东昆仑造山带拆沉作用的数值模拟

在构建东昆仑造山带晚古生代—早中生代地质-物理模型的基础上,利用FLAC软件模拟了幔源岩浆底侵后形成的榴辉岩岩石圈拆沉作用及动力学机制,结果表明,东昆仑造山带在幔源岩浆底侵后确实发生过岩石圈拆沉作用,昆北、昆中、昆南地区的拆沉量差异较大,并形成以橄榄岩、榴辉岩和中酸性麻粒岩为源区的岩浆活动;柴达木地区未发生拆沉作用,而是下沉,同时在高密度层(榴辉岩)的顶部存在较多的断裂。文章探讨了拆沉作用与大规模岩浆活动、盆地形成、C型埃达克岩的关系,认为镁铁质岩石的特殊性质是导致拆沉作用发生的直接动力,岩石圈拆沉之后的深部约束受拆沉的量及范围控制;论证了东昆仑造山带的岩石圈拆沉作用触发了柴达木盆地的形成,并形成一系列热液矿床。     

东天山康古尔构造带红丘陵段主期构造变形温度及时代约束——来自石英EBSD组构的证据

康古尔构造带位于东天山觉罗塔格造山带北部,是构建中亚造山带晚古生代增生造山过程的关键。系统建立康古尔构造带的变形样式和变形条件,对进一步理解其构造背景和动力学机制具有重要意义。本文基于康古尔构造带红丘陵段构造解析、糜棱岩显微构造和石英c轴组构分析,厘定出2期构造变形：D1期为南北向挤压韧性剪切,变形温度为500~650℃;D2期为右行剪切,变形温度小于350℃。综合已有区域构造热年代学数据分析认为,D1期变形时间为294~280 Ma,形成于康古尔有限洋盆闭合后的中天山地块与吐哈地块南北向碰撞挤压过程,D2期右行剪切发生于276~242 Ma的后碰撞陆内缩短环境。本研究可为康古尔构造带晚古生代构造演化过程提供重要支撑。     

滇东岩溶断陷盆地水资源脆弱性评价

滇东岩溶断陷盆地区独特的"土在楼上,水在楼下"的岩溶地质地貌特征,导致水资源脆弱性问题逐步突出.当前水资源成为限制当地居民生活、区域经济发展和生态健康的重要因素之一.本研究以滇东断陷盆地中32区县为例,采用经典DPSIR模型为基础构建评价模型,选取水资源开发利用率、人均水资源量等具有代表性的18个指标构建水资源脆弱性评价指标体系,使用熵值法和层次分析法相互结合进行赋权,对滇东岩溶断陷盆地石漠化区的水资源脆弱性进行了评估.结果表明:滇东岩溶断陷盆大部分区县水资源脆弱性为中度及重度脆弱,其中马龙县、华宁县、罗平县为轻度脆弱.禄劝县、开远市、个旧市和泸西县等县为重度脆弱区,耕地石漠化面积比、人均水资源量、供蓄水比、生态需水满足率以及万元工业增加值用水量是驱动该区域水资源脆弱的关键因素.通过该区域水资源脆弱性评估,本研究有针对性地提出了滇东岩溶断陷盆水资源适应性管理对策,为有效缓解该区域水资源脆弱性提供科学依据.     

再论山脊壶穴的冰川融水成因——兼与施雅风院士商榷

针对施雅风院士新提出的壶穴之"负球状风化"说,笔者特撰文与施老商榷。笔者认为:壶穴的形成并不受花岗岩中节理的控制,也与风化作用无关,不能用"负球状风化"来解释。壶穴是高速旋转水流侵蚀的结果,在中国东部花岗岩山脊上发现的壶穴是第四纪冰川融水侵蚀的标志。近年来观察到的格陵兰冰上湖泊的突然排泄为壶穴的冰川融水成因说提供了重要的证据。壶穴成因争论的本质是中国东部是否曾经发育过第四纪冰川,建议第四纪学界关注中国东部第四纪冰川的其他地貌标志。韩同林研究员的"冰臼论"促进了中国东部第四纪冰川地貌的再研究,应当给予积极评价。     

河西走廊东部大风气候特征及预报

利用河西走廊东部1971—2010年4个气象站大风（≥6级,即10min平均风速≥10.8～13.8m/s）资料,系统分析了该区大风的时空分布、强度和持续性等气候特征。结果表明,河西走廊东部大风天气主要发生在山区和沙漠边缘;年、年代际大风日数总体呈减少趋势,3—5月是大风的高发期,占全年大风日数的34.8%～56.8%,其次是2月、6月和11月;各强度大风日数的变率较大,随着大风强度的增强,大风日数迅速减少;大风天气具有持续性特征,最大风速大多出现在持续大风时段内。采用2003—2007年逐日20时ECMWF数值预报格点场资料,按照Press准则进行预报因子初选,运用逐步回归预报方法进行预报因子精选,使用最优子集回归建立大风预报方程,并用双评分准则（CSC,couple score criterion）确定各季节各地大风预报全局最优的显著性方程,预报方程通过了α=0.01的显著性检验。预报方程回代拟合率为66.7%～73.4%,预报准确率为58.8%～67.5%,达到了一定的预报水平,可为大风的业务预报提供客观有效的指导产品。采用最大靠近原则确定了大风预报临界值和预报、预警的级别。     

A new species of eucypris (ostracoda) from wellington

Eucypris pratensis sp. nov. is described from Wellington. It is considered conspecific with the one previous record of the genus from North Island, New Zealand.     

Spectral features of the New Zealand deep‐water ocean wave climate

The wave climate at the Maui site off the west coast of the North Island and off the east coast of Great Barrier Island to the east of the North Island are examined. This is done by means of average wave spectra derived from a 2‐year database, acquired from Waverider buoy measurements made over 1980 and 1981. The average spectra provide information about the individual sea states which characterise the wave climate, and show that on average the sea state on the east coast is less energetic than it is on the west coast. Further, it is seen that this difference results largely from a dominant and persistent long‐period south‐westerly swell of 12.4 s period which is present at the Maui location but absent from the Great Barrier Island seas.     

莱州湾东岸海底地下水来源判别及量值估算

采用稳定同位素——¹⁸O、D, 结合常规离子分析结果确定了莱州湾东岸海底地下水的来源, 并采用数值方法估算了其量值。结果表明: 莱州湾东岸海底地下水主要来源于波浪、潮汐的海水补给, 同时在一定程度上受地下水径流排泄的影响, 三者对海底地下水的贡献率分别为 31.0%, 56.3%和 12.7%。研究结果对于合理开发、科学保护海底地下水具有重要现实意义。     

A study of non-linear tidal propagation in shallow inlet/estuarine systems Part II: Theory

The generation of tidal asymmetries is clarified via numerical integration of the one-dimensional equations for channel geometries characteristic of shallow estuaries. Channels without tidal flats develop a time asymmetry characterized by a longer falling than rising tide. This behavior is enhanced by strong friction and large channel cross-sectional area variability over a tidal cycle. Resulting tidal currents have a shorter, intense flood and a longer, weak ebb (flood-dominant). Addition of tidal flats to the channels can produce a longer rising tide and stronger ebb currents (ebb-dominant), if the area of tidal flats is large enough to overcome the effects of time-variable channel geometry. Weaker friction with flats can also produce this asymmetry.Despite the physical complexity of these systems, essential features of estuarine tidal response can be recovered from one-dimensional models. Shallow estuaries are shown to have a system response leading to stable, uniform senses of tidal asymmetry (either flood- or ebb-dominated, due to phase-locking of forced tidal constituents), with down-channel development in magnitude of asymmetry. These concepts are illustrated by modeling idealized representations of tidal channels at Nauset Inlet, MA, and Wachapreague Inlet, VA, which have flood- and ebb-dominance, respectively.     

PERMAFROST DEGENERATION IN THE EAST OF QINGHAI-XIZANG PLATEAU

ＰＥＲＭＡＦＲＯＳＴＤＥＧＥＮＥＲＡＴＩＯＮＩＮＴＨＥＥＡＳＴＯＦＱＩＮＧＨＡＩ－ＸＩＺＡＮＧＰＬＡＴＥＡＵ￥ＺｈｕＬｉｎｎａｎ；ＷｕＺｉｗａｎｇ；ＬｉｕＹｏｎｇｚｈｉ；ＬｉＤｏｎｇｑｉｎｇ（ＳｔａｔｅＫｅｙＬａｂｏｒａｔｏｒｙｏｆＦｒｏｚｅｎＳｏｉ...