Computerized vision for the geologist

The digital computer can be a tireless friend and assistant to the geologist. The computer has no innate intelligence, but given adequate programs to analyze and interrelate the information on maps, photos, surveys, and other material, the computer can serve as an analytical tool and consultant. To the geologist's qualitative knowledge, theories, and models can be added the possibility of the computer's mathematically precise numerical answers, confirming or refuting the original ideas. In the interactive mode in particular, a dialogue between the geologist and the computer is established, where the geologist and the computer can complement each other's abilities. The basic principles of processing two-dimensional geological data, such as maps, charts, photos, and survey results, are discussed. Some comparisons are also made between the rule-based methods of Prospector, developed at Stanford Research Institute, and the more intuitively guided image-based procedures of GIAPP, developed on the equipment at the National Research Council of Canada, in collaboration with the Geological Survey of Canada and the University of Ottawa.     

Latitudinal and longitudinal variation in aerosol characteristics from Sun photometer and MODIS over the Bay of Bengal and Arabian Sea during ICARB

Spatial variations in aerosol optical properties as function of latitude and longitude are analysed over the Bay of Bengal and Arabian Sea during ICARB cruise period of March–May 2006 from in situ sun photometer and MODIS (Terra, Aqua) satellite measurements. Monthly mean 550 nm aerosol optical depths (AODs) over the Bay of Bengal and Arabian Sea show an increase from March to May both in spatial extent and magnitude. AODs are found to increase with latitude from 4°N to 20°N over the Bay of Bengal while over Arabian Sea, variations are not significant. Sun photometer and MODIS AODs agree well within ±1σ variation. Bay of Bengal AOD (0.28) is higher than the Arabian Sea (0.24) latitudinally. Aerosol fine mode fraction (FMF) is higher than 0.6 over Bay of Bengal, while FMF in the Arabian Sea is about 0.5. Bay of Bengal α(～1) is higher than the Arabian Sea value of 0.7, suggesting the dominance of fine mode aerosols over Bay of Bengal which is corroborated by higher FMF values over Bay of Bengal. Air back trajectory analyses suggest that aerosols from different source regions contribute differently to the optical characteristics over the Bay of Bengal and Arabian Sea.     

无人机摄影测量在矿山地质环境调查中的应用

为解决传统的人工野外矿山地质环境调查易受交通、地形影响,且劳动强度大、效率低、成本高等问题,将无人机摄影测量技术应用在矿山地质环境调查中。以长春市净月东升采石场为研究区,利用RTK（实时动态差分技术）获取地面控制点坐标,采用大疆精灵4无人机进行航空摄影,在Pix4Dmapper建立的研究区三维模型上经量测、解译等,提取研究区内矿坑面积、边坡方位、长度、高度、体积和表面积以及滑坡、崩塌堆积体和断层等矿山地质环境相关的几何信息,制作了研究区地形图、DOM（数字正射影像）和DSM（数字表面模型）,同时解译了边坡大量随机结构面迹线和产状信息。结果表明,基于无人机摄影测量技术的矿山地质环境调查可以快速获取矿山地质环境信息,获取的结构面倾向、倾角误差分别在5°和4°以内,可满足矿山地质环境调查精度要求。     

由历史文献记载反演逐年网格点降水量距平场——气候史料客观定量研究的新探讨

本文尝试由历史文献记载直接反演网格式降水量距平场.这项探讨是利用计算机的文字处理功能,以"中国三千年气象记录总集"1)为基本资料,通过对各地点、各年份气候记载的赋值处理,用Cressman插值方法初步反演生成1501～1900年网格降水量距平场,其时间分辨率为1a,空间分辨率为1°×1°经纬度.这样的网格资料定量含义明确,空间和时间的连续性好,可以方便地与数值模拟结果进行对比,和进行降水的时间、空间变率研究,还可由它生成空间间隔均匀的降水量距平指数的时间序列,进行气候变化分析.     

南海中部和北部海域重力异常特征与地壳构造关系

1976年,中国科学院南海海洋研究所与国家海洋局南海分局共同协作使用“向阳红”五号海洋调查船,利用西德GSS-2型海洋重力仪和我国的CHHK-1型核子旋进式磁力仪,在南海珠江口外海域(北纬22°—17°、东经113°50′—115°10′),进行约3000公里的海洋重力、磁力和测深。设计的测线方向为南北向,测线距为10海里。     

中南地区地质调查中北斗卫星技术应用研究

主要介绍了基于北斗卫星的野外地质调查系统在丛峦叠障、植被覆盖茂密的中南地区野外地质调查中应用的情况,包括野外作业管理、人员安全保障以及遥感异常查证等。试验结果显示,利用该系统基本可实现野外地质调查人员的实时地理位置显示、历史轨迹回放、态势分析以及路线规划等;试验区内系统的通讯基本通畅,可以实现终端与终端、终端与指挥机之间的双向短报文通讯;利用北斗系统的定位功能,可实时记录异常查证点信息,对室内解译的遥感成果进行及时调整和修改,提高了野外地质调查的工作效率。      

Delineation of groundwater potential zone in Chhatna Block, Bankura District, West Bengal, India using remote sensing and GIS techniques

Groundwater is one of the most valuable natural resources, which is an immensely important and dependable source of water supply in all climatic regions over the world. Groundwater is in demand in areas where surface water supply is inadequate and nonsexist in the Chhatna Block, Bankura district and is located on the eastern slope of Chotonagpur Plateau, which is mapped on 73 I/15, 73 I/16 and 73 M/3, and falls between latitude 23°10′–23°30′N and longitude 86°47′–87°02′E. It represents plain land and gentle slope, which is responsible for infiltration and groundwater recharge. The groundwater in this region is confined within the fracture zones and weathered residuum. The present investigation is, therefore, undertaken to delineate potential zones for groundwater development with the help of a remote-sensing study. IRS–LISS-III data along with other data sets, e.g., existing toposheets and field observation data, have been utilized to extract information on the hydrogeomorphic features which include valley fills, buried pediment moderate, buried pediment shallow and structural hills, lineament density contour and slope map of this hard rock terrain. The target of this study is to delineate the groundwater potential zones in Chhatna block, Bankura District, West Bengal. Satellite imagery, along with other data sets, has been utilized to extract information on the groundwater controlling features of this study area. Three features (hydrogeomorphology, slope, and lineaments) that influence groundwater occurrences were analyzed and integrated. All the information layers have been integrated through GIS analysis and the groundwater potential zones have been delineated. The weighted index overlay method has been followed to delineate groundwater potential zones. The results indicate that good to excellent groundwater potential zones are available in almost the entire block. The results show that there is good agreement between the predicted groundwater potential map and the existing groundwater borehole databases. The area is characterized by hard rock terrain—still due to the presence of planation surface along valley fills; it became the prospective zone. The area has been categorized into four distinct zones: excellent, good, fair and poor. Excellent groundwater potential zones constitute 30–35 % of the total block area; good groundwater potential zones occupy a majority of the block, covering approximately 55–60 % and the fair potential zones occupy about 10–15 % of the total block. Poor potential zones occupy a very insignificant portion (less than 1 %).     

Weichselian and Holocene palaeoenvironmental history of the Bol'shoy Lyakhovsky Island, New Siberian Archipelago, Arctic Siberia

Cryolithological, ground ice and fossil bioindicator (pollen, diatoms, plant macrofossils, rhizopods, insects, mammal bones) records from Bol'shoy Lyakhovsky Island permafrost sequences (73°20′N, 141°30′E) document the environmental history in the region for the past c. 115 kyr. Vegetation similar to modern subarctic tundra communities prevailed during the Eemian/Early Weichselian transition with a climate warmer than the present. Sparse tundra‐like vegetation and harsher climate conditions were predominant during the Early Weichselian. The Middle Weichselian deposits contain peat and peaty soil horizons with bioindicators documenting climate amelioration. Although dwarf willows grew in more protected places, tundra and steppe vegetation prevailed. Climate conditions became colder and drier c. 30 kyr BP. No sediments dated between c. 28.5 and 12.05 ¹⁴C kyr BP were found, which may reflect active erosion during that time. Herb and shrubby vegetation were predominant 11.6–11.3 ¹⁴C kyr BP. Summer temperatures were c. 4 °C higher than today. Typical arctic environments prevailed around 10.5 ¹⁴C kyr BP. Shrub alder and dwarf birch tundra were predominant between c. 9 and 7.6 kyr BP. Reconstructed summer temperatures were at least 4 °C higher than present. However, insect remains reflect that steppe‐like habitats existed until c. 8 kyr BP. After 7.6 kyr BP, shrubs gradually disappeared and the vegetation cover became similar to that of modern tundra. Pollen and beetles indicate a severe arctic environment c. 3.7 kyr BP. However, Betula nana, absent on the island today, was still present. Together with our previous study on Bol'shoy Lyakhovsky Island covering the period between about 200 and 115 kyr, a comprehensive terrestrial palaeoenvironmental data set from this area in western Beringia is now available for the past two glacial–interglacial cycles.     

Mapping joint hurricane wind and surge hazards for Charleston,South Carolina

Combined effects of hurricane wind and surge can pose significant threats to coastal cities. Although current design codes consider the joint occurrence of wind and surge, information on site-specific joint distributions of hurricane wind and surge along the US Coast is still sparse and limited. In this study, joint hazard maps for combined hurricane wind and surge for Charleston, South Carolina (SC), were developed. A stochastic Markov chain hurricane simulation program was utilized to generate 50,000 years of full-track hurricane events. The surface wind speeds and surge heights from individual hurricanes were computed using the Georgiou’s wind field model and the Sea, Lake and Overland Surges from Hurricanes (SLOSH) model, respectively. To validate the accuracy of the SLOSH model, the simulated surge levels were compared to the surge levels calculated by another state-of-the-art storm surge model, ADCIRC (Advanced Circulation), and the actual observed water elevations from historical hurricane events. Good agreements were found between the simulated and observed water elevations. The model surface wind speeds were also compared with the design wind speeds in ASCE 7-10 and were found to agree well with the design values. Using the peak wind speeds and maximum surge heights, the joint hazard surfaces and the joint hazard maps for Charleston, SC, were developed. As part of this study, an interactive computer program, which can be used to obtain the joint wind speed and surge height distributions for any location in terms of latitude and longitude in Charleston area, was created. These joint hazard surfaces and hazard maps can be used in a multi-hazard design or risk assessment framework to consider the combined effects of hurricane wind and surge.     

全国1:200 000数字地质图（公开版）空间数据库

全国1：200 000数字地质图空间数据库是基于目前中国唯一的、实测的、全国性的1：200 000区域地质调查成果,由全国多家单位共同完成的全国性基础地质学空间数据库之一。数据库在空间上包含1 163幅1：200 000地质图数据,覆盖整个国土范围的72%,包含MapGIS和ArcGIS两种格式,总数据量达到90 GB。数据库主要资料来源于1：200 000区域地质调查报告和地质图及矿产图,原始资料时间跨度从20世纪50年代中期到90年代初期。全国1：200 000数字地质图（公开版）空间数据库通过国家级验收,数据完整性、逻辑一致性、位置精度、属性精度、接缝精度均符合中国地质调查局制定的有关技术规定和标准的要求,质量优良可靠。全国1：200 000数字地质图空间数据库是国家空间数据的重要组成部分,为国民经济信息化提供数字化空间平台,为国家和省级各部门进行区域规划、地质灾害监测、地质调查、找矿勘查、宏观决策等提供信息服务。     

孙吴-嘉荫盆地白垩系淘淇河组-太平林场组砂岩主量元素的地球化学特征

沉积盆地中砂岩的地球化学特征主要受物源区控制,碎屑岩的地球化学成分可揭示沉积物的地质信息.笔者通过对孙吴-嘉荫盆地白垩系淘淇河组-太平林场组砂岩的主量元素地球化学特征分析,结合砂岩薄片碎屑成分统计表明:淘淇河组-太平林场组时期物源区的大地构造背景主要为活动大陆边缘,包括大陆岛弧和大洋岛弧.物源区母岩类型主要为花岗岩,中酸性火山岩及低级变质岩.盆地不同位置物源区的大地构造背景和母岩类型有所不同.结合区域地质资料综合分析认为:在淘淇河组-太平林场组沉积时期,小兴安岭仅在太平林场组时期不是盆地主要物源区,而佳木斯地块一直是盆地东部的一个主要物源区.     

Short-period oscillations in outgoing longwave radiation over the summer monsoon region

Empirical orthogonal function (EOF) analysis is applied to daily outgoing longwave radiation (OLR) data to identify the major modes of oscillation over the summer monsoon region (7·5° N-32·5° N, 62·5° E-142·5° E) for two summers 1975 and 1977, each consisting of 120 days from 18 May through 14 September. Power spectrum analysis of time-dependent coefficients of the dominant eigenvectors exhibit spectral peaks in the long (<15 days) and short (4–8 days) period ranges. A detailed study is confined to 4–8 day filtered OLR perturbations. Standard deviation patterns of filtered OLR show large intraseasonal variability in the activity of monsoon disturbances over the Bay of Bengal. Lag-correlations reveal systematic westward movement of 4–8 day OLR perturbations from the Western Pacific to the Bay of Bengal in both summers. EOF analysis is also applied to 4–8 day filtered OLR data to further investigate possible teleconnections in disturbance activity between the Western Pacific and the Bay of Bengal. A compositing technique is utilized to detail the structural features (zonal wavelength and phase speed) of 4–8 day OLR disturbances. Composite diagrams for summer 1975 showed that OLR disturbances which originated near northeastern Burma moved west ward with phase speed (wavelength) of about 3–4° per day (≈20–25° longitude) reaching maximum intensity in the Bay of Bengal. In summer 1977, the disturbance activity in the Bay of Bengal was associated with OLR perturbations which originated in the Western Pacific and moved westward across the South China Sea and Indochina with phase speed (wavelength) of above 8° per day (40° longitude).     

Environmental-economic evaluation of the filling and reclamation process in the bay of Santander,Spain

The historical development of a process of reclamation of intertidal areas in an estuary has been quantitatively studied by means of old engravings, maps, navagation charts, and aerial photographs. These show that about 83 percent of the natural coastline of the estuary has disappeared, nearly two-thirds of its intertidal area has been covered, and over 40 percent of its volume has been lost. The rate of this artificial process is several tens of times faster than that of the natural sedimentation. Extrapolation of the observed trends shows that, if these continue, the intertidal areas would disappear completely in 31 to 105 years. Theoretical calculations based on comparisons with other estuaries show that the accumulated loss in the productivity of living matter (in the form of primary producers), since the process started about 140 years ago, could reach 1.5·10¹⁰ kg. This could represent, considering several possible food chains, the equivalent of the food necessary to sustain several thousand people for life. An economic analysis of the impact of the process has been made by considering, first, the decrease in fish and shellfish catches in the bay (using historical data and data about present clam productivity) and the decrease in its aesthetic quality and recreational potential. These were determined by means of interviews with the population to obtain a “demand curve” for the willingness to pay for the preservation and use of the bay. Second, the price of the man-made land obtained was considered. The data obtained show that the economic losses would offset the benefits within 10 to 30 years.     

利用重力异常反演马里亚纳海沟海底地形

针对利用船舶测量海底地形效率低和成本高的缺点,选取西太平洋板块俯冲菲律宾板块而形成的马里亚纳海沟所在海域作为实验区域,依据重力地质方法（GGM）,利用重力异常数据反演海底地形。采用移去恢复技术确定了重力地质法模型的密度差异常数为2.32 g/cm³。分析比较了GGM海深模型、ETOPO1模型和直接将船测点海深数据格网化（模型1）3种海深模型之间的差异,并依据反演结果对"挑战者深渊"两侧地貌进行了研究。结果表明：GGM模型反演海底地形的结果优于ETOPO1模型,更优于将船测点海深数据直接格网化的结果;模型相对误差与海深的关系不大,受海底地形变化影响明显;在船测数据匮乏或者过于稀疏的海域,模型间海深差值结果较大;"挑战者深渊"海沟两侧的地貌有明显差异,在海沟南侧水深小于5 000 m的浅海部分,坡度平缓（2°~5°）,而在水深大于5 000 m的部分,坡度明显增大（10°~15°）;海沟北侧在整个下降阶段坡度很大（10°~15°）,11°45'N附近出现一个缓冲地带。     

Fractionation of carbon and oxygen isotopes and magnesium between coexisting metamorphic calcite and dolomite

Fractionations of carbon and oxygen isotopes and magnesium between coexisting dolomite and calcite have been determined for marbles and calcareous schists of a wide variety of metamorphic environments from Vermont and the Grenville Province of Ontario. Concordant equilibrium fractionations are given by 83% of the samples. Calibration of the isotopic thermometers using the Mg-calcite solvus thermometer gave in the temperature range: 650°>T°>100°C $$ \begin{gathered} 1,000\ln \alpha _{D - Ct}^{O^{18} } = 0.45 (10^6 T^{ - 2} ) - 0.40 \hfill \\ 1,000\ln \alpha _{D - Ct}^{O^{18} } = 0.18 (10^6 T^{ - 2} ) + 0.17. \hfill \\ \end{gathered} $$ These isotopic fractionation expressions differ significantly from the experimentally derived relations, including the dolomite-Mg-calcite C¹³ partial exchange experiments of this study. Temperature ranges obtained for the metamorphic zones of Vermont are: chlorite zone, 210° to 295° C; biotite zone, 255° to 400° C; staurolite-kyanite zone, 110° to 550° C. In amphibolite-facies rocks the quenched partition relations can be complex. The temperature of quench or recrystallization may be as large as 400° C below the inferred metamorphic maximum. Oxygen isotope disequilibrium in high grade rocks, particularly from the Chester dome area, Vermont, is characterized by large negative δO _D ¹⁸ –δO _Ct ¹⁸ values. The size of the equilibrium exchange system for carbon and oxygen isotopes and magnesium is small, less than a few inches across the inferred relict bedding. This is attributed to the lack of a mobile pore fluid except in systems undergoing decarbonation. C¹³/C¹² ratios in Grenville and Vermont marbles and O¹⁸/O¹⁶ ratios in Grenville and greenschist-facies Vermont carbonates span the range of ancient limestones. Staurolite-kyanite zone calcareous schists and marbles from the Chester dome area, Vermont are depleted in O¹⁸(δO¹⁸=12 to 20‰) due to equilibrium or disequilibrium decarbonation and some partial exchange. Extrapolation of the dolomite-calcite fractionation expressions to 20° C indicates that dolomite is enriched in O¹⁸ by about 4.9‰ and in C¹³ by about 2.4‰.     

煤田资料的铀矿二次开发技术及其找矿意义——以二连盆地ZS煤田铀矿点的发现为例

在中国北方主要盆地铀矿地质调查工作中,煤田自然伽马异常作为主要矿化信息和找矿线索,为一系列铀矿床(点)的快速发现奠定了坚实基础。为进一步提高煤田资料铀矿二次开发的高效性和准确性,运用水成铀矿理论,以中国二连盆地ZS煤矿区典型铀矿点的发现为例,初步探讨了煤田资料的铀矿二次开发技术,提出了"异常筛选与选区分析、原位验证与环境判别、等时地层格架建立与沉积体系分析、综合分析与靶区定位"四位一体的煤矿区铀矿地质调查模式。这对中国北方含煤盆地铀矿地质调查工作提供了新的找矿思路和技术路线,具有较重要的指导意义。     

Sources and history of PAHs in lake sediments from oil-producing and industrial areas,northeast China

Abundance, sources, and historical records of polycyclic aromatic hydrocarbons (PAHs) in sediment cores of three lakes located in northeast China were evaluated. One lake was located in a rural oil field area, one in an industrial urban oil field area, and the third in an urban industrialized area without oil field influence. Cores from each lake were divided into 1-cm sections, dated using ¹³⁷Cs techniques, and 16 priority PAH compounds were measured. Total PAH concentrations were greater in industrial areas than in rural area, regardless of associated oil production. Only petroleum sources of PAHs were identified in lakes near oil fields between 1950s and 1980s, while sources of liquid fossil fuel combustion were persistently identified in the industrial urban lake. From 1990s to 2000s, PAH concentrations, especially high molecular weight PAHs, significantly increased in all lakes, which were consistent with the economic development in China, suggesting a change in energy use from wood burning and petroleum (oil) to liquid fossil fuel combustion. Environmental risk was low to moderate in sediments of the three lakes studied, and increases in high molecular weight PAHs during 1900s–2000s is a concern.     

Structural and tectonic interpretation of geophysical data along the Eastern Continental Margin of India with special reference to the deep water petroliferous basins

The study area encompasses the Eastern Continental Margin of India (ECMI) and the adjoining deep water areas of Bay of Bengal. The region has evolved through multiple phases of tectonic activity and fed by abundant supply of sediments brought by prominent river systems of the Indian shield. Detailed analysis of total field magnetic and satellite-derived gravity data along with multi channel seismic reflection sections is carried out to decipher major tectonic features, basement structure, and the results have been interpreted in terms of basin configuration and play types for different deep water basins along the ECMI. Interpretation of various image enhanced gravity and magnetic anomaly maps suggest that in general, the ENE–WSW trending faults dominate the structural configuration at the margin. These maps also exhibit a clear density transition from the region of attenuated continental crust/proto oceanic crust to oceanic crust based on which the Continent Ocean Boundary (COB) has been demarcated along the margin. Basement depths estimated from magnetic data indicate that the values range from 1 to 12 km below sea level and deepen towards the Bengal Fan in the north and reveal horst–graben features related to rifting. A comparison of basement depths derived from seismic data indicates that in general, the basement trends and depths are comparable in Cauvery and Krishna–Godavari basins, whereas, in the Mahanadi basin, basement structure over the 85°E ridge is clearly revealed in seismic data. Further, eight multichannel seismic sections across different basins of the margin presented here reveal fault pattern, rift geometries and depositional trends related to canyon fills and channel–levee systems and provide a basic framework for future petroleum in this under explored frontier.     

The stratigraphic implications of long‐term terrace agriculture in dynamic landscapes: Polycyclic terracing from Kythera Island,Greece

Geoarchaeological work in conjunction with the Kythera Island Project indicates that significant portions of the island are now or have at some time been terraced. Geoarchaeological observations and local historical records confirm extensive terracing during the last few centuries. Detailed stratigraphic, soil, and sediment analysis along with radiocarbon dating suggest, however, that some of the slopes and small drainages of the island were terraced more than once and that this relatively recent phase of terracing followed earlier efforts, some dating to the early second millennium B.C. (Bronze Age). During each phase of slope organization significant amounts of soil were moved locally on the slopes. Polycyclic terracing has, therefore, interesting implications for surface survey visibility, preservation of archaeological record, early agricultural landscapes and soils, and past land use, as well as for interpretation of local records of Holocene sediment mobilization and valley alluviation. Geoarchaeological investigation of terraces may reveal unique archaeological information not available in urban or village dwelling sites. Early features, such as those reported in this paper, however, usually remain hidden due to the remarkable lack of stratigraphic investigations of non‐site landscapes. © 2008 Wiley Periodicals, Inc.