青岛C类榴辉岩的岩石学矿物学及其地质意义

本文利用X荧光光谱定量分析、电子探针分析和X衍射分析对青岛C类榴辉岩作了岩石学、岩石化学和矿物化学研究,计算了青岛C类榴辉岩的成岩温度、压力条件及古地温梯度,最后提出了其成因是早元古代早期华南陆块向华北陆块俯冲时,大洋碱性橄榄玄武岩在低温高压环境发生变质作用形成C类榴辉岩和蓝闪石片岩。早元古代的变质作用使C类榴辉岩平衡温度升高,蓝闪石片岩消失。     

胶东—苏北古碰撞带三相变质作用

本文报道了胶东—苏北古碰撞带附近存在的高温低压变质的麻粒岩相、高温高压变质的A—B类榴辉岩相和高压低温变质的C类榴辉岩相三种变质相系,以及与高温低压麻粒岩相有关的Ⅰ型花岗岩带,它们在空间上相协调,在时间上相一致。其经历了早元古代早期的华南—华北陆块碰撞事件、早元古代角闪岩相变质事件和早元古代末期大陆推覆构造事件,使得高温低压麻粒岩相岩石发生退变质作用,低温高压C类榴辉岩相岩石发生进变质作用,蓝闪石片岩消失,并导致高温高压的A—B类榴辉岩相和高压低温的C类榴辉岩相在空间上相叠置。     

胶东—苏北构造带特征及动力学演化

提出胶东—苏北构造带以广泛出露榴辉岩和超基性岩、普遍发育韧性剪切带和糜棱岩带为特征,具混杂岩特点。它经历了早元古代大陆推覆构造事件(2000～2400Ma)、早元古代末低角闪岩相变质热事件(1800～2000Ma)和元古代末大陆推覆构造事件(6O0～800Ma)。该构造带是华北陆块与华南陆块之间的过渡带。     

鲁苏榴辉岩套的特征及其动力学演化

鲁苏榴辉岩套以广泛分布各类榴辉岩、密切伴生石榴石橄榄岩、石榴石麻粒岩等高压岩石组合 ,普遍发育韧性变形带 ,大量出露燕山晚期碱性花岗岩及深源脉岩为特征。它已经历三迭纪早期华南陆块与华北陆块的碰撞事件、大陆逆掩推覆构造事件及后期白垩纪早期开始的大陆伸展构造事件 ,是我国华南陆块与华北陆块之间的重要过渡单元。     

青岛榴辉岩相变质古洋壳的特征及其成因

利用电子探针等方法研究了青岛榴辉岩相变质古洋壳(蛇纹岩、C类榴辉岩和基性糜棱岩)的岩石学和地球化学特征。确定了它们为华南陆块与华北陆块拼合前的古洋壳,当其俯冲于华北陆块之下时在深部发生碱质交代及低温高压变质作用(C类榴辉岩相)。     

威海地区高压岩石组合及其成因演化

利用矿物地质温压计估算变质高峰期温压条件、退变质作用温压条件。研究表明,本区为鲁苏构造带的北延部分,代表本区晚元古代华南陆块与华北陆块的碰撞及三叠纪华北陆块向华南陆块推覆事件的发生和演化。     

鲁南榴辉岩的Sm—Nd等时年龄及其构造意义

讨论山东诸城胶南混杂岩系中的榴辉岩属地壳角闪岩相变质成因,其Sm—Nd等时年龄为222±6Ma,~(143)Nd/~(144)Nd初始比值为0.51136±0.00003,θ(T) 为-19.4±0.5,代表了早三叠世华南陆块与华北陆块碰撞拼合,并发生高压变质作用。后期的陆壳推覆及伸展构造使深部榴辉岩上升侵位于胶南混杂岩系中。     

南黄海千里岩岛榴辉岩的矿物化学及成因探讨

南黄海千里岩岛地处中国华南板块与华北板块缝合线位置,其基底由强烈韧性变形的构造片麻岩组成,并出露具重要大地构造标型意义的超高压榴辉岩类岩石。本文通过对南黄海千里岩岛榴辉岩中主要造岩矿物石榴石的矿物化学研究,探讨了榴辉岩的成因。研究表明,千里岩地区高压变质岩是由于华北与华南两大陆块拼合时,处于其间的岛弧拉斑玄武岩沿碰撞带下插到华北陆块之下,从而使千里岩地区发生高压变质作用,形成了榴辉岩和片麻岩等,后期的构造折返使其上升到地壳上部。     

江苏东海毛北榴辉岩的矿物化学及其成因问题

本文利用电子探针,分析了江苏东海毛北榴辉岩中的石榴石和单斜辉石的化学组成。利用矿物地质温度计,计算了毛北榴辉岩的成岩平衡温度。结合本区的大地构造环境,提出在早元古代末期,华北陆块曾发生向南的大型堆覆构造,苏北地区即为推覆体前缘。     

鲁苏榴辉岩的地球化学

以微量元素、稀土元素、Ｓｒ和Ｎｄ同位素变异特征为依据，确定鲁苏榴辉岩为多成因、多来源和多阶段，指出主要是在印支期扬子陆块与华北陆块碰撞造山作用过程中，挤入的上地幔碎片以及不同原岩类型的壳内高压变质岩碎块。燕山晚期的区域构造热事件使得某些榴辉岩的同位素体系再平衡。     

鲁苏榴辉岩套的岩石——构造组合与地质演化

提出鲁苏榴辉岩套的分布、岩石组合及构造形变特征。依据成岩条件和同位素年龄探讨了其地质演化,认为它们形成于三叠纪早期的碰撞造山作用和白垩纪早期的伸展构造作用。     

中国东部沿海第四纪古环境的探讨 Ⅰ.试论“生物环境容忍带”与生物气候界线

本文提出“生物环境容忍带”概念,讨论生物对气候环境的适应性和一定条件下的容忍性,以此为据,论证了中国东部沿海23000年以来的生物气候界线、冰缘外围环境和气候环境变迁轮廓。     

Okinawa Trough genesis: structure and evolution of a backarc basin developed in a continent

The Okinawa marginal basin was opened by crustal extension into the Asian continent, north of the Taiwan collision zone. It is located behind the Ryukyu Trench subduction zone and the Ryukyu active volcanic arc. If we except the Andaman Sea, the Okinawa Trough is the only example of marginal backarc basin type, opened into a continent at an early stage of evolution. Active rifting and spreading can be observed. Synthesis of siesmic reflection, seismic refraction, drilling, dredging and geological field data has resulted in interpretative geological cross sections and a structural map of the Ryukyu-Okinawa area. The main conclusions of the reconstruction of this backarc basin/volcanic arc evolution are. (1) Backarc rifting was initiated in the volcanic arc and propagated along it during the Neogene. It is still active at both ends of the basin. Remnants of volcanic arc are found on the continental side of the basin. (2) There was synchronism between opening and subsidence of the Okinawa Trough and tilting and subsidence of the forearc terrace. The late Miocene erosional surface is now 4000 m below sea-level in the forearc terrace, above the trench slope. Retreat and subsidence of the Ryukyu trench line relative to the Asian continental plate, could be one of the causes of tilting of the forearc and extension in the backarc area. (3) A major phase of crustal spreading occurred in Pliocene times 1.9 My ago in the south and central Okinawa Trough. (4) En échelon rifting and spreading structures of the central axes of the Okinawa Trough are oblique to the general trend of the arc and trench. The Ryukyu arc sub-plate cannot be considered as a rigid plate. Rotation of 45° to 50° of the southern Ryukyu arc, since the late Miocene, is inferred. The timing and kinematic evolution of the Taiwan collision and the south Okinawa Trough opening suggest a connection between these two events. The indentation process due to the collision of the north Luzon Arc with the China margin could have provoked: lateral extrusion; clockwise rotation (45° to 50° according to palaeomagnetic data) and buckling of the south Ryukyu non-volcanic arc; tension in the weak crustal zone constituted by the south Ryukyu volcanic arc and opening of the south Okinawa Trough. Similar lateral extrusions, rotations, buckling and tensional gaps have been observed in indentation experiments. Additional phenomena such as: thermal convection, retreating trench model or anchored slab model could maintain extension in the backarc basin. Such a hypothetical collision-lateral backarc opening model could explain the initiation of opening of backarc basins such as the Mariana Trough, Bonin Trough, Parece Vela — Shikoku Basin and Sea of Japan. A new late Cenozoic palaeogeographic evolution model of the Philippine Sea plate and surrounding areas is proposed.     

河口最大浑浊带形成的动力模式和数值试验

应用改进的ECOM模式,耦合泥沙输运模型,研究理想河口最大浑浊带形成的动力机制。河口最大浑浊带位于滞流点处,上下游余流均向该处输运泥沙,造成该处泥沙汇合,而由流场辐合产生的上升流又使该处的泥沙不易落淤。南岸(河口东向)的泥沙浓度比北岸高,最大浑浊带位于南岸,这是由于盐水入侵带来的高盐水位于北岸的底层,其斜压效应使底层的环流由北向南流动,把底层高浓度的泥沙向南岸平流,聚集于南岸底层。除上游河流泥沙来源外,强大的涨落潮流冲刷床面,使沉降于床面的泥沙再次悬浮,成为余流输运泥沙的来源之一。     

Tectonic Significance of the Taitung Canyon, Huatung Basin, East of Taiwan

Since the beginning of formation of Proto-Taiwan, the subducting Philippine (PH) Sea plate has moved continuously through time in the N307° direction with respect to Eurasia (EU), tearing the EU plate. The subducting EU plate includes a continental part in the north and an oceanic part in the south. The boundary B between these two domains corresponds to the eastern prolongation of the northeastern South China Sea ocean-continent transition zone. In the Huatung Basin (east of Taiwan), the Taitung Canyon is N065° oriented and is close and parallel to B. Seismic profiles show that the southern flank of the canyon corresponds to a fault with a normal component of a few tens of meters in the sediments and possible dextral shearing. Several crustal earthquakes of magnitude >%6 are located beneath the trend of the Taitung Canyon and focal mechanisms suggest that the motion is right-lateral. Thus, faulting within the sedimentary sequence beneath the Taitung Canyon is a consequence of underlying dextral strike-slip crustal motions. As the continental part of the EU slab located north of B has been recently detached, some subsequent dextral strike-slip motion might be expected within the EU slab, along the ocean-continent transition zone, which is a potential zone of weakness. We suggest that the dextral strike-slip motion along the ocean-continent boundary of the EU slab might trigger the observed dextral strike-slip motion within the overlying PH Sea crust and the associated faulting within the sediments of the Huatung Basin, beneath the Taitung Canyon. An erratum to this article is available at .     

南海晚新生代构造运动与天然气水合物资源

南海在新生代经历过两次海底扩张产生了南海洋盆.南海北部和南部原来都是被动大陆边缘,但北部在晚新生代由于菲律宾海板块与欧亚板块在台湾地区发生了碰撞,使陆缘遭受到北西向挤压,在陆缘上产生了北西向左旋走滑活动,我们命名此次构造活动为东沙运动;南部陆缘在早中新世末由于南移的南沙地块与婆罗洲地块发生了碰撞,加上此时北移的菲律宾海板块在明都洛岛地区与欧亚板块发生碰撞,以及南部的东南苏拉威西地块与西北苏拉威西地块发生碰撞,在南海南部产生了挤压构造,我们命名此次构造运动为南沙运动.这两次新生代的构造运动改变了南北陆缘的性质,北部陆缘有人因此称之为准被动陆缘,而南部陆缘的南部则变成了挤压边缘.南海南北陆缘在晚新生代受到的挤压活动,对油气成藏和天然气水合物的形成有重要的推动作用,因为挤压活动有利于流体的流动,进而在适当的地方形成油气藏和天然气水合物.