Sökning: "hydrothermal fluids"

Visar resultat 1 - 5 av 27 avhandlingar innehållade orden hydrothermal fluids.

1. 1. Hydrothermal mobilisation of Au and other metals in the oceanic crust: Implications for the formation of VMS deposits

   Författare :Clifford Patten; Iain Pitcairn; Rodney Allen; Alasdair Skelton; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ODP Hole 1256D; hydrothermal fluids; seawater-derived fluids; hydrothermal alteration; metal mobility; volcanic massive sulphide deposit;

   Sammanfattning : .... LÄS MER

3. 2. Organics in hydrothermal fluids from ultramafic-hosted vents of the Mid-Atlantic Ridge

   Författare :cecile konn; Stockholms universitet; []
   Nyckelord :hydrothermal; organics; serpentinization; origin of life;

   Sammanfattning : The process of serpentinization at slow spreading ridges is due to the circulation of seawater through outcropping mantle rocks. The peridotites of the mantle are altered via fluid-rock interaction generating, in the presence of Fe bearing minerals, high CH4- and H2-concentrations in the water column. LÄS MER

4. 3. Origin of organic compounds in fluids from ultramafic-hosted hydrothermal vents of the Mid-Atlantic Ridge

   Författare :Cécile Konn; Nils Holm; Jean-Luc Charlou; Barbara Sherwood Lollar; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Serpentinisation; hydrocarbons; organic compounds; ultramafic; hydrothermal; geochemistry; origin of life; Other earth sciences; Övrig geovetenskap; Other chemistry; Övrig kemi; Exogenous geochemistry; Exogen geokemi; geokemi; Geochemistry;

   Sammanfattning : Natural gas, primarily methane (CH4), is produced in substantial amounts in ultramafic-hosted hydrothermal systems. These systems could also generate oil (heavier hydrocarbons) and the first building blocks of life (prebiotic molecules). In the presence of iron bearing minerals, serpentinisation reactions generate H2. LÄS MER

5. 4. Hydrothermal alteration of organic matter at spreading centers

   Författare :Eva Andersson; Bernd R.T. Simoneit; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry; Kemi; Biogeochemistry; biogeokemi;

   Sammanfattning : Alteration of organic matter, mainly amino acids, at sub-seafloor hydrothermal conditions has been investigated by performing laboratory experiments and by studying deep-sea sediments from hydrothermally active areas on the northern Juan de Fuca Ridge, northeast Pacific Ocean.Quaternary sediments from Middle Valley and the eastern flank of the Juan de Fuca Ridge recovered during the Ocean Drilling Program Legs 139 and 168 have been analyzed for total hydrolyzable amino acid concentrations, individual amino acid abundances and stereochemistry in order to evaluate the effects of hydrothermal stress on the decomposition of sedimentary amino acids. LÄS MER

7. 5. Constraining the timing of veins, faults and fractures in crystalline rocks by in situ Rb-Sr geochronology

   Författare :Mikael Tillberg; Henrik Drake; Mats E. Åström; Thomas Zack; Johan Hogmalm; Bjarne Almqvist; Linnéuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; geochronology; brittle deformation; crustal fluids; mineral precipitation; ancient microbial activity; Precambrian craton; Scandinavia; Natural Science; Naturvetenskap;

   Sammanfattning : Precambrian cratons are continent cores archiving the oldest crustal histories on Earth. The crystalline basement of cratons is typically characterized by complex arrays of multiple fracture and fault generations hosting minerals formed by fluids flowing through fracture networks. LÄS MER