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International Ocean Discovery Program (IODP) Expedition 378 was designed to recover the first comprehensive set of Paleogene sedimentary sections from a transect of sites strategically positioned in the South Pacific Ocean to reconstruct key changes in oceanic and atmospheric circulation. These sites would have provided an unparalleled opportunity to add crucial new data and geographic coverage to existing reconstructions of Paleogene climate. Following the ~15 month postponement of Expedition 378 and subsequent port changes that resulted in a reduction of the number of primary sites, testing and evaluation of the research vessel JOIDES Resolution derrick in the weeks preceding the expedition determined that it would not support deployment of drill strings in excess of 2 km. Consequently, only one of the originally approved seven primary sites was drilled. Expedition 378 recovered the first continuously cored, multiple-hole Paleogene sedimentary section from the southern Campbell Plateau at Site U1553. This high-southern latitude site builds on the legacy of Deep Sea Drilling Project Site 277 (a single, partially spot cored hole), providing a unique opportunity to refine and expand existing reconstructions of Cenozoic climate history. As the world's largest ocean, the Pacific Ocean is intricately linked to major changes in the global climate system. Previous drilling in the low-latitude Pacific Ocean during Ocean Drilling Program Legs 138 and 199 and Integrated Ocean Drilling Program Expeditions 320 and 321 provided new insights into climate and carbon system dynamics, productivity changes across the zone of divergence, time-dependent calcium carbonate dissolution, bio- and magnetostratigraphy, the location of the Intertropical Convergence Zone, and evolutionary patterns for times of climatic change and upheaval. Expedition 378 in the South Pacific Ocean uniquely complements this work with a highlatitude perspective, especially because appropriate high-latitude records are unobtainable in the Northern Hemisphere of the Pacific Ocean. Expedition 378 provides material from the South Pacific Ocean in an area critical for high-latitude climate reconstructions spanning the early Paleocene to late Oligocene. Site U1553 and the entire corpus of shore-based investigations will significantly contribute to the challenges of the "Climate and Ocean Change: Reading the Past, Informing the Future" theme of the 2013-2023 IODP Science Plan (How does Earth's climate system respond to elevated levels of atmospheric CO2? How resilient is the ocean to chemical perturbations?). Furthermore, Expedition 378 provides material from the South Pacific Ocean in an area critical for high-latitude climate reconstructions spanning the Paleocene to late Oligocene. [ABSTRACT FROM AUTHOR]

Copyright of Abstract of the Geological Congress of Turkey / Türkiye Jeoloji Kurultayı Bildiri Özleri is the property of TMMOB JEOLOJI MUHENDISLERI ODASI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Abstract of the Geological Congress of Turkey / Türkiye Jeoloji Kurultayı Bildiri Özleri is the property of TMMOB JEOLOJI MUHENDISLERI ODASI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Abstract of the Geological Congress of Turkey / Türkiye Jeoloji Kurultayı Bildiri Özleri is the property of TMMOB JEOLOJI MUHENDISLERI ODASI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Afghanistan has a complicated geologic and tectonic setting due to its position between two active plates of Indian and Eurasia. The country is composed of a serious of tectonic crustal block, which are separated by faulting systems. With consideration of these active faults, besides other types of magmatic rock complexes, ultramafic rocks have widely distribution over the various part of the country. Based on the previously geological investigation of, most of the ultramafic complexes have distribution within Logar province, Southeastern Afghanistan. This work will mostly focus on the two permissive complexes of Eocene - age ultramafic complexes which are mostly distributed in the eastern part of the country, also the mineral deposits types related to these complexes will be reviewed. In addition, further additional areas are interested for the presence of ultramafic rocks based on the some field evidence in which the findings will be included in the paper. The geologic age of ultramafic massifs situated within the territory of Afghanistan are from Archean, Proterozoic, Paleozoic, Mesozoic, and Cenozoic in which some of them are in contradiction. The distribution, age, characteristics, related mineral deposition of the mentioned areas for the ultramafic rocks in Afghanistan will briefly reviewed and discussed in this paper. [ABSTRACT FROM AUTHOR]

The present article is the second part of two contributions presenting the taxonomy of planktonic foraminiferal assemblages from the Paleocene and Eocene in the Lom depression. Taxonomical descriptions of 24 species belonging to 7 genera (Hantkenina Cushman, 1924 - 3 species, Acarinina Subbotina, 1953 - 11 species, Mоrozovella McGowran and Luterbacher, 1964 - 4 species, Igorina Davidzon, 1976 - 1 species, Globanomalina Haque, 1956 - 1 species, Pseudohastigerina Banner and Blow, 1959 - 1 species, Turborotalia Cushman and Bermudez, 1949 - 3 species), 3 families (HANTKENINIDAE Cushman, 1927, TRUNCOROTALOIDIDAE Loeblich and Tappan, 1961, HEDBERGELLIDAE Loeblich and Tappan, 1961) and 1 superfamily (GLOBIGERINOIDEA Carpenter, Parker and Jones, 1862) of Suborder GLOBIGERININA Delage and Hérouard, 1896 are given following the classification of Pearson et al. (2006). 15 species are first described in Bulgaria. [ABSTRACT FROM AUTHOR]

The present article is the first part of two contributions presenting the taxonomy of planktonic foraminiferal assemblages from the Paleocene and Eocene in Lom depression. Taxonomical descriptions of 21 species belonging to 6 genera (Catapsydrax Bolli, Loeblich and Tappan, 1957 – 1 species, Paragloborotalia Cifelli, 1982 – 1 species, Pаrasubbotina Olsson, Hemleben, Berggren and Liu, 1992 – 3 species, Globigerina d’Orbigny, 1826 – 1 species, Subbotina Brotzen and Pozaryska, 1961 – 12 species, Globigerinatheka Brönnimann, 1952 – 3 species), 1 family (GLOBIGERINIDAE Carpenter, Parker and Jones, 1862) and 1 superfamily (GLOBIGERINOIDEA Carpenter, Parker and Jones, 1862) of Suborder GLOBIGERININA Delage and Hérouard, 1896 are given following the classification of Pearson et al. (2006). 12 species are first described in Bulgaria. The foraminiferal data were obtained from 376 samples of drill cuttings and core from 12 boreholes. [ABSTRACT FROM AUTHOR]

Copyright of Abstract of the Geological Congress of Turkey / Türkiye Jeoloji Kurultayı Bildiri Özleri is the property of TMMOB JEOLOJI MUHENDISLERI ODASI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Gold Standard Ventures' (GSV) 115 km2 Railroad-Pinion Project is located 40 km southwest of Elko, Nevada, in the Railroad Mining District. The project is centered on the fourth and southernmost dome-shaped window on the Carlin Trend, a northwest alignment of sedimentary rock-hosted gold deposits exceeding 100 million ounces of past production and current resource. The domes are cored by igneous intrusions that uplift and expose Paleozoic rocks and certain stratigraphic contacts favorable for the formation of Carlin-style gold and precious-base metal skarn deposits. The Railroad Dome is cored by the Bullion Stock, a 1.3 km-diameter, Eocene granodiorite intrusion. 40Ar/39Ar and U-Pb dating of igneous rocks and alteration minerals indicate the igneous and hydrothermal activity occurred between ~38.9 and 37.5 Ma. Igneous rocks were emplaced during at least five separate episodes that produced at least ten distinct rock types. Surrounding the stock is a 1.0-km-wide contact metamorphic aureole developed in Paleozoic siliciclastic and carbonate rocks. Drilling within the hornfels aureole has identified two distinct styles of mineralization: 1) stacked, spatially separate, oxide gold, silver, copper, and zinc zones in hornfels dissolution collapse breccia at Bald Mountain; and 2) skara-hosted silver, copper, lead, and zinc mineralization at Sylvania. The Bald Mountain discovery is defined by 16 widely-spaced drill holes that intersect disseminated gold, silver, copper, and zinc mineralization over a 1.6 by 1.2 km area. Mineralization is open in all directions and coincides with a distinct 4.0 by 1.1 km gravity low, and with west-northwest-striking rhyolite and dacite porphyry dikes. Gold, copper, and to a lesser extent zinc mineralization is hosted in collapse-brecciated, spotted hornfels of the Webb Formation, above Devils Gate Formation marble. Gold and copper zones are tabular and spatially separate, with gold occurring in the upper portion and copper located in the lower part of the breccia. The upper oxidized gold zone ranges from 3 to 57 m thick and average grades range from 0.35 to 3.5 g Au/t. The lower copper zone ranges from 8 to 105 m thick and average grades range from 0.2 to 0.6 wt.%. Disseminated silver occurs above and within the gold and copper zones. Alteration associated with mineralization includes vertically-extensive oxidation, argillization, silicification and quartz veining. Sylvania is a new silver, copper, lead, and zinc skarn discovery. Skarn occurs along the west-northwest-striking, dike-filled Standing Elk fault near the margin of the Bullion Stock. The Standing Elk fault is part of a larger, 0.5-km-wide by 5-kmlong corridor of west-northwest-striking dikes. Two inclined core holes contain multiple silver and base metal skarn zones (e.g. RRB12-03: 57m of 58.3 g/t Ag, 0.78% Cu from 278.4-335.4m) developed in the Devil's Gate Formation. Mineralization is open in all directions. Prograde alteration includes bleaching, andradite and grossularite garnets, pyroxene, and endoskarn in the Bullion Stock. Retrograde alteration includes deep oxidation, clays and muscovite. 40Ar/39Ar and U-Pb dating indicate skarn mineralization formed during emplacement of the 38.2 Ma Bullion Stock. [ABSTRACT FROM AUTHOR]

Carlin-type gold deposits at Long Canyon and West Pequop in the Pequop Mountains are two of Nevada's newest and most significant exploration discoveries. These discoveries have generated great interest, because they lie far east of the known gold trends in the Paleozoic carbonate platform previously considered less prospective for large gold deposits. Host rocks were deformed and variably metamorphosed, probably during the Late Cretaceous Sevier Orogeny. Recent work demonstrates the presence of abundant, previously unrecognized and still poorly documented intrusions, mostly of Jurassic (~159 to 165 Ma) and Eocene (~39 to 41 Ma) age, with fewer late Cretaceous dikes (Bedell et al., 2010). The range in age and composition of igneous rocks of the Pequops is consistent with that observed regionally. The primary goals of this study are to establish the character, absolute and relative timing, and spatial relationships between tectonism, magmatism, and hydrothermal activity that led to significant gold deposition in this geologic setting. Abundant dikes, sills, and small, irregular, mafic to silicic intrusions are recognized in four areas of the Pequop Mountains. In addition, the Nanny Creek area ~5 km north of Long Canyon contains locally sourced Eocene volcanics. Jurassic intrusions are widespread and compositionally diverse, ranging from lamprophyre and monzodiorite through granodiorite and granite. The Long Canyon gold deposit contains a swarm of Jurassic lamprophyre and monzodiorite dikes and sills, and identical dikes are present at West Pequop. Our preliminary 40Ar/39Ar dating of hornblende and biotite phenocrysts from chloritized lamprophyre dikes at Long Canyon provide imprecise Jurassic ages, which are consistent with previous U/Pb ages from other Pequop Mountains locations. Distinctive textures, mineralogy, and geochemistry of Long Canyon lamprophyres are indistinguishable from those of Jurassic lamprophyres of the Carlin trend and Cortez area. Small, irregular lenses of Late Cretaceous(?) garnet-muscovite leucogranite occur in areas of highest metamorphic grades along the west flank of the Pequops Mountains. Leucogranite is peraluminous, which, together with its close spatial association with high-temperature metamorphic rocks, suggests a crustal melt origin. Eocene igneous rocks occur in at least three, possibly four, areas of the Pequop Mountains. Intrusions in two areas in and near West Pequop are high-silica, spherulitic rhyolite (41-39 Ma), whereas an undated but probably Eocene dike at Long Canyon is basaltic. High-silica rhyolite dikes differ compositionally from andesite through low-silica rhyolite lavas of the ~39 Ma Nanny Creek volcanic center suggesting two loci for Eocene activity. Spherulitic textures in the Eocene rhyolites where they intrude high-grade metamorphic rocks suggest: 1) very shallow level of emplacement ~40 Ma, and 2) significant exhumation pre-40 Ma. In seeming conflict with this interpretation, Eocene volcanic rocks at Nanny Creek and regionally everywhere rest on uppermost Paleozoic rocks, indicating little exhumation by that time. Source plutons for widespread Jurassic and Eocene igneous rocks remain uncertain. A large (265 km2) magnetic anomaly centered in Goshute Valley and extending west into the southern Pequop Mountains may represent source plutons for both Jurassic and Eocene dikes and sills. A small part of this anomaly overlaps with the Jurassic Silver Zone Pass pluton in the neighboring Toano Range. Other sources, especially for silicic compositions, may not be resolvable because of their inherently weak magnetism. Gold mineralization at Long Canyon postdates the swarm of Jurassic mafic dikes and sills, which host ore and provide some structural controls to mineralization. Mineralization at West Pequop is likely more tightly constrained, because spherulitic rhyolite dikes dated at ~40 Ma nearby are hydrothermally altered and host gold. [ABSTRACT FROM AUTHOR]

Surface exposures at Battle Mountain, Nevada, of the Elder Creek porphyry system yield a nearly horizontal cross section through a deeply exposed Cu-Au porphyry system that is part of widespread Late Eocene to Early Oligocene magmatism in north-central Nevada. Detailed field mapping (1:5,000 scale) of lithology, structure, hydrothermal alteration, veins, and associated sulfides combined with the petrographic study of 95 thin sections and microprobe analyses, has led to a greater understanding of this magmatic-hydrothermal system in both time and space. Crosscutting relationships between alteration types and veins permit hydrothermal alteration to be divided into six main categories, including potassic and sericitic alteration derived from magmatic fluids, and sodic-calcic, potassic-calcic, calcic, and propylitic alteration that may be derived mainly from non-magmatic fluids. Mineralization associated with these alteration types, in conjunction with published fluid inclusion studies, were used to place constraints on the temperatures of formation and the oxidation and sulfidation state of this system. The Elder Creek area is underlain by clastic rocks of the Cambrian Harmony Formation forming the upper plate of the Dewitt Thrust, a splay of the Roberts Mountain Thrust of the Devonian-Mississippian Antler Orogeny. These strata are intruded by Devonian diabase dikes and four Eocene (~40-41 Ma) intrusive units, including a two-phase composite stock composed of a crowded granodiorite porphyry (40.3Ü.0 Ma), a quartz-eye granodiorite porphyry (40.7±0.6 Ma), a set of hornblende granodiorite dikes (40.3±0.9 Ma), and late quartz monzonite dikes (40.6±0.6 Ma and 40.7±0.5 Ma) which crosscut alteration and mineralization. The Eocene intrusions contain accessory magnetite, titanite, apatite, zircon, and, in places, allanite; magmatic sulfides have not been recognized. The presence of titanite + magnetite and relatively Mg-rich biotite indicate that the magmas were relatively oxidized. Potassic, sericitic, sodic-calcic, potassic-calcic, calcic, and propylitic alteration types form distinct zones within and around the composite pluton and were defined based upon observed mineral assemblages. Alteration in siliciclastic rocks and igneous rocks includes: potassic alteration (Qz+Bio+Kspar±Rut with Po+Asp+Cpy+Py), sericitic alteration (Qz+Ser+Py with varying amounts of Chl+Asp+Cpy), sodic-calcic alteration (Na-plag+Act+Chl+Tit+Ep+Ap associated with the removal of metals from the host rocks), potassic-calcic alteration (Kspar+Act+Ep+Tit+Ap), calcic alteration (Ca-plag+Act+Dio+Qz along with disseminated Po+Cpy + pentlandite + gersdorffite + minor sulfides and Ni-arsenides) and propylitic alteration (Chl+Ser+Py±Act derived from more dilute fluids). Elder Creek is interpreted to be deeply exposed based on the abundance of sodiccalcic alteration, the scarcity of sulfides, and the occurrence of this system in two of the deeper thrust plates at Battle Mountain. Exhumation reflects a combination of erosion and partial structural dismemberment, the latter caused by three generations of NW- and NE-trending normal faults. Elder Creek resembles other porphyry related Cu-Au systems at Battle Mountain, in that all have similar ages, sulfidation states, oxidation states, types of alteration, and igneous rocks. Based alteration and structure, Elder Creek is the deepest exposed, Copper Canyon represents a mid-level exposure, and Buffalo Valley and Copper Basin represent the highest levels of a porphyry system in the Battle Mountain mining district. [ABSTRACT FROM AUTHOR]

Studies of Carlin-type deposits (CTDs) in Nevada show that many formed during the Eocene at shallow depths of < 2 km and in the presence of relatively reduced, meteoric-derived water. These shallow depths, and the extensive hydrothermal circulation associated with CTDs, suggest that some Carlin-type ore fluids likely migrated close to or even breached the paleosurface. The nature of these near-surface, Carlintype systems may differ from more typical, deeper-formed systems. Here, we describe precious-metal mineralization that occurred at shallow depths associated with the Emigrant CTD in the southern Carlin trend. The Emigrant CTD contains a mineable oxide resource of ~1.2 million ounces of Au and is located 3 km east of the "gold-only" Rain CTD (~1.24 million ounces Au from past production). Ore at Emigrant occurs along the unconformable contact between the Devonian Guilmette Limestone and Devonian-Mississippian Pilot Shale, largely as dissolution breccia and bedding replacements containing chalcedonic and jasperoidal quartz, calcite, barite, iron oxides, and clays. Structural ore controls include the west limb of the Emigrant anticline, a doubly-plunging, open fold, and the sub-parallel, N-striking, W-dipping Emigrant fault. Unusual among CTDs, the Emigrant deposit contains high silver contents, and Au/Ag ratios for oxidized ore and carbon-sulfide mineralized rock average ≤ 0.5, in contrast to Au/Ag of 3 to > 10 that typify most CTDs. About 300 m south of the Emigrant mine, Eocene sedimentary and volcanic rocks rest with only slight angular discordance on Mississippian and Devonian clastic rocks. The Paleozoic rocks are highly mineralized ~125 meters beneath this unconformity in a zone that is the southward continuation of the Emigrant deposit. Here, a basal conglomerate of probable late Eocene age is also hydrothermally altered. On this basis and an inferred Eocene age for gold deposition, we estimate the Emigrant deposit formed between about 125 meters and 500 meters paleodepth after adjusting for erosion. Other CTDs located at and near Eocene unconformities in north-central Nevada bear resemblance to the Emigrant deposit. Examples include the Pinon or Trout Creek deposit 15 km southwest of Emigrant and Rain, the Alligator Ridge cluster of deposits in the southern Ruby Mountains, and the Maverick Springs deposit in the Maverick Springs Range just east of the Ruby Mountains. Published work indicates very shallow depths of formation, high silver contents, low Au/Ag ratios (~1 to 0.03), and an abundance of chalcedonic quartz. Shallowly -formed CTDs differ from classic CTDs in having: 1) more chalcedony in jasperoid, 2) a proportionately greater volume affected by silicification, 3) elevated silver contents, and 4) low Au/Ag. Ore characteristics of shallow CTDs resemble the latest paragenetic stages of deeper-seated CTDs, which include overprints of vugfilling chalcedony, barite, calcite, stibnite, zinc-rich sphalerite, marcasite, and adularia. These characteristics may result from cooling and dilution of a late-stage and relatively Au-depleted Carlin-type ore fluid with near-surface, oxidized waters. In this shallow setting, boiling is expected to be a potentially important mechanism for precipitation of precious metals. Recognition of shallow expressions of Carlin-type hydrothermal systems should be useful for targeting deeper, classic, gold-only CTDs. [ABSTRACT FROM AUTHOR]

Early to Late Eocene magmatic activity produced mafic to intemediate lavas, dikes, pyroclastic rocks and coeval granitic intrusions, forming ∼ E-W trending magmatic belt in north of Izmir-Ankara suture zone (NW Anatolia). This study reports new 40Ar/39Ar geochronology, major-trace element geochemistry and Sr-Nd-Pb isotope data from Eocene mafic lavas and dikes of this magmatic belt in order to constrain mantle source charateristics and evolution of mafic volcanism beneath NW Anatolia. Ranging from basalt, basaltic andesite to basaltic trachyandesite, mafic dikes and lavas include both calc-alkaline and transitional (calc-alkaline to tholeiitic) affinity. They are slightly-moderately enriched in large ion lithophile elements and light rare earth elements with respect to high field strength elements and show negative Nb, Ta, and Ti anomalies typical of subduction related magmatic suites. Basaltic lavas and dikes are characterized by 87Sr/86Sr(I) compositions ranging from 0.70530 to 0.70415, positive eNd (2.7-6.6) and restricted Pb-isotope compositions (206Pb/204Pb:18.6-18.7, 207Pb/204Pb:15.6-15.66 and 208Pb/204Pb: 38.60-38.87). The 40Ar/39Ar cooling ages (37.8-41.1 Ma) obtained from this study combined with radiometric ages from literature indicate that mafic volcanism was dominant between early and late Eocene. 40Ar/39Ar ages, geochemistry and Sr-Nd-Pb isotope data indicate the involment of a depleted (MORB-like) mantle modified by earlier subduction event(s) in the genesis of Eocene basaltic lavas and dikes. The break-off of Neotethyan slab may have caused the rise of asthenospheric mantle below NW Anatolia, resulting in a linear zone of asthenospheric upwelling in the study area. [ABSTRACT FROM AUTHOR]

We document the occurrence of adakite like porphyries in NW Anatolia and report a comprehensive data set (petrography, major-trace element geochemistry, Sr-Nd isotope compositions and 40Ar/39Ar radiometric ages) from them in order to evaluate the causes, melt sources and petrological evolution of Adakitic magmatism in NW Turkey. A number of Eocene plutons and porphyries emplaced into the Izmir-Ankara suture zone (IASZ), which represents the collision zone between Anatolide-Tauride platform and Sakarya continent. Adakite-like porphyries form stocks, sills and dikes that are spatially and temporally associated with Eocene plutons emplaced into ophiolitic and blueschist rocks of Tavjanli zone. Petrographically, they can be classified as porphyritic microgranite, and microgranodiorite. They display holocrystalline, microgranular porphyritic textures, and composed mainly of plagioclase, K-Feldspar, quartz, hornblend and biotite. Geochemically, adakitic rocks have high SiO2 (69.43-63.80), Al2O3 (15.44-16.64) contents, high Sr/Y (113.39-214.92) and La/Yb(n) (35.33-80.18) ratios and low Y(6.2-11.5), Yb (1.07-0.54) contents, and display enrichments of LILE and LREE , depletion of HFSE and lack of Eu anomaly. Our 40Ar/39Ar ages obtained from adakite-like porphyries (53.7 to 54.0 Ma) indicate that adakitic magmatism occurred during the Early Eocene in NW Anatolia, as documented in Eastern Pontides (NE Turkey). They have moderately enriched 87Sr/86Sr (54) (0.70620-0.70660) and low εNd (54) (-2.73 to 0.59). Geochemistry and isotope compositions of adakitic porphyries indicate that they most likely to be produced by partial melting of garnet-bearing lower crustal lithologies and its interaction with mantle melt. Assimilation combined with fractional crystallization (AFC) was played an important role during the evolution of these melts at shallower crustal levels. Geochronology, geochemistry and geology of Adakitic porphyries and geology of the NW Anatolia indicate that adakitic magmatism was not formed above an actively dehydrating subducted slab. Instead, our observations are consistent with a magmatism that is more typical of syn-convergent extensional tectonic settings. Formation of adakitic melts require increased heat flow at about 54 Ma that might have occurred by slab break-off. [ABSTRACT FROM AUTHOR]