德国钻探达到了新的深度

几百名德国的重要人物、科学家和工程师，与来自10个国家的技术人员一起，聚集在西德温迪施埃申巴赫巴伐利亚州开始德国大陆钻探计划(KTB)的主钻孔的工作。     

世界上主要国家的大陆科学钻探概况

1992年11月,经济合作和发展组织(OECD)在法国召开了第二次大科学论坛,论题是“深部钻探”.笔者根据1993年OECD出版的深部钻探专辑,编译了此文,供参考.一、大陆科学钻探所要解决的关键性地球科学问题     

地震研究进展与趋势——全球地震科学钻探研究综述

近年来大地震频繁发生,造成了巨大的人员伤亡和财产损失,认识地震和地震发生机制已成为地质学家和地球物理学家共同的奋斗目标。科学钻探是获取地下深部物质、了解深部信息的最直接、最有效、最可靠的方法,因此,科学钻探是认识和揭示地震断裂作用的最佳手段。本文介绍了目前世界上主要的地震科学钻探计划,包括位于环太平洋地震带的日本野岛(Nojima)断层科学钻探计划、台湾车笼埔断裂钻探计划(TCDP)、圣安德烈斯断裂深部观测钻探计划(SAFOD)、新西兰深部断层钻探计划(DFDP)、日本南海海槽发震带试验钻探计划(NanTroSEIZE)、日本海沟地震快速钻探计划(JFAST)和大陆内部地震的汶川地震断裂带科学钻探计划(WFSD),简要概括了这些科学钻探计划所取得的有关地震研究的重要进展与贡献,并且通过这些成果探讨了未来地震研究趋势。     

世界最大深海考察船出发探秘：将钻探海床以下7000m

2006年1月16日，日本建造的世界上最大的探测船“地球”号启航，开始钻探试验。这艘承载着科学家“深入地心”梦想的庞然大物随后将驶向太平洋地壳最薄处，开展一项史无前例的大洋科考计划——向人类从未到达过的地幔层发起冲击，追寻地球深处的秘密。     

大陆科学钻探的新发现与研究主题

大陆科学钻探是当代地球科学的重大科学工程之一,也是带动21世纪地球科学发展的关键。概括了20多年来大陆科学钻探取得的主要成就,并对其面临的科学主题作了详细阐述;最后对我国开展大陆科学钻探提出了几点建议。     

“地壳一号”钻机顺利完成井架起升

本刊讯2013年11月17日,用于松辽盆地资源与环境科学钻探工程（以下简称：松科二井）施工的“地壳一号”万米科学钻探钻机顺利完成了井架起升。     

国际大洋钻探计划的组织与运作方式

文章在概述大洋钻探计划的基础上，重点介绍了大洋钻探计划的管理、运作和科学咨询方式，介绍了有关国家参加大洋钻探计划和组织机构与合作模式。     

综合大洋钻探计划（Integrated Ocean Drilling Program）

综合大洋钻探计划（IODP）是一项通过研究海底沉积物和岩石来探究地球历史和结构的国际研究计划，该计划以其前身深海钻探计划（DSDP）和大洋钻探计划（ODP）为基础，使用多种钻探平台（包括：立管钻探、非立管钻探、特定任务钻探平台）实现其科学目标。     

资讯

正ODP大洋钻探计划,1985-2003国际大洋钻探计划(ODP,1985-2003)计划及其前身的深海钻探(DSDP,1968-1983)是二十世纪地球科学领域历时最长,参加国家最多,也是最成功的国际合作。我国于1998年正式加入国际大洋钻探计划,1999年以同济大学汪品先院士为首席科学家的南海ODP184航次,实现了在中国海进行大洋钻探的零的突破,也使我国海洋地质学研究一举进入国际深海研究的前沿。     

图片新闻

正ODP大洋钻探计划,1985-2003国际大洋钻探计划(ODP,1985-2003)计划及其前身的深海钻探(DSDP,1968-1983)是二十世纪地球科学领域历时最长,参加国家最多,也是最成功的国际合作。我国于1998年正式加入国际大洋钻探计划,1999年以同济大学汪品先院士为首席科学家的南海ODP184航次,实现了在中国海进行大洋钻探的零的突破,也使我国海洋地质学研究一举进入国际深海研究的前沿。     

Seismic anisotropy of the crystalline crust: what does it tell us?

The study of the directional dependence of seismic velocities (seismic anisotropy) promises more refined insight into mineral composition and physical properties of the crystalline crust than conventional deep seismic refraction or reflection profiles providing average values of P-and S-wave velocities. The alignment of specific minerals by ductile rock deformation, for instance, causes specific types of seismic anisotropy which can be identified by appropriate field measurements.
Vice versa , the determination of anisotropy can help to discriminate between different rock candidates in the deep crust. Seismic field measurements at the Continental Deep Drilling Site (KTB, S Germany) are shown as an example that anisotropy has to be considered in crustal studies. At the KTB, the dependence of seismic velocity on the direction of wave propagation in situ was found to be compatible with the texture, composition and fracture density of drilled crustal rocks.     

Fractal variability in superdeep borehole — implications for the signature of crustal heterogeneities

The deep and superdeep boreholes of the German Continental Deep Drilling Program (KTB) provide probably the most extensive data archive on in-situ properties of metamorphic crustal rock from a single site. Analysis of the variability of several geophysical parameters point out fractal features and a degree of correlation between data values comparable to 1/f-noise. Accordingly, the Earth's crust, at the KTB site, can be statistically described as an inhomogeneous medium whose properties are basically invariant from metre to kilometre scale. Piecewise homogeneous models appear to be inadequate to represent petrophysical properties, at least in the vertical dimension, and 1/f-noise offers a far more suitable concept to simulate heterogeneities in the Earth's crust.     

On the origin of saline fluids in the KTB (continental deep drilling project of Germany)

Highly saline fluids were encountered during the German Continental Deep Drilling Project (KTB) from depths ranging between 2 and 3 km to about 9 km. The most reliable data were obtained from samples extracted during a long-term pumping test in the 4000-m deep KTB pilot hole. Some 460 m³ CaNaCl brines with about 68 g l⁻¹ total dissolved solids (TDS) and some 270 m³ associated gases, mainly N₂ and CH₄ were pumped to the surface from the main fracture system situated near the bottom of the pilot hole. Geochemical and isotopic data support the hydraulic tests which suggest the presence of an open and large fluid reservoir at depth. The pumped fluids from this main fracture system were released from a deep reservoir situated at more than 5500 m depth which is hydraulically connected with the 9101 m deep KTB main hole, drilled some 250 m to the northeast of the pilot hole.While Ca and Sr contents of the extracted brines may be the result of water-rock interaction, Cl is most likely of external origin. The Cl is hypothesized to derive from geotectonic processes rather than to descending infiltration of paleo-seawater (evaporitic brines). The sampled fluids have probably migrated from a deeper reservoir to their present position since the Cretaceous-Tertiary period due to tectonic activity. However, several isotopic studies have identified an admixture of descending paleowaters down to more than 4000 m depth. The high ³⁶ClCl ratio of the fluids sampled during the long-term pumping test point to a host rock highly enriched in UTh, unlike the sampled KTB country rocks. The fluid reservoir is believed to be in contact with the Falkenberg granite massif situated about 2 km to the E of the KTB holes capable of supplying sufficient neutron flux for considerable subsurface production of 36C1. The NaCl(K, SO₄) precursor fluids of the CaNaCI brines were produced in the course of extensive tectonic processes since the Late Caledonian within the Bohemian Massif.     

Scaling behaviour of vertical magnetic susceptibility and its fractal characterization: an example from the German continental deep drilling project (KTB)

The variations of rock magnetism reflect the geological inhomogeneities of the earth's crust, i.e. its petrological-mineralogical and structural organization. The present state of the crust bears meaningful information of its past dynamic processes and evolution. We analysed magnetic susceptibility data series from the boreholes of the German Continental Deep Drilling Project (KTB). By means of spectral and rescaled-range (R/S) analyses we could detect a scaling behaviour of magnetic data series and quantify it in fractal terms. In particular, the R/S method yields more precise results than the Fourier analysis and leads to Hurst coefficients H > 0.5, which means that the magnetic variations exhibit some persistence with depth. Because of the relation between rock magnetism and crustal features, we suggest that the magnetic vertical inhomogeneities in the KTB area can be described by a self-affine model with H 0.8, corresponding to a fractal dimension D 1.2.     

KTB地球物理测井的组织管理

德国大陆科学钻探计划(KTB)是一项庞大的科学工程,钻探了世界上第二口大陆超深孔.在这宏大的计划当中,地球物理测井技术发挥了其独特的作用.系统地介绍了在KTB运作过程中地球物理测井的组织、管理及运行体制.     

Time dependent strain recovery of cores from the KTB — Deep drill hole

Summary The time dependent strain recovery is investigated for drill cores of two rock types from the German Continental Deep Drilling Project (KTB). The strains are measured with inductive displacement transducers in the core axis and in three different radial directions under constant conditions of temperature and moisture. It turns out that the process of time dependent strain recovery is closely connected with the emission of acoustic signals. A non-foliated, fine grained lamprophyre (depth: 2231.50 m) and a strongly foliated gneiss (depth: 2415.90 m) show a distinctly different relaxation behaviour. The relaxation times for both, deformation and acoustic emissions, are approximately the same and 57 hours for the lamprophyre and 28 hours for the gneiss. In the case of the viscoelastically isotropic lamprophyre principal in situ stresses have been calculated.     

On the origin of saline fluids in the KTB (Continental Deep Drilling Project of Germany)

Highly saline fluids were encountered during the German Continental Deep Drilling Project (KTB) from depths ranging between 2 and 3 km to about 9 km. The most reliable data were obtained from samples extracted during a long-term pumping test in the 4000-m deep KTB pilot hole. Some 460 m³ Ca–Na–Cl brines with about 68 g l⁻¹ total dissolved solids (TDS) and some 270 m³ associated gases, mainly N₂ and CH₄ were pumped to the surface from the main fracture system situated near the bottom of the pilot hole. Geochemical and isotopic data support the hydraulic tests which suggest the presence of an open and large fluid reservoir at depth. The pumped fluids from this main fracture system were released from a deep reservoir situated at more than 5500 m depth which is hydraulically connected with the 9101 m deep KTB main hole, drilled some 250 m to the northeast of the pilot hole.While Ca and Sr contents of the extracted brines may be the result of water–rock interaction, Cl is most likely of external origin. The Cl is hypothesized to derive from geotectonic processes rather than to descending infiltration of paleo-seawater (evaporitic brines). The sampled fluids have probably migrated from a deeper reservoir to their present position since the Cretaceous–Tertiary period due to tectonic activity. However, several isotopic studies have identified an admixture of descending paleowaters down to more than 4000 m depth. The high ³⁶Cl/Cl ratio of the fluids sampled during the long-term pumping test point to a host rock highly enriched in U–Th, unlike the sampled KTB country rocks. The fluid reservoir is believed to be in contact with the Falkenberg granite massif situated about 2 km to the E of the KTB holes, capable of supplying sufficient neutron flux for considerable subsurface production of ³⁶Cl. The Na–Cl–(K-, SO₄) precursor fluids of the Ca–Na–Cl brines were produced in the course of extensive tectonic processes since the Late Caledonian within the Bohemian Massif.     

The Cretaceous and younger thermal history of the KTB site (Germany): apatite fission-track data from the Vorbohrung

A detailed fission-track analysis was carried out on 41 apatite samples from the 4001-m-deep pilot hole of the German Continental Deep Drilling Program (KTB). The investigations include dating by the population method and length measurements of horizontal confined tracks. Age and length information indicate that all samples above the present-day partial annealing zone cooled from temperatures above 120?°C in the Cretaceous. The top two kilometres of the profile show less variation of age with depth than was expected. Modelling of the profile indicates that the distribution of fission track ages with depth requires that the profile was disturbed during or after cooling through the partial annealing zone. Modelling of individual samples reveals that at least the upper 2?km experienced reverse faulting, effectively thickening the upper part of the rock column by up to 1000?m in the Tertiary. A present-day partial annealing zone for apatite was observed between 2000 and 4000?m (～60–110?°C). This confirms earlier in situ observations of the position of the partial annealing zone.     

Nd-Sr isotopic and trace element study of rocks and fluids from the continental deep drilling Project (KTB), Germany

Geochemical analyses were interpreted on the dominant lithological units and on a deep crustal fluid from the Continental Deep Drilling Project (KTB) Pilot Hole, situated at the western margin of the Variscan Bohemian Massif. The biotite gneiss (from 384 m depth) shows a rare earth element pattern very similar to the European shale composite with Nd model ages of 940 Ma (CHUR) and 1.4 Ga (DM). The lamprophyre dike in the upper profile (1549 m), a nepheline and olivine normative basalt, is geochemically and isotopically similar to rocks from the Tertiary Central European Volcanic Province. The lower metabasite sequence (3575–4000 m), with an intrusion age of approximately 500 Ma, is made up primarily of highly metamorphosed subalkalic olivine basalts. The geochemical characteristics of the metabasites are a (La/Yb)_N of 5–10, an La concentration of 20–50 times chondrite as well as (⁸⁷Sr/⁸⁶Sr)_i of 0.7035–0.7038 and _Nd(T) of 4–6. These values suggest a depleted mantle source for the igneous precursors, evolving by assimilation-fractional crystallization processes with up to 25% of upper crust into the ultramafic, basaltic, and intermediate rock types of the metabasite sequence. The strong geochemical and chronological similarities between the KTB metabasites and rocks from the Münchberg Massif suggest that these units belong to the same lithological complex. The high salinity as well as the radiogenic ⁸⁷Sr/⁸⁶Sr ratio of 0.709413 in the KTB fluid from 4000 m depth might be the result of migrating fluids reacting with the regional Permo-Mesozoic evaporite deposits, followed by extensive Sr isotopic exchange with the upper crust.