Effective bandwidths for a class of non Markovian fluid sources

1997 ◽  
Vol 27 (4) ◽  
pp. 263-274 ◽  
Author(s):  
Kimon Kontovasilis ◽  
Nikolas Mitrou
Keyword(s):  
Effective Bandwidths ◽  
Fluid Sources

scholarly journals Reevaluating Fluid Sources During Skarn Formation: An Assessment of the Empire Mountain Skarn, Sierra Nevada, USA

2018 ◽  
Vol 19 (10) ◽  
pp. 3657-3672 ◽  
Author(s):  
Evan J. Ramos ◽  
Marc A. Hesse ◽  
Jaime D. Barnes ◽  
Jacob S. Jordan ◽  
Jade Star Lackey
Keyword(s):  
Sierra Nevada ◽  
Fluid Sources

Hydrofractures and crustal-scale fluid flow

2021 ◽  
Author(s):  
Paul D. Bons ◽  
Tamara de Riese ◽  
Enrique Gomez-Rivas ◽  
Isaac Naaman ◽  
Till Sachau
Keyword(s):  
Fluid Flow ◽  
Large Scale ◽  
Low Flow ◽  
Fault System ◽  
Tectonic Activity ◽  
Field Evidence ◽  
Dehydration Reactions ◽  
Matrix Flow ◽  
Matrix Porosity ◽  
Fluid Sources

<p>Fluids can circulate in all levels of the crust, as veins, ore deposits and chemical alterations and isotopic shifts indicate. It is furthermore generally accepted that faults and fractures play a central role as preferred fluid conduits. Fluid flow is, however, not only passively reacting to the presence of faults and fractures, but actively play a role in their creation, (re-) activation and sealing by mineral precipitates. This means that the interaction between fluid flow and fracturing is a two-way process, which is further controlled by tectonic activity (stress field), fluid sources and fluxes, as well as the availability of alternative fluid conduits, such as matrix porosity. Here we explore the interaction between matrix permeability and dynamic fracturing on the spatial and temporal distribution of fluid flow for upward fluid fluxes. Envisaged fluid sources can be dehydration reactions, release of igneous fluids, or release of fluids due to decompression or heating.</p><p> </p><p>Our 2D numerical cellular automaton-type simulations span the whole range from steady matrix-flow to highly dynamical flow through hydrofractures. Hydrofractures are initiated when matrix flow is insufficient to maintain fluid pressures below the failure threshold. When required fluid fluxes are high and/or matrix porosity low, flow is dominated by hydrofractures and the system exhibits self-organised critical phenomena. The size of fractures achieves a power-law distribution, as failure events may sometimes trigger avalanche-like amalgamation of hydrofractures. By far most hydrofracture events only lead to local fluid flow pulses within the source area. Conductive fracture networks do not develop if hydrofractures seal relatively quickly, which can be expected in deeper crustal levels. Only the larger events span the whole system and actually drain fluid from the system. We present the 10 square km hydrothermal Hidden Valley Mega-Breccia on the Paralana Fault System in South Australia as a possible example of large-scale fluid expulsion events. Although field evidence suggests that the breccia formed over a period of at least 150 Myrs, actual cumulative fluid duration may rather have been in the order of days only. This example illustrates the extreme dynamics that crustal-scale fluid flow in hydrofractures can achieve.</p>

scholarly journals Dispersion and Intersection of Hydrothermal Plumes in the Manus Back-Arc Basin, Western Pacific

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhigang Zeng ◽  
Xiaoyuan Wang ◽  
Bramley J. Murton ◽  
Haiyan Qi ◽  
Berit Lehrmann ◽  
...  
Keyword(s):  
Water Column ◽  
Ph Value ◽  
Chemical Properties ◽  
Hydrothermal Systems ◽  
Pacmanus Hydrothermal Field ◽  
Different Depths ◽  
Hydrothermal Plumes ◽  
Back Arc ◽  
Physical And Chemical ◽  
Fluid Sources

The composition of hydrothermal plumes reflects the physical and chemical characteristics of seafloor hydrothermal fluids, which in turn reflects the host rock and subseafloor reaction conditions as well as the water column processes that act to alter the plumes as they disperse and age. Here, we show that the turbidity, current, pH value, dissolved Fe (dFe), and dissolved Mn (dMn) compositions of hydrothermal plumes can be used to understand the spatial distribution and source of hydrothermal systems in the submarine geological environment. Data were obtained from 18 hydrocast stations, among which the water column samples were collected at 8 stations during the MANUS cruise of R/V KEXUE in 2015. The results showed that the Satanic Mills plume and Fenway plume rose approximately 140 m and 220 m above the seafloor, respectively. In the Satanic Mills plume, dFe remained longer than dMn during lateral plume dispersal. There was a clear intersection of the Satanic Mills plume and Fenway plume between 1625 m and 1550 m in the PACMANUS hydrothermal field, and the varied dispersion trends of the mixed plumes were affected by current velocities at different depths. The physical and chemical properties of the seawater columns in the Manus Basin were affected by the input of high-Mn, high-Fe, and low-Mg vent fluids. The turbidity and dFe, dMn, and dissolved Mg concentrations in the sections of the plumes proximal to the Satanic Mills, Fenway, and Desmos vent sites were generally higher (turbidity, Mn, and Fe) and lower (Mg) than those in the sections of the plumes that were more distal from the vent sites. This implied that the plumes proximal to their vent fluid sources, which were interpreted to have relatively young ages, dispersed chemically over time, and their concentrations became more similar to those of the plumes that were more distal from their vent fluid sources.

Sign in / Sign up

Export Citation Format

Share Document