A5017639088- Geological and Geochemical Analysis
- earthquake and tectonic studies
- Hydrocarbon exploration and reservoir analysis
- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Geochemistry and Geologic Mapping
- Geological formations and processes
- High-pressure geophysics and materials
- Geological and Geophysical Studies
- Paleontology and Stratigraphy of Fossils
- Seismic Imaging and Inversion Techniques
- Geological and Geophysical Studies Worldwide
- Geological Studies and Exploration
- Geomagnetism and Paleomagnetism Studies
- Hydraulic Fracturing and Reservoir Analysis
- Reservoir Engineering and Simulation Methods
- Geochemistry and Elemental Analysis
- Drilling and Well Engineering
- Geophysical and Geoelectrical Methods
- Maritime and Coastal Archaeology
- Superconducting Materials and Applications
- Minerals Flotation and Separation Techniques
- Cryospheric studies and observations
- Groundwater and Isotope Geochemistry
- Planetary Science and Exploration
University of Leeds
2013-2024
International Ocean Discovery Program
2017
Czech Academy of Sciences, Institute of Geophysics
2016
Universities UK
2014
University of Cambridge
1984
University of Dundee
1984
Deformed rocks sampled from a corrugated detachment fault surface near the Mid‐Atlantic Ridge (15°45′N) constrain conditions of deformation and strain localization. Samples recovered in situ record restricted to cold (shallow) lithosphere (greenschist facies), with no evidence for significant high‐temperature either at zone or footwall it. High‐temperature (∼720–750°C) is observed only two sites, cannot be directly linked detachment. Detachment faulting was coeval dyke intrusions that cross...
It is generally assumed that the seawater-derived fluids feed black smoker vent fields on seafloor are discharged vertically from depths of 1–3 km. We present new oxygen and strontium isotope data show at temperatures 300–400 °C were focused along a low-angle detachment fault 15°45'N near Mid-Atlantic Ridge. Isotopic alteration most extreme ever reported oceanic rocks altered similar temperatures, indicating intensely fluid flow both in recharge discharge parts hydrothermal system. Rare...
Research Article| October 01, 1988 Deep fluid circulation in fault zones Andrew M. McCaig 1Department of Earth Sciences, University Leeds, Leeds LS2 9JT, England Search for other works by this author on: GSW Google Scholar Author and Article Information Publisher: Geological Society America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print 0091-7613 Geology (1988) 16 (10): 867–870. https://doi.org/10.1130/0091-7613(1988)016<0867:DFCIFZ>2.3.CO;2 history Cite View This Citation Add to...
Research Article| October 01, 2002 Direct geological evidence for oceanic detachment faulting: The Mid-Atlantic Ridge, 15°45′N C.J. MacLeod; MacLeod 1Department of Earth Sciences, Cardiff University, CF10 3YE, UK Search other works by this author on: GSW Google Scholar J. Escartín; Escartín 2Laboratoire de Geosciences Marines (CNRS UMR 7097), Institut Physique du Globe, 75252 Paris, France D. Banerji; Banerji 3Department Geosciences, University Houston, Texas 77204, USA G.J. Banks; Banks...
Serpentinization of olivine-rich troctolite from core 227, Integrated Ocean Drilling Program (IODP) Hole U1309D ranges <10% to >90%. Two episodes serpentinization are recognized. The first, dominant in weakly serpentinized samples, is an approximately isochemical (except for water) replacement olivine (Fo84–85) by a mixture serpentine (antigorite, Mg-number 92) and brucite (amakinite-rich; 65). compositions the minerals type 1 veins reflection Fe–Mg exchange between + formed during early...
[1] Expeditions 304 and 305 of the Integrated Ocean Drilling Program cored logged a 1.4 km section domal core Atlantis Massif. Postdrilling research results summarized here constrain structure lithology Central Dome this oceanic complex. The dominantly gabbroic sequence recovered contrasts with predrilling predictions; application ground truth in subsequent geophysical processing has produced self-consistent models for Dome. presence many thin interfingered petrologic units indicates that...
The upper mantle is critical for our understanding of terrestrial magmatism, crust formation, and element cycling between Earth's solid interior, hydrosphere, atmosphere, biosphere. Mantle composition evolution have been primarily inferred by surface sampling indirect methods. We recovered a long (1268-meter) section serpentinized abyssal peridotite interleaved with thin gabbroic intrusions. find depleted compositions notable variations in mineralogy controlled melt flow. Dunite zones...
Olivine-rich troctolites of Integrated Ocean Drilling Program hole U1309D contain abundant veins along which the olivine has been serpentinized. Where serpentinite cut plagioclase altered to prehnite and in many places core vein grossular. We show that these Ca-rich assemblages, we call micro-rodingites, need not have formed by Ca-metasomatism. Instead micro-rodingites could occurred during serpentinization as a nearly closed-system process (apart from addition water release H2 Na+). argue...
Direct dating of mylonite evolution: a multi-disciplinary geochronological study from the Moine Thrust Zone, NW Scotland
Abstract Mylonites from shear zones cutting Hercynian gneisses in the central Pyrenees have been studied thin section and using electron microprobe. The contain retrogressive greenschist facies assemblages implying introduction of an aqueous fluid during deformation zones. Textural evidence suggests that fluid‐rock interaction occurred throughout active life Whole‐rock chemical changes are documented a variety mylonitic lithologies retrogressed country rocks. overall effect was to reduce...
Quartz veins occupying extensional fractures that formed relatively late in the Alpine thrusting history of Pyrenees contain abundant inclusions hypersaline brines. Small amounts bitumen also occur. A range brine compositions is apparent from freezing behavior fluid different samples, with large variations Na/Ca ratio, but many individual samples only one composition. All types display a bimodal distribution homogenization temperature, which interpreted as result fluctuation pressure maximum...
Research Article| April 01, 2012 Hydrothermal circulation and the dike-gabbro transition in detachment mode of slow seafloor spreading Andrew M. McCaig; McCaig 1Institute Geophysics Tectonics, School Earth Environment, University Leeds, Leeds LS2 9JT, UK Search for other works by this author on: GSW Google Scholar Michelle Harris 2National Oceanography Centre, Southampton, Southampton SO14 3ZH, Geology (2012) 40 (4): 367–370. https://doi.org/10.1130/G32789.1 Article history received: 31 Aug...
The use of fluid-mobile elements and their isotopes to track fluid-mediated subduction zone processes requires an accurate estimate the volatile element systematics subducting oceanic crust. Near-ridge hydrothermal circulation represents primary means by which seawater can penetrate crust produce enrichments in (B, Sr, Li, U, Cl etc.), particularly at slow-spreading ridges where hydrated mantle peridotite (ie. serpentinite) is commonly exposed seafloor. However no previous drilling has...
IODP Expedition 399 drilled a record 1268m hole (U1601C) in the Atlantis Massif oceanic core complex, sampling serpentinised harzburgites and dunites, cut by gabbro net-vein complex (Lissenberg et al., 2024). The near ridge environment of Massif, well constrained exhumation section detachment faulting (Escartin 2022), allows us to constrain recent (~6 million year) history this important abyssal peridotites exceptionally well. In addition, Site U1601 is located only 800 m from Lost City...