A5038483356- Geological and Geochemical Analysis
- Paleontology and Stratigraphy of Fossils
- Geochemistry and Geologic Mapping
- Geological Studies and Exploration
- earthquake and tectonic studies
- High-pressure geophysics and materials
- Geochemistry and Elemental Analysis
- Astro and Planetary Science
- Geology and Paleoclimatology Research
- Hydrocarbon exploration and reservoir analysis
- Historical and Archaeological Studies
- Archaeology and ancient environmental studies
- Geological formations and processes
- Image Processing and 3D Reconstruction
- Methane Hydrates and Related Phenomena
- Ancient and Medieval Archaeology Studies
- Marine Biology and Ecology Research
- Marine and environmental studies
- Landslides and related hazards
- Clay minerals and soil interactions
- Geomagnetism and Paleomagnetism Studies
- Isotope Analysis in Ecology
- Pleistocene-Era Hominins and Archaeology
- Geological Modeling and Analysis
Norwegian Geological Survey
2009-2024
Mineralogical and geochemical data for ca. 1720 Ma Si-Fe-Mn seafloor-hydrothermal sedimentary rocks (exhalites) near the Jones Hill Zn-Cu-Pb-Ag-Au volcanogenic massive sulfide (VMS) deposit, northern New Mexico, provide valuable insights into redox state of late Paleoproterozoic deep sea-water. Distal exhalites ~1200 m south deposit form beds 0.5–2 thick composed interlayered iron formation metachert. The consists mostly quartz magnetite, includes 0.3–3-cm-thick laminae fine-grained...
Research Article| April 01, 2003 Paleozoic and Mesozoic silica-rich seawater: Evidence from hematitic chert (jasper) deposits Tor Grenne; Grenne 1Geological Survey of Norway, Leiv Eirikssons vei 39, N-7491 Trondheim, Norway Search for other works by this author on: GSW Google Scholar John F. Slack 2U.S. Geological Survey, National Center, MS 954, Reston, Virginia 20192, USA Author Article Information Publisher: Society America Received: 28 Jun 2002 Revision 03 Dec Accepted: 05 First Online:...
Research Article| March 01, 2010 THE GEOLOGY AND GEOCHEMISTRY OF EAST AFRICAN OROGEN IN NORTHEASTERN MOZAMBIQUE R. BOYD; BOYD Geological Survey of Norway, N-7491 Trondheim, email: Rognvald.Boyd@ngu.no; Oystein.Nordgulen@ngu.no Search for other works by this author on: GSW Google Scholar Ø. NORDGULEN; NORDGULEN R.J. THOMAS; THOMAS British Survey, Keyworth, United Kingdom, bthomas@bgs.ac.uk B. BINGEN; BINGEN Bernard.Bingen@ngu.no; Terje.Bjerkgard@ngu.no; Tor.Grenne@ngu.no;...
Modern marine hydrothermal vents occur in a wide variety of tectonic settings and are characterized by seafloor emission fluids rich dissolved chemicals rapid mineral precipitation. Some systems vent only low-temperature Fe-rich fluids, which precipitate deposits dominated iron oxyhydroxides, places together with Mn-oxyhydroxides amorphous silica. While proportion this mineralization is abiogenic, most the result metabolic activities benthic, Fe-oxidizing bacteria (FeOB), principally...
Abstract The Trondheim Region ophiolites in the Mid-Norwegian Caledonides represent variably tectonized ophiolite fragments. We present high-precision thermal-ionization mass spectrometry and secondary-ion (SIMS) U–Pb zircon dates, whole-rock geochemical Sm–Nd data Lu–Hf analyses that permit timing nature of various stages evolution to be elucidated. Plagiogranite intrusions dated at 487 480 Ma have relatively juvenile Nd Hf isotopic compositions (ε Nd( t ) =6.3, ε Hf( =8.2–12.4)....
Stratiform beds of jasper (hematitic chert), composed essentially SiO2 (69–95 wt %) and Fe2O3 (3–25 %), can be traced several kilometers along strike in the Ordovician Lokken ophiolite, Norway. These siliceous are closely associated with volcanogenic massive sulfide (VMS) deposits interpreted as sea-floor gels that were deposited by fallout from hydrothermal plumes silica-rich seawater, which plume-derived Fe oxyhydroxide particles promoted flocculation rapid settling large (~200 μm)...
New geochemical, isotopic and age data from igneous rocks complement earlier models of a long-lived complex accretionary history for East African Orogen lithologies north the Blue Nile in western Ethiopia, but throw doubt on paradigm that ultramafic complexes region represent ophiolites suture zones. Early magmatism is represented by metavolcanic sequence dominated pyroclastic deposits predominantly basaltic andesite composition, which give Rb–Sr whole-rock errorchron 873±82 Ma. Steep REE...
Petrological and geochemical data denote that the Late Arenig–Early Llanvirn Hølonda Porphyrites belong to subduction-related shoshonite association. Original compositions ranged from absarokite through latite, their very evolved nature signifies a mature arc aYnity in an active continental margin setting. Much of variation can be interpreted terms fractional crystallization followed by varying admixture cumulus phases ascending melt accumulation phenocrysts within magmatic feeder system....
New U–Pb zircon dating yields a crystallization age of 458±3 Ma for the largely gabbroic Grøndalsfjell Intrusive Complex in Gjersvik Nappe Caledonian Upper Allochthon Scandinavia. This is identical, within error, to adjacent Møklevatnet that dominated by quartz monzodiorite (456±2 Ma), and two intrusive suites may be regarded as members composite intrusion here referred Nesåa Batholith. Mafic this calc-alkaline batholith are characterized slightly positive ε Nd –ε Sr values, marked...
Abstract The Lower Ordovician Løkken ophiolite fragment shows a tripartite subdivision of its thick volcanic sequence into: (1) an Upper Volcanic Member (UVM) transitional MORB/IAT character, comprising basalts or, in related, thrust‐bounded sequence, bimodal basalt‐rhyolite assemblage; (2) Middle (MVM) derived from widely variable, generally MORB‐related magmas; and (3) (LVM) N‐type MORB which locally passes into underlying sheeted dyke complex. UVM LVM were fed relatively deep‐seated magma...
Summary In the Caledonides of central Norway, volcano-sedimentary successions, Lower and Upper Hovin Horg Groups (Ordovician to ?Lower Silurian), unconformably overlie a variable substrate which includes fragmented oceanic crust ensimatic immature arc assemblages initially deformed metamorphosed in earliest Ordovician times. western areas, remnants mid-Ordovician, evolved island-arc complex comprise volcanic-plutonic suite clear calc-alkaline affinity. To E, Trondheim district, continental...
The Hoydal volcanogenic massive sulfide deposit is associated with thick basaltic sheet flows toward the middle of a 1- to 2-km-thick, low-metamorphic, inverted, Lower Ordovician ophiolitic volcanite sequence in central Norwegian Caledonides, just east major (25+ million metric tons) orebody at Lokken.Hoydal one very few Scandinavian Caledonian strata-bound deposits which retains dominantly sea-floor depositional features, due minimal effects later deformation and metamorphism. This study...
The Lokken orebody is situated within a 1- to 2-km-thick Lower Ordovician metavolcanic sequence of ophiolitic affinity. deposit probably the largest ophiolite-hosted massive sulfide body in world and originally contained 25 30 million metric tons ore. It has primary elongated morphology; shape was largely controlled by its sheetlike, fissure-related, hydrothermal feeder zone which underlies central part stratiform along entire length. very well defined down at least 300 m below...
New stable isotopic data from mineral separates of albite, scapolite, amphibole, quartz, and calcite metasomatic rocks (Bamble lithotectonic domain) give increased knowledge on fluid type, source, evolution during metamorphism. Albite a variety albitites gives δ 18 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">S</mml:mi><mml:mi...
Shoshonitic to ultrapotassic, mantle-derived volcanic rocks found within certain accretionary and collisional settings have trace element patterns comparable those of common arc-related rocks, but with extreme enrichments in highly incompatible elements. Such previously unknown the Scandinavian Caledonides, been discovered Oppdal area Trondheim Nappe Complex, central Norway. The are part Skarvatnet unit, which consists (1) Kinna succession, (2) Storgruvpiken rhyolite, (3) Skaret...
Arc-continent collision, followed by subduction polarity flip, occurs during closure of oceanic basins and contributes to the growth continental crust. Such a setting may lead highly unusual association ultrapotassic mid-ocean ridge basalt (MORB)-type volcanic rocks as documented here from an Ordovician succession Scandinavian Caledonides. Interbedded with deep-marine turbidites, pillow basalts evolve depleted-MORB (εNdt 9.4) enriched-MORB 4.8) stratigraphically upward, reflecting...