Plio-Quaternary evolution of the Küçük Menderes Graben Southwestern Anatolia,Turkey

The Küçük Menderes Graben (KMG) is part of the horst-graben system of southwestern Anatolia (Turkey), bounded by the Bozda? horst in the north and the Ayd?n horst in the south. The Plio-Quaternary evolution of the KMG has been evaluated using the nature of the Miocene-Quaternary fill sediments and palaeostress analysis of slip data measured in different parts of the graben.

The graben is composed of five subbasins—the Kiraz, Ödemi?, Bay?nd?r, Da?k?z?lca-Torbal? and Selçuk—that are connected to each other through narrow Quaternary troughs. The Da?k?z?lca, Kiraz and Selçuk basins bear Miocene and younger sequences whereas the other subbasins are largely filled by Quaternary sediments. The maximum thickness of the Quaternary fill reaches about 270 m in the Ödemi? and Bay?nd?r subbasins.

The calculated slip results indicate multidirectional extension, three successive deformational periods, and possible counterclockwise rotation in the KMG during the post-Miocene period. The first phase was a strike-slip regime under N-S compression, followed by a second phase of deformation which resulted in ENE-WSW extension with strike-slip components. The final phase of deformation was NE-SW extension which constituted the final evolution of the KMG.

The graben gained its present morphological configuration via the onset of E-W-trending, high-angle normal faulting imposed on the regionwide synformal structure during the Plio-Quaternary. The KMG evolved as a result of rifting during the Plio-Quaternary which followed Late Miocene unroofing of the Menderes Massif and the evolution of the Büyük Menderes and Gediz grabens.     

Seismic stratigraphy and depositional history of the Büyükçekmece Bay since Latest Pleistocene,Marmara Sea,Turkey

High-resolution seismic data shed light on latest Pleistocene and Holocene sedimentation beneath the Büyükçekmece Bay, northern shelf area of the Marmara Sea, Turkey. Discontinuous fluvio-marine and marine deposits overlying the erosional truncation surface of Oligocene–Lower Miocene deposits are as thick as 30 m and preserved preferentially within the incised valleys that were controlled by some old faults. A series of prograding shoreline, laterally passing to the latest Pleistocene–Holocene valley-fill deposits, are thought to have accumulated mainly during times of shoreline transgression and sea-level rise. The overall morphology and stratigraphic setting observed in the Büyükçekmece Bay and at the southern outlet of the Bosphorus Strait have nearly same characteristics, implying that similar hydrodynamic conditions, erosional and depositional processes were mainly under the control of strong northerly flows during the Late Quaternary. These flows were less powerful in the Büyükçekmece region with decreased sediment input and smaller accommodation space.     

Spatial Variability of Cr2O3% in the Kizilyüksek-Yataardiç Chromite Deposit,Adana, Turkey

Knowledge of the spatial variability of grade is important for commercial evaluation of mineral deposits. The low-grade, Kizilyuksek-Yataardic chromite deposit in Karsanti, Adana is one of the greatest reserves in western Anatolia, Turkey and offers great potential. However this deposit lacks geologic information needed to provide a better understanding of the spatial variability of Cr₂O₃%. In this paper, geostatistical tools are used to improve the understanding of the vertical variability of Cr₂O₃%. The vertical variability is characterized by an average down-hole variogram from core measurements. The variogram exhibits nested structures at 10, 50, and 100 m. Because geologic information is not adequate to explain the source of these features, geostatistical simulation of Cr₂O₃% with depth is used. The results indicate that the chromite mineralization is characterized by zonal structure, with average size of the zones being 50 m, and average distance between them being 100 m. A study of the most variable holes also shows that these holes have the greatest effect on the average down-hole variogram.     

Effect of Construction Material on Dam Type Selection of the Büyük Karaçay Dam (Hatay, Turkey)

This paper covers the investigation of construction materials and selection of the dam type for the Büyük Karaçay Dam, which was planned to be constructed on Büyük Karaçay River 20 km to the SW of Hatay (Southern Turkey). The purposes of the dam are irrigation, domestic water supply, and producing energy. Auxiliary structures locations have been determined during the study of detailed geological maps of the dam axis and reservoir area. Quality, quantity and hauling distance of natural construction materials were effective to select different dam types. For engineering geological studies exploration boreholes were drilled at the dam site; pressuremeter tests were performed in order to determine bearing capacity and elasticity properties of rocks; pressured water tests were also performed to determine permeability of the dam site. Moreover, physical and mechanical properties of rocks were determined by the laboratory test. In the feasibility stage, the dam type was chosen as the central core rock-fill dam, depending on state of natural construction materials. In design stage dam type was changed as faced symmetrical hardfill dam. Finally, the dam type was revised again during the design stage as concrete face rockfill dam.     

Impacts of climate change on groundwater recharge in Küçük Menderes River Basin in Western Turkey

Groundwater is an important component of the global freshwater supply and is affected by climate. There is a strong need to understand and evaluate the impacts of climate change over the long term, in order to better plan and manage precious groundwater resources. Turkey, located in Mediterranean basin, is threatened by climate change. The purpose of this study was, through a quantitative overview, to determine the impacts of climate change on the groundwater recharge rates in Küçük Menderes River Basin in western Turkey. According to the data of Ödemi? and Selçuk meteorological stations located in the basin, there is a significantly decreasing trend in precipitation combined with increasing trends in temperature and evaporation observed in 1964–2011. The calculations of groundwater recharge with hydrologic budget method for the observation period showed an approximately 15% decline in groundwater recharge in the basin. Thus, the combined impacts of climate change and excessive groundwater pumping, due to increasing water demand, have caused a significant decline in groundwater levels. Consequently, the proper management of the groundwater resources threatened by climate change requires effective governance to both mitigate the adverse impacts of climate change and facilitate the adaptation of sustainable integrated water management policies.     

A combined polarizing microscope,XRD, SEM,and specific gravity study of the petrified woods of volcanic origin from the Çamlıdere-Çeltikçi-Güdül fossil forest,in Ankara,Turkey

The fossil forest in the Çaml?dere-Çeltikçi-Güdül region of the province of Ankara in Turkey has a large number of petrified coniferous and oak tree remains. Petrification occurred in volcanic ashes and tuffs with permineralization, and Fe, Mg, Ca and Ni ions played important roles in the substitution of Si for C. However, the petrified wood samples are heterogeneous in colouration, weight, toughness, and durability, despite being obtained from the same source. Those features are very important for end-users because petrified woods, if cut and polished, are used widely as both decorative indoor tiles and gemstone objects, but heterogeneous materials suffer large wastage while they are being worked and used.Chemical analyses, specific gravity measurements, polarizing microscope studies, X-ray diffraction patterns, and scanning electron image evaluations were performed to classify and identify the homogenous material of the petrified woods relating to its physical and mineralogical characteristics.The different characteristics of the petrified wood samples are due to their varying inner structures, which depend on the replacement silica-building phases and their ratios, and silica particle sizes. Thin sections and XRD patterns revealed that petrified woods in the region were silicified by replacement with both chalcedonic quartz components, including chalcedony (length-fast quartz), moganite and orthorhombic-silica (length-slow quartz), and opalline quartz components including opal-CT and opal-C (length-slow quartz). The scanning electron microscope images were shown that the internal structures of the petrified woods consist of mostly submicron-sized (100–800 nm), and partially nano-sized (60–120 nm) silica-building particles.So, the petrified wood samples can be firstly classified into five main-groups based on their colourations and specific gravity values, then, into three sub-groups based on the principal chalcedonic and opalline quartz silica-building phases and related particle sizes, and also weighing, toughness, and durability. In the first group (samples 1, 2, and 3), the crystallinity gradation of the petrified woods can be classified as quasi-coarse crystalline because they include mainly chalcedony and moganite phases with 800–200 nm ranging in particle size. They are heavy, tough, and resistance as a material, as shown by specific gravity values of 2.60, 2.56, and 2.54, respectively. In the second group (sample 4), the crystallinity gradation of the petrified wood can be classified as quasi-fine crystalline because it includes mainly o-silica and moganite phases with 400–100 nm ranging in particle size. It is medium-heavy, semi-tough and quasi-resistance as a material, as shown by a specific gravity value of 2.42. In the third group (sample 5), the crystallinity gradation of the petrified wood can be classified as quasi-nano-crystalline because it includes mainly opal-CT and opal-C phases with 120–60 nm ranging in particle size. The material is slight, brittle, and weak as a material, as shown by a specific gravity value of 2.18.Ultimately, in the petrified wood found in the Çaml?dere-Çeltikçi-Güdül region of Ankara province in Turkey, it is revealed that samples 1, 2, and 3 represent flint and chalcedony quartz mineral species, samples 4 and 5 represent chalcedony and opal quartz mineral species.     

Settlement Analysis of Açu Dam,Brazil

Geotechnical and Geological Engineering - The Armando Ribeiro Gonçalves Dam, popularly known as The Açu Dam, is an important geotechnical construction in Rio Grande do Norte state,...     

Diatomaceous Earth in Shanwang,Liuchü,Shantung

Ⅰ.INTRODUCTION Diatomaceous earth is known to occur in the vicinity of Shanwang,(Long.118°34'E,Lat.36°32'N)Linchü district,Shantung.The sitewhich has furnished the material discussed in this report,lies 2 li and     

Erzmikroskopische Beobachtungen an natürlich erhitzten,insbesondere pseudobrookitführenden Vulkaniten

Ohne ZusammenfassungMeinem hochverehrten Lehrer, Herrn Professor Dr.Paul Ramdohr, zum 65. Geburtstag gewidmet.     

Age and Chemistry of Miocene Volcanic. Rocks from the Kiraz Basin of the Küçük Menderes Graben: Its Significance for the Extensional Tectonics of Southwestern Anatolia,Turkey'

Neogene volcanic rocks and granitoid plutons are among the most important geological components of western Turkey. Although they are voluminous north of the Gediz Graben, they are very scarce to the south, where volcanic rocks occur as isolated small exposures in a small number of localities. The Kiraz Basin of the Küçük Menderes Graben is a key locality, in which Tertiary volcanic rocks crop out at three locations. These rocks have been chemically analysed and dated (³⁹Ar-⁴⁰Ar whole rock and biotite analyses) in order to understand their tectonic setting of emplacement and its relation to the wider structure of western Anatolia. Whole rock and biotite ³⁹Ar-⁴⁰Ar ages vary between 13.9 ± 0.2 Ma and 14.6 ± 0.2 Ma.

The Kiraz volcanic rocks are calc-alkaline, with a compositional range from basaltic andesite to dacite. They are strongly enriched in the light ion lithophile elements (LILE) and have chemistries typical of lavas erupted in subduction-related settings. Their close association with rift-bounding faults suggests eruptions via conduits flanking grabens in an extensional environment. The difference in chemical composition and age between the Kiraz volcanic rocks and the slightly older calc-alkaline volcanic rocks north of the Gediz Graben is attributed to their relatively younger ages and greater proximity to the Aegean Arc. Their calc-alkaline chemistry reflects magma generation influenced by the slab descending beneath this arc and eruption/emplacement in an extensional setting.     

Mineral chemical investigation on sulfide mineralization of the Istala deposit,Gümüşhane,NE-Turkey

The mineralogy of the Istala deposit, Gümüşhane, northeastern Turkey, was studied in detail, and a geochemical investigation was carried out using electron probe micro-analysis (EPMA). Sphalerite, galena, chalcopyrite and pyrite are the major sulfide minerals found in the Istala deposit, with minor amounts of bornite, idaite, tetrahedrite–tennantite, anilite, yarrowite, mckinstryite, covellite and chalcocite. In addition to these, barite and a small quantity of quartz occur as gangue minerals. Based on the textural relations and mineral assemblages, five different stages of crystallization have been recognized. Mineral paragenesis of the first four stages has been found to be similar, whereas clear enrichment has been observed in the modal abundance of the copper sulfide mineral assemblage at the fifth-stage ore formation. Whole-rock geochemical analyses of the Istala ore show an enrichment of Ag content up to 3328 ppm. Optical observations and EPMA study indicated that abundant silver mineralization was found in the Istala ore, especially during the later-stage ore deposition. Repetition to the presence of native silver in the samples, a significant amount of silver was incorporated in bornite, idaite, tetrahedrite–tennantite, anilite, yarrowite, mckinstryite, covellite and chalcocite, whereas a trace amount of silver has been detected in sphalerite, galena, chalcopyrite and pyrite. The homogenization temperatures (T_h) of the primary fluid inclusions were measured between 98 and 284 °C, with frequency peaks around 140 °C, 190 °C and 240 °C. All data obtained support the theory that later stage copper-rich sulfides, formed under the low temperature conditions, are responsible for the large amounts of silver content in the Istala mine.     

Late Quaternary evolution of the Gediz and Büyük Menderes grabens,Western Anatolia,Turkey

The Gediz and the Büyük Menderes Graben basins, two of the most important structural elements of western Anatolia, markedly differ in their palaeogeographic evolution during the Holocene. On the basis of the study of the facies and the geomorphological characteristics of the youngest sedimentary fills it is suggested that the evolution of the Büyük Menderes basin has a simple progradational history while the Gediz River basin has shown a complex evolution mainly controlled by intense tectonic periods. Comparison between the palaeogeographic evolution of these basins points to the fact that tectonism has been more effective in the Gediz basin during the Holocene.     

Die Goldfelder von Ondundu,Südwestafrika

Zusammenfassung Bei Ondundu (Südwestafrika) sind Quarzlagergänge und Serien solcher erschlossen worden, die, von Quergängen aus durch Abfolgen des alten Granits gespeist, im frühen Faltungsvorgang zwischen die aufgeblätterten Damaraschichten lit par lit intrudiert worden sind und am weiteren Faltungsverlauf teilnahmen.Obwohl diese Lagergänge nur geringe Mächtigkeit besitzen, lassen ihre serienweise Häufung mit nur wenig Schieferzwischenmittel, ihr Durchhalten auf weite Erstreckungen hin und ihr verhältnismäßig hoher Goldgehalt von 10–15 g per Tonne Ganggestein einen gewinnbringenden Bergbau in kleinem Ausmaß möglich werden.     

Instability analyses of Merhülietsa slide, Kohima, Nagaland

Part of Merhülietsa colony of Kohima town and the national highway passing through it was devastated by a landslide on May 13, 2007. This unstable zone affected by rotational failure lies in the Disang sediments comprising shale with intercalations between thin-bedded siltstone and fine-grained sandstone. The shales are sheared, crumpled, and weathered to a high degree. This is attributed to a strike-slip fault and two shear fractures. Geotechnical analysis was carried out in the area and a factor of safety of 0.60 obtained for the slide mass. Similar work is extended to the surrounding area which had developed tension fractures. A slip circle drawn from tension cracks helps define future failure planes. A factor of safety of 0.93 is obtained indicating the possibility of progression of the slide zone. Rock mass rating of the shales surrounding the slide zone indicates poor rock condition, pointing to danger of collapse with further progression of the slide zone.     

Tertiary Volcanic and Tectonic Evolution of the Ayas-Güdül-Celtikci Region,Turkey

Volcanic activity in the Ayas-Güdül-Celtikci region began by Oligocene (?)-early Miocene time and persisted until the end of early Pliocene time. It commenced with andesitic breccias and lavas at the base of the series and evolved through the deposition of ignimbritic and laharic volcanic material toward intermediate levels of the succession. Caldera formation followed this period of volcanic activity. Ephemeral lakes covering the region caused the subaqueous extrusion of the latest lavas during this period of activity. Afterward, limnic and fluvial sedimentation Occurred in the region during a period of volcanic quiescence. This mid-late Miocene deposition was followed by new basaltic activity. The volcanism was controlled by conjugate fault sets, N45W and N15E, representing pure-shear stress in a N20W direction, from the late Oligocene to the end of the early Pliocene. Normal dip-slip faults having a N55E trend were created by local N25W tension, presumably because of the North Anatolian fault, after early Pliocene time.     

Differentiation im Chagnon-Orford-Intrusiv-Komplex,Südostteil der Provinz Quebec,Kanada

Zusammenfassung Der Chagnon-Orford-Intrusiv-Komplex ist durch einen zweifachen Zonarbau gekennzeichnet: einmal ein ausgedehnter Zonarbau mit Ultrabasiten in den tieferen Lagen und einer Folge saurerer Differentiationsprodukte in den dachnahen Gebieten des Lakkolithen; zum anderen ein regelmäßiger Wechselrhythmus von Peridotit- und Pyroxenitstreifen in den unteren Partien des Intrusivs. Der Autor ist der Meinung, daß die deutlich in Erscheinung tretende zonale Anordnung der Gesteine im Chagnon-Orford-Lakkolith auf eine gravitative Differentiation in situ zurückzuführen ist.

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The Chagnon-Orford Intrusive Complex is characterized by two types of banding: first, a large-scale zoning consisting of ultrabasic rocks at the bottom overlain by belts of successively more acid differentiates at the roof of the laccolith; secondly, a rhythmic banding near the floor of the intrusive, consisting of alternating peridotite and pyroxenite layers. The writer is of the opinion that the zonal arrangement of the Chagnon-Orford laccolith is the result of differentiation in situ under the influence of gravity.

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Résumé Le complexe intrusif de Chagon-Orford se caractérise par une structure zonaire double: une structure zonaire avec ultrabasites dans les parties profondes et une série de produits de différenciation plus acides dans la partie du laccolite proche du toit; d'autre part, un ensemble à disposition rythmique régulière formé de lits de péridotite et de pyroxénite se trouve dans la partie inférieure de l'intrusion. L'auteur est d'avis que la disposition zonaire des roches dans le laccolite de Chagnon-Orford est à rapporter à une différenciation in situ par gravité.

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Chagnon-Orford - . , .