Curie Point Depth Investigation of Central Anatolia,Turkey

The residual aeromagnetic total field intensity anomalies in central Anatolia were calculated from the regional aeromagnetic anomalies surveyed by the Mineral Research and Exploration (MTA) of Turkey. The residual aeromagnetic data were analyzed to produce Curie point estimates by the method of OKUBO et al. (1985). The Curie point depth of central Anatolia varies from 7.9 km and 22.6 km. The shallowest Curie point depths were observed around the Cappadocia and Erciyes Volcanic complexes in central Anatolia. A good correlation was deduced between the Curie point depths and the heat-flow data measured previously, which is most certainly important for the geothermal resources of the region. The shallow Curie point depths also correlate well with the hot spring locations in central Anatolia.     

Computational properties of a new horizontal staggered grid

On variable configuration in the horizontal direction, Winninghoff[1] had some discussions in the 1960s. Subsequently, according to the thoughts of Winning- hoff, Liu Yudi[2―9] has widely and deeply studied al- most all the existing horizontal grids from the fre- quency and group velocity of inertia gravity and Rossby waves. Results show that although Arakawa C grid is the best one among all existing horizontal grids, it also has some shortcomings. For example, there is still an “average…     

A comparison of plastic and plankton in the north Pacific central gyre

The potential for ingestion of plastic particles by open ocean filter feeders was assessed by measuring the relative abundance and mass of neustonic plastic and zooplankton in surface waters under the central atmospheric high-pressure cells of the North Pacific Ocean. Neuston samples were collected at 11 random sites, using a manta trawl lined with 333 u mesh. The abundance and mass of neustonic plastic was the largest recorded anywhere in the Pacific Ocean at 334 271 pieces km² and 5114 g km², respectively. Plankton abundance was approximately five times higher than that of plastic, but the mass of plastic was approximately six times that of plankton. The most frequently sampled types of identifiable plastic were thin films, polypropylene/monofilament line and unidentified plastic, most of which were miscellaneous fragments. Cumulatively, these three types accounted for 98% of the total number of plastic pieces.     

Determination of the three-dimensional seismic structure of the crust and upper mantle in the Central Midlands of England

Summary. Teleseismic P -wave residuals relative to CWF, a permanent shortperiod seismic station on Charnwood Forest in the Central Midlands of England, have been determined for two small aperture arrays deployed over the Precambrian block of Charnwood and its surrounding Phanerozoic sediments. The data have been inverted to produce a block model of the P -wave velocity variations in the crust and upper mantle beneath the study region. The results are consistent with significant variations penetrating to a depth of at least 50 km. Low velocities are associated with two upper crustal intrusive bodies, the Caledonian Mountsorrel granodiorite and the South Leicestershire diorites. A longer-wavelength variation at lower crustal/upper mantle depths could arise from the Moho dipping to the south-west beneath the study region, and whose strike sub-parallels the dominant Charnian trend of the major basement structures in this part of Central England.     

THE UNEVEN DEVELOPMENT AND SPATIAL DIFFUSION OF CHINESE CENTRAL CITIES

ＴＨＥ ＵＮＥＶＥＮ ＤＥＶＥＬＯＰＭＥＮＴ ＡＮＤ ＳＰＡＴＩＡＬ ＤＩＦＦＵＳＩＯＮ ＯＦ ＣＨＩＮＥＳＥ ＣＥＮＴＲＡＬ ＣＩＴＩＥＳ ＮｉｎｇＹｕｅＡｎｎ（宁越敏）；ＹａｎＺｈｏｎｇｍｉｎ（严重敏）（ＴｈｅＩｎｓｔｉｔｕｔｅｏｆＧｅｏｇｒａｐ...     

Zircon U–Pb ages from tuff beds of the upper Mesozoic Tetori Group in the Shokawa district,Gifu Prefecture,central Japan†

Abstract The upper Mesozoic Tetori Group contains numerous fossils of plants and marine and non‐marine animals. The group has the potential to provide key information to improve our understanding of the Middle Jurassic to Early Cretaceous biota of East Asia. However, the depositional age of the Tetori Group remains uncertain, and without good age constraints, accurate correlation with other areas is very difficult. As a first step in obtaining reliable ages for the formations within the Tetori Group, we used laser ablation‐inductively coupled plasma–mass spectrometry to measure the U–Pb ages of zircons collected from tuff beds in the Shokawa district, Takayama City, Gifu Prefecture, central Japan. The youngest reliable U–Pb ages from the tuff beds of the Ushimaru, Mitarai and Okurodani Formations are 130.2 ± 1.7, 129.8 ± 1.0 and 117.5 ± 0.7 Ma, respectively (errors represent 2 SE). These results indicate that the entire Tetori Group in the Shokawa district, which was previously believed to be correlated to the Upper Jurassic to Lower Cretaceous, is in fact correlated to the Lower Cretaceous. The maximum ages of the Ushimaru, Mitarai and Okurodani Formations are late Hauterivian to Barremian, late Hauterivian to Barremian and Barremian to Aptian, respectively.     

Fammenian–Tournaisian dextral ductile shear in the French Variscan belt

The South Armorican Shear Zone consists of a set of faults that runs across the southern Armorican Massif and extends eastwards to the Massif Central. One of its branches, the Cholet Shear Zone of South Brittany, can be correlated with the North-Millevaches–La Courtine Shear Zone in the Massif Central. It was active immediately after the regional Frasnian anatexis (372–368 Ma) as a right-lateral strike-slip fault. The horizontal offset, which can be estimated between 110 and 170 km, was achieved before the emplacement of non-deformed Late Tournaisian calc-alkaline and peraluminous granites (355–350 Ma). This newly established age of activity (Fammenian–Tournaisian) of the Cholet–La Courtine Shear Zone (CCSZ) has to be taken into account in geodynamical reconstructions of the Variscan belt of western Europe. To cite this article: C. Cartannaz et al., C. R. Geoscience 338 (2006).     

反循环中心取样钻探技术在第三系砾岩金勘探中的应用

根据在第三系砾岩金普查勘探过程中钻孔浅、地层情况复杂、取心质量要求高、远离水源、处于低山丘陵区的特点，采用反循环中心取样钻探工艺，针对不同的地层采取不同的钻进技术参数及工艺措施，取得了较好的技术成果及经济效益。     

吉林中部漂河川镁铁-超镁铁质杂岩带的特征：对华北东北缘构造带性质和演化的约束

漂河川镍矿的辉长岩锆石SHRIMPU-Pb定年给出了222Ma±8Ma的年龄,表明其形成于晚三叠世。研究结果表明,该岩体不属于蛇绿岩的成员,而是热侵位的镁铁—超镁铁质岩,侵位时代在区域性的变质变形事件之前。结合地球化学资料、相邻地区的大地构造相及热年代学的研究结果,认为区域上的造山作用主幕很可能发生在中生代,而不是原来认为的二叠纪末。漂河川和相关地区的镁铁—超镁铁质岩应该形成于碰撞造山之前,很可能属于大陆边缘裂谷性质。     

InSAR干涉像对的方位向频谱滤波

干涉图的质量是影响InSAR数据处理结果的重要因素。根据干涉图中噪声的不同来源,重点分析了在重复轨道干涉测量模式下,主辅影像多普勒中心频率不一致的成因及其对干涉图的影响。利用SAR影像方位向频谱的特点,在影像上检测得到了多普勒中心频率。并推导了方位向频谱预滤波函数的具体形式。针对ERS数据的实验证明:文中的算法能有效消除主辅影像方位向频谱包络的差异,提高干涉像对的相干性,改善干涉图质量。