中国大陆科学钻探主孔榴辉岩中石榴石和绿辉石原位激光探针分析及其成岩成矿指示意义

本文以中国大陆科学钻探主孔0～2000m岩芯中的榴辉岩为对象,运用EMPA和LA-ICP-MS技术,系统测定了榴辉岩中石榴石和绿辉石的主量与微量元素组成,并据此讨论了它们的成岩成矿意义.研究结果表明,CCSD主孔榴辉岩中石榴石富重稀土和Sc、Y、Co,而绿辉石则富中稀土和Pb、Sr、V,石榴石和绿辉石的高场强元素(特别是Nb、Ta)含量均很低.石榴石存在不同程度的Ce负异常,指示榴辉岩的形成过程中卷入有地表氧化条件下形成的风化沉积物.石榴石具有低的Zr/Y比值,绿辉石普遍具有高的Sr含量,这些特征说明榴辉岩(特别是高钛榴辉岩)的原岩可能为遭受过壳源物质混染与交代的富集地幔部分熔融的产物.高钛与低钛榴辉岩中石榴石和绿辉石在主量及微量元素组成上存在一定差别,总体而言,高钛榴辉岩中石榴石具高的MgO含量和较高的MgO/TFeO比值,以及较高的稀土和Sc含量,而绿辉石则相对富TFeO、MnO,并具有较高的Sr、Zr、Hf含量.高钛榴辉岩中石榴石和绿辉石常出现不同程度的Eu正异常,Cr含量均显著低于低钛榴辉岩.综合分析表明,高钛榴辉岩的原岩最可能为富斜长石的辉长质侵入岩,原岩组成的差异应是导致二类榴辉岩中石榴石和绿辉石矿物化学组成存在差异的主要原因.     

Determination of the origin of mineralization and groundwater salinity in the Adrar region in the southwest of Algeria

To some extent, the sedimentary sequence with the largest groundwater reserves in northern Sahara is marked by a certain water table level, regionally known as the "Continental Intercalaire"(CI). "Continental Intercalaire"(CI) refers to "Continental Intercalary" widely distributed among three countries. Algeria, Tunisia and Libya, which have significant potential of water resources. As it is the only water resource relatively easily accessible to the inhabitants of the Sahara, it is widely developed. The physico-chemical characteristics of statistical processing in principal component analysis(PCA) and the chemical phase measurement of groundwater in the unconfined aquifer captured by "Foggaras"(traditional system irrigation composed of well system linked by a horizontal channel from their bases) and the deep drillings located in the study area were accessible. Therefore, there were some favorable conditions for comparing the chemistry of these waters with the standards of potability established by the World Health Organization. Then, the study detected the origin of excessive mineralization and the excessive content of Na, Cl, K, Mg and Ca that originated from the leaching of the clay and carbonate layers of the "Continental Intercalaire". In addition, the enrichment in NO_2~-, NO_3~- and SO_4~(2-) was due to the excessive use of fertilizer in the whole region for shallower Foggaras waters, and this study also showed the dominant chemical facies of groundwater related to the significant abundance of these mineral salts in this thick aquifer horizon.     

德国大陆科学钻探的地壳流体研究

简要地介绍了德国大陆科学钻探过程中壳流体的开发成果,以及与流体研究相关的某些问题。德国两个大陆科学钻孔提供了可达９１９１ｍ深结晶基底中古流体和现代流体样品,以及它们留在矿物和岩石化学、同位素成分上的指纹。据此,再以再造地壳流体的时空分布、化学成分、迁移途径、源区和演化过程。     

水平定向钻进铺管孔／管直径比设计取值方法

孔／管直径比是水平定向钻进铺管工程的重要基础设计参数,其取值大小直接关系到工程的成败、效率、安全和铺设后的管道运行安全。采用力学分析方法建立的回拖阻力数值模型及开发的专用软件,可以方便快捷地对孔管直径比取值进行精确的量化评价,并能够较好地解决工程设计中的一些复杂的数值计算问题,具有良好的推广应用前景。     

悬链线法在水平定向钻轨迹设计中的应用探究

铝孔轨迹设计是非开挖水平定向钻施工中一项重要内容。其最优化设计在国内已较成熟,但多数优化设计未从力学方面进行优化设计。针对这一情况,引入悬链线法来优化水平定向钻轨迹设计。通过悬链线法的计算可知,优化后的轨迹不仅有利于降低钻杆回转阻力和扭矩消耗,提高机械钻速,增长管道使用年限,同时与传统设计方法相比较,其计算出的轨迹长度也比传统圆弧轨迹长度略短,表明了悬链线法在水平定向钻轨迹设计上具有一定的优势。     

苏通大桥二期试桩后压浆的施工及效果检测

随着高层建筑和大型桥梁的兴建,钻孔灌注桩在工程中已得到了极为广泛的应用。但是,钻孔灌注桩的固有缺陷,例如孔底沉渣、孔壁泥浆、端阻力、侧阻力发挥不同步等,限制了其承载力的发挥并且沉降较大。由此,钻孔灌注桩压力注浆技术应运而生,并被逐渐应用于工程实践中。所以,对桩的后压浆施工工艺、受力机理等技术问题进行研究是非常重要的。在国内外现有的理论研究和工程应用基础上,通过对苏通大桥Ⅱ期的试桩工程施工,详细阐述了桩端后压浆技术的具体应用。同时,利用钻孔取心及CT检测技术分析后压浆的施工效果。     

浅论水平定向钻进敷设管材

水平定向钻进铺设技术在国内应用日益广泛,但是现行相关管材标准严重滞后,难以满足实际需要。本文对现行水平定向钻进铺设所涉及到的管材进行简要论述,建议相关部门尽快制定相关的水平定向钻进铺设管材标准,并与现行水平定向钻进技术规范协调一致,以促进水平定向钻进工程在国内的健康发展。     

The Pleistocene evolution of the East Antarctic Ice Sheet in the Prydz bay region: stable isotopic evidence from ODP Site 1167

Ocean Drilling Program Leg 188, Prydz Bay, East Antarctica is part of a larger initiative to explore the Cenozoic history of the Antarctic Ice Sheet through direct drilling and sampling of the continental margins. In this paper, we present stable isotopic results from Ocean Drilling Program (ODP) Site 1167 located on the Prydz Channel Trough Mouth Fan (TMF), the first Antarctic TMF to be drilled. The foraminifer-based δ¹⁸O record is interpreted along with sedimentary and downhole logging evidence to reconstruct the Quaternary glacial history of Prydz Bay and the adjacent Lambert Glacier Amery Ice Shelf System (LGAISS). We report an electron spin resonance age date of 36.9±3.3 ka at 0.45 m below sea floor and correlate suspected glacial–interglacial cycles with the global isotopic stratigraphy to improve the chronology for Site 1167. The δ¹⁸O record based on planktonic (Neogloboquadrina pachyderma (s.)) and limited benthic results (Globocassidulina crassa), indicates a trend of ice sheet expansion that was interrupted by a period of reduced ice volume and possibly warmer conditions during the early–mid-Pleistocene (0.9–1.38 Ma). An increase in δ¹⁸O values after 900 ka appears to coincide with the mid-Pleistocene climate transition and the expansion of the northern hemisphere ice sheet. The δ¹⁸O record in the upper 50 m of the stratigraphic section indicates as few as three glacial–interglacial cycles, tentatively assigned as marine isotopic stages (MIS) 16–21, are preserved since the Brunhes/Matuyama paleomagnetic reversal (780 ka). This suggests that there is a large unconformity near the top of the section and/or that there may have been few extreme advances of the ice sheet since the mid-Pleistocene climate transition resulting in lowered sedimentation rates on the Prydz Channel TMF. The stable isotopic record from Site 1167 is one of the few available from the area south of the Antarctic Polar Front that has been linked with the global isotopic stratigraphy. Our results suggest the potential for the recovery of useful stable isotopic records in other TMFs.     

Evaluation of the relative roles of global versus local sedimentary controls on Middle to Late Pleistocene formation of continental margin strata,Canterbury Basin,New Zealand

Determining the relative influence of eustasy versus local sedimentary processes on strata formation is a fundamental challenge in the study of continental margin stratigraphy. In this paper, the relative contribution of these factors on continental margin evolution during the Middle to Late Pleistocene is evaluated using samples from Integrated Ocean Drilling Program Expedition 317. Core‐logging, biostratigraphy and quantitative X‐ray diffraction mineralogy are used to delineate continental shelf sedimentary systems. Major lithological unconformities bound stratigraphic sequences that contain recurring compositional patterns and that resemble other examples of Middle to Upper Pleistocene sequences. However, a preliminary chronology suggests that sequence boundary formation cannot be linked ‘one to one’ with eustatic cycles and therefore these sequences can contain multiple ca 100 ka eustatic cycles. Smaller amplitude, higher frequency transitions in sediment composition are interpreted as stratigraphic sequences driven by more rapid perturbations in the interplay of accommodation and sediment supply; their stratigraphy is variable in time and across the shelf, suggesting a strong influence of local sedimentary forcing in their formation. Changes in sediment composition after the Middle Pleistocene Transition indicate that sediment transfer from onshore sources in the glaciated Southern Alps to the middle‐shelf occurred over a single 100 ka glacio‐eustatic cycle, with an additional 100 ka lag before the mineralogical signal was preserved on the outer‐shelf. This phenomenon is coincident with rapid shelf progradation in this basin, suggesting a causal relation between across‐shelf sediment transport and margin progradation. This is one of very few studies that provide insights at the core scale into the processes driving continental margin evolution during the Middle to Late Pleistocene. This work shows that compositional changes in mud‐dominated successions can lead to a sequence stratigraphic interpretation and the identification of high‐frequency sequences, which may not be possible using a conventional stratigraphic approach.     

用拉格朗日插值法求钻程坐标及其PC—1500程序

传统方法绘制的钻程线投影图,往往成为较明显的折线。不符合本来是圆滑曲线的钻程线,且其误差也较大,而用拉格朗日插值法可以根据已得到的测斜结果,拟合出一条圆滑的钻程线。本文介绍了用这种方法编制的PC—1500机BASIC程序,使地质人员可用该机计算制图,摆脱繁锁的手工操作,提高工效和成图质量。