减少旋挖钻机主卷扬钢丝绳磨损的方法探讨          下载免费PDF全文

张刚  李晓亮  李寒菊 《探矿工程》2013,40(8):61-63

从旋挖钻机天轮支架的结构型式,卷扬滑轮材料的选取及热处理、卷扬卷筒的设计要素、钢丝绳的选型、施工时底盘的放置状态、卸土方式、以及提引器的润滑等方面探讨了减少旋挖钻机卷扬钢丝绳磨损的有效方法。  相似文献   

安徽寿县新元古界球-枕状构造的双重成因与古地震脉动旋回研究   总被引：1，自引：0，他引：1  

王熙  王明镇 《地质学报》2013,87(6):823-831

在安徽寿县新元古界四十里长山组下部粉砂-细砂岩沉积地层中,发育一组具有双重成因的球-枕状软沉积物变形构造.对露头剖面进行实地观测研究显示,变形构造形成于浅海陆棚边缘斜坡带的地震灾变事件层中.由于滑塌砾石落入表层粉砂质软沉积层,在地震震颤应力作用下形成具砾石核心的球-枕状体,又在地震脉动旋回性连续震颤作用下,继续沉陷至下部液化砂层中,形成了具有双重成因的球-枕状软沉积变形构造.它经受了地震、海啸、滑塌、滑褶、震颤晃动沉陷、液化泄水、软塑性紧缩变形等多项复杂的同沉积变形作用过程.显示出该地震事件具有前震阶段、主震阶段、余震阶段等多次震颤脉动旋回性地质作用的地质事件,地震能量强度最大应超过里氏7级,为研究海洋震积岩的软沉积变形及脉动旋回性过程提供了重要的实物资料.  相似文献   

Utility of clay Minerals in the Determination of Sedimentary Transport Patterns in the Bay of Cadiz and the Adjoining Continental Shelf (SW-Spain)     

《Geodinamica Acta》2013,26(5-6):259-272

The contents and the distribution of clay minerals in modern sediments of the Cadiz bay and the continental shelf have been studied aiming to establish the sedimentary exchange model and the pathways followed by the clay fraction between the bay and the adjoining continental shelf. The most abundant clay minerals in the muddy sediments consist mainly of illite, smectite, interstratified illite-smectite, kaolinite and chlorite. The application of factor analysis method (PCA) to clay minerals data are considered to be useful in the determination of sedimentary transport patterns. The data from clay mineral assemblages, and their distribution map, make possible to establish the fine sediments transport paths in the study area using clay mineral as natural tracers. This model of transport takes in consideration the facies distribution, the supplies sources and the way of fine sediments are incorporated to the marine environment.

Two flows paths have been established: the outflows coming from Cadiz bay and the littoral zones; and the inflows coming from external marine zones of the bay. These flows are controlled by tidal currents and the morphology of the coast. The action of surge and the marine currents, specially the Atlantic Surface Water flow, are also important in the transport of fine sediments coming from sources located to the north of the study zone.  相似文献   

Late Quaternary core stratigraphy of the northern New South Wales continental shelf     

J. J. Roberts  R. Boyd 《Australian Journal of Earth Sciences》2013,60(1):141-156

On the southeast Australian continental margin, mixed siliciclastic and temperate carbonate sediments are presently forming along the narrow 20–35 km‐wide northern New South Wales shelf over an area of 4960 km². Here, year‐round, highly energetic waves rework inner and mid‐shelf clastic sediments by northward longshore currents or waning storm flows. The strong East Australian Current flows south, sweeping clastic and outer shelf biogenic sands and gravels. Quaternary siliciclastic inner shelf cores consist of fine to medium, lower shoreface sand and graded storm beds of fine to coarse sand. Physically abraded, disarticulated molluscs such as Donacidae and Glycymeridae form isolated gravel lags. Highstand inner shelf clastics accumulate at 0.53 m/10³ y in less than 50 m water depth. Clastic mid‐shelf cores contain well‐sorted, winnowed, medium shoreface sands, with a fine sand component. Fine sand and mud in this area is discharged mainly from New South Wales’ largest river, the Clarence. The seaward jutting of Byron Bay results in weakened East Australia Current flows through the mid‐shelf from Ballina to Yamba allowing the fine sediments to accumulate. Quaternary carbonate outer shelf cores have uniform and graded beds forming from the East Australian Current and are also influenced by less frequent storm energy. Modern clastic‐starved outer shelf hardgrounds are cemented by coralline algae and encrusting bryozoans. Clay‐sized particles are dominantly high‐Mg calcite with minor aragonite and smectite/kaolinite. Carbonate sands are rich in bryozoan fragments and sponge spicules. Distinctive (gravel‐sized) molluscs form isolated shells or shell lag deposits comprising Limopsidae and Pectinidae. The upper slope sediments are the only significant accumulation of surficial mud on the margin (18–36 wt%), filling the interstices of poorly sorted, biogenic gravels. Pectinid molluscs form a basal gravel lag. During highstand the outer shelf accumulates sediment at 0.40 m/10³ y, with the upper slope accumulating a lower 0.23 m/10³ y since transgression. Transgression produced a diachronous (14–10 ka) wave‐ravinement surface in all cores. Relict marine hardgrounds overlie the wave‐ravinement surface and are cemented by inorganic calcite from the shallow and warm East Australian Current. Transgressive estuarine deposits, oxygen isotope Stage 3–5 barriers or shallow bedrock underlie the wave‐ravinement surface on the inner and mid shelf. Northern New South Wales is an example of a low accommodation, wave‐ and oceanic current‐dominated margin that has produced mixed siliciclastic‐carbonate facies. Shelf ridge features that characterise many storm‐dominated margins are absent.  相似文献   

The ecology of worm populations in the Erins Vale formation (late permian) southern Sydney Basin     

J. W. Pickett 《Australian Journal of Earth Sciences》2013,60(3):313-320

The distribution, mode of occurrence and population densities of extensive colonies of worms, and the morphology of their thick‐walled tubes are described. Interaction between two species occurring in certain strata enables the feeding habits of the tube‐builders to be reconstructed, and they are thus identified as terebellid worms. The worms when alive were less than 5 mm in diameter and had tentacles 27 mm long. Their environmental situation was near the southern edge of an extensive area of marine deposition covering much of the Sydney Basin. The depth was below wave base. The worm populations were buried alive during deposition of sheets of sediment, probably resulting from intermittent sudden flooding events in coastal rivers.  相似文献   

The morphology and late Quaternary paleogeomorphology of the continental shelf off Sydney,NSW     

A. D. Albani  P. C. Rickwood  P. G. Quilty  J. W. Tayton 《Australian Journal of Earth Sciences》2013,60(6):681-694

Shallow seismic-reflection profiling and proton-precession magnetometry have been conducted over the continental shelf off Sydney between Broken Bay (in the north) and Bate Bay (in the south) as well as over part of the upper continental slope in the area east of the coastline between Narrabeen and Port Hacking. In this area, four major paleodrainage channels incise the bedrock, within the coastal estuaries and on the inner and mid-shelf:

1. the Hawkesbury paleo-watercourse, which is joined offshore by four lesser paleochannels, that we call the Newport, Mona Vale, Narrabeen and Long Reef paleo-watercourses;

2. the Parramatta paleo-watercourse, which is joined by the Bondi paleo-watercourse;

3. the Botany paleo-watercourse and

4. the Georges paleo-watercourse, which is joined under the Kurnell Peninsula land isthmus by the Cooks paleo-watercourse, and then by the Hacking paleo-watercourses in Bate Bay.

Of these paleodrainages, only that of the Hawkesbury River has discernible expression at depths >120 m, the sea-level low and inferred paleo-shoreline of the Last Glacial Maximum (LGM) at ca 20 ka. Some of the lesser paleo-watercourses are manifested only at depths shallower than the ?120 m paleo-shoreline and include those of the Maroubra paleo-watercourse and the combined Manly/North Head paleo-watercourses. Paleochannels detected below the LGM shoreline are those of:

• the ancestral Hawkesbury River;

• the minor Peak paleo-watercourse east of Coogee, which is discernible at depths shallower than the ?100 m isobath and is maintained to depths greater than ?210 m; and

• the minor Island paleo-watercourse whose head terminates at ～?140 m east of Bronte, lies entirely below the LGM paleo-shoreline, and can be traced to a depth of ?260 m.

Based on the paleotopographic and sediment-infill geophysical records obtained, 10 stages in the evolution of the paleo-watercourses are proposed.  相似文献   

Comparison of tropical,carbonate and temperate,siliciclastic tidally dominated sedimentary deposits: Examples from the Australian continental shelf     

P. T. Harris 《Australian Journal of Earth Sciences》2013,60(3):241-254

Surficial deposits of the tidally influenced Australian shelf seas exhibit a variation in fades related to energy gradient. These deposits comprise a high energy gravelly facies, a mobile sand sheet facies and a low energy muddy sand facies. Such a facies distribution conforms generally with the existing model of continental shelf tidal sedimentation, derived for the west European tidal seas. However, the carbonate rich and mainly warm water deposits of the Australian shelf differ from the mainly quartzose and temperate cold‐water deposits of the European type case in terms of: (i) the role of seagrasses in trapping fine‐grained sediment; and (ii) the relative importance of the production of carbonate mud by mechanical erosion of carbonate grains. Seagrasses in Spencer Gulf, Gulf of St Vincent and Torres Strait are located in regions of strong tidal currents, associated with bedforms and gravel lag deposits. Thus, in the case of tropical carbonate shelves, seagrass deposits containing fine‐grained and poorly sorted sediments are located in close proximity to high energy gravel and mobile sand facies. In contrast, the European model (for temperate, siliciclastic shelves) places facies in a regional gradient with a wide separation (in the order of 50–100 km).

Of the locations reviewed, the Gulf of St Vincent, Bass Strait, southern Great Barrier Reef, Torres Strait and Gulf of Carpentaria exhibit zones of carbonate mud accumulation. The production and winnowing of carbonate mud from the mobile sand facies is a factor that must be taken into account in the assessment of a sediment budget for this facies, and which is of relatively greater importance for carbonate shelves. Insufficient data are presently available from the macrotidal North West Shelf to test the applicability of the model to this region.  相似文献   

国际海洋与海洋专属经济区权益维护研究     

吴洁 《地域研究与开发》2007,26(1):54-57

21世纪是海洋世纪.在全球范围内大规模开发、利用、共享海洋资源是这个时代的一个发展的主题.文章从国际海洋法角度,阐述了大陆架划界的基本理论依据,对3种不同划界方法进行了对比分析,主张遵循国际海洋法自然延伸原则和公平原则的划界科学依据.在缓解大陆架油气矿产资源开发方面,文章提出应遵循"搁置争议,共同开发"的准则,进一步做好必要的科学技术准备,依据法律维护我国海洋专属经济区权益.  相似文献   

Glaciopanspermia: Seeding the terrestrial planets with life?     

Joop M. Houtkooper 《Planetary and Space Science》2011,59(10):1107-1111

The question whether life originated on Earth or elsewhere in the solar system has no obvious answer, since Earth was sterilized by the Moon-forming impact and possibly also during the LHB, about 700 Ma after the formation of the solar system. Seeding by lithopanspermia has to be considered. Possible sources of life include Earth itself, Mars, Venus (if it had a more benign climate than today) and icy bodies of the solar system. The first step of lithopanspermia is the ejection of fragments of the surface into space, which requires achieving at least escape velocity. As the velocity distribution of impact ejecta falls off steeply, attention is drawn to bodies with lower escape velocities. Ceres has had, or still has, an ocean more than 100 km deep, with hydrothermal activity at its rocky core. The possible presence of life, its relative closeness to the terrestrial planets and Ceres' low escape velocity of 510 m/s suggest that Ceres could well be a parent body for life in the solar system.Icy impact ejecta - hence glaciopanspermia - from Ceres will be subject to evaporation of volatiles. Spores may be loosened by evaporation and enter the atmospheres of the terrestrial planets as micrometeorites.The seeding of the terrestrial planets from Ceres would result in (1) detection of life in the crustal layers of Ceres; (2) a commonality of Cerean life with Terran and possible Martian and Venusian life and (3) biomarkers of Cerean life, which might be found in the ice at the Moon's poles and on the surface of other main belt asteroids.  相似文献   

Phytoplankton composition and its ecological effect in subsurface cold pool of the northern Bering Sea in summer as revealed by HPLC derived pigment signatures   总被引：2，自引：2，他引：0  

ZHUANG Yanpei  JIN Haiyan  LI Hongliang  CHEN Jianfang  WANG Bin  CHEN Fajin  BAI Youcheng  LU Yong  TIAN Shichao 《海洋学报(英文版)》2014,33(6):103-111

CHEMTAX analysis of high-performance liquid chromatography(HPLC) pigment was conducted to study phytoplankton community structure in the northern Bering Sea shelf, where a seasonal subsurface cold pool emerges. The results showed that fucoxanthin(Fuco) and chlorophyll a(Chl a) were the most abundant diagnostic pigments, with the integrated water column values ranging from 141 to 2 160 μg/m2 and 477 to 5 535 μg/m2, respectively. Moreover, a diatom bloom was identified at Sta. BB06 with the standing stock of Fuco up to 9 214 μg/m3. The results of CHEMTAX suggested that the phytoplankton community in the northern Bering Sea shelf was dominated by diatoms and chrysophytes with an average relative contribution to Chl a of 80% and 12%, respectively, followed by chlorophytes, dinoflagellates, and cryptophytes. Diatoms were the absolutely dominant algae in the subsurface cold pool with a relative contribution exceeding 90%, while the contribution of chrysophytes was generally higher in oligotrophic upper water. Additionally, the presence of a cold pool would tend to favor accumulation of diatom biomass and a bloom that occurred beneath the halocline would be beneficial to organic matter sinks, which suggests that a large part of the phytoplankton biomass would settle to the seabed and support a rich benthic biomass.  相似文献