川东南石宝矿区龙潭组页岩气(煤层气)潜力分析 ——以SD1井为例

二叠系龙潭组是四川盆地最主要的海陆过渡相页岩气勘探层位。通过钻井岩芯和薄片观察、X射线衍射、扫描电镜、有机地球化学分析、孔渗测试、现场解吸和等温吸附等手段, 以SD1井为例, 对川东南石宝矿区龙潭组烃源岩特征和页岩气潜力进行研究。结果表明: 1)研究区SD1井龙潭组泥页岩累计厚度约47.74 m, 与煤层及粉-细砂岩交互出现, 主要为分流间湾和沼泽微相沉积; 2)泥页岩总体黏土矿物含量高(平均值为49.7%), 富菱铁矿、黄铁矿和锐钛矿, 缺乏长石和其他碳酸盐矿物; 3)有机质主要由镜质组构成, 干酪根δ13C集中分布在–22.8‰ ~ –24.2‰之间, 以Ⅲ型干酪根为主, 有机质丰度高(TOC平均值为7.37%), 处于过成熟生干气阶段, 生烃潜力大; 4)储集空间主要包括微裂缝、有机质孔、溶蚀孔和晶间孔, 孔隙度变化在3.05%~4.35%之间, 平均值为3.79%; 渗透率约为0.486 μD, 远小于0.1 mD, 具超低孔超低渗特征; 5)现场解吸泥页岩含气量为0.61～4.70 m3/t, 平均值为2.16 m3/t, 含气性相对较好, 饱和吸附气含量均大于2.00 m3/t, 显示出良好的吸附性能。综合研究认为, 川东南石宝矿区龙潭组页岩气开发潜力较大, 龙潭组上段中部C14–C17碳质泥岩夹煤层组合和龙潭组中段上部C20–C24碳质泥岩夹煤层组合为主力勘查层段。     

Economic drivers of contemporary smallholder agriculture in a transitional economy: A case study of Hu Village from southwest China

Based on an in‐depth case study of a rural community, this paper documents the contemporary state of Chinese smallholder agriculture and the changes that it has been experiencing in the context of dramatic socio‐economic transition through the lens of three main economic drivers: livelihood diversification, market conditions and government interventions. Results reveal that the change in Chinese smallholder agriculture has been complex and multidimensional. All three factors exert profound influence and shape the current state of Chinese agriculture. Massive rural‐urban migration has resulted in labour shortages, which in turn have led to a reduction in agricultural diversity and land use intensity and a shift from traditional labour‐intensive technologies to modern capital‐intensive technologies. However, because of well‐developed agricultural markets, input use levels are similar across farmer categories (such as income diversification), helping to maintain productivity. Furthermore, reduced profits from farming due to increasing input prices and decreasing output prices have exerted pressure on smallholders to increasingly turn to nonfarm activities and have also triggered a thriving informal land transfer market, which was previously non‐existent. Policy implications include the need to strengthen local economies, improve market conditions, invest in rural infrastructures and facilitate smallholders' mobility.     

Planning Beijing: socialist city,transitional city,and global city

Cities are centers of economic, social, and political change, and urban planning is a process responding to and guiding urban change and development. In the Maoist era and under the influence of socialist ideology, China limited urbanization while promoting industrialization, and urban planning served as an instrument for socialist construction. Since the reform of the late 1970s, Chinese cities have experienced unprecedented growth and restructuring. However, the gradualist, exploratory reform—exemplified by Deng Xiaoping’s slogan “crossing the river by feeling the stones”—makes Chinese cities constantly change without clear directions for future development. This paper uses Beijing as a case study to analyze changing institutional and global contexts underlying the transformation of Chinese cities, and planners’ responses and dilemmas in making plans and implementing them. We found that market reforms, rapid growth, and dramatic change make urban master plans quickly out of date, forcing Chinese planners to frequently revise these master plans. We also found that the content of urban master planning in China has broadened from physical planning, and Chinese planning has adapted to market reform through utilizing concepts of visioning, flexibility, and governance. Increasingly what we call a “hybrid” form of planning is arising in which global concepts and Chinese ideas interweave in order to direct the shape and form of the Chinese metropolis.     

Factors controlling the distribution of transitional metal elements in marine hydrogenic ferromanganese crusts

A series of selective dissolution experiments were conducted on the hydrogenic ferromanganese crusts collected near Line Island to study the geochemistry of Mn, Fe, Cu, Co, Ni and Ti. Despite of the fact that the very close intergrowth between amorphous ferric oxyhydroxides and δ-MnO2 exists in the hydrogenic ferromanganese crusts, there is no isomorphous substitution between iron and manganese. This is because the two elements in oxides have different crystal chemistry and geochemistry, such assertion bein...     

鄂尔多斯农牧交错土地利用格局的演变与机理

依据史料和已有研究成果恢复了鄂尔多斯农牧交错土地利用格局的演变过程,即清代、民国是一个由自发开垦到政府组织开垦、由汉人租佃开垦到蒙汉共同开垦、由鄂尔多斯周缘 向其内部深入的过程。进而从自然条件、人口压力、经济利益和民族融合等因素的作用探讨 鄂尔多斯农牧交错土地利用格局的演变机理。清代气候进入暖湿期,为土地开垦奠定了条件; 生态系统脆弱性又阻碍了过度开垦。中国人口空前增长和耕地单产徘徊促使耕地开发向边疆 拓展;鄂尔多斯与周边的人口梯度力以及黄土高原土地退化对人口的排斥力是促进鄂尔多斯土地开垦的根本动力。无论是民间自发的还是政府组织的,都是在追逐利益中促进了土地开垦;同时,中央与地方、蒙古人与汉人、豪强与贫民之间的利益争夺阻碍了开垦进程。蒙汉 人口结构改变和开垦中建立的共同利益关系促进了民族融合,其中的彼此接受和排斥,既加强了农业的地位,又巩固了畜牧业的地位。鄂尔多斯的农牧交错土地利用格局正是这些因素 的共同驱动和阻碍的平衡中形成和发展的。     

秦巴山区马尾松林和油松林的空间分布及亚热带与暖温带界线划分

秦岭不仅是中国南北的地理分界线,也是中国亚热带和暖温带的气候分界线,在中国地理生态格局中占有重要的地位和作用。由于过渡带的复杂性、过渡性和异质性以及划分指标、研究目的的不同,学术界关于这一南北地理—生态分界线的具体位置一直有争论。为了进一步揭示秦巴山区过渡带的特征,明确中国南北地理—生态分界线的位置,本文选择马尾松（Pinus massoniana）林和油松（Pinus tabulaeformis）林这两类分别代表中国南方亚热带针叶林和北方温带针叶林的植被,结合研究区SRTM地形数据、气温和降水数据等,以年降水、最冷月（1月）气温、最热月（7月）气温和年均温为气候指标,详细分析了这两类植被在秦巴山区的空间分布及二者分界线处的气候条件。结果表明：① 马尾松林和油松林的分界线及相应位置的气候指标可以作为亚热带与暖温带界线划分的植被—气候指标之一。秦巴山区亚热带针叶林（马尾松林）与温带针叶林（油松林）的分界线位于伏牛山南坡至汉中盆地北缘一线（秦岭南坡）海拔1000~1200 m处;分界线处气候指标稳定：年降水750~1000 mm,年均温12~14 ℃,最冷月气温0~4 ℃,最热月气温22~26 ℃。② 通过综合的植被—气候指标来划分秦巴山区亚热带和暖温带的界线,能更科学地确定气候带分界线的位置及过渡带的特征,更全面地反映地表植被—气候格局的变化。此外,秦巴山区亚热带与暖温带的界线应该是由亚热带与暖温带针叶林分界线、阔叶林分界线、灌丛分界线等组成的一个过渡带。本文的研究结果为亚热带与暖温带划分指标的选取提供了一定的科学依据。     

人文自然耦合视角下过渡性地理空间概念、内涵与属性和研究框架

从人文自然耦合的视角看,过渡性地理空间是介于自然和人文之间的复合地带,凸显人地关系地域系统的特殊性与复杂性。其中,山区是过渡性地理空间的主体,是全国国土空间高质量发展与治理的关键区域,对其系统深刻理解与认知亟待全面加强。立足于人文自然耦合系统层面阐释过渡性地理空间的概念、内涵与属性,并借鉴多学科理论与方法,结合地理编解码技术,探索性提出基于色差渐变原理的过渡性地理空间研究的科学框架,以期深刻阐释过渡性地理空间人文自然耦合演化过程及其机理,并为提升过渡性地理空间国土空间功能与优化国土空间开发格局提供科学指导和决策依据,这对于丰富人地关系地域系统研究做出新的探索具有应用价值。     

新疆阿尔泰大喀拉苏花岗岩年代学、地球化学特征及其构造意义

大喀拉苏似斑状黑云母二长花岗岩出露于新疆阿尔泰南缘,是研究阿尔泰二叠纪构造环境的理想对象。采用LA-Q-ICP-MS锆石U-Pb定年获得其加权平均年龄为(261.4±2.1)Ma,属中二叠世。岩石具有高Si(SiO2质量分数为69.03%~70.94%)、富Al(Al2O3为14.18%~14.71%)、富K(Na2O/K2O值为0.70~0.87)的特征,A/CNK值为1.02~1.04,属高钾钙碱性弱过铝质花岗岩,显示I-A过渡型特点。微量元素表现出Rb、Th、Pb、Nd、Sm的相对正异常;Ti、P、Sr和Ba的负异常;稀土元素显示轻稀土元素强富集、重稀土元素平缓及明显的负Eu异常(0.55~0.82)。岩石的εNd(t)值和两阶段模式年龄分别为2.66~3.01和0.79~0.80Ga。综合区域地质资料和岩体地球化学特征,认为大喀拉苏黑云母二长花岗岩形成于后造山伸展环境,岩浆来源于地幔和地壳物质的混合,并在岩浆源区经历了分离结晶作用。     

地震勘探安全距离的标定方法研究

随着地震勘探的不断推进及人类活动范围的扩大,地震采集工作无法避免会涉及到越来越多的复杂地表条件和采集环境,如城区、油区等障碍物繁多的地区及环境高敏感区域。大量障碍物既影响地震采集质量和资料品质,也给施工安全造成威胁。在过渡带地震勘探中,由于激发方式多样化,安全距离的确定较为复杂,稍有不慎,很容易引起安全事故和造成资料缺失。本文基于振动效应的原理对混源激发中的安全距离进行理论探讨和实际测试,其结果对于复杂地区的地震勘探施工有着一定的指导意义。     

全球变化与海岸海洋科学发展

研究海陆过渡带的表层系统作用过程、环境资源特性及发展变化规律,与人类生存发展关系密切。全球气候与海平面自然变化、全球性频繁的地震、火山构造活动研究及国际海洋权益之重新组合,促进海岸海洋科学的新发展。