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本文概述了建国以来我国海洋地质调查与研究工作取得的丰硕成果。论述区域地质调查在海洋地质基础工作和未来海洋开发中的战略意义,介绍了国内外海洋区域地质调查的现状,对开展这项调查的可行性条件,以及进行1/100万海洋区域地质调查的项目内容、技术方法和提交成果等提出了设想和建议。 相似文献
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Foundations of offshore structures are designed to withstand a combination of static and cyclic loads due to ocean waves. Wave action on offshore structures can cause a significant amount of cyclic horizontal and vertical forces to be transmitted to the soil through the foundation. In all these cases, these cyclic loads are considered to be superimposed over the initial sustained static stress due to the self-weight of structures. This study considers various factors that influence the development of deformation and pore water pressure in a typical cemented marine clay. These results show that the sustained static shear stress significantly influences the strength and deformation behavior of marine clay under cyclic loading. Up to a certain range of sustained static stress, there is an improvement in strength during cyclic loading and the cyclic strains are greatly reduced. 相似文献
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Foundations of offshore structures are designed to withstand a combination of static and cyclic loads due to ocean waves. Wave action on offshore structures can cause a significant amount of cyclic horizontal and vertical forces to be transmitted to the soil through the foundation. In all these cases, these cyclic loads are considered to be superimposed over the initial sustained static stress due to the self-weight of structures. This study considers various factors that influence the development of deformation and pore water pressure in a typical cemented marine clay. These results show that the sustained static shear stress significantly influences the strength and deformation behavior of marine clay under cyclic loading. Up to a certain range of sustained static stress, there is an improvement in strength during cyclic loading and the cyclic strains are greatly reduced. 相似文献
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The achievement progresses of investigation and studies on marine hazardous geology are summarized and presentsd in the late 20 century in China. The importance, research value and presentday studies of marine hazardous geology, a newly developing branch of geoscience, are well expatiated.Several often confused concepts and theories are explained and redefined here. The comment on the means of investigations, assessment of marine hazardous geology, as well as its evolution, innovation,existing questions and future tasks are also introduced and presented. The concepts of “hazard geology“,“geohazard“, “map of marine hazard geology“, “integrated evaluaton on seafloor stablity“ are respectively discussed, including their definition, research objects, methods and contents. The types and classification of marine hazardous geology, principles and methods of marine hazardous geology map compilation, the assessment methods and models of marine hazardous geology environment and seafloor stability and so on are also discussed. 相似文献
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Core 7710, recovered on the George Bligh/Rockall Channel, is composed of fine grained ocher-colored sediments rich in ferriferous smectite (montmorillonite, beidellite). These sediments were deposited during early Eocene in a shallow marine environment. Their mineralogic, chemical and isotopic constituents indicate subaerial weathering of lower Eocene intermediate igneous rocks (ferrodiorite, marscoiite) eroded from the still-emergent George Bligh and Rockall Banks. Lack of any post Eocene Sediments may be due to major morphologic and hydrologic changes forming sedimentation gaps. 相似文献
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The Ostreaelv Formation (latest Pliensbachian–Toarcian) of the Neill Klinter Group is exposed along a >105 km wide, ENE-trending section in Jameson Land, East Greenland. Deposition took place in a large embayment (Jameson Land Basin) that was connected to the proto-Norwegian-Greenland Sea. Lithofacies in the Ostreaelv Formation range from clean sandstone to muddy heterolithic facies typified by strong grain-size contrasts.The Ostreaelv Formation is divided into four distinct and overall retrograding allostratigraphic units each composed of a characteristic set of tide-influenced, tide-dominated and wave-influenced facies associations. The allostratigraphic units are bounded by subaerial unconformities, interpreted as sequence boundaries, and are up to 75 m thick and 16 to >20 km in width. The allostratigraphic units include a sandy heterolithic estuary bay-head delta succession overlain by two sandy tide-dominated estuary fill successions, interbedded with a muddy heterolithic offshore marine succession. Each of the three estuarine allostratigraphic units was accumulated in an incised valley formed during fall in relative sea level and filled during successive transgressions with sediment supplied from marine and reworked fluvial deposits.In the three incised valleys fluvial sediments were deposited on top of an initial subaerial unconformity surface (SU) and were later reworked by succeeding transgressive ravinement along a transgressive surface (TS), thus creating combined SU/TS sequence boundaries. The data from the Ostreaelv Formation also provides knowledge and conceptual understanding of valley infill processes (tidal current, wave and fluvial energy), and both lateral and vertical variations in lithofacies architecture within incised valleys.Moreover, the study provides quantitative input data, such as incised valley dimensions, sand-containing capacity, and geometry to subsurface reservoir characterisation and modelling efforts of estuary fill successions. 相似文献
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现代海洋地质学及其发展 总被引:1,自引:0,他引:1
近几十年来,海洋的重要性愈来愈明显,海洋地质学作为海洋科学中最活跃的一门科学也取得了很大的发展。对海洋地质学的研究内容、意义以及当前发展的现状和趋势作了介绍。 相似文献
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Knowledge of the full present-day stress tensor and pore pressure has significant applications in the exploration and production of conventional and unconventional hydrocarbon reservoirs. The Darling Basin of New South Wales, Australia, is an old sedimentary basin (Late Cambrian/Silurian to Early Carboniferous) in which there was limited information about the present-day stress field prior to this study. In this paper we evaluate the contemporary stress field of the Darling Basin using a dataset from recent exploration wells and perform a geomechanical risk assessment with respect to borehole stability, fracture/fault generation and reactivation. Our interpretations of borehole failures in borehole image logs reveal a prevailing east-west orientation of the maximum horizontal stress throughout the Darling Basin. The estimates of the magnitudes for the vertical, minimum and maximum horizontal stress in the studied wells indicate a transition between thrust and strike-slip faulting stress regime at 600–700 m depths, where the magnitude of vertical stress and minimum horizontal stress are close to each other. However, the presence of borehole breakouts and drilling-induced tensile fractures, that we observe in the image logs at greater depths (900–2100 m) indicate a transition into a strike-slip tectonic stress regime below a depth range of approximately 700–900 m. These findings are in agreement with overcoring stress measurements east and west of the investigated wells. Furthermore, there are several Neogene-to-Recent geological structures in the study area that indicate thrust faulting with an east-west oriented maximum horizontal stress orientation around this old sedimentary basin. The consistency between the orientation of maximum horizontal stress determined from wellbore data and neotectonic structures is significant, and implies that horizontal stress orientations derived from very recent geological features may be valuable inputs to geomechanical models in the absence of wellbore or other data. However, the recent surface geological structures suggest a thrust faulting stress regime that is in slight contrast to the transition between thrust and strike-slip stress regime (SH > Sh ∼ Sv) indicated by petroleum data, and highlights a potential pitfall of using neotectonic structures in geomechanical models. In particular, careful attention and verification should be made when using neotectonic structures for input, calibration or confirmation of geomechanical models, especially in intraplate tectonic settings such as Australia. 相似文献
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Jeffrey S. Hanor 《Geo-Marine Letters》1981,1(3-4):169-172
Fluids discharged from subaerial springs along faults on a sediment diapir near the mouth of the Mississippi River are derived
from buried marine pore waters which have been extensively altered chemically by processes of bacterial respiration, mineral
precipitation and, possibly, by fractionation due to the presence of clays of high exchange capacity.
Vertical mass transport of dissolved components in many shallow marine sediments is controlled by long-term compaction, diffusion
and bioturbation. In areas of rapid sediment deposition, however, these processes can be overwhelmed by catastrophic episodes
of sediment failure, vertical mixing and upward discharge of water, gas and dissolved species. 相似文献
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D. Mallinson S. Locker M. Hafen D. Naar A. Hine D. Lavoie S. Schock 《Geo-Marine Letters》1997,17(4):237-245
Geophysical surveys and ground truth data are compared from a site in the Dry Tortugas, Florida. Seismic data reveal six
depositional sequences bounded by high-amplitude reflectors interpreted as subaerial unconformities. Chirp sonar data reveal
structure within the Holocene depositional sequence that is correlated to ground truth data. Sedimentary units within the
Holocene sequence record a transition from a low-energy, lagoonal environment, to a high-energy, shallow marine environment,
to a moderate-energy, slightly deeper marine environment. Forward modeling and impedance inversion reveal good agreement between
sediment physical properties, acoustic properties measured by the electric logger, and the chirp sonar data. 相似文献
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我国西沙群岛海产蓝藻类的种类极为丰富。但迄今为止除黎尚豪报导过西沙群岛永兴岛的陆生习性的27种蓝藻外,尚未见过任何报告。本文为西沙群岛海产蓝藻类研究的第一部分。根据的材料是中国科学院海洋研究所1975年和1976年在西沙群岛采集的,计127号。本文仅报道11种,隶于颤藻科(Oscillatoriaceae)的6属,其中4种在我国为海产蓝藻的新记录。 相似文献
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To improve the understanding of the distribution of reservoir properties along carbonate platform margins, the connection between facies, sequence stratigraphy, and early diagenesis of discontinuities along the Bathonian prograding oolitic wedge of the northeastern Aquitaine platform was investigated. Eight facies are distributed along a 50 km-outcropping transect in (1) toe-of-slope, (2) infralittoral prograding oolitic wedge, (3) platform margin (shoal), (4) open marine platform interior, (5) foreshore, and (6) terrestrial settings. The transition from shallow platform to toe-of-slope facies is marked in the field by clinoforms hundred of meters long. Carbonate production was confined to the shallow platform but carbonates were exported basinward toward the breakpoint where they cascaded down a 20–25° slope. Ooid to intraclast grainstones to rudstones pass into alternating marl-limestone deposits at an estimated paleodepth of 40–75 m. Three sea-level falls of about 10 m caused the formation of discontinuities corresponding to sequence boundaries. Along these discontinuities, erosional marine hardgrounds formed in a high-hydrodynamic environment at a water depth of less than 10 m, displaying isopachous fibrous cements and meniscus-type cements. The cements pass landward into meniscus and microstalactitic forms along the same discontinuities, which are characteristic of subaerial exposure. During the deposition of transgressive systems tracts, carbonate accumulation remained located mostly on the shallow platform. Energy level increased and carbonates were exported during the deposition of highstand systems tracts forming the infralittoral prograding oolitic wedge. During the deposition of lowstand systems tracts, carbonate production fell to near zero and intraclast strata, derived from the erosion of hardgrounds on the shallow platform, prograded basinward. Early diagenetic cements are related exclusively to discontinuities that are not found within the prograding wedge because of the continuous high sedimentation rate under lower hydrodynamic conditions. This absence of early cementation within the infralittoral prograding oolitic wedge was conducive to porosity conservation, making such features good targets for carbonate reservoir exploration. This study proposes a novel sequence stratigraphy model for oolitic platform wedges, including facies and early diagenesis features. 相似文献
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青岛城市地质与可持续发展 总被引:5,自引:1,他引:5
青岛是黄海环胶州湾的一颗璀灿明珠,是一座闻名于世、风景秀丽的滨海城市,也是我国北方海岸带上重要的港口、旅游城市。海岸带是海/陆相互作用的一个特殊地带,是人类频繁活动、生产建设与经济发展最活跃的地域,同时也是一个生态环境比较脆弱的地区。了解青岛城市及其海岸带的地质环境特征与演化规律,合理规划开发、利用、保护和综合治理,以便有效地抵卸人类生存环境的不断恶化,走可持续发展的道路。从青岛城市的地质构造、矿产资源和地质环境的实际状况和自然属性出发,探讨了海洋地质在由海洋科学城向海洋产业城转变过程中的作用以及城市地质与可持续发展之路。 相似文献
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我国海洋环境地质 总被引:1,自引:1,他引:1
我国海洋地质环境研究始于20世纪50至60年代,80至90年代是我国海洋环境地质学形成和快速发展时期。灾害地质是海洋环境地质研究的先行领域,全球变化研究也取得长足进展。全球变化、区域海洋环境地质调查、滨海城市地质、沿海地下水环境、海洋灾害地质、海底不稳定性、滨海湿地、人类活动对海洋地质环境影响等,都是今后我国海洋环境地质研究的重要方向。我国海岸带地质环境,具有构造活动性强、入海泥沙大、多风暴潮、人工环境非常突出等特征。海岸带基本环境问题包括地质资源利用、人为工程环境、流域环境变化、海平面上升等对海岸带环境影响4个方面。黄河、长江、珠江三大三角洲,除共性问题外,还存在各自独特的环境地质问题。海底不稳定性和灾害地质因素是目前近海环境地质学研究的主要课题,大抵可分为构造、斜坡、底型和结构4种不稳定性。中国近海有六大类约40种灾害地质因素。根据地质环境特征,中国近海可分为17个环境地质区。 相似文献
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Anthony F. Randazzo 《Geo-Marine Letters》1984,4(3-4):145-146
Sea level fluctuations and shoreline migrations are responsible for commonly oriented ridges and hills of north-central Florida. Lake Wales Ridge is the principal geomorphic feature of the region, with younger ridges, including Trail Ridge, occurring to the north and east.Sand is the dominant sediment size of the deposits forming these ridges, but gravels and clay beds also occur. Cross-laminations and burrowing are prominent in certain horizons. Generalized sections resemble marine regressive patterns and a marine barrier environment. The deposits reflect a prograding shoreline and the subaerial evolution of the Florida peninsula. 相似文献
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The Vents Program of the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory is an interdisciplinary research initiative that brings together scientists from a wide range of disciplines, including geophysics, geology, physical oceanography, chemistry, and biology. Each discipline collects a variety of data types of varying structures and requiring intercomparison. The challenge of scientific information management is thus approached with a view of supporting data from multiple survey, mapping, and sampling tools and subject to multiple levels of interpretation. The ultimate objective is a system that integrates the functions of data storage, selective retrieval, display, and archiving. The results of our ongoing efforts in scientific information modeling and management have produced a relational database in which marine geological, geophysical, chemical, and biological observations can be accessed by any investigator. 相似文献