原油裂解对油包裹体均一温度和捕获压力的影响及其地质意义

通过原油裂解动力学和石油包裹体热动力学模拟方法系统阐述了地质条件下原油裂解过程对油包裹体均一温度及捕获压力的影响.结果表明:初始裂解阶段(T_R＜13%,T＜160 ℃),油包裹体均一温度随原油裂解呈增大趋势,捕获压力呈减小趋势;随着裂解程度增大(T_R＜24%,T＜190 ℃),油包裹体均一温度随原油裂解呈减小趋势,捕获压力呈增大趋势,但此阶段油包裹体均一温度仍高于初始捕获时均一温度,捕获压力仍小于初始捕获压力;此后,随着原油裂解程度不断增大,油包裹体均一温度持续减小甚至到负值,捕获压力则持续增大甚至超过静岩压力.封闭条件下低程度的原油裂解(T＜160 ℃,T_R＜13%)只会形成常压或者低压;而较高程度的原油裂解(T_R＞40%)才会形成超压,甚至超过上覆静岩压力(T_R＞70%).深部原油裂解气勘探中要特别注意地层温度位于160~190 ℃范围内的常压到低压油气藏,而地层温度高于190 ℃原油裂解气勘探应以找超压-超高压油气藏为主.      

稻田土壤中甲烷产生率的实验研究

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.     

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

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...     

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

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.     

菲律宾Zambales蛇绿岩套的再研究：对其特提斯来源的启示

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.     

http://www.sciencedirect.com/science/article/pii/S1674987112000655

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.     

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

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.     

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

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。