太行山南缘新生代的隆升与断陷过程

作者通过太行山南缘夷平面、河流阶地、山前盆地和中新生代断裂的调查研究,揭示了太行山南缘新生代的断陷与隆升过程,认为太行山南缘地区新生代以来的构造活动以断裂的断陷、隆升为特征,分为三个相对稳定夷平时期和三个快速隆升阶段,形成三级夷平面.第四纪以来的快速隆升过程可进一步划分为六次相对快速抬升和六个相对稳定堆积时期,形成六级阶地.古近纪断陷活动强烈,第四纪除山前断裂以外,其它断裂未见活动.     

Significance of interdune deposits and bounding surfaces in aeolian dune sands

Bounding surfaces and interdune deposits provide keys for detailed interpretations of the development, shape, type, wavelength and angle of climb of aeolian bedforms, as well as overall sand sea conditions. Current alternate interpretations of bounding surfaces require very different, but testable models for sand sea deposition. Two perpendicular traverses of Jurassic Entrada Sandstone, Utah, reveal relations among cross-strata, first-order bounding surfaces, and horizontal strata. These field relations seem explicable only as the deposits of downwind-migrating, climbing, enclosed interdune basins (horizontal strata) and dune bodies consisting of superimposed smaller crescentic dunes (cross-stratified deposits). A 1.7 km traverse parallel to the palaeowind direction provides a time-transgressive view showing continuous cosets of cross-strata, first-order bounding surfaces and interdune deposits climbing downwind at an angle of a few tenths of a degree. Changes occur in the angle of climb, cross-strata structure, and interdune deposits; these reflect changes in depositional conditions through time. A 1.5 km traverse perpendicular to the palaeowind direction provides a view at an instant in geological time showing first-order bounding surfaces and interdune deposits forming flat, laterally discontinuous lenticular bodies. The distribution of interdune sedimentary structures in this traverse is very similar to that of some modern interdune basins, such as those on Padre Island, Texas. Hierarchies of bounding surfaces in an aeolian deposit reflect the bedform development on an erg. The presence of three orders of bounding surfaces indicates dune bodies consisting of smaller, super-imposed dunes. The geometry of first-order bounding surfaces is a reflection of the shape of the inter-dune basins. Second-order bounding surfaces originate by the migration of the superimposed dunes over the larger dune body and reflect individual dune shape and type. Third-order bounding surfaces are reactivation surfaces showing stages in the advance of individual dunes. The presence of only two orders of bounding surfaces indicates simple dunes. Modern and Entrada interdune deposits show a wide variety of sediment types and structures reflecting deposition under wet, damp, and dry conditions. Interdune deposits are probably the best indicators of overall erg conditions and commonly show complex vertical sequences reflecting changes in specific depositional conditions.     

龙门山南段前陆区古冲积扇分析及河流地貌面序列的建立——基于地貌面的测年数据、野外地貌分析与调查

通过对龙门山南段古青衣江冲积扇的调查,分析并还原了不同时期的古地貌面,结合现代青衣江两侧分布的阶地,建立了龙门山南段前陆区中更新世以来的地貌面序列。青衣江贯通龙门山南段前陆区,是利用河流阶地研究区域复杂构造的合适对象。但存在的问题是:一方面,龙门山前陆区气候湿润,风化严重,较老的河流阶地遭受侵蚀严重而不易保存;另一方面,河流阶地只能反映顺河流单一方向的构造活动特征。为解决这些问题,本文一方面对古青衣江残留的名邛冲积扇和丹思冲积扇进行分析,重建古冲积扇面,并实测多条地貌综合剖面反映扇体与沉积特征;另一方面,通过对冲积扇与现代河流阶地的实地测量,对比分析了两者的空间关系,发现名邛冲积扇早于青衣江阶地,而丹思冲积扇a、b两期（DS-a和DS-b）分别与阶地T6、T5同时形成。基于这些详细的地貌分析,建立了前陆区的地貌面序列。在进一步测试了各级地貌面的年龄后,得出了不同时期河流产生地貌面的年龄与分布范围,其中包括大邑砾岩、名邛冲积扇、丹思冲积扇以及现代青衣江阶地T6~T1。地貌面序列的建立扩大了利用河流阶地研究构造活动的时间尺度与空间范围。另外,对地貌面的成因分析发现,其发育明显受控于气候变化:名邛冲积扇和丹思冲积扇均形成于间冰期的气候温暖时,分别为深海氧同位素MIS 13和MIS 9,并在冰期结束沉积,而在随后的间冰期（深海氧同位素MIS 11与MIS 7）发生河流改道导致冲积扇废弃;同时,青衣江各级河流阶地也具有明显的气候阶地特征,与冰期、间冰期的交替相对应。     

大渡河金川-巴底河段河流地貌特征研究

对大渡河中游金川-巴底河段水系格局、河谷形态、河流阶地及第四纪沉积物进行研究,分析河流地貌的发育特征、影响因素以及发育演化史,为区域稳定性评价提供依据。研究表明,该区域为具有夷平面的深切峡谷地貌区,发育三级夷平面和4~6级阶地,河流地貌发育经历三个阶段,河流地貌的形成与演化受构造、岩性影响明显。     

Bog development and environmental conditions as shown by the stratigraphy of Store Mosse mire in southern Sweden

Macrofossil analyses, pollen analyses, and ¹⁴C datings were carried out on profiles from a bog complex in southern Sweden. The development started with a Carex fen c. 6,000 B. P. which transformed to bog c. 1,000 years later. The bog has developed through three stages separated by highly humified peat layers, recurrence surfaces, 3 and 2m below the present bog surface, and formed c. 2,500 and 1,200 B. P., respectively. The fen formation and the initiation of the last two bog stages were contemporaneous with high water levels in lakes of the region. The transition to bog and the formation of the two highly humified peat layers may be related to low water levels in lakes. It is probable that changes in the development of the mire were caused by the climate, since varying water levels are thought to be dependent on variations in the climate.     

Mechanisms of shear failure in artificial fractures of sandstone and their implication for models of hydromechanical coupling

Summary Direct shear tests, in which the behaviour of the rock surfaces during shear could be continuously observed, were used to study the shear failure of a profiled and clean discontinuity artificially prepared from natural sandstone. Displacement transducers were used to measure the normal and shear displacements. A series of strain gauges glued on the sides of the upper block provided information on the change of the stress field occurring close to the discontinuities whilst shear displacement increased, and these changes were then compared with the behaviour of the profiled surface. The results of the laboratory tests, the sequence of photographs taken for most of them, and the results conducted with a sample of similar shape made from the same rock material and tested in a rotary shear machine, allowed several stages and mechanisms of failure to be defined: static friction and mobilization of initial shear stiffness; mobilization of sliding; mobilization of brittle fracture; post-peak failure of the teeth; descent of the teeth; gliding and ploughing; commencement of second cycle of shearing. In many respects these stages are similar to those occurring between sliding surfaces of metal and suggest that the analyses developed in tribology may be relevant to the development of constitutive models for predicting the hydromechanical coupled behaviour of a discontinuity with shear displacement. Such models will have to consider these different stages of shear, because the original discontinuity changes its geometry with displacement and is filled with gouge which changes its grain size with displacement.     

A petrographie study of the process of serpentinisation in ophiolites and the ocean crust

The process of serpentinisation is illustrated by 17 samples showing different degrees of serpentinisation chosen from a large number of peridotites and serpentinites from the ocean floor and from ophiolite complexes. Observations of textural relationships were made by optical and scanning electron microscope. Mineral identification was confirmed by X-ray diffraction. Of the serpentine polymorphs, lizardite forms during early stages of serpentinisation and displays a characteristically platy morphology. Olivine and pyroxene are replaced by lizardite until no olivine remains. At this stage chrysotile begins to crystallise as fine fibres characteristically filling veins and actually replacing lizardite throughout the rock. Antigorite is confined to sheared surfaces and is rare in the ocean floor forming the latest polymorph. Both ocean floor and ophiolite samples show well developed mesh textures in hand specimen, while a much smaller web network of serpentine occurs on some ocean floor samples. Serpentines from ophiolites show two morphological types of lizardite which may have formed at different temperatures.     

基于冠层温度的作物缺水研究进展

冠导温度信息可以很好地反映作物的水分状况。自20世纪70年代以来，基于冠层温度的作物缺水指标的研究经历了三个阶段，即单纯研究冠层温度本身变化特征的第一阶段、以冠层能量平衡原理为基础的作物水分胁迫指数的第二阶段和考虑冠层和土壤的复合温度的水分亏缺指数的第三阶段。指标的局长也由使用手持式红外辐射仪信息扩大到使用航空和卫星遥感信息。这一类指标在点和区域尺度上均可应用。加强这一类指标的研究对于我国北方地区农作物的有效灌溉和区域水资源的管理都有重要意义。     

Progradational gravel beach sequences in a moderate- to high-energy, microtidal marine environment

The anatomy of progradational gravel beaches was analysed in two different tectonic settings: the strongly subsiding Messinian foreland basin of the eastern Southern Alps and the rising Pleistocene marine terraces of the outer margin of the Apenninic chain. Progradation took place near the mouths of fan-delta or braid-delta distributaries debouching in microtidal landlocked basins (palaeo-Adriatic and palaeo-Ionian seas). A wind-wave climate, comparable to that of the present-day, was characterized by periodic intense storm activity. Most of the beachface progradation is thought to have taken place during the post-storm recovery and fair-weather stages, whereas the impact of storms is mostly recorded by the cutting of erosional surfaces on the beachface and by emplacement of poorly-sorted and coarse-grained gravels on the shoreface by storm-intensified seaward-trending flows and behind the highest berms by washover processes. Analysis of the sequences led to the identification of a number of typical divisions which are differently developed in the two settings compared here. The characteristics of the Apenninic sequences suggest a strongly variable wind-wave climate, with periodic changes from a relatively dissipative barred morphology during storms, accompanied by strong longshore currents and rip development, to a more reflective state, typical of recovery and fair-weather stages. The Southern Alpine sequences, on the other hand, are characterized by poor evidence of barred morphology and of longshore currents and widespread effects of shear- and gravity-sorting in the lower-beachface gravels. These features indicate a comparatively more reflective average state, due to location of beaches along the deeply embayed head of the palaeo-Adriatic, and the very narrow directional width of the incoming wave spectrum, which was almost shore-normal most of the time. In addition to well-developed shape zonation of gravels, the common presence of wave-generated gravel megaripples in the Southern Alpine sequences indicates the greater influence of long-period waves, due to the greater available fetch distances. In both settings the cyclicity is thought to be genetically related to minor changes of sea-level.     

Mega sheath fold of the Mahadevi hills, Cauvery Suture Zone, southern India: Implication for accretionary tectonics

The Mahadevi hills, located in the axial zone of Cauvery Suture Zone, comprise a sequence of granulite facies rocks represented by garnet-bearing pyroxene granulites and quartzo-feldspathic gneisess interfolded with banded iron formations. Structural mapping with hand held GPS reveals that the Mahadevi hills constitute a mega sheath fold structure exposing well developed easterly plunging extension lineations. Depressional and culmination surfaces are well demarcated in association with elliptical map patterns. The development of the mega sheath fold structure is genetically related to the regional thrust-nappe tectonics, supporting the model of subduction-accretion-collisional history for the evolution of the Cauvery Suture Zone.     

A unified mechanical and retention model for saturated and unsaturated soil behaviour

The coupled mechanical and water retention elasto-plastic constitutive model of Wheeler, Sharma and Buisson (the Glasgow coupled model, GCM) predicts unique unsaturated isotropic normal compression and unsaturated critical state planar surfaces for specific volume and degree of saturation when soil states are at the intersection of mechanical (M) and wetting retention (WR) yield surfaces. Experimental results from tests performed by Sivakumar on unsaturated samples of compacted speswhite kaolin confirm the existence and form of these unique surfaces. The GCM provides consistent representation of transitions between saturated and unsaturated conditions, including the influence of retention hysteresis and the effect of plastic volumetric strains on retention behaviour, and it gives unique expressions to predict saturation and de-saturation conditions (air-exclusion and air-entry points, respectively). Mechanical behaviour is modelled consistently across these transitions, including appropriate variation of mechanical yield stress under both saturated and unsaturated conditions. The expressions defining the unsaturated isotropic normal compression planar surfaces for specific volume and degree of saturation are central to the development of a relatively straightforward methodology for determining values of all GCM parameters (soil constants and initial state) from a limited number of laboratory tests. This methodology is demonstrated by application to the experimental data of Sivakumar. Comparison of model simulations with experimental results for the full set of Sivakumar’s isotropic loading stages demonstrates that the model is able to predict accurately the variation of both specific volume and degree of saturation during isotropic stress paths under saturated and unsaturated conditions.     

Paleosols,red sediments,and the Old Stone Age in Greece

As elsewhere in the Mediterranean, the Quaternary of Greece stands out by the red color of many of its paleosols and sediments. Both are important, but, in a geoarchaeological context, the distinction between palaeosols and sediments is crucial because they carry different information. Paleosols mature with age, forming a chronosequence that can be studied with simple field methods. The youngest paleosols, some 2000 years old, are at the base of a series of six maturity stages, the most mature of which exceeds 100,000 years in age. Paleosols are useful stratigraphic tools: They identify Palaeolithic land surfaces, correlate regionally variable lithologies, and furnish relative and rough absolute dates for Quaternary sediments and Palaeolithic findspots. Red sediments, on the other hand, are the oxidized residue of limestone weathering that once blanketed large regions where limestone dominates the bedrock. Now mainly redeposited in dissolution basins and closed tectonic troughs of the karst surface, they are the key to water—and wildlife-rich environments valued by Palaeolithic hunter–gatherers and modern farmers. © 1998 John Wiley & Sons, Inc.     

尼日尔三角洲Stubb Creek油田阿格巴达组层序地层学研究

根据测井、岩屑录井及地震资料,尼日尔三角洲Stubb Creek油田阿格巴达组可划分为SQl、SQ2、SQ3 3个层序.每个层序均由低位体系域、海侵体系域和高位体系域组成,符合Vail经典的层序地层学模式.各层序低位体系域底部在地震剖面上表现为一系列的削截面,高位体系域由下超面组成.层序界面还表现为沉积相的突变面.最大海泛面位于自然伽玛最大值处.低位体系域砂体在研究区北部最发育,向南部逐渐减薄,这与研究区的物源位于北部有关.研究区沉积体系包括下切谷充填、浅海陆棚和三角洲沉积体系.下切谷沉积体系分布在各层序低位体系域,浅海陆棚沉积体系分布在海侵体系域和高位体系域,而三角洲沉积体系仅分布在高位体系域.     

From centre to periphery: Changing spatial structures in Rural South India, 985–1985

The paper is an attempt on polarized development. over the last millennium, focussing on a small agrarian region in the Tamil country of South India. From the perspective of Friedmann's General Theory, the paper traces the development of this region through five successive stages of integration, each of which encompassed the study area into a wider and more complex spatial system. Elementary innovations are identified that, at each of these stages, generated specific types of authority-dependency relationships which, in turn, integrated the respective innovative cores and their dependent peripheries into single spatial systems. The paper shows how the institutional and spatial structures of rural South India have been successively transformed in this process, to serve the needs of the various core regions. It also demonstrates how, since colonial times, new types of authority-dependency relationships have emerged that, by organizing the dependency of the peripheries through systems of market and supply, have resulted in development of the core regions, on the one hand, and underdevelopment of the peripheries, on the other.     

东非鲁武马盆地海底旋回坎沉积演化及控制因素

鲁武马盆地海底水道—朵体过渡带具有高波脊和深刻槽相间的旋回坎地貌.利用高品质的三维地震资料,借助多种地震解释技术,对水道—朵体过渡带内不同期次旋回坎的形态、尺度、移动方式开展细致描述,分析多期旋回坎演化规律.研究结果表明,鲁武马盆地海底水道—朵体过渡带内主要发育三期旋回坎,同一期次旋回坎内部地震反射连续性较差,同相轴以...     

一脉状矿床成矿构造的研究

緒言热液充填脉状矿床的成矿过程往往是长期的、多阶段的,而且构造断裂的控制作用十分明显。因此,正确划分矿化阶段和查明每次成矿构造空间的规律性,对理解成矿过程和生产实际工作有着重要意义。只有当构造的间歇活动和成矿溶液的脉动作用在特定的时间和条件下统一起来时,才能形成单独的一次矿化阶段。     

Reconstructing fluvial bar surfaces from compound cross‐strata and the interpretation of bar accretion direction in large river deposits

The interpretation of fluvial styles from the rock record is based for a significant part on the identification of different types of fluvial bars, characterized by the geometric relationship between structures indicative of palaeocurrent and surfaces interpreted as indicative of bar form and bar accretion direction. These surfaces of bar accretion are the boundaries of flood‐related bar increment elements, which are typically less abundant in outcrops than what would be desirable, particularly in large river deposits in which each flood mobilizes large volumes of sediment, causing flood‐increment boundary surfaces to be widely spaced. Cross‐strata set boundaries, on the other hand, are abundant and indirectly reflect the process of unit bar accretion, inclined due to the combined effect of the unit bar surface inclination and the individual bedform climbing angle, in turn controlled by changes in flow structure caused by local bar‐scale morphology. This work presents a new method to deduce the geometry of unit bar surfaces from measured pairs of cross‐strata and cross‐strata set boundaries. The method can be used in the absence of abundant flood‐increment bounding surfaces; the study of real cases shows that, for both downstream and laterally accreting bars, the reconstructed planes are very similar to measured bar increment surfaces.     

Pedosedimentary development and palaeoenvironmental significance of the S1 palaeosol on the northeastern margin of the Qinghai-Xizang (Tibetan) Plateau

The S1 pedocomplex, correlated to Oxygen Isotope Stage 5 of the ocean cores, has been traced west of the Loess Plateau on to the extreme northeastern margin of the Qinghai-Xizang (Tibetan) Plateau in China. Detailed micromorphological analysis of closely spaced thinsections from the pedocomplex at this site provides the basis for reconstruction of the sequence of pedosedimentary processes and associated palaeoenvironmental changes occurring during this time interval. The six pedosedimentary stages identified are interpreted in terms of temporal variations in depositional rates, size of particles transported and availability of moisture for pedogenic alteration, as determined by changing balances in dominance of winter and summer monsoonal forces. Two main ‘soil-forming intervals’ are identified: the more extensive of the two in terms of resultant pedological features reflects pedogenic alteration at a relatively ‘stable’ land surface under a semi-arid climate during the later part of pedosedimentary stage 2. The other main period corresponds to pedosedimentary stages 4 and 5, when leaching and bioturbation processes were active at aggrading surfaces, leading to development of an accretionary unit without clear differentiation of horizons. Pedosedimentary stages 1, 3 and 6 were characterised mainly by rapid rates of coarse loess accumulation, with synsedimentary modification restricted to surface slaking and crust formation, and minor localised redistribution of calcite.     

Garnet porphyroblast timing and behaviour during fold evolution: implications from a 3-D geometric analysis of a hand-sample scale fold in a schist

Detailed 3‐D analysis of inclusion trails in garnet porphyroblasts and matrix foliations preserved around a hand‐sample scale, tight, upright fold has revealed a complex deformation history. The fold, dominated by interlayered quartz–mica schist and quartz‐rich veins, preserves a crenulation cleavage that has a synthetic bulk shear sense to that of the macroscopic fold and transects the axis in mica‐rich layers. Garnet porphyroblasts with asymmetric inclusion trails occur on both limbs of the fold and display two stages of growth shown by textural discontinuities. Garnet porphyroblast cores and rims pre‐date the macroscopic fold and preserve successive foliation inflection/intersection axes (FIAs), which have the same trend but opposing plunges on each limb of the fold, and trend NNE–SSW and NE–SW, respectively. The FIAs are oblique to the main fold, which plunges gently to the WSW. Inclusion trail surfaces in the cores of idioblastic porphyroblasts within mica‐rich layers define an apparent fold with an axis oblique to the macroscopic fold axis by 32°, whereas equivalent surfaces in tabular garnet adjacent to quartz‐rich layers define a tighter apparent fold with an axis oblique to the main fold axis by 17°. This potentially could be explained by garnet porphyroblasts that grew over a pre‐existing gentle fold and did not rotate during fold formation, but is more easily explained by rotation of the porphyroblasts during folding. Tabular porphyroblasts adjacent to quartz‐rich layers rotated more relative to the fold axis than those within mica‐rich layers due to less effective deformation partitioning around the porphyroblasts and through quartz‐rich layers. This work highlights the importance of 3‐D geometry and relative timing relationships in studies of inclusion trails in porphyroblasts and microstructures in the matrix.     

黑龙江省东部残留盆地群构造演化特征及其油气勘探意义

由牡丹江断裂、敦-密断裂、依-舒断裂和大和镇断裂所控制的中新生代盆地群是东北地区重要的合煤、含油气盆地。该盆地群的中新生代成盆过程以脆性伸展为主，发育断陷或裂陷层序，而坳陷层序(热沉降层序)不发育。古构造发育史、盆地沉降史和伸展史研究表明，研究区盆地群普遍经历了早期快速沉降(断陷期)-盆地衰减、抬升剥蚀-后期快速沉降-稳定衰减(或抬升剥蚀)。区内的成盆与构造演化过程分为涉及全区的中生代陆缘断陷期(J3-K1)、第一构造反转期(K2-E1)、新生代陆内裂陷期(E2-E3)和第二构造反转期(N)4个阶段，反映了两大盆地构造演化旋回。构造演化特征一方面为油气的多期成藏提供了盆地动力学条件，另一方面改造或破坏动、静态地质要素的时空分布及其匹配关系。