1971-2010年河南省霜期的时空分布及其对气温的响应     

姬兴杰  李凤秀  王纪军 《气象与环境学报》2015,31(1):67-75

利用1971-2010年河南省均匀分布的110个地面气象站霜的观测资料,采用线性倾向率和单相关分析法,对近40 a河南省初霜期、终霜期和无霜期的时空分布特征及其对气温的响应进行研究,利用M-K法分析霜期的突变特征。结果表明：1971-2010年河南省平均无霜期为221.3 d,纬度与初霜期（R=-0.806）和无霜期（R=-0.707）均呈显著负相关,与终霜期（R=0.557）呈显著正相关;初霜期以2.6 d/10 a的速率呈明显推迟（p<0.01）,而终霜期的线性变化趋势不明显,无霜期以4.7 d/10 a的速率呈明显延长（p<0.01）;初霜期、终霜期和无霜期的突变点均在1998年。从各地区看,初霜期在各地区呈明显推迟,豫西地区推迟趋势最大（3.5 d/10 a,p<0.01）;终霜期仅在豫西和豫南地区呈显著提前;除豫东地区外,无霜期在其余5个地区均呈明显延长,豫西地区延长趋势最大（7.7 d/10 a,p<0.01）。从各观测站霜期的变化趋势空间分布来看,初霜期显著推后、终霜期显著提前和无霜期明显延长的站点分布在豫西和豫南地区。河南省初霜期与10月、终霜期与3月气温因子相关性较强;初霜期推迟和终霜期提前主要由气温升高引起的,其中平均最低气温是最重要的影响因素。初霜期推迟和终霜期提前导致无霜期延长。  相似文献   

塔里木克拉通北缘阔克塔格西富碱侵入岩成因及其构造意义——锆石U- Pb年代学、岩石地球化学及Sr- Nd- Hf- O同位素制约     

潘蓓蓓  黄河  张招崇  王涛  吴欢欢  秦切  李海舟 《地质学报》2023,97(7):2195-2221

富碱侵入岩具有深源浅成的属性,是示踪地幔组成的窗口。位于东天山与塔里木克拉通北缘交界处的阔克塔格以西出露一处以正长岩为主体、包含少量中—基性岩石单元的富碱侵入岩。LA- ICP- MS锆石U- Pb测年显示其侵位于227~224 Ma之间,为印支期岩浆作用产物。该岩体具有富碱（Na2O+K2O=7. 93%~ 12. 28%）、富铝（Al2O3=15. 62%~18. 67%）、贫镁（MgO=0. 12%~4. 01%）、贫钛（TiO2=0. 14%~1. 63%）的特征,属于准铝质的（A/CNK=0. 78~1. 00）高钾钙碱性—钾玄岩系列。微量元素表现出高场强元素Nb、Ta、Th、U、Zr、Hf的富集,不相容元素Sr、P、Ti的亏损特征;轻重稀土分馏明显（（La/Yb）N=15. 09~34. 90）,表现为轻稀土强烈富集的右倾型曲线,Eu异常变化较大（δEu=0. 12~1. 72）。在同位素组成上,富碱侵入岩呈现相对宽泛但总体富集的全岩Sr- Nd和锆石Hf同位素特征,(87Sr/86Sr)i=0. 70489~0. 70581,εNd(t)=14. 56~6. 74,εHf(t)=11. 48~+3. 06,锆石δ18O值（5. 49‰~6. 87‰）略高于地幔值（5. 3‰±0. 6‰）。阔克塔格西富碱侵入岩具A1型花岗岩特征,形成于板内伸展构造环境中。基于主、微量元素及Sr- Nd- Hf- O同位素特征,笔者认为该杂岩体为同源岩浆演化产物,源于富集岩石圈地幔的原始岩浆上升并经历AFC（同化混染- 分离结晶）过程。晚三叠世塔里木克拉通北缘—东天山—北山地区处于板内构造体制,A1型花岗岩和正长岩差异化的时空分布特征很可能记录了古亚洲洋自西到东 “剪刀式”的闭合过程。  相似文献   

山西灵丘支家地铅锌银矿矿石微观组构及地球化学特征对成矿期次的指示意义     

覃娴瑟  吴堑虹  于洪立 《大地构造与成矿学》2011,35(1):118-127

山西灵丘支家地铅锌银矿床为中生代隐爆角砾岩型多金属热液矿床。通过显微镜、扫描电镜对矿石进行观察,发现矿石发育显示不同成矿阶段的矿物组合,矿物溶蚀结构、硫化物角砾、脉状、环带等结构构造,并分析了这些结构构造对成矿期次的指示意义;黄铁矿、闪锌矿、方铅矿等硫化物的S、Fe、Cu、Zn、Pb、Ag、In、Sn、Sb元素含量分布显示早期成矿阶段形成的硫化物较晚期的富Ag、In、Sn、Sb;不同成矿阶段的方铅矿Pb同位素组成没有明显差别。矿石的微观结构构造、硫化物元素组成特征说明该矿区发育两次成矿作用,而且二者间存在构造及热液蚀变的间断,Pb同位素特征则说明两次成矿发生于同一大地构造背景,该认识为该矿成矿模型的建立及找矿工作提供了新思路。  相似文献   

新疆查岗诺尔铁矿地质特征及成矿机理探讨     

胡秀军  汪帮耀  张海军 《化工矿产地质》2011,33(2):87-92

查岗诺尔铁矿床位于伊犁地块北缘博罗科努岛弧带.矿区广泛出露石炭纪火山岩.矿区的主要矿物共生组合为磁铁矿+石榴石+阳起石(绿帘石)组合.矿床大致可以分为早、中、晚三个成矿期.矿床是由富铁的安山质岩浆分异形成,并且后期受到热液作用的叠加改造.隐爆作用伴随整个成矿过程.该矿床成因上属于受到热液作用叠加改造的火山岩型铁矿床.  相似文献   

山东省前寒武纪地层形成时代——同位素地质测年的证据     

王世进  万渝生  宋志勇  杨恩秀  董春艳  王伟 《山东地质》2011,(11):1-6

精确同位素地质测年结果表明,沂水岩群形成时代为2 760～2 700Ma,泰山岩群雁翎关岩组、柳杭岩组下亚组和孟家屯岩组形成时代为2 750～2 700Ma,均属新太古代早期;泰山岩群柳杭岩组上亚组、山草峪岩组形成时代为2 600～2 540Ma（被峄山岩套石英闪长岩和傲徕山岩套二长花岗岩侵入）,济宁岩群岩浆锆石年龄（2 561±24）Ma,均属新太古代晚期。荆山群和粉子山群的形成时代为古元古代晚期。芝罘群碎屑锆石U-Pb年龄（1 658±32）Ma、（1 792±43）Ma,形成时代为中元古代。云台岩群花果山组碎屑锆石U-Pb年龄800～740Ma,形成时代为新元古代。  相似文献   

Virtual wave gauges based upon stereo imaging for measuring surface wave characteristics     

Adam J. Bechle  Chin H. Wu 《Coastal Engineering》2011

A virtual wave gauge (VWG) technique based on stereo imaging is developed to remotely measure water wave height, period, and direction. VWG minimizes computational costs by directly tracking the elevation of the water surface at selected points of interest using a Eulerian based dynamic searching algorithm. Results show that the VWG technique developed in this paper dramatically improves efficiency by two orders of magnitude compared to the traditional Lagrangian–Eulerian based point cloud method of stereo image processing. VWG is tested against traditional wave wire gauges to within 98% accuracy for significant wave height. Furthermore, the flexibility of the VWG is demonstrated in two field applications. First in an offshore breaking wave case, an array of VWGs is used to efficiently measure wave directionality. Second to investigate the reflection coefficient of a rock-mounted structure interacting with nearshore waves, linear and spatial VWG arrays are designed and implemented based on a priori information of the wave field from a preliminary VWG measurement. Overall, we demonstrate that the flexible and computational efficient VWG technique has the potential to make real-time remote stereo imaging wave measurements a reality.  相似文献   

Appraisal of storm beach buffer width for cyclonic waves     

F.-C. Lee  John R.-C. Hsu  W.-H. Lin 《Coastal Engineering》2011

The loss of beach sand from berm and dune due to high waves and surge is a universal phenomenon associated with sporadic storm activities. To protect the development in a coastal hazard zone, hard structures or coastal setback have been established in many countries around the world. In this paper, the requirement of a storm beach buffer, being a lesser extent landward comparing with the coastal setback to ensure the safety of infrastructures, is numerically assessed using the SBEACH model for three categories of wave conditions in terms of storm return period, median sand grain size, berm width, and design water level. Two of the key outputs from the numerical calculations, berm retreat and bar formation offshore, are then analysed, as well as beach profile change. After having performed a series of numerical studies on selected large wave tank (LWT) test results with monochromatic waves using SBEACH, we may conclude that: (1) Berm erosion increases and submerged bar develops further offshore as the storm return period increases for beach with a specific sand grain size, or as the sand grain reduces on a beach under the action of identical wave condition; (2) Higher storm waves yield a large bar to form quicker and subsequently cause wave breaking on the bar crest, which can reduce the wave energy and limit the extent of the eroding berm; (3) A larger buffer width is required for a beach comprising small sand grain, in order to effectively absorb storm wave energy; and (4) Empirical relationships can be tentatively proposed to estimate the storm beach buffer width, from the input of wave conditions and sediment grain size. These results would benefit a beach nourishment project for shore protection or design of a recreational beach.  相似文献   

不同饵料对真蛸亲体产罗同量、受精卵孵化率及初孵幼体大小的影响     

刘兆胜  刘永胜  郑小东  曲海波 《海洋科学》2011,35(10):81-85

分别采用文蛤（Meretrix meretrix）、菲律宾蛤仔（Ruditapes philippinarum）、缢蛏（Sinonovacula constrzcta）、许氏平鲌（Sebastodes fuscescens）投喂处于产卵、护卵期的真蛸（Octopus vulgaris）亲体,通过测量亲蛸摄食量、产卵量、...  相似文献   

西畴县近48年来降水及气温小波分析     

刘云生  黄国平  王顺江 《云南地理环境研究》2011,23(2):90-92

利用连续小波分析1962～2009年西畴县年降水量和年平均气温序列的小波变化特征,揭示了西畴县降水量与平均气温存在多时间尺度的周期变化特征。其中降水有2个明显的特征时间尺度,分别是4年和8年,平均气温存在以准2～4年为周期的周期振荡。此外,也可以看出近48年来,平均气温存在明显升高的趋势,降水也有减少的趋势,为掌握西畴县的气候变化规律及今后的气象预报服务工作提供了一定的参考价值。  相似文献   

Re–Os and U–Pb Geochronology of Porphyry and Skarn Types Copper Deposits in Jilin Province,NE China          下载免费PDF全文

Yong Zhang  Shu–Wen Xing  Quan–Heng Song  Yan Wang  Zheng–Tao Yu  Xiao–Hui Du  Yu–Bo Ma  Zeng–Jie Zhang 《Resource Geology》2015,65(4):394-404

Jilin Province in NE China lies on the eastern edge of the Xing–Meng Orogenic Belt. Mineral exploration in this area has resulted in the discovery of numerous large, medium, and small sized Cu, Mo, Au, and Co deposits. To better understand the formation and distribution of both the porphyry and skarn types Cu deposits of the region, we examined the geological characteristics of the deposits and applied zircon U–Pb and molybdenite Re–Os isotope dating to constrain the age of the mineralization. The Binghugou Cu deposit yields a zircon U–Pb age for quartz diorite of 128.1 ± 1.6 Ma; the Chang'anpu Cu deposit yields a zircon U–Pb age for granite porphyry of 117.0 ± 1.4 Ma; the Ermi Cu deposit yields a zircon U–Pb age for granite porphyry of 96.8 ± 1.1 Ma; the Tongshan Cu deposit yields molybdenite Re–Os model ages of 128.7 to 130.2 Ma, an isochron age of 129.0 ± 1.6 Ma, and a weighted mean model age of 129.2 ± 0.7 Ma; and the Tianhexing Cu deposit yields molybdenite Re–Os model ages of 113.9 to 115.2 Ma, an isochron age of 114.7 ± 1.2 Ma, and a weighted mean model age of 114.7 ± 0.7 Ma. The new ages, combined with existing geochronology data, show that intense porphyry and skarn types Cu mineralization was coeval with Cretaceous magmatism. The geotectonic processes responsible for the genesis of the Cu mineralization were probably related to lithospheric thinning. By analyzing the accumulated molybdenite Re–Os, zircon U–Pb, and Ar–Ar ages for NE China, it is concluded that the Cu deposits formed during multiple events coinciding with periods of magmatic activity. We have identified five phases of mineralization: early Paleozoic (~476 Ma), late Paleozoic (286.5–273.6 Ma), early Mesozoic (~228.7 Ma), Jurassic (194.8–137.1 Ma), and Cretaceous (131.2–96.8 Ma). Although Cu deposits formed during each phase, most of the Cu mineralization occurred during the Cretaceous.  相似文献