锤击法在桩基质量检测中的应用及实测曲线分析

锤击法在桩基质量检测中是一种行之有效的手段。本文结合工程实例对桩的常见缺陷及其反射波特征作了浅析,对锤击法实测曲线判读和解释进行了归纳总结。     

遥感技术支持下的喀斯特地区生态环境状况初步研究

本文依靠GIS与遥感处理软件（ENVI为主要工具）对TM影像进行处理，并结合GPS仪与摄影摄像资料的使用，通过大量的野外实地调查采样，对工作区土地类型进行了分析研究，并划分了生态土地类型。     

Potential Usage of Remote Sensing Data in Studying the Behaviour of Shore Drift Along Kerala Coast, India

Landsat images were analysed to examine direction, amount and behaviour of long-shore drift and its contribution towards deciding areas vulnerable to coastal erosion and accretion along the coast of Kerala. Two approaches are adopted while utilizing the remote sensing data. Net shore-drift direction is determined firstly by studying various coastal landform indicators and secondly by studying offshore turbidity distribution patterns. Landform indicators study suggest that during the south-west monsoon period, strong southerly currents are eroding protruded sectors and depositing eroded material, though partially, along varying sectors. Whereas during the rest of the year, under the influence of a northerly current, accretion is taking place along retreating sectors which has been reflected in the development of beach ridges. Turbidity pattern distribution exhibited by satellite image suggests that for January and February, long-shore drift is from south to north. The results of the two studies were found to be comparable. It may be concluded that shore-drift direction, which can be determined effectively by remote sensing, is season-dependent and plays a significant role in deciding the areas of coastal erosion and accretion.     

高山峡谷区1:50000地质填图技术方法探索与实践——以新疆乌什北山为例

新疆乌什北山填图试点项目充分发挥遥感技术的先导作用,探索1:50000高山峡谷区填图方法。不同分辨率遥感数据在岩性、构造解译等方面的差异表明多源遥感数据综合解译能有效提高解译程度。研究认为同一遥感数据最佳波段组合图像、Landsat-8和Worldview-2数据协同图像增强了对岩性和构造识别的能力。高光谱遥感矿物填图和岩性分类、基于ASTER热红外遥感数据的岩石化学成分填图等是高山峡谷区填图有效技术方法。利用ETM和ASTER数据开展矿化蚀变信息提取,结果表明ASTER较ETM数据在铁染异常、羟基异常等提取方面具有更大的优势。分析认为多元信息综合预测是区域找矿的重要途径。根据乌什北山地质地貌特征,选择其中有效技术方法或技术方法组合开展1:50000地质填图,结果显示在减少剖面测制和路线地质调查数量的同时,达到了填图精度,并取得了若干重要研究成果,为区域构造演化和成矿规律分析总结提供了资料支撑。      

The interpretation of inverse isochron diagrams in Ar/Ar geochronology

The concepts involved in the construction and interpretation of inverse isochron diagrams used in ⁴⁰Ar/³⁹Ar geochronology are reviewed. The diagrams can be useful as a means of recognising atmospheric argon and excess ⁴⁰Ar, incorporated in the mineral lattice, which cannot be recognised from ⁴⁰Ar/³⁹Ar spectra. The age established using an inverse isochron plot, unlike that yielded by a spectrum, is not affected by trapped argon ⁴⁰Ar/³⁶Ar ratios that are different from the atmospheric argon ratio (e.g. due to excess ⁴⁰Ar), and may contribute to a better age interpretation. However, a heterogeneous distribution of excess ⁴⁰Ar or heterogeneous argon loss can cause ‘false’ isochrons, with axial intercepts indicating an incorrect age and an incorrect trapped argon composition. Inconsistency between the ages from a spectrum and from the associated inverse isochron plot may indicate the degree of inaccuracy of isochrons. However, it is possible that both the spectrum and inverse isochron yield the same incorrect age. The importance of considering all possible interpretations before assigning an age to a specimen is stressed.     

Landscapes in Music: Space,Place and Time in the World's Greatest Music

The purpose of this article is twofold. The first is to suggest that techniques for mapping public disagreements over claims to knowledge, or controversies, can act as assistive devices for researchers in geography to move from research topics to research questions. A second purpose is to offer a recipe or “how-to” guide of specific approaches and free scholarly software that researchers without specialized coding skills can use to achieve their own controversy mapping goals. We use a case of creating a controversy map covering the issue of transboundary movements of electronic waste (e-waste) to illustrate how these approaches and software can be associated together so that other researchers may put them to use for their own controversy mapping purposes.     

Wisconsinan Late-glacial environmental change in Newfoundland: A regional review

The distribution of 75 lake and bog sites, from which pollen stratigraphical evidence relevant to the late Quaternary of Newfoundland has been obtained, is presented. The detailed records of lithology, pollen and diatoms, supplemented by geochemical data, are discussed for three of the sites — Southwest Brook Lake, Woody Hill Brook Pond and Leading Tickles — and interpretations made are based on vegetational history, relative climatic changes and extent of ice cover. Radiocarbon data from 14 sites are summarised. A summary chart of Late-glacial environmental changes, including a qualitative palaeotemperature curve, is provided.     

Recent aquatic ecosystem response to environmental events revealed from Pb sediment profiles

The ²¹⁰Pb dating method was first introduced by Goldberg (1963), and since then has been applied to study sediment from lakes, estuaries and coastal marine environments. Hundreds of studies around the world have used ²¹⁰Pb as a geochronological tool in aquatic ecosystems. However little attention has been paid to the potential of this naturally occurring isotope as an environmental tracer of ecological events. Here we report three instances in which ²¹⁰Pb profiles measured on undisturbed sediment cores from lakes, rivers and fjords show us the potential of ²¹⁰Pb profile as a tracer of natural and anthropogenic processes. The methodology used here is a suite of techniques combining biogeochemistry (micro-electrodes), paleomagnetism (susceptibility), sediment characteristics (LOI) and visualization (SPI and X-ray) applied to the interpretation of ²¹⁰Pb profiles. We measured ²¹⁰Pb profiles on sediments from a river, Cruces River (Chile), which recorded a clear shift in the water chemistry caused by a pulp mill effluent to the river. Here metal mobilization and remobilization of the tracer may be the cause of the observed profile. We also measured ²¹⁰Pb profiles in sediment from two fjords of Southern Chile (Pillan and Reñihue), the sudden deposition change of fresh ²¹⁰Pb with depth observed could very well be the result of bioturbation but it occurred in a seafloor area deprived of bioturbators. In this case, ²¹⁰Pb recorded the onset of aquaculture activities (fish farming) that took place two decades ago. Finally, ²¹⁰Pb profiles measured in two lakes in the “pampa Argentina”: Epecuen and Venado showed a particular shape with depth. These profiles apparently registered a sudden depositional event with recent ²¹⁰Pb material, probably related to strong shifts in precipitation and drought cycles in that part of the world. These three examples show that ²¹⁰Pb profiles provide valuable information not only on geochronology, but also related to natural and anthropogenic short term processes, as shown here, but these are not always reported and well understood.