic granulite of the Kouibli area (Archean part of the Man Rise, western Ivory Coast) displays a primary assemblage (M1) containing garnet, diopsidic clinopyroxene, red-brown pargasitic amphibole, plagioclase (andesine), rutile, ilmenite and quartz. This assemblage is associated with a subvertical regional foliation. Symplectites that developed at the expense of the M1 assemblage contain orthopyroxene, clinopyroxene, plagioclase (bytownite), green pargasitic amphibole, ilmenite and magnetite (M2). Multiequilibrium thermobarometric calculations and P–T pseudosections calculated with thermocalc suggest granulite facies conditions of ∼ 13 kbar, 850 °C and <7 kbar, 700–800 °C for M1 and M2, respectively. In agreement with the qualitative information obtained from reaction textures and chemical zoning of minerals, this suggests an evolution dominated by decompression accompanied by moderate cooling. A Sm–Nd garnet – whole-rock age of 2.03 Ga determined on this sample indicates that this evolution occurred during the Palaeoproterozoic. It is argued that from the geodynamic point of view the observed features are best explained by homogeneous thickening of the margin of the Archean craton, re-heated and softened due to the accretion of hot, juvenile Palaeoproterozoic crust, as well as coeval intrusion of juvenile magmas. Crustal shortening was mainly accommodated by transpressive shear zones and by lateral crustal spreading rather than large-scale thrust systems. 相似文献
A mafic granulite of the Kouibli area (Archean part of the Man Rise, western Ivory Coast) displays a primary assemblage (M1) containing garnet, diopsidic clinopyroxene, red-brown pargasitic amphibole, plagioclase (andesine), rutile, ilmenite and quartz. This assemblage is associated with a subvertical regional foliation. Symplectites that developed at the expense of the M1 assemblage contain orthopyroxene, clinopyroxene, plagioclase (bytownite), green pargasitic amphibole, ilmenite and magnetite (M2). Multiequilibrium thermobarometric calculations and P–T pseudosections calculated with thermocalc suggest granulite facies conditions of ∼ 13 kbar, 850 °C and <7 kbar, 700–800 °C for M1 and M2, respectively. In agreement with the qualitative information obtained from reaction textures and chemical zoning of minerals, this suggests an evolution dominated by decompression accompanied by moderate cooling. A Sm–Nd garnet – whole-rock age of 2.03 Ga determined on this sample indicates that this evolution occurred during the Palaeoproterozoic. It is argued that from the geodynamic point of view the observed features are best explained by homogeneous thickening of the margin of the Archean craton, re-heated and softened due to the accretion of hot, juvenile Palaeoproterozoic crust, as well as coeval intrusion of juvenile magmas. Crustal shortening was mainly accommodated by transpressive shear zones and by lateral crustal spreading rather than large-scale thrust systems. 相似文献
44.
论绿色文明与民族边疆山区农村经济的可持续发展——以云南省西双版纳为例 总被引:2,自引:0,他引:2
云南边疆、山区、少数民族地区,寻求森林生态系统与经济系统的协调发展,寻求攀元民族文化下的山区资源利用可持续发展战略,是加强民族团结,实现各民族共同繁荣富裕、区域经济发展的关键。文中运用高新技术遥感(RS)、地理信息系统(GIS),结合村寨社区调查,对云南西双版纳6种主体少数民族传统用地习俗、土地结构变迁及农村经济发展等方面进行了分析研究评价,在此基础上初步探讨山区边疆少数民族地区传统文化与农村经济持续发展的关系,提出看法及供商榷。 相似文献
45.
通过对大荔人遗址地层地貌的观察与实测,发现洛河大荔人遗址段的地层主要由3套陆相沉积物组成:底部的新近纪和早更新世湖相堆积,中部中更新世的河相堆积以及上部中更新世晚期至全新世的黄土堆积。在洛河大荔人遗址段可以误别出四级阶地,从河流地貌特点和各级阶地的地层特征看,该阶地皆为其座型阶地。运用古土壤断代法和区域河流阶段地发生对比法得出洛河在该地区演化的时间序列:0.9-0.72MaB.P.,0.50-0.40MaB.P.,0.10MaB.P.,0.01MaB.P.在此基础上对该地区地貌演化模式进行了讨论。 相似文献
46.
当代地球系统的突变性质与确立“人法地”文明观 总被引:1,自引:0,他引:1
现代地球系统即为包括人类圈在内的五元地球表层系统。自本世纪50年代以来,它已进入了一个具有突变性质的新时期,本文从变化速度,逆向巨变,较低水平人类圈的迅猛膨胀和确立“人法地”文明观等方面分别讨论了这一重要时期的表象,实质,根源和前景。 相似文献
47.
知识经济与人地关系地域系统 总被引:1,自引:0,他引:1
林炳耀 《云南地理环境研究》1998,10(2):1-13
通过探讨人地关系地域系统中的生产力要素,重点分析了第五次产业革命的生产力特征及其对人地关系地域系统的深刻影响:(1)信息产业的发展水平成为经济发展水平的衡量标准;(2)信息产业与传统产业相结合改变着工业、商业、城市布局的基本特征;(3)基因工程产业改变着传统农业的性质及其功能;(4)新能源产业为经济的可持续发展开拓着新的前景;(5)知识园区的发展改变着城市与区域的空间结构;(6)多极化城镇体系将在 相似文献
48.
爆破振动对铁厂沟村房屋选择性破坏的调查与分析 总被引:2,自引:1,他引:1
乌鲁木齐矿务局露天矿的剥离爆破对距爆点1km外的铁厂沟材房屋产生了选择性破坏,振动对个体房屋的破坏呈现出鲜明的选择性,不同房屋遭受的破坏程度差异极大。 相似文献
49.
关于南京猿人生存时期的气候环境讨论 总被引:12,自引:3,他引:9
根据南京猿人产地(葫芦洞)中的孢粉分析结果推测当时气温明显比现在低,可能相当于一次冰期。该结论与南京猿人共生的哺乳动物化石群的性质是一致的。 相似文献
50.
滩海区人工岛场地地震安全性评价 总被引:2,自引:1,他引:1
本文以辽河口滩海区人工岛场地为例, 从区域地震地质、近场区地震地质、区域地震活动等方面, 讨论了滩海区人工岛基本地震地质环境特点, 在此基础上, 完成场地地震烈度、地震设防参数、场地地震地质灾害等影响人工岛场地安全性的因素评价。结果说明, 从场地地震安全性角度, 本文所评价的场地, 对人工岛兴建是适宜的。 相似文献