三峡库区耕地变化研究   总被引：23，自引：2，他引：21  

曹银贵  王静  程烨  付梅臣  饶彩霞  许宁 《地理科学进展》2006,25(6):117-125

三峡工程是世界性的伟大工程,三峡工程的兴建推动了三峡库区的经济发展.在三峡库区经济发展的过程中,耕地成为经济发展的重要资源.本文利用三峡库区1990~2004年的耕地面积和社会经济资料,采用统计分析与实证研究的方法,分析了三峡库区耕地变化的过程,了解库区耕地变化的驱动力,探寻了耕地数量模拟预测的新方法,为库区耕地的保护和经济可持续发展提供参考.结果表明：(1)三峡库区15年来耕地面积及人均耕地面积呈减少的趋势,不同的库区段也如此;(2)三峡库区历年耕地面积与对应年人均GDP的关系曲线呈倒"U"型,并且相关年份耕地的变化与GDP的变化不同步,呈现相对脱钩的状态,三峡库区耕地的变化与城市化的发展及退耕政策休戚相关;(3)在库区耕地模拟预测研究中表明,传统的多元线性回归分析方法的模拟精度不及BP神经网络的模拟精度,并利用BP神经网络预测了三峡库区2010年和2015年的耕地面积,其预测结果具有一定的合理性.  相似文献   

The Decoupling Relationship between the Expansion of Urban Construction Land and Economic Growth in Jilin Province     

LIU Baotao 《资源与生态学报(英文版)》2019,10(3):275-281

In order to explore the relationship between urban construction land and economic development, this paper uses a decoupling model to analyze the decoupling relationship between expansion of urban construction land and economic growth in Jilin Province. The results show that from 2000 to 2015, the decoupling of urban construction land expansion and economic growth in Jilin province tended to be reasonable. The paper divides urban decoupling into three categories. The first type consists of ideal cities, including Liaoyuan and Baishan. The second type includes basic ideal cities like Changchun, Tonghua, Songyuan, Baicheng, and Yanbian. The third type consists of non-ideal cities, including Jilin and Siping. This paper puts forward relevant measures to promote the further decoupling of construction land expansion and economic growth in order to realize the sustainable use of land resources.  相似文献   

Late Cenozoic brittle deformation in the Southern Patagonian Andes: Record of plate coupling/decoupling during variable subduction?          下载免费PDF全文

Vanesa Barberón  Christian Sue  Matías Ghiglione  Gonzalo Ronda  Eugenio Aragón 《地学学报》2018,30(4):296-309

The Andes of southern Patagonia experienced a Miocene shift towards faster and higher angle subduction followed by the approach and collision of the Chile oceanic ridge. We present a kinematic study characterizing palaeostress fields computed from brittle tectonics to better constrain upper crustal deformation during this complex scenario. Although previous studies already suggested variable kinematics, it is striking that in a long‐lasting subduction environment, the computed palaeostress tensors are mostly strike‐slip (55%), while 35% are extensional, and only 10% compressive which are concentrated along a main frontal thrust. Cross‐cutting relationships and synsedimentary deformation indicate that a long‐lived strike‐slip regime was punctuated by a lower Miocene extensional event in the foreland before the main compressional event. The results are discussed in contrasting geodynamic models of plate coupling/decoupling versus direction and rate of convergence of the subducting plate, to explain the main mechanisms that control back‐arc deformation.  相似文献   

基于物质流分析的城市工业经济脱钩问题研究——以天津市2001-2012年面板数据为例     

李虹  黄丹林  理明佳 《地域研究与开发》2015,(1)

随着经济的快速发展,资源约束下环境问题日益突出,生态文明建设要求社会经济系统在物质增长的同时,环境和资源日益改善以满足循环经济的发展需求。当前经济增长与环境资源状况呈现耦合关系,违背了可持续发展的要求和目标。结合天津市工业系统物质流指标,分析其当前经济耦合程度,采用物质流输入输出指标进行脱钩分析,并对主要指标的组成部分分别赋予权重,基于指数时间序列的指标组成部分进行脱钩分析。结果表明,实现工业经济脱钩的关键在于从化石能源开采、金属矿产使用等方面转变经济发展方式,达到工业系统的碳排放、废弃物及水体污染减排目标,以实现工业经济系统的可持续发展及保障生态文明建设的顺利实施。  相似文献   

Effects of melt fractional crystallization on Sr-Nd and Lu-Hf isotope systems: a case study of Triassic migmatite in the Sulu UHP terrane     

《International Geology Review》2012,54(7):783-800

The Weihai migmatite in the Sulu ultra-high-pressure (UHP) metamorphic terrane, eastern China, underwent partial melting in the Late Triassic during its exhumation. The primary partial melts experienced a decompressional fractional crystallization (DFC) process to produce plagioclase (Pl)-rich leucosome crystallized under eclogite to granulite facies conditions and K-feldspar (Kfs)-rich pegmatitic veins crystallized under amphibolite-facies conditions. In this study, our results demonstrate that the DFC process can cause decoupling between whole-rock Sr and Nd isotopes. The Pl-rich leucosome has ε_Nd(t) values (–10.4 to ?15.0) and initial (⁸⁷Sr/⁸⁶Sr) ratios (0.708173–0.712476) very similar to those of the melanosome, but the Kfs-rich pegmatitic veins have homogeneous ε_Nd(t) values (?14.8 to ?15.2) and significantly high initial (⁸⁷Sr/⁸⁶Sr) ratios (0.713882–0.716284). Our results also suggest that the DFC process can change zircon ¹⁷⁶Yb/¹⁷⁷Hf and ¹⁷⁶Lu/¹⁷⁷Hf isotopic ratios, with no effect on ¹⁷⁶Hf/¹⁷⁷Hf ratios or ε_Hf (t) values. Zircon ¹⁷⁶Yb/¹⁷⁷Hf and ¹⁷⁶Lu/¹⁷⁷Hf ratios increase dramatically from the Pl-rich leucosome to the Kfs-rich pegmatitic veins, but zircon ¹⁷⁶Hf/¹⁷⁷Hf ratios (Pl-rich leucosomes = 0.282330 ± 0.000017; Kfs-rich pegmatitic veins = 0.282321 ± 0.000026) and ε_Hf (t) values (Pl-rich leucosomes = ?10.9 ± 0.6; Kfs-rich pegmatitic veins = ?11.6 ± 0.8) remain almost unchanged. We propose that the isotopic decoupling between the Pl-rich leucosome and Kfs-rich pegmatitic vein might be caused by melt fractional crystallization occurring too rapidly to allow complete equilibrium between them.  相似文献   

Neoproterozoic subducted materials in the generation of Mesozoic Luzong volcanic rocks: Evidence from apatite geochemistry and Hf-Nd isotopic decoupling   总被引：1，自引：0，他引：1  

Ming Tang  Xi-Sheng Xu  Cheng Zhu 《Gondwana Research》2012,21(1):266-280

A combined study including apatite geochemistry, zircon U-Pb, Lu-Hf isotopes and whole-rock geochemistry including Nd isotopes was carried out for the late Mesozoic volcanic rocks from the Luzong Basin, in the lower Yangtze River region, South China. Whole-rock geochemistry indicates the enrichments of large ion lithophile elements (LILE) and light rare earth elements (LREE) as well as depletions of Nb, Ta and Ti. The extremely low Cl contents in apatites strongly contrast with the rather high-K contents in whole rocks. Potential loss of Cl during syn- and post-magmatic processes having been ruled out, Cl-K decoupling is attributed to be a feature inherited from the primary magma, which indicates the involvement of highly dehydrated sediments and altered oceanic crust in the mantle source. A calculation based on apatite and whole-rock geochemistry further illustrates that the source was composed of four end-members in the perspective of Cl/K, Cl/Nb and F/K ratios. The Hf-Nd isotopes are decoupled for the basaltic trachytes from the lower volcanic sequences in the Luzong Basin, with rather low ε_Hf(t) values (mean = − 10.3) and inconsistent Hf-Nd model ages (Hf ~ 1.8 Ga, Nd ~ 1.3 Ga), which indicate the “zircon effect” that in turn requires the incorporation of continental detritus in the source via subduction. However, Hf and Nd isotopes are nearly coupled for the rocks from the upper volcanic sequences in the Luzong Basin. Late-Mesoproterozoic two-stage Hf and Nd model ages (ca. 1.2 Ga) of rocks from the upper volcanic sequences in the Luzong Basin are similar to those of the Neoproterozoic igneous rocks from the Jiangnan orogen, suggesting their relationship with the same subduction event. Based on the combined apatite geochemistry and Hf-Nd isotopes, this work suggests that the source of Luzong volcanic rocks might incorporate Neoproterozoic subducted slab fragments and detrital sediments that had been blocked in the deep lithospheric mantle below the Luzong area since the Neoproterozoic assembly between the Yangtze and Cathaysia blocks. The partial melting may be triggered by the back-arc lithospheric extension related to the subduction of Paleo-Pacific plate in the late Mesozoic.  相似文献   

中国东部燕山期和四川期岩石圈构造滑脱与岩浆起源深度   总被引：9，自引：0，他引：9  

万天丰  王亚妹  刘俊来 《地学前缘》2008,15(3):1-35

较确切地研究岩石圈内部构造滑脱面在地质历史时期形成的时间和部位是当前大地构造学研究的一个重要课题。通过大量收集中国东部燕山期(205~135Ma)和四川期(135~52Ma)岩浆起源深度资料来判断岩石圈内部和底部是否存在局部的构造滑脱界面,是否发生层圈相互作用,是否发生部分的解耦现象,是一种可行的研究方法。研究表明,中国东部燕山期和四川期岩石圈板块的构造滑脱、圈层的解耦作用及相互作用主要集中在中地壳、莫霍面与区域性主干断层的交线附近,而岩石圈板块的底面却并不存在大幅度的滑移。中国东部燕山期和四川期岩浆活动比较发育的地区基本上都位于大兴安岭—山西西部—武陵山—十万大山一线以东地区,而在此线以西地区岩浆活动相当微弱。笔者认为,在侏罗—白垩纪时期,该线以西缺少岩浆活动的地区可能就是当时的大陆型岩石圈,而该线以东岩浆活动剧烈的地区可能就属于海陆过渡型岩石圈。中国东部岩石圈的转型和"变薄",不太可能是深部地幔羽、去根作用、深部地幔热物质上涌或大陆伸展作用的结果,也不太可能与太平洋板块的俯冲作用有直接联系。  相似文献   

河南省能源消费特征及影响因素分析     

王笑天  焦文献  陈兴鹏  张子龙 《地域研究与开发》2016,(1):144-149

利用统计年鉴数据分析河南省能源消费的总体特征,运用IPAT等式对河南省能源消费的影响因素进行定量研究,并通过脱钩分析进一步研究河南省能源消费与经济增长的动态关系。结果表明:河南省能源消费总量较大且仍保持逐年递增;经济发展是影响能源消费总量增长的主导因素,技术进步对其起重要的抑制作用;能源消费与经济发展总体上呈弱脱钩关系,并呈现出向强脱钩转变的趋势;优化能源消费结构、提高技术水平和能源利用效率有助于控制河南省能源消费总量的增长,最终实现社会经济的可持续发展。  相似文献   

东北地区产业发展与工业SO2排放的时空耦合效应   总被引：2，自引：1，他引：1  

马丽  张博  杨宇 《地理科学》2016,36(9):1310-1319

以工业SO₂为对象,以东北地级市（ 本文“地级市”包括东北三省内的哈尔滨、长春、沈阳、大连4个副省级城市。）为研究单元,运用脱钩指数分析了工业产值变化与SO₂排放规模变化的动态耦合关系及空间格局,并利用LMDI因素分解法对各地市工业SO₂排放变化从规模增长、结构转型和技术升级3方面进行解析。研究发现,在东北地区产业发展过程中,工业产值规模的增长对工业SO₂排放增长呈现正向驱动;而工业技术的进步和节能减排措施的使用促进了工业SO₂排放的降低,而产业结构的作用因区域而异。在环渤海湾地区以及辽源、松原、鹤岗、伊春、七台河、绥化等以木材加工和煤电为核心产业发展的城市,能源基础原材料产业比重的上升促进了地区工业SO₂排放的增加。最后根据不同地市工业SO₂减排的主要驱动因素和限制因素,针对性的分类型、分区域提出促进东北地区产业绿色转型的政策建议。  相似文献   

黄河流域产水产沙、输移和沉积系统的划分   总被引：4，自引：1，他引：4  

张欧阳  许炯心 《地理研究》2002,21(2):188-194

根据Schumm提出的河流系统的理论对黄河流域地貌系统进行了划分。结果表明 ,整个黄河流域地貌系统可以很明确地分为产水产沙系统、输移系统和沉积系统 ,其模式与Schumm的理想流域模式非常吻合 ,同时又表现出其特殊性。以河口镇为界 ,黄河流域上游和中下游两部分分别具有对应的产水系统、产沙系统和河道输移系统 ,各子系统处于动态变化过程中 ,存在一种强耦合关系 ,这种特点主要是由黄河流域的历史发育过程决定的。  相似文献