This paper presents the preliminary results regarding the lithostratigraphy, petrography and petrology of James Ross Island Volcanic Group dominating the Lachman Crags and Cape Lachman lava-fed deltas in the Ulu Peninsula, James Ross Island north-eastern Antarctic Peninsula. Studied lava-fed deltas were produced via Late Miocene to Pleistocene sub-marine and sub-glacial volcanism and made up four main lithofacies: a- bottomset pillow lavas, peperites and associated volcanoclastic/siliciclastic deposits; b- foreset-bedded hyaloclastite breccias; c- intrusions (feeder dykes, sills, and plugs) and d- topset subaerial lavas. Collectively these lithofacies record the transition from an effusive subaqueous to an effusive subaerial eruption environment. All lava samples and dykes from bottomset, foreset and topset lava-fed delta associations are olivine-phyric alkali basalts and are mineralogically and geochemically homogeneous. These eruptive products display significant enrichments in alkali contents and have ocean island basalt (OIB)-type, intra-plate geochemical signatures characterized by enrichments in all highly to moderately incompatible trace elements relative to basaltic rocks from ocean ridge settings. Volcanic products from a number of different eruptive periods display limited variations in major and trace element relative abundances, indicating derivation from a relatively homogeneous mantle source. The results of quantitative modelling of geochemical data is consistent with the view that the primary melts from which these mafic alkaline rocks were originated are the products of relatively small degrees (~3-7%) of partial melting of a volatile-bearing, metasomatized mantle source. The magmatism is likely the result of extension-driven mantle upwelling.

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<p>Marmara Granitoid (MG) is an E-W trending sill-like magmatic body exposed in the center of the Marmara Island, NW Anatolia, Turkey. MG is lower Eocene in age and was concordantly emplaced into metamorphic basement rocks of Saraylar Marble and Erdek Complex. It is represented by a deformed granodiorite which widely displays protomylonitic-mylonitic textures with prominent foliation and lineation. Foliation planes display a mean dip direction-angle of 335/29 and mineral stretching lineations show mean trend-plunge of 286/34. Mica-fishes, rotated porphyroclasts and micro-faults are commonly observed and serve as shear gauges pointing out to a dextral movement. Mineral deformation thermometers such as myrmekite development, chessboard extinction, grain boundary migration (GBM), sub-grain rotation recrystallization (SGR), and bulging recrystallization (BLG) in quartz crystals indicate that solid-state deformation of the MG has experienced a high-temperature ductile deformation and superimposed ductile to brittle deformation.</p><p>Three-dimensional strain ellipsoid measurements are investigated on the MG in order to determine the relative amounts of pure shear and simple shear deformation and the mean kinematic vorticity number (W<sub>m</sub>). The image processing of quartz grains is used as strain markers to obtain the three-dimensional best-fit ellipsoids. The results show that, Lode’s ratio (ν) of the samples change between -0.010 and -0.650 and Flinn’s k-values range from 1.026 to 11.157 indicating to a general constrictional (prolate) deformation. The calculated kinematic vorticity numbers change between 0.429 and 0.958 which show that shear deformation of MG is mostly dominated by simple shear. All of these micro and meso structural properties and three-dimensional strain and kinematic analyses collectively suggest that MG has experienced a dextral transtensional deformation.</p>

<p>South Shetland Islands in Western Antarctica is dominated by a widespread magmatism through Meso-Cenozoic due to the magmatic arc created by the subduction of Phoenix plate along the South Shetland trench. Within the scope of 4th Turkish Antarctic Expedition (TAE-IV) and Turkey-Poland Bilateral cooperation, field studies were conducted in Admiralty Bay (King George Island) that host various magmatic units  in order to understand the magmatic evolution beneath Meso-Cenozoic Western Antarctica.</p><p>Magmatic products consists of Paleocene-Eocene aged volcanic and subvolcanic rocks in Admiralty Bay. Volcanic rocks are represented by terrestrial lavas and pyroclastic rocks (agglomerates, tuffs and volcanic breccias) while subvolcanic rocks consist of dykes and stocks. According to the petrographic investigations, volcanic and subvolcanic rocks in the area mostly display disequilibrium textures such as sieve textures and embayments in plagioclase and pyroxenes, patchy and oscillatory zoning in different generations of plagioclases and the existence of K-Feldspar xenocrysts with reaction rims along the borders.</p><p>Geochemically, the compositions of the magmatic rocks in the study area range from dacite to basalt. Volcanic and subvolcanic rocks show similar geochemical signatures. The samples show mostly calc-alkaline affinities. There are two predominant compositional variations, felsic and intermediate-mafic. Their MgO content ranges within 0.28-1.20 wt. % for the more felsic lavas and 2.78-5.24 wt. % for intermediate-mafic lavas. Their Al<sub>2</sub>O<sub>3</sub> contents are relatively high (14.91-24.29 wt. %). The samples are slightly enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE) compared to HFSE and HREE. The samples display high Th/Yb ratios ranging from 3.78 to 0.69. Strong depletions in Nb and Ti elements are observed as typical indicators for subduction zone magmatism. Although most of the samples show similar patterns in spider diagrams, a strong discrepancy is seen in immobile elements such as Hf and Zr, resulting in positive anomalies in felsic and negative anomalies in intermediate-mafic rocks. Similarly, negative Eu anomalies observed only in the felsic rocks. Eu/Eu* ratios varies within 0.59-0.71 for felsic rocks, and 0.85-1.12 for intermediate-mafic rocks. These different patterns in different compositions suggest an open system differentiation for the melt evolution. Petrographic and geochemical evaluations indicate that the magma beneath Meso-Cenozoic Western Antarctica is originated from lithospheric mantle metasomatized by subduction components, and fractional crystallization/assimilation fractional crystallization contributed to the magmatic evolution.</p><p> </p><p> </p><p> </p>

<p>Eocene granitoids in NW Anatolia occurred following the continental collision between Sakarya Continent and Tauride-Anatolide Platform and mark the onset of post-collisional magmatism in the region. One of the representative members of the Eocene granitoids, the Tepeldağ pluton crops out as two isolated granitic bodies and is intruded into the Cretaceous blueschist assemblages (Kocasu formation) and ophiolitic rocks within the Izmir-Ankara-Erzincan suture zone (IAESZ). South Tepeldağ pluton (STP) is composed mainly of granodiorite with subordinate quartz diorite, which show transitional contacts. Aplitic dykes crosscut the pluton as well as the country rocks. STP includes a number of mafic microgranular enclaves (MME) of gabbro/diorite composition.</p><p>Geochemically, STP shows distinct I-type affinity with a metaluminous to slightly peraluminous (ASI ≤1.02) nature. The samples are medium-K to high-K calc-alkaline in character. They exhibit depletion in HFSE (Ti, Hf, Zr, Nb and Ta) compared to large ion lithophile elements (Rb, Ba, Th, U, K) and presents negative Nb, P, Ti anomalies. STP displays slight negative Eu anomalies (Eu/Eu* = 0.7–1.2), enrichment in LREE and flat HREE patterns in chondrite-normalized spider diagrams. MELTS modeling (with initial parameters of 1–3 kbar pressure, 2–3% water and QFM-NNO oxygen fugacity buffers) indicate that compositional variations in STP samples can be interpreted as a result of open system processes (assimilation fractional crystallization) rather than a reflection of fractional crystallization in the upper crustal magma chamber. All thermodynamic simulations dictate a crustal assimilation, especially in the late stages of the magmatic process, with a MgO, Na<sub>2</sub>O and Al<sub>2</sub>O<sub>3</sub>-rich assimilant similar to the suture zone (IAESZ) rocks.</p>