Petrogenesis of the ü?kap?l? Granitoid and its Mafic Enclaves in Elmal? Area (Ni?de, Central Anatolia, Turkey)

The Late Cretaceous ükapili Granitoid including mafic microgranular enclaves intruded into metapelitic and metabasic rocks, and overlain unconformably by Neogene ignimbrites in the Ni de area of Turkey. It is mostly granite and minor granodiorite in composition, whereas its enclaves are dominantly gabbro with a few diorites in composition. The ükapili Granitoid is composed mainly of quartz, K-feldspar, plagioclase, biotite, muscovite and minor amphibole while its enclaves contain mostly plagioclase, amphibole, minor pyroxene and biotite. The ükapili Granitoid has calcalkaline and peraluminous (A/CNK= 1.0-1.3) geochemical characteristics. It is characterized by high LILE/HFSE and LREE/HREE ratios ((La/Lu) N = 3-33), and has negative Ba, Ta, Nb and Eu anomalies, resembling those of collision granitoids. The ükapili Granitoid has relatively high 87Sr/86Sr (i) ratios (0.711189-0.716061) and low εNd (t) values (-5.13 to -7.13), confirming crustal melting. In contrast, the enclaves are tholeiitic and metaluminous, and slightly enriched in LILEs (K, Rb) and Th, and have negative Ta, Nb and Ti anomalies; propose that they were derived from a subduction-modified mantle source. Based on mineral and whole rock chemistry data, the ükapili granitoid is H-(hybrid) type, post-collision granitoid developed by mixing/mingling processes between crustal melts and mantle-derived mafic magmas.     

BOOK REVIEWS

Book Reviews in are this Article Northern Waters . Clive Archer and David Scivener , EDS. Principles of Geographical Information Systems for Land Resources Assessment . P. A. Burrough . The Great Lakes: An Environmental Atlas and Resource Book. Environment Canada , United States Environmental Protection Agency , Brock University , AND Northwestern University . Uneven Development in Southern Europe: Studies of Accumulation, Class, Migration and the State. Rays Hudson AND Jim Lewis , EDS. Hazards: Technology and Fairness. Robert W. Kates and Alvin M. Weinberg . The Price of War. Urbanization in Vietnam 1954–85. Nigel Thrift and Dean Forbes . Population Structures and Models: Developments in Spatial Demography. Robert Woods and Philip Rees , EDS. Evaluating Earthquake Hazards in the Los Angeles Region-An Earth-Science Perspective. J. I. Ziony , ed .     

Effects of changing land use on the microbial water quality of tidal creeks

Population growth along the southeastern United States coast has precipitated the conversion of forested watersheds to suburban and urban ones. This study sampled creeks representing forested, suburban, and urban watersheds along a longitudinal gradient for indicators of water quality, including traditional indicator bacteria (fecal coliforms and enterococci) and alternative viral indicators (male-specific and somatic coliphages). Tested microorganisms were generally distributed with highest concentrations in creek headwaters and in more developed watersheds. The headwaters also showed the strongest predictive relationship between indicator concentrations and urbanization as measured by impervious cover. A seasonal pattern was observed for indicator bacteria but not for indicator viruses. Coliphage typing indicated the likely source of contamination was nonhuman. Results suggest that headwater creeks can serve as sentinel habitat, signaling early warning of public health concerns from land-based anthropogenic activities. This study also implies the potential to eventually forecast indicator concentrations under land use change scenarios.     

The Stanley unconformity in Lake Huron basin: evidence for a climate-driven closed lowstand about 7900 <Superscript>14</Superscript>C BP,with similar implications for the Chippewa lowstand in Lake Michigan basin

J.L. Hough in 1962 recognized an erosional unconformity in the upper section of early postglacial lake sediments in northwestern Lake Huron. Low-level Lake Stanley was defined at 70 m below present water surface on the basis of this observation, and was inferred to follow the Main Algonquin highstand and Post-Algonquin lake phases about 10 ¹⁴C ka, a seminal contribution to the understanding of Great Lakes history. Lake Stanley was thought to have overflowed from the Huron basin through the Georgian Bay basin and the glacio-isostatically depressed North Bay outlet to Ottawa and St. Lawrence rivers. For this overflow to have occurred, Hough assumed that post-Algonquin glacial rebound was delayed until after the Lake Stanley phase. A re-examination of sediment stratigraphy in northwestern Lake Huron using seismic reflection and new core data corroborates the sedimentological evidence of Hough’s Stanley unconformity, but not its inferred chronology or the level of the associated lowstand. Erosion of previously deposited sediment, causing the gap in the sediment sequence down to 70 m present depth, is attributed to wave erosion in the shoreface of the Lake Stanley lowstand. Allowing for non-deposition of muddy sediment in the upper 20 m approximately of water depth as occurs in the present Great Lakes, the inferred water level of the Stanley lowstand is repositioned at 50 m below present in northwestern Lake Huron. The age of this lowstand is about 7.9 ± 0.3¹⁴C ka, determined from the inferred ¹⁴C age of the unconformity by radiocarbon-dated geomagnetic secular variation in six new cores. This relatively young age shows that the lowstand defined by Hough’s Stanley unconformity is the late Lake Stanley phase of the northern Huron basin, youngest of three lowstands following the Algonquin lake phases. Reconstruction of uplift histories for lake level and outlets shows that late Lake Stanley was about 25–30 m below the North Bay outlet, and about 10 m below the sill of the Huron basin. The late Stanley lowstand was hydrologically closed, consistent with independent evidence for dry regional climate at this time. A similar analysis of the Chippewa unconformity shows that the Lake Michigan basin also hosted a hydrologically closed lowstand, late Lake Chippewa. This phase of closed lowstands is new to the geological history of the Great Lakes. This is the ninth in a series of ten papers published in this special issue of Journal of Paleolimnology. These papers were presented at the 47th Annual Meeting of the International Association for Great Lakes Research (2004), held at the University of Waterloo, Waterloo, Ontario, Canada. P.F. Karrow and C.F.M Lewis were guest editors of this special issue.     

EROSION AND SEDIMENTATION PROBLEMS IN SOME ASIAN COUNTRIES

1 INTRODUCTIONFrom 1989 to 1993, as project managers of the UNDP/UNESCO project entitled Regional TrainingProgramme on Erosion and Sedimentation for Asia, the writers had the privilege of meeting manyoutstanding hydraulic engineers of this region and came to learn of some important erosion andsedimentation problems thereof. Some issues as noted by the writers are presented in the followingalong the some comments. These issues are mainly concerned with rivers. It should be stated tha…     

伊兹米特地震发生的构造环境分析

土耳其地震构造具有新生性。东安纳托利亚地震带和北安纳托亚地震带的活动断裂都是晚第三纪以来开始出现、演化和发展的,而土耳其西部地震区的张性断陷盆地出现的时代更晚。土耳其活动构造类型丰富：东部发育压性或压扭性构造;北部为走滑型断裂;西部则是拉张型正断裂;中部为一个构造相对稳定的块体,即安纳托利亚块体。土耳其是研究块体与周缘断裂构造相互关系以及断裂力学相互转换的一个理想场所。北安纳托利亚断裂带是一条典型     

伊兹米特地震地表破裂带和发震构造特点

１９９９年伊慈米特７．４级地震地表破裂带表现清楚。在几何学特点上,它基本上由４个破裂段斜裂组合而成,沿破裂段可见不同的构造组相样式。在破裂段的阶区,主要发育张性构造。破裂段的最在工为５１ｍ,在运动学上,以右旋走滑运动为主,最大位错３．８ｍ‘走滑段最大垂直位错０．６ｍ。向观震中与地表最大位理合,基本上处于破裂带中间地段。地城寺表破裂带的动力学和几何学特征与震源机制解反映出来的结果相一致。     

伊兹米特地震的几点启示

土耳其伊兹米特Ｍｓ７．４地震后,中国地震局于１９９９年８月２５日派出了以张国民教授为团长的由７人组成的赴土耳其地震现场考察专家组。他们到地震现场进行了考察,从该震中得到了几点启示。