稻田土壤中甲烷产生率的实验研究   总被引：12，自引：0，他引：12       下载免费PDF全文

上官行健  王明星  R.Wassmann 《大气科学》1993,17(5):604-610

本实验旨在研究稻田土壤中甲烷产生率对稻田CH_4排放的影响.观测结果表明:土壤各深度的甲烷产生率有很大的变化范围(1—4639ng·h~(-1)·g~(-1)d.w.).主要的甲烷产生区域是7—17cm深的土壤层,其中以13cm深的土壤层上的生成速率最大.土壤中甲烷产生率与稻田CH_4排放率在水稻生长的某些阶段有较好的相关性,但它的季节变化却不能与排放的季节变化完全耦合.在水稻生长期,土壤中甲烷产生率随时间而增大,并在8月份水稻收割前达到最大,其日平均值在38—767 ng·h~(-1)·g~(-1)d.w.间变动.稻田土壤中甲烷产生率也存在日变化,一般在下午达到最大值,但却没有发现它与土壤温度有明显的相关关系.在不同施肥及水稻品种的稻田土壤中也观测到不同的甲烷产生率.在土壤中产生的甲烷最多只有28.8％被排放到大气中,而其余多于71.2％的则被氧化在土壤中.  相似文献   

Photometric observations of three high mass X-ray binaries and a search for variations induced by orbital motion     

Gordon E. Sarty  Bogumil Pilecki  Daniel E. Reichart  Kevin M. Ivarsen  Joshua B. Haislip  Melissa C. Nysewander  Aaron P. LaCluyze  Helen M. Johnston  Robert R. Shobbrook  Lászl L. Kiss  Kinwah Wu 《中国天文和天体物理学报》2011,(8)

We searched for long period variation in V-band,IC-band and RXTE X-ray light curves of the High Mass X-ray Binaries(HMXBs) LS 1698 /RX J1037.5-5647,HD 110432 /1H 1249-637 and HD 161103 /RX J1744.7-2713 in an attempt to discover orbitally induced variation. Data were obtained primarily from the ASAS database and were supplemented by shorter term observations made with the 24-and 40-inch ANU telescopes and one of the robotic PROMPT telescopes. Fourier periodograms suggested the existence of long period variat...  相似文献   

慢滑动事件震源参数的标度关系     

Haiying  Gao  D.A.Schmidt  R.J.Weldon  II  翟璐媛  译 《世界地震译丛》2013,(Z1):13-23

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晚古生代冈瓦纳的演化长逾13500 km的基墨利超级地体的裂离及其向亚洲的漂移     

Jason R. ALI  Jonathan C. AITCHISON  Haz M.C. CHEUNG  Sam S.Y.CHIK  SUN Ya-dong 《地球学报》2012,33(S1):2-3

The Cimmerian terrane forms an almost unbroken chain stretching >13,500 km, from central southern Europe to western Indonesia, via SE Europe, the Middle East, Afghanistan, Tibet, SW China and Myanmar. Ar-guably, it is Earth’s most spectacular example of a “sliver” terrane, dwarfing in size more recently devel-oped examples, for instance the Palawan Block in the western Philippines, and the Lord Howe Rise in the Tasman Sea. The presentation will first outline the in-triguing geological features associated with this unique tectonic entity. Following that, recently obtained results following paleomagnetic investigations of two lower Permian rift-related basalt suites will be summarized (Abor Volcanics in northeastern India and Woniusi Ba-salts in Yunnan, China). The two studies are part of a larger programme of ongoing research aimed at deducing (I) the geodynamic configuration that generated the un-usual rifting system, and (II) exactly how Cimmeria fit-ted against Gondwana prior to its dispersal in the Early Permian. The critical unit is Baoshan, which we fit against Gondwana within a narrow longitudinal belt close to where northern India and northwestern Australia were once in close proximity (Fig. 1). Furthermore, we suggest that Sibumasu lay to directly the east, offshore of Australia; Qiangtang and Lhasa almost certainly sat to the west (off northern Greater India-SE Arabia), but we are uncertain as to their exact configuration. Our findings will be compared with several rather different models that have been published in recent years. The new pa-leomagnetic constraint highlights the flexibility authors currently have in reconstructing the region, principally because of the overall lack of similar high-quality data from the various blocks. We explain how new data could resolve these ambiguities, thereby offering more robust explanations for eastern Gondwana’s late Paleozoic de-velopment.  相似文献   

菲律宾Zambales蛇绿岩套的再研究：对其特提斯来源的启示     

Karlo L. QUEA?O  Carla B. DIMALANTA  Graciano P. YUMUL JR.  Decibel V. FAUSTINO-ESLAVA  Edanjarlo J. MARQUEZ  Noelynna T. RAMOS  Keisuke ISHIDA  Shigeyuki SUZUKI  Ricky C. SALAPARE  Michael Peter M. SANCHEZ  Juan Miguel R. GUOTANA  Rose Ann B. CONCEPCION 《地球学报》2012,33(S1):58-58

A number of geological studies have already been conducted on the Zambales Ophiolite Complex (ZOC), a north-south trending complete ophiolite sequence exposed in the western portion of Central Luzon, Philippines. Previous works recognized the ZOC as being made up of two blocks, the Acoje and the Coto, acting as an arc-back arc pair sometime during the Eocene.  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987112000655   总被引：1，自引：1，他引：0  

G.H.Grantham  P.Mendonidis  R.J.Thomas  M.Satish-Kumar 《地学前缘(英文版)》2012,3(6):755-771

Four different varieties of charnockitic rocks,with different modes of formation,from the Mesoproterozoic Natal belt are described and new C isotope data presented.Excellent coastal exposures in a number of quarries and river sections make this part of the Natal belt a good location for observing charnockitic field relationships.Whereas there has been much debate on genesis of charnockites and the use of the term charnockite.it is generally recognized that the stabilization of orthopyroxene relative to biotite in granitoid rocks is a function of low aH₂O（±high CO₂）,high temperature,and composition （especially Fe/（Fe +Mg））.From the Natal belt exposures,it is evident that syn-emplacement.magmatic crystallization of chamockite can arise from mantle-derived differentiated melts that are inherently hot and dry（as in the Oribi Gorge granites and Munster enderbite）,as well as from wet granitic melts that have been affected through interaction with dry country rock to produce localized charnockitic marginal facies in plutons（as in the Portobello Granite）.Two varieties of post-emplacement sub-solidus chamockites are also evident.These include charnockitic aureoles developed in leucocratic,biotite.garnet granite adjacent to cross-cutting enderbitic veins that are attributed to metamorphic-metasomatic processes（as in the Nicholson’s Point granite,a part of the Margate Granite Suite）,as well as nebulous,patchy charnockitic veins in the Margate Granite that are attributed to anatectic metamorphic processes under low-aH_O fluid conditions during a metamorphic event.These varieties of chamockite show that the required physical conditions of their genesis can be achieved through a number of geological processes,providing some important implications for the classification of charnockites,and for the interpretation of charnockite genesis in areas where poor exposure obscures field relationships.  相似文献   

幔源角闪石巨晶中硫化物熔融包裹体研究   总被引：1，自引：0，他引：1  

李大鹏  杜杨松  S. D. SCOTT  秦新龙  A. F. A. MARQUES  R. N. S. SODHI 《地质学报》2012,86(7):1091-1105

硫化物熔融包裹体研究是认识硫化物矿床成矿元素来源和演化的重要手段,由于硫化物熔融包裹体的体积较小(粒径仅为10～20μm),其详细化学元素组分的难以获得一直是制约进一步研究的瓶颈。笔者在前人研究的基础上,借助于扫描电镜、电镜能谱和二次飞行时间离子探针(Tof-SIMS)对产于铜陵地区角闪石巨晶中的硫化物熔融包裹体进行了详细的研究,首次获得了一套精确的矿物化学资料和元素分布图。矿物学研究表明,角闪石巨晶在上地幔和下地壳均有结晶,温压区间分别为T:850～900℃(温度),P:0.70×109～0.82×109Pa(压力),对应深度D:23.10～27.06km;和T:900～950℃,P:1.09×109～1.17×109Pa,D:35.97～38.61km。元素分布图显示,硫化物熔融包裹体主要有两种元素组成体系:S-Fe-Mn-Ni-Rb-Sr-Ba和S-Fe-Cu-Sr,幔源硫化物体系中Mn、Ni、Rb、Ba等元素具有相似的性质特征可共溶,与Cu则表现出不混溶。在铜陵地区,上地幔的部分熔融形成了一套碱性玄武岩浆,后受岩浆底侵作用和壳幔相互作用影响,底侵进入下地壳深位岩浆房,发生结晶分异和同化混染作用,形成一套轻度演化的玄武岩浆,可能为辉长质。上地幔和下地壳的角闪石巨晶分别是由上地幔碱性玄武岩浆和下地壳轻度演化的玄武岩浆(辉长质)高压下结晶的产物。当上地幔碱性玄武岩浆上侵到下地壳深位岩浆房以后,发生结晶分异作用,又由于地壳硅镁层的混染作用,使得玄武岩浆中硫溶解度降低,促其熔离,从而释放大量的硫(S,以及Ni、Cu、Cr)。角闪石巨晶中的硫化物熔融包裹体正是在下地壳深位岩浆房中,由正在结晶的角闪石巨晶在结晶分异和轻度演化的玄武质岩浆中捕获的不混溶硫化物熔融液滴形成的。铜陵地区在中生代经历了一个长期的大规模的岩浆底侵作用和壳幔相互作用过程,由于下地壳硅镁层混染作用使得轻度演化的玄武岩浆释放大量硫,必然会在莫霍面附近形成大规模高浓度的硫富集区,这些组分在岩浆上侵作用、地壳减薄作用或者裂谷作用的影响下很容易再活化,进入区域岩浆-热液流体系统,最终参与形成区域大规模的硫化物矿床。  相似文献   

The Flight Dynamics of Tapejara,a Pterosaur From the Early Cretaceous of Brazil with a Large Cranial Crest     

Sankar CHATTERJEE  and R. Jack TEMPLIN 《《地质学报》英文版》2012,86(6):1377-1388

Tapejara wellnhoferi, a small azhdarchoid pterodactyloid from the Early Cretaceous Santana Formation of Brazil, provides critical information about the aerodynamic function of its spectacular head crest. The cranial crests in pterodactyloids were sexually dimorphic and are thought to have evolved in adult males in response to female mate choice. However, the location of cranial crests in front of the center of gravity would create instability in the yaw axis during flight and may seem like a handicap. Vertically aligned webbed feet probably suppressed the yawing rotations and instability from the crest. Here we show that the crest functioned as a front rudder to make agile turn and mediate flight control. A computer simulation model suggests that Tapejara had a large excess of muscle power available above the power required for continuous flapping flight. It could easily takeoff from a perch, ground, or water surface and land safely on the ground. It was an excellent glider with a gliding angle close to 4o and a cruising speed of 27 km/h. Tapejara could soar efficiently on the windward side of cliffs or circle on rising thermals over tropical waters for efficient long-distance flight. Various control surfaces in the wings of Tapejara analogous to the slat, aileron, elevator, fin, rudder, and horizontal stabilizer of an aircraft made pterodactyloids versatile flyers.  相似文献   

黄土高原东北缘矾山剖面的古地磁新结果     

陈蕴  王喜生  裴军令  R.L 《第四纪研究》2012,32(4):597-607

黄土高原不同地区发育的黄土-古土壤序列在东亚冬、夏季风记录上存在一定的差异性,而目前的研究多集中在黄土高原腹地.本文以黄土高原东北缘北京邻区矾山剖面S6～L9段地层为研究对象,开展了详细的古地磁、岩石磁学、粒度及地球化学测试分析.结果表明:1)与黄土高原腹地典型剖面同时段地层相比,矾山黄土成壤程度偏低,所受夏季风的影响...  相似文献   

从2004年苏门答腊—安达曼巨型逆冲断层破裂得到的经验教训     

P. Shearer  R．Burgmann  赵雯佳译  吕春来校 《世界地震译丛》2012,(1):1-23

发生于2004年的苏门答腊—安达曼地震,因其规模巨大,并且造成了毁灭性的后果,而得到广泛的研究。研究者通过分析大量高质量的地震、大地测量和地质数据,提出很多构造模型,以进一步了解这次地震的破裂长度、持续时间、断层几何形状、破裂速度和滑动过程等信息。一些最新的模型尽管在细节上有所不同,但在大尺度特征上都是一致的,例如,沿着整个长1300～1500km的破裂区域都有明显的同震滑动。块体滑动的速度非常快,足以辐射出地震波。由于这次地震的规模很大,使用传统方法进行数据处理会面临很多困难和挑战,这也促使人们创造和发展新的分析和反演方法,如多源反演、高频体波成像,以及通过卫星观测海啸浪高和重力变化等。苏门答腊巨型逆冲断层地震是40年来发生的最大地震,也是到目前为止资料记载保存最完好的地震,但它的一些特性与其他大的俯冲带地震看起来没有根本上的不同。  相似文献