The metamorphism and exhumation of the Himalayan metamorphic core, eastern Garhwal region, India

[1] Geothermobarometric together with micro- and macro-structural data indicate ductile flow in the metamorphic core of the Himalaya in the Garhwal region of India. Peak metamorphic pressure and temperature increase dramatically across the Main Central Thrust (MCT) from ~5 kbar and ~550°C in the Lesser Himalayan Crystalline Sequence (LHCS) to ~14 kbar and ~850°C at ~3 km above the MCT in the Greater Himalayan Sequence (GHS). Pressures within the GHS then decrease upsection to ~8 kbar while temperatures remain nearly constant at ~850°C up to the structurally overlying South Tibetan Detachment (STD). The GHS exhibits sheath fold geometries are indicative of high degrees of ductile flow. Overprinting ductile structures are two populations of extensional conjugate fractures and normal faults oriented both parallel and perpendicular to the orogen. These fractures crosscut major tectonic boundaries in the region such as the MCT and STD, and are found throughout the LHCS, GHS, and Tethyan Sedimentary Sequence (TSS). The thermobarometric and metamorphic observations are consistent with a form of channel flow. However, channel flow does not account for exhumational structures that formed above the brittle-ductile transition. To explain all of the features seen in the metamorphic core of the Garhwal region of the Himalaya, both the theories of channel flow and critical taper must be taken into account. Channel flow can explain the exhumation of the GHS from the middle crust to the brittle-ductile transition. The most recent extensional deformation is consistent with a supercritical wedge

Normal faulting sequence in the Pumqu-Xainza Rift constrained by InSAR and teleseismic body-wave seismology

Normal faulting earthquakes play an important role in the deformation of continents, and pose significant seismic hazard, yet important questions remain about their mechanics. We use InSAR and body-wave seismology to compute dislocation models and centroid moment solutions for four normal-faulting earthquakes (Mw 5.7–6.2) that occurred in the Pumqu-Xainza Rift (PXR), southern Tibet, a region where low-angle normal faulting has previously been inferred. We also use the fault locations and slip to investigate the correlation between earthquakes and surface topography, and to calculate stress interactions between the earthquakes. The InSAR and body-wave models give consistent focal mechanisms except for the magnitude of the 1996 event, which may be overestimated due to postseismic deformation in the long-interval interferograms. We calculate the static stress changes due to coseismic slip and find that the 1993 event was too distant to cause triggering of the later events, but that the 1998 event pair occurred in regions of increased Coulomb stress resulting from the 1996 event. All the fault planes found here dip at 40–60°, reinforcing the absence in observations for low-angle normal faulting earthquakes (dip < 30°) whose focal planes can be determined unambiguously. The fault planes of the 1993 and 1996 events are not associated with any obvious surface geomorphology, suggesting that sometimes it is unreliable to resolve the focal plane ambiguity by geomorphology, even for Mw 6.2 events. Furthermore, these events occurred outside the center of the rift, indicating that the active faulting is more distributed and over a length-scale at least 25–50 km east-west in extent, rather than confined to the 20 km width seen in the current mapped faulting and topography. These results suggest that seismic hazard in other extensional zones worldwide might also be more broadly distributed than suggested by geomorphology

Quaternary uplift rates of the Central Anatolian Plateau, Turkey: insights from cosmogenic isochron-burial nuclide dating of the Kızılırmak River terraces

The Central Anatolian Plateau (CAP) in Turkey is a relatively small plateau (300 × 400 km) with moderate average elevations of ∼1 km situated between the Pontide and Tauride orogenic mountain belts. Kızılırmak, which is the longest river (1355 km) within the borders of Turkey, flows within the CAP and slowly incises into lacustrine and volcaniclastic units before finally reaching the Black Sea. We dated the Cappadocia section of the Kızılırmak terraces in the CAP by using cosmogenic burial and isochron-burial dating methods with 10Be and 26Al as their absolute dating can provide insight into long-term incision rates, uplift and climatic changes. Terraces at 13, 20, 75 and 100 m above the current river indicate an average incision rate of 0.051 ± 0.01 mm/yr (51 ± 1 m/Ma) since ∼1.9 Ma. Using the base of a basalt fill above the modern course of the Kızılırmak, we also calculated 0.05–0.06 mm/yr mean incision and hence rock uplift rate for the last 2 Ma. Although this rate might be underestimated due to normal faulting along the valley sides, it perfectly matches our results obtained from the Kızılırmak terraces. Although up to 5–10 times slower, the Quaternary uplift of the CAP is closely related to the uplift of the northern and southern plateau margins respectively

Possibilities of using bacteriophages for biological control of tomato bacterial speck disease (Pseudomonas syringae pv. tomato).

TEZ10523Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 2017.Kaynakça (s. 49-54) var.xiv, 88 s. : res. (bzs. rnk.), tablo ; 29 cm.Domates (Solanum lycopersicum L.), dünyada en fazla üretimi yapılan sebzedir. Pseudomonas syringae pv. tomato (Pst) adlı bakteri domateste bakteriyel benek hastalığına neden olmaktadır. Bu hastalığın mücadelesinde farklı yöntemler araştırılmaktadır. Bu yöntemlerden biri de bakteriyofajların kullanımıdır. Bakteriyofajlar, bakterilerin doğal düşmanlarıdır, bakteriler dışında hiçbir canlıyı öldürmezler. Bu çalışmada Pst’yi eriten bakteriyofajların izolasyonu ve Pst’nin biyolojik mücadelesinde bakteriyofajların potansiyel kullanım olanakları araştırılmıştır. Bu kapsamda, Adana ve Mersin illerinde 17 tarla, 12 sera ve 4 ticari fidelikten bakteriyel benek hastalığı belirtisi gösteren bitki örnekleri toplanmıştır. NYGA (Nutrient Yeast Glycerol Agar) besi yeri kullanılarak bitki örneklerinden Pst’yi eriten bakteriyofaj izolasyonu gerçekleştirilmiştir. Petrilerin 27oC’de 36 saat inkübasyonundan sonra plak (inhibisyon alanı) oluşumları gözlenmiş ve 47 adet bakteriyofaj saflaştırılmıştır. Elde edilen bakteriyofajlar içerisinde CMN 33 kodlu bakteriyofajın tohum kökenli hastalığı tamamen (%100) baskıladığı ve çimlenmeyi %14.6 oranında arttırdığı, CMN 34 bakteriyofajı ise hastalığı %65.8 baskıladığı, çimlenmeyi de %21.6 oranında arttırdığı tespit edilmiştir. CMN 33 ve CMN 34 bakteriyofajlarının domatesteki saprofitik floraya ve domateste patojen olan diğer bakteriyel etmenlere herhangi bir etkisinin olmadığı da belirlenmiştir. Araştırma sonucunda CMN 33 ve CMN 34 bakteriyofajlarının bakteriyel benek hastalığına spesifik olduğu (monofaj) tespit edilmiştir. Bildiğimiz üzere, bu çalışma ülkemizde bakteriyofajların bitki hastalıklarının biyolojik mücadelesinde tohum uygulaması olarak kullanılan ilk çalışmadır.Tomato (Solanum lycopersicum L.), is the most widely grown vegetable crop throught the world. The bacterium known as Pseudomonas syringae pv. tomato (Pst), causes bacterial speck disease on tomatoes. Alternative control strategies are studied for that disease management. The use of the bacteriophages is one of those strategies. Bacteriophages are natural enemies of bacteria and extremely specific to their targeted hosts without affecting any other bacteria. In this study, isolation of Pseudomonas syringae pv. tomato-lysing bacteriophages and the possibility of using these bacteriophages as biological control agents were investigated. Therefore, samples of tomato plants with typical symptoms of bacterial speck disease were collected from 17 tomato fields, 12 greenhouses and four nurseries in Adana and Mersin provinces. The bacteriophages were isolated from the sample using NYGA medium. As a result, after 36 hours of incubation, the plaques (inhibition zones) were observed and 47 bacteriophages were purified. Among the obtained bacteriophages, the CMN 33 isolate was completely (100 %) suppressed the growth of pathogen and increased the germination rate by %14.6, whereas the CMN 34 isolate was suppressed the pathogen by 65.8 % and increased the germination rate by 21.6 %. It was determined that these bacteriophages (CMN 33 and CMN 34) were specific to Pseudomonas syringae pv. tomato and had no effect on the saprophytic bacterial flora on tomatoes. To our knowledge, this is the first study to investigate the possibility of using bacteriophages for biological control of plant diseases in Turkey

Geothermal gradient variation in the Büyük Menderes Graben: implications for geothermal potential of the graben, Western Anatolia, Turkey

The Büyük Menderes Graben (BMG) is an E-W oriented active extensional geothermal basin within the Menderes Massif, a metamorphic core complex, in Western Anatolia, Turkey. 1500 (megawatts-energy) MWe of installed geothermal capacity for power production exist as of December 2019 in Western Anatolia, mostly generated in the BMG. While the BMG is a vastly producing geothermal resource, it is predicted that it has higher production potential. However, other studies do not include field scale 3D geologic models or geothermal gradient maps. This study aims to first quantitatively test the geothermal gradients in the Aydın-İncirliova-Osmanbükü Geothermal Field (IGF), then map the information. This study also aims to compare the IGF with a neighboring geothermal field. To complete this study, information from stratigraphic columns, bottom hole temperatures, and continuous temperature logs from 13 geothermal wells is utilized with Leapfrog Geothermal to create 3D models of the geology and subsurface temperature distribution. Then, isothermal contour maps of the field are created. The geologic modeling suggests that synextensional deposition has occurred within the graben. The temperature modeling suggests both that thermal breakthrough may have occurred in the field, and that the IGF has a higher geothermal gradient than the nearby Germencik Geothermal Fiel

Upper Cenomanian-Lower Campanian Derdere and Karababa formations in the Cemberlitas oil field, southeastern Turkey: their microfacies analyses, depositional environments, and sequence stratigraphy

The frontal belt of the southeastern Anatolia fold-thrust belt in Turkey contains several small to mid-size oilfields, producing from carbonate reservoirs of the Cretaceous Mardin group. Many of these fields are found along narrow, asymmetrical anticlinal structures, associated with the formation of the fold-thrust belt. The emberlitas oil field in Adiyaman, southeastern Turkey, is one of the most important oilfields in the region. It produces from the Upper Cretaceous Derdere and Karababa formations of the Mardin group. We have conducted a detailed study of the microfacies, depositional environments, and sequence stratigraphy of the Karababa (Coniacian-lower Campanian) and Derdere (mid-Cenomanian-Turonian) formations in the oil field. Eight microfacies in the Karababa and Derdere formations have been identified; the microfacies in the Karababa formation are 1) mollusk-echinoid wackestone/packstone, 2) dolomitic planktonic foraminifera wackestone, 3) planktonic foraminifera bearing wackestone/packstone, and 4) phosphatic-glauconitic planktonic foraminifera bearing wackestone. The microfacies in the Derdere formation are 5) lime mudstone, 6) bioclastic wackestone/packstone, 7) medium-coarse crystalline dolomite, and 8) fine crystalline dolomite. These microfacies suggest that the Derdere formation was deposited in lagoonal to shelf depositional environments and the Karababa formation was deposited in a deep to shallow marine intrashelf basin. Two third-order sequence boundaries of late Turonian and early Campanian in age have been recognized in the reservoir interval. Depositional sequences contain transgressive and highstand systems tracts. These sequences are compared with those in other regions to differentiate the local, regional, and global factors that controlled sedimentation within the emberlitas oil field area

Geochemistry, geochronology, and cathodoluminescence imagery of the Salihli and Turgutlu granites (central Menderes Massif, western Turkey): Implications for Aegean tectonics

The Menderes Massif (western Turkey) is an important metamorphic core complex located in the Aegean region; geochemical and geochronological data from this extensional domain facilitates our understanding of large-scale extension of the Earth's lithosphere. S-type, peraluminous granites (Salihli and Turgutlu) that intrude the Alasehir detachment which bounds the northern edge of the central Menderes Massif may have been generated due to subduction of the Eastern Mediterranean floor along the Hellenic trench. In situ Th-Pb ion microprobe monazite ages from the granites range from 21.7 ± 4.5 Ma to 9.6 ± 1.6 Ma (± 1 σ). Higher uncertainty in the ages is attributed to monazite common Pb, but the range is consistent with cathodoluminescence (CL) imagery that document complex textures within the samples. Salihli and Turgutlu granites share many similar characteristics, including multiple generations of plagioclase (some with shocked cores), plagioclase replacing K-feldspar and the development of myrmekite, evidence for fluid interaction, and multiple generations of microcracks and microfaults. The granites may have evolved from compositionally distinct magma sources, as Salihli samples in general contain allanite as the major accessory mineral, whereas Turgutlu granites contain monazite. However, the CL imagery document similar alteration textures. The youngest Turgutlu monazite grain (11.5 ± 0.8 Ma) is located in the rim of a K-feldspar grain close to myrmekite, and the youngest Salihli monazite grain (9.6 ± 1.6 Ma) is located in the outer edge of an altered plagioclase crystal. These ages likely time episodes of deformation as the granites were subjected to exhumation along the Alasehir detachment. Ages reported here are similar to dates constraining extension reported elsewhere in the Aegean, but indicate a level of complexity when linking movement within the Menderes Massif to the large-scale geodynamic processes that created other metamorphic core complexes in the region. Difficulties exist in linking the ages obtained from the granites to specific tectonic events due to the presence of secondary alteration textures, generations of mineral growth, and multiple episodes of deformation. © 2009 Elsevier B.V