辉石巨晶中有序排列球体构造的发现

在贯穿于汉诺坝玄武岩的碳酸岩筒中发现的辉石巨晶中，沿着一系列平行的{001}裂理面三维有序地分布了大小近于相等的球构造，主要有金属球体和玻璃球体，或者由金属、玻璃等物质共同组成的多相球体。三维有序排列现象及其复杂的矿物组合是在怎样的物理－－化学条件下形成的，这些条件又反映了怎样的地球动力学环境，是两个有意义的科学问题。     

冲断构造与正反转构造物理模拟实验的研究进展

冲断构造和正反转构造是我国西部叠合盆地中典型的构造样式,其构造物理模拟实验是研究和模拟自然界冲断构造（正反转构造）变形特征和动力学过程的一种有效的实验方法。在查阅大量相关资料的基础上,本文概述了物理模拟实验的发展历史,以及国内外在实验理论、实验技术和从二维到三维转变等方面的研究现状。目前,构造物理模拟实验已被广泛应用于构造地质学、石油构造地质学等众多研究领域,是油气勘探研究由定性描述跨入半定量-定量分析的有效途径之一。本文分别阐述了冲断构造和正反转构造在近年来取得的进展：1）在冲断构造物理模拟实验方面,介绍了双指向冲断构造和推覆体、地表作用对冲断构造的影响以及冲断构造中地层缩短量和应变等3方面的进展;2）在正反转构造物理模拟实验方面主要讲述了基底对反转构造演化型式的制约以及反转临界条件的三维构造模拟取得的进展。同时,认为物理模拟在未来的发展过程中应紧密结合数值模拟、高精度成像技术和数据采集技术等。作为研究构造变形机制的重要媒介,冲断构造物理模拟在塑性变形对冲断构造的影响、如何反映现代构造地质学成果以及模拟过程中如何加入化学物质迁移等问题方面仍存在不足。此外,高端实验室的建设和模拟技术也是构造物理模拟实验面临的一个问题。     

Pseudotachylyte-bearing strike-slip duplex structures in the Fort Foster Brittle Zone,S. Maine

Detailed (1:60 scale) mapping of the Fort Foster Brittle Zone in the mylonitic Rye Formation of southernmost Maine has revealed the intricate internal duplex structure of a system of probable Paleozoic-age dextral strike-slip faults that have produced abundant pseudotachylyte and minor breccia. The internal configuration of this brittle zone consists of a mosaic of individual pseudotachylyte generation zones as slab-duplex structures. Individual duplex zones are up to 100 m in length and 1 m or less in width and are defined by pairs of layer-parallel slip surfaces along which frictional melts were produced. These slab-duplex structures are interpreted as zones of displacement transfer between long, overlapping, layer-parallel en échelon strike-slip fault surfaces. Contractional duplexes develop layer-parallel compressional structures that tend to shorten and thicken the fault-bounded slabs by the formation of lateral ramps and conjugate faults, kinks and asymmetric folds. Extensional duplexes develop layer-parallel stretching and thinning by the formation of oblique dextral shears, high-angle conjugate pairs and localized fault breccias. The production of pseudotachylyte by friction melting along layer-parallel fault surfaces in these exposures is attributed to rapid slip during paleoseismic events. The rupture structures developed during these events may be characteristic of fault structure and mechanics at near-focal depths in a strike-slip seismogenic zone.     

Arumberia-type structures in the Upper Vendian of the Urals

Problematic arumberia-type structures are widespread in Upper Proterozoic sedimentary rocks deposited in depositional environments subject to periodic desiccation and fluctuating salinity. Here we report two new occurrences of arumberia-type structures in the Krutikha Member of the Upper Vendian Chernyi Kamen Formation on the western slope of the Central Urals (Us??va River) and the Zigan Formation of the Asha Group in the South Urals (new road Sterlitamak-Beloretsk). The results of the study of these structures significantly expand paleontological characteristics of the Upper Vendian non-marine rocks and allow us to re-examine the paleontological importance of the hastily forgotten group of arumberia-type organisms. We distinguished six varieties of arumberia-type structures that for the sake of convenience were given formal Latin names in binominal nomenclature although they are not biological species. Two species??Arumberia banski and A. vindhyanensis??were erected by previous researchers, whereas the A. beckeri, A. ollii, A. usvaensis, and A. multykensis varieties are recognized for the first time. Despite similarity to erosional structures on the bottom of turbidite beds, erosion does not explain the genesis of the entire spectrum of arumberia-type structures including those preserved on ripple marks, with evidence of soft-body deformation, or with ribbon and filamentous fabric replaced by clay minerals. The diversity of arumberia could be only a manifestation of living systems. The species of Arumberia are distinguished by their different biostratinomy, the distance between the main structural units, the preservation of the main structural units, and the presence of additional structures between the main structural units. Most likely, the diversity of arumberia reflects not only taphonomic, but also ontogenetic and phenotypic variation. The level of morphological complexity and biostratinomic features of arumberia apparently exceed the organization of microbial mats and represent a non-actualistic type of microbial communities. The occurrence in extremely shallow-water depositional setting suggests that arumberia had evolved an adaption to periodic desiccation and that arumberia-type organisms, along with microbial mats, had been an important factor of sediment biostabilization in the Late Vendian non-marine environments.     

Fragments of continental structures in the Indian Ocean

Fragments of continental structures (microcontinents) composed of sialic rocks are widespread in the Indian Ocean, where they are located in its African, Australian, and Indian margins. The origin of these fragments is related to splitting off from continent margins along faults and further seaward motion driven by the tectonic flow of mantle masses.     

Growth of salt-induced structures in the Norwegian-Danish basin

Five relatively deep-seated salt plugs, situated in the Norwegian-Danish Basin, have been investigated. The Zechstein salt has pierced the Triassic and probably also the Jurassic strata in the area. In two of the structures salt has also intruded Lower Cretaceous strata. Otherwise, however, the relative upward movement of the salt has only resulted in the formation of salt-induced dome-shaped structures in the Lower Cretaceous and younger sediments overlying the salt plugs.Isopach maps, based on seismic reflection data, show that, as a rule, relative upward movement of the salt plugs has occurred during sedimentation. Such movements find their expression in local thinning of the interval, superimposed, as a rule, on a regional thickening.Using on-structure and off-structure thickness data, a quantity called the “convergence” can be calculated which numerically measures the proportional thinning of an interval over a given structure. The convergence values, thus calculated, show that there was continuous structural growth in all four structures that can be investigated in this way in Lower Cretaceous and later times except in Eocene times when there possibly was no growth at all in any of the four investigated structures.It is also found that a typical time-rate of growth during the post-Jurassic for these salt-induced structures is 1 mm per 1000 years (1 · 10⁻³ mm/year) except for the Eocene where the rate of growth was possibly zero.     

大型走滑断裂对青藏高原地体构架的改造

青藏高原的大型走滑断裂有13条,已确定的大型韧性走滑断裂主要形成于3个时期:早古生代、印支期和新生代以来.印度/亚洲碰撞(60～50Ma)以来形成的大型韧性走滑构造位于青藏高原的南部,而且主要在喜马拉雅山链的东、西两侧,如西侧的喀喇昆仑和恰曼韧性右行走滑断裂,东侧的鲜水河-小江和哀牢山-红河韧性左行走滑断裂、崇山-澜沧江、嘉黎-高黎贡山和萨盖韧性右行走滑断裂等.主要的变形特征表现为早期具有地壳深部的韧性走滑剪切带性质,在后期抬升过程中,由韧性→韧脆性→脆性应变转化;而在青藏高原北部,表现为古韧性走滑剪切带的再活动,如阿尔金-康西瓦、东昆仑左行走滑断裂,以及新生的脆性断裂,如海源左行走滑断裂等.本文在青藏高原13条大型走滑断裂研究及综合研究的基础上,阐述不同时期的大型走滑断裂,以及它们在青藏高原地体拼合及碰撞造山中的作用,包括走滑断裂与走滑型褶皱造山、走滑断裂与挤压/转换型造山、走滑断裂与挤压盆-山体系、走滑断裂与地体相对位移和走滑断裂与地体的侧向挤出,以及走滑断裂与构造结的形成.     

Evidence of progressive deformation in minor structures in Western Asturias (N. W. Spain)

Examples of progressive deformation provided by minor structures are not frequent in the geological literature. In NW Spain some minor structures in Lower Paleozoic inhomogeneous layered material may be interpreted as the result of progressive deformation during the Hercynian Orogeny. The examples described include structures generated by progressive contraction (folded wedges), contraction followed by elongation (folds disrupted by boudinage) and elongation followed by contraction (folded boudins).     

Folded structures in the Khibina apatite deposits

The Kukisvumchorr-Yukspor apatite-nepheline body of the Kola Peninsula is a thick sheet-type lens which dips 28-32° NE. The rich upper zone consists of spotted, spotted-banded, and brecciated ores, whose mean P_2MO₅ content is 26-28 percent. The lower, of band ed-lens ores together with reticulate and large block types, have a mean P_2MO₅ content of 16-18 percent. Poikilitic nepheline syenites overlie, and ijolites and urtites underlie the ore body. The apatite-nepheline ore field is an arc-shaped belt at the boundary between foyaites and khibinites in the general structure of the Khibina massif. Mining has shown that the early idea of only minor tectonic activity and little disturbed igneous complexes is wrong. A great variety of internal structure is present and shown in several illustrations. Most prominent are folded structures that in places resemble a highly dislocated sedimentary complex. Variations in the type of folding indicate that the various ore zones were formed at different times. Forms in the earlier lower zone are larger and more regular, whereas those in the upper zone indicate increasing tectonic activity. Plicative dislocations in the rich upper zone are not related to folding in the lower zone; they have their own genetic types. They are less regular gray golds. Study of the structure of the massif must continue and survey methods must allow for tectonic features. — W. D. Lowry.     

Granites and thermal structures in the lithosphere

The production of melts of the granite clan on a significant scale requires participation of continental crust. Such crust will melt when heated from below by a mantle thermal anomaly, or when thickend to 40 km or more. Sites of melting, and the time sequences of melting associated with subduction and underplating processes, and collision processes, are complex. In both these processes, at least six melting sites may be involved. The final chemical and isotopic composition of granitic melts depends on a very complex array of processes, which include: source composition, composition of subducted materials, magma mixing, magma underplating, assimilation-fractionation-cooling processes. Resolution of granite melt dynamics requires an integrated attack, using modern seismic and electrical measurements, in regions where the continental crust is abnormally thick or hot.

---

Zusammenfassung Die Produktion von Granitschmelzen im grö\eren Ausma\e erfordert die Beteiligung kontinentaler Kruste. Die Kruste wird aufgeschmolzen, wenn sie von unten durch eine Wärmeanomalie des Mantels aufgeheizt wird oder wenn sie mächtiger als 40 km wird. Der Ort des Aufschmelzens und die Zeitabfolge des Schmelzens, die im Zusammenhang mit Subduktion Plattenstapelung und Kollisionsprozessen ablaufen, sind äu\erst komplex. Diese Prozesse sind mindestens auf sechs verschiedene Areale zu lokalisieren, in denen Aufschmelzung möglich ist. Die endgültige chemische und isotopenchemische Zusammensetzung von Granitschmelzen hängt von einer sehr komplexen Proze\abfolge ab, wobei zu berücksichtigen sind: Die Zusammensetzung des Ausgangsmaterials, die Zusammensetzung subduzierten Materials, Magmenmischung, Magmenunterströmung und Proze\e der Assimilation, Fraktionierung und Abkühlung. Um die Dynamik einer Granitschmelze zu erkennen, bedarf es moderner seismischer und geoelektrischer Methoden in Gegenden, wo die kontinentale Kruste ungewöhnlich dick oder hei\ ist.

---

Résumé La production en quantité importante de liquides de la famille granitique requiert la participation de la croûte continentale. Celle-ci fond lorsqu'elle est chauffée d'en bas par une anomalie thermique du manteau, ou quand son épaisseur s'accroÎt jusqu'à 40 km ou plus. Les endroits où se développe la fusion, ainsi que son déroulement temporel, associé aux processus de subduction et d'underplating, sont complexes. Pour chacun de ces deux processus, six sites de fusion ou moins peuvent Être définis. Les compositions chimique et isotopique finales des liquides granitiques dépendent d'un ensemble de processus très complexes, qui comportent: la composition de la source, la composition des matériaux subductés, le mélange de magmas, les processus d'assimilation, de fractionement et de refroidissement.La compréhension de la dynamique de la fusion granitique requiert une approche intégrée qui comporte la mise en oeuvre de méthodes sismiques et géoélectriques modernes dans des régions où la croûte continentale est anormalement chaude ou anormalement épaisse.

---

. , , , 40 . , . , , , . , : , , , , . , , , .

---

---

Based on a lecture presented at the Granit Symposium, Gie\en 1986. London     

Brittle tectonic structures and palaeostress analysis in the Isle of Wight,Wessex basin,southern U.K.

Brittle tectonic analysis of Cretaceous–Paleogene sediments at a total of 17 sites located in the Isle of Wight (U.K.) enables four main tectonic events that occurred prior to and after the folding to be identified and successive palaeostress tensors to be determined using the inversion method. Three of the events can be shown to have occurred prior to the folding: (1) a syn-sedimentary extension of Upper Cretaceous age; (2) a strike-slip faulting regime with an ESE–WNW direction of compression; (3) a compressional regime, marked by strike-slip faulting, with an NNE–SSW to N–S direction of compression. The fourth and last compressional event took place after the folding and is characterised both by reverse and strike-slip faulting, with a dominant N–S direction of compression. Syn-folding faults also developed between the third and fourth events. All four events can be connected to the extensional tectonics and different steps of structural inversion, both of which were integral to the development and evolution of the Wessex basin.     

Glacio-dynamic structures from the Blackwater Formation, Co. Wexford, Ireland

A series of large-scale glacio-dynamic structures exposed in 10 km of coastal cliff cut through the Screen Hills kame-morainc, Co. Wexford. Ireland, is descrihed. The structures range from simple ovcrfolds to complex multiple thrusts, have a consistent structural trend, and result from marginal deformation by an ice-sheet moving from the NE. The relationship between the structures and other, gcomorphic and stratigraphic components is resolved into a simple model of repeated ice-marginal oscillation during a phase of overall glacial retreat.     

山东省灵山岛负载构造和球-枕构造研究

本文运用野外露头考察、沉积岩石学、地质统计等方法,对灵山岛的负载构造和球-枕构造进行研究。这些负载构造和球-枕构造侧向延伸好,在整个剖面上连续分布,具有多尺度、多形态、多组合等特点。形成负载构造和球-枕构造的前提条件是地层密度的倒置(上大下小),变形的根本驱动力是沉积物自身的重力。球-枕构造和负载构造的形成机制相同,只是变形程度和阶段不同。根据不对称负载构造受横向剪切力分析,证明早白垩世时该盆地存在古斜坡,并且SE高、NW低。综合考虑地震触发形成震积岩的标志特征和灵山岛的构造地质背景,认为本研究区的负载构造和球-枕构造系古地震触发形成。     

On stereoimages of some structures in the solar atmosphere

Three-dimensional structures in the solar chromosphere and corona are considered. It is demonstrated that two photoheliograms separated by ～1 day can be used (using computer-graphics methods) to construct a stereo image of the Sun. The algorithm for this is presented and carried out for H_α images of the total disk. A bulge in the equatorial region resulting from the differential rotation of the Sun can be seen in the stereo image. Structures called Whitney pleats in catastrophe theory are observed in the solar corona. Such structures are encountered in prominences. The well-known helmets (or streamers) are pleats of heliospheric plasma sheets. Isophotes for such a sheet and the degree of polarization of the radiation in the pleat are calculated and compared with observational data.     

On granitoid emplacement and related structures. A review

Granitoid magmas are emplaced at the upper crust under a complex interaction of gravitational processes and horizontal tectonics. Natural intrusive bodies show a wide variety of structural patterns that must be strongly related with their dynamic history of ascent and emplacement. Comparisons of natural structural patterns with experimental and numerical models are necessary to interpret in a coherent fashion the emplacement mechanism involved.From natural, experimental, numerical and theoretical considerations one can reach important conclusions on the problem of ascent and final emplacement of granitoid magmas in the Earth's crust. The present paper reviews the principal emplacement mechanisms referred to in the literature; that is, doming, diapirism, ballooning, stoping, cauldron subsidence and dike propagation.Dike propagation is the most effektive process in magma transport from deep zones in the crust and upper mantle. Extensional fractures for dike propagation and magma ascent can be developed at depth in the crust according to the modern dike propagation theory. In orogenic domains, magmas reach the upper crust through narrow channels or dikes and are accumulated in a final reservoir in the form of a discordant supracrustal pluton or a ballooning pluton if, during emplacement, any regional deformation acts simultaneously.

---

Zusammenfassung Die Intrusion granitischer Magmen in die obere Krust ist das Ergebnis eines komplexen Zusammenspiels von schwerkraftbedingten Prozessen und horizontalen, tektonichen Bewegungen. Die gro\e Vielfalt tektonischer Strukturen von granitischen Plutonen spiegelt die Geschichte der Dynamik, ihres Aufstieges und ihrer Platznahme wider. Um den jeweils vorhandenen Intrusionsmechanismus zusammenhängend deuten zu können, sind Vergleiche der natürlichen, tektonischen Elemente mit experimentellen und numerischen Modellen notwendig. Hieraus lassen sich gegebenenfalls weitreichende Schlüsse zum Problem des Aufstiegs und der endgültigen Platznahme der Magmen in der Erkruste ziehen.In dieser Arbeit werden die wesentlichen Aufstiegsmechanismen von Magmen aus der Literatur diskutiert. Im Einzelnen sind dieses: Aufwölbung, Diapirismus, Aufweitung, Abbau, Kraterbildung und Gangentwicklung.Das Vordringen von Gängen ist der wirksamste Proze\ des Magmentransports aus tieferen Zonen der Kruste und des oberen Mantels. Ausdehnungsklüfte lassen sich als Ursache für das Vordringen von Gängen und den Magmenaufstieg nach der heutigen Theorie über die Entwicklung von Gängen in der tiefen Kruste herleiten. In orogenen Zonen erreichen Magmen die obere Erdkruste durch enge Kanäle oder Gänge und reichern sich dort auch in Form eines dikordanten, subkrustalen oder aufgweiteten Plutons an, wenn gleichzeitig mit der Platznahme regionaltektonische Deformationen ablaufen.

---

Resumen Los magmas graníticos se emplazan en la corteza superior bajo una compleja interaccion entre procesos gravitatorios y tectónica horizontal. Los cuerpos intrusivos naturales muestran una amplia variedad de patrones estructurales que pueden estar directamente relacionados con la dinámica de ascenso y emplazamiento. Para explicar de forma cohérente el mecanismo de emplazamiento implicado en un plutón es necesario establecer comparaciones entre patrones estructurales de plutones y modelos experimentales y numéricos.A partir de consideraciones naturales, experimentales, numéricas y teóricas, se pueden extraer importantes conclusiones sobre el problema del ascenso y emplazamiento de magmas en la corteza. En este trabajo se revisan los principales mecanismos de emplazamiento referidos en la literatura; es decir, doming, diapirismo, ballooning, stoping, cauldron subsidence y propagación de diques.Propagación de diques es el proceso más efectivo en el transporte de magmas desde zonas profundas en la corteza y manto superior. De acuerdo con la moderna teoría de propagación de diques, las fracuras extensionales pueden producirse en profundidad en la corteza. En dominios orogénicos, los magmas alcanzan la corteza superior a través de estrechos canales o diques y se acumulan en un reservorio final, bien en forma de plutones discordantes supracrustales, o bien en la forma de un »ballooning pluton« si durante el emplazamiento actûa alguna deformación regional.

---

, . . , . . , , . : , , , , . . . . , , , , .

     

准噶尔盆地南缘阿什里地区地质构造基本特征

准噶尔盆地南缘阿什里地区紧邻北天山造山带前缘,受北天山造山系逆冲构造作用的影响,区内构造变形十分强烈.野外地质调查和地震勘探证实,该区逆掩推覆构造现象普遍,阿什里地区头屯河构造西侧较大范围的石炭系露头为逆冲推覆、遭受剥蚀后残留的外来岩块.结合前人对准南地区侏罗纪沉积演化、盆地格局和三叠系、侏罗系沉积特征和沉积相分析研究成果,笔者建议对准南地区盆地边界南扩,以侏罗系分布范围划定盆地南界.除前人普遍认识到北天山前缘存在三排背斜构造带之外,证实紧靠北天山盆山结合部还存在一排以头屯河背斜为代表的背斜构造带,对提升该地区的油气勘探前景具有重要意义.     

Evolution of structures and fabrics in the Barbados Accretionary Prism. Insights from leg 110 of the Ocean Drilling Program

Detailed analysis of ODP Leg 110 cores provides evidence for a complex structural evolution of the frontal thrust system in the northern Barbados Accretionary Prism. Initial east-directed in-sequence thrusts are biostratigraphically documented, and are overprinted towards the west by out-of-sequence overthrusts, largescale folds and penetrative deformation of the accreted rocks. This structural progression is interpreted to reflect the need for secondary shape adjustments of the accretionary prism in order to maintain a critical taper. At present the basal décollement is located within Lower Miocene strata. Accreted Eocene sediments suggest either fossil frontal off-scraping at a lower stratigraphic level or duplex formation and underplating.The present localization of the basal detachment is provoked by a zone of initial high porosity in the Lower Miocene radiolarian-rich mudstones. Shearing is accompanied by partial porosity breakdown in a 30–40 m wide zone of intense scaly fabrics and stratal disruption that constitutes the Atlantic-Caribbean plate boundary at present. Large displacements are taken up by a relatively narrow zone of contact strain. Initially the preferred orientation of clay minerals (incipient scaly fabrics) may be a flattening fabric, but with progressive rotational flow the scaly planes may act as discrete microshears and provide small-scale flow partitioning. Alternatively, scaly fabrics may be interpreted as brittle microshears. Mud-filled veins are present in the accreted rocks as well as at the oceanic reference site east of the deformation front. Carbonate-filled veins are restricted to the accreted rocks. This indicates persistence of high fluid pressures, but a fundamental change in the type of fluid-rock interaction during frontal accretion tectonics.     

Modeling the heat development in hydrating CPB structures

Cemented paste backfill (CPB) is a mixture of dewatered tailings, hydraulic binders and water. In addition to contributing to the stability of mine workplaces, CPB greatly benefits the environment by minimizing surface tailings disposal. Hence, it has become one of the most commonly used ways in mine backfilling around the world. Temperature can significantly affect the mechanical properties of cemented backfill. A source of heat in CPB is produced by binder hydration. Hence, a FLAC based numerical model is developed to predict and analyse the heat developed by hydrating CPB structures. To validate the model, results of the developed model are compared with three case studies (mathematical, laboratory, and field investigations). The validation results show a good agreement between the developed model and these cases. The effects of stope geometry, thermal properties of both rock and CPB, filling rate, binder content and initial boundary conditions are also investigated.     

Coherent structures in the dynamics of the large-scale solar magnetic field

Variations in the mean solar magnetic field (MSMF) are studied in both the frequency-time and longitude-time domains. A wavelet analysis of the MSMF clearly demonstrates that variations in the mean field are not stationary. Combined with longitude-time diagrams for the background solar magnetic field (BSMF), the analysis reveals the emergence of the background field, which occurs discretely at intervals of 1.5–2 years. Based on an analysis of the fine structure in MSMF variations, we develop a numerical technique to study timedependent heliographic-longitude distribution of the large-scale magnetic field. A detailed picture of the rotation of the large-scale magnetic field is derived for activity cycles 20–23. Coherent structures are detected in longitude-time diagrams obtained by deconvolving the MSMF series. These structures are related to discrete rigid-rotation modes of the large-scale magnetic fields. Various rotational modes coexist and replace one another. During the phase of activity growth, modes with periods of 27.8–28.5 days dominate, whereas a mode with a rotational period of about 27 days dominates during the decline phase. Occasionally, modes with periods of 29–30 days appear. Most structures in the longitude-time MSMF distribution correspond to similar structures in the BSMF distribution for the northern or southern hemisphere. Chronologically, the emergence of the BSMF has frequently been accompanied by changes in the solar rotational regime and has been correlated with variations in the polarity asymmetry in the course of the 11-year activity cycle.