Fluid Inclusion Evidence of Coseismic Fluid Flow Induced by Dynamic Rupture

2017 ◽  
pp. 37-45 ◽  
Author(s):  
Thomas M. Mitchell ◽  
Jose M. Cembrano ◽  
Kazuna Fujita ◽  
Kenichi Hoshino ◽  
Daniel R. Faulkner ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Fluid Inclusion ◽  
Dynamic Rupture

Isotope analysis of vein-hosted fluid inclusions: A case study on fracture-controlled fluid flow in the Albanian foreland fold-and-thrust belt

2020 ◽  
Author(s):  
Stefan de Graaf ◽  
Casimir Nooitgedacht ◽  
Hubert Vonhof ◽  
Jeroen van der Lubbe ◽  
John Reijmer
Keyword(s):  
Fluid Flow ◽  
Fluid Inclusion ◽  
Fluid Inclusions ◽  
Continuous Flow ◽  
Isotope Exchange ◽  
Meteoric Water ◽  
Isotope Ratios ◽  
Isotope Data ◽  
Exchange Processes ◽  
Migration Pathways

<p>Vein-hosted fluid inclusions may represent remnants of subsurface paleo-fluids and therefore provide a valuable record of fracture-controlled fluid flow. Isotope data (δ<sup>2</sup>H and δ<sup>18</sup>O) of fluid inclusions are particularly useful for studying the provenance and type of paleo-fluids circulating in the subsurface. Although isotopic analysis of sub-microliter amounts of fluid inclusion water is not straightforward, major steps forward have been made over the past decade through the development of continuous-flow set-ups. These techniques make use of mechanical crushing at a relatively low-temperature (110˚C) and allow for on-line analysis of both δ<sup>2</sup>H and δ<sup>18</sup>O ratios of bulk fluid inclusion water. However, continuous-flow techniques have mostly been used in speleothem research, and have not yet found a widespread application on vein systems for hydrogeological reconstructions.</p><p>We used isotope data of fluid inclusions hosted in calcite vein cements to reconstruct regional fluid migration pathways in the Albanian foreland fold-and-thrust system. Tectonic forces during thrust emplacement typically instigate distinct phases of fracturing accompanied by complex fluid flow patterns. The studied calcite veins developed in a sequence of naturally fractured Cretaceous to Eocene carbonate rocks as a result of several fracturing events from the early stages of burial onward. Fluid inclusion isotope data of the veins reveal that fluids circulating in the carbonates were derived from an underlying reservoir, which consisted of a mixture of meteoric water and evolved marine fluids, probably derived from deep-seated evaporites. The meteoric fluids infiltrated in the hinterland before being driven outward into the foreland basin. The fluid inclusion isotope data furthermore show that meteoric water becomes increasingly dominant in the system through time as migration pathways shortened and marine formation fluids were progressively flushed out.</p><p>The diagenetic stability of fluid inclusions is of key interest in the study of their isotope ratios. Recrystallization, secondary fluid infiltration and isotope exchange processes could potentially drive alterations of fluid inclusion isotope signatures after entrapment. In this case, however, isotope signatures of fluid inclusions seem to have remained largely unaltered, despite the Cretaceous to Tertiary age of the vein system. Oxygen isotope exchange processes between the fluid inclusion water and host mineral could have been inhibited at the relatively low temperatures of vein formation (i.e. <80˚C). Although more research into the diagenetic stability of fluid inclusion isotope ratios is required, the fluid inclusion isotope record has potential as a powerful tool for fluid provenancing in subsurface fluid flow systems.</p>

Record of fluid flow history through fractured conglomerates, Lower Old Red Sandstone of central Scotland

2004 ◽  
Vol 40 (2) ◽  
pp. 145-157 ◽  
Author(s):  
Martin Baron ◽  
John Parnell
Keyword(s):  
Fluid Flow ◽  
Low Temperature ◽  
Fluid Inclusion ◽  
Fault Zone ◽  
Middle Devonian ◽  
Multiple Populations ◽  
Red Sandstone ◽  
Boundary Fault ◽  
Moderate Salinity ◽  
Oriented Parallel

SynopsisExtensively fractured quartzite clasts in Lower Old Red Sandstone conglomerates adjacent to the Highland Boundary Fault Zone in central Scotland contain multiple populations of healed microfractures delimited by fluid inclusion planes. Microthermometric analysis indicates that the healing of microfractures oriented perpendicular to the trend of the Highland Boundary Fault Zone, which probably formed during Acadian overthrusting towards the SE along the fault zone in Middle Devonian times, involved moderate temperature (Th 102 to 238°C), low to moderate salinity (3 to 17 wt% NaCl eq.) aqueous fluids. The clasts also contain a second set of fluid inclusion planes oriented parallel to the Highland Boundary Fault Zone, which formed during extension associated with the intrusion of late Carboniferous quartz dolerite dykes. The healing of this set of microfractures involved low temperature (Th 58 to 155°C), low to moderate salinity (1 to 12 wt% NaCl eq.) aqueous fluids.

scholarly journals Triassic fluid mobilization and epigenetic lead-zinc sulphide mineralization in the Transdanubian Shear Zone (Pannonian Basin, Hungary)

2014 ◽  
Vol 65 (3) ◽  
pp. 177-196 ◽  
Author(s):  
Zsolt Benkó ◽  
Ferenc Molnár ◽  
Marc Lespinasse ◽  
Kjell Billström ◽  
Zoltán Pécskay ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Fluid Inclusion ◽  
Lead Isotope ◽  
Pannonian Basin ◽  
Regional Scale ◽  
Age Dating ◽  
Late Triassic ◽  
Maximum Temperature ◽  
Lead Zinc ◽  
Hydrothermal Veins

Abstract A combined fluid inclusion, fluid inclusion plane, lead isotope and K/Ar radiometric age dating work has been carried out on two lead-zinc mineralizations situated along the Periadriatic-Balaton Lineament in the central part of the Pannonian Basin, in order to reveal their age and genetics as well as temporal-spatial relationships to other lead-zincfluorite mineralization in the Alp-Carpathian region. According to fluid inclusion studies, the formation of the quartzfluorite- galena-sphalerite veins in the Velence Mts is the result of mixing of low (0-12 NaCl equiv. wt. %) and high salinity (10-26 CaCl2 equiv. wt. %) brines. Well-crystallized (R3-type) illite associated with the mineralized hydrothermal veins indicates that the maximum temperature of the hydrothermal fluids could have been around 250 °C. K/Ar radiometric ages of illite, separated from the hydrothermal veins provided ages of 209-232 Ma, supporting the Mid- to Late-Triassic age of the hydrothermal fluid flow. Fluid inclusion plane studies have revealed that hydrothermal circulation was regional in the granite, but more intensive around the mineralized zones. Lead isotope signatures of hydrothermal veins in the Velence Mts (206Pb/204Pb = 18.278-18.363, 207Pb/204Pb = 15.622-15.690 and 208Pb/204Pb = 38.439-38.587) and in Szabadbattyán (206Pb/204Pb = 18.286-18.348, 207Pb/204Pb = 15.667-15.736 and 208Pb/204Pb = 38.552-38.781) form a tight cluster indicating similar, upper crustal source of the lead in the two mineralizations. The nature of mineralizing fluids, age of the fluid flow, as well as lead isotopic signatures of ore minerals point towards a genetic link between epigenetic carbonate-hosted stratiform-stratabound Alpine-type lead-zinc-fluorite deposits in the Southern and Eastern Alps and the studied deposits in the Velence Mts and at Szabadbattyán. In spite of the differences in host rocks and the depth of the ore precipitation, it is suggested that the studied deposits along the Periadriatic-Balaton Lineament in the Pannonian Basin and in the Alps belong to the same regional scale fluid flow system, which developed during the advanced stage of the opening of the Neo-Tethys Ocean. The common origin and ore formation process is more evident considering results of large-scale palinspastic reconstructions. These suggest, that the studied deposits in the central part of the Pannonian Basin were located in a zone between the Eastern and Southern Alps until the Early Paleogene and were emplaced to their current location due to northeastward escape of large crustal blocks from the Alpine collision zone

Fluid flow within the damage zone of the Boccheggiano extensional fault (Larderello–Travale geothermal field, central Italy): structures, alteration and implications for hydrothermal mineralization in extensional settings

2010 ◽  
Vol 148 (4) ◽  
pp. 558-579 ◽  
Author(s):  
FEDERICO ROSSETTI ◽  
LUCA ALDEGA ◽  
FRANCESCA TECCE ◽  
FABRIZIO BALSAMO ◽  
ANDREA BILLI ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Fluid Inclusion ◽  
Hydrothermal Fluid ◽  
Damage Zone ◽  
Central Italy ◽  
Fluid Pressure ◽  
Lithostatic Pressure ◽  
Anisotropic Permeability ◽  
Ore Deposit ◽  
Permeability Structure

AbstractThe Neogene extensional province of southern Tuscany in central Italy provides an outstanding example of fossil and active structurally controlled fluid flow and epithermal ore mineralization associated with post-orogenic silicic magmatism. Characterization of the hydrodynamic regime leading to the genesis of the polysulphide deposit (known as Filone di Boccheggiano) hosted within the damage zone of the Boccheggiano Fault is a key target to assess modes of fossil hydrothermal fluid circulation in the region and, more generally, to provide inferences on fault-controlled hydrothermal fluid flow in extensional settings. We provide a detailed description of the fault zone architecture and alteration/mineralization associated with the Boccheggiano ore deposit and report the results of fluid inclusion and stable oxygen isotope studies. This investigation shows that the Boccheggiano ore consists of an adularia/illite-type epithermal deposit and that sulphide ore deposition was controlled by channelling of hydrothermal fluids of dominantly meteoric origin within the highly anisotropic permeability structure of the Boccheggiano Fault. The low permeability structure of the fault core compartmentalized the fluid outflow preventing substantial cross-fault flow, with focused fluid flow occurring at the hangingwall of the fault controlled by fracture permeability. Fluid inclusion characteristics indicate that ore minerals were deposited between 280° and 350°C in the upper levels of the brittle extending crust (lithostatic pressure in the order of 0.1 GPa). Abundant vapour-rich inclusions in ore-stage quartz are consistent with fluid immiscibility and boiling, and quartz ore vein textures suggest that mineralization in the Boccheggiano ore deposit occurred during cyclic fluid flow in a deformation regime regulated by transient and fluctuating fluid pressure conditions. Results from this study (i) predict a strongly anisotropic permeability structure of the fault damage zone during crustal extension, and (ii) indicate the rate of secondary (structural) permeability creation and maintenance by active deformation in the hangingwall of extensional faults as the major factor leading to effective hydraulic transmissivity in extensional terranes. These features intimately link ore-grade mineralization in extensional settings to telescoping of hydrothermal flow along the hangingwall block(s) of major extensional fault zones.

Fluid flow and syntectonic veining in an Ediacaran-Cambrian foreland fold–thrust zone, western margin of the São Francisco Craton, Brazil

2021 ◽  
pp. jgs2020-061
Author(s):  
Melina C. B. Esteves ◽  
Frederico M. Faleiros
Keyword(s):  
Fluid Flow ◽  
Fluid Inclusion ◽  
Analytical Data ◽  
Microstructural Analysis ◽  
Fluid Pressure ◽  
Content Type ◽  
Western Margin ◽  
Metasedimentary Rocks ◽  
Supplementary Material ◽  
Fault Valve

The western margin of the São Francisco Craton, central Brazil presents a 1300 km long foreland fold–thrust belt where Ediacaran-Cambrian (560–520 Ma) metasedimentary rocks from the Bambuí Group were subsequently deformed during post-collisional stages (520–495 Ma) related to Gondwana assembly. This scenario provides an opportunity to quantify fluid flow regimes and fault-related processes that were active in exhumed foreland fold–thrust zones, which were estimated based on structural, microstructural and fluid inclusion studies of syntectonic veins and host rocks. Kaolinite-bearing synkinematic mineral assemblages from metasedimentary rocks, thermodynamic models and grain-scale deformation accommodated by dissolution–precipitation creep and intracrystalline deformation indicate metamorphic and deformational conditions of 250–270°C. Subhorizontal extensional veins formed under subhorizontal shortening and subvertical extension, supporting vein development under a fold–thrust regime that formed regional NW–SE-trending thrust fault zones and megafolds with NW–SE-trending axes. Orientation and growth microstructures indicate that NW–SE-trending subvertical cleavage-parallel veins formed under subhorizontal NE–SW extension, compatible with those inferred to produce mapped kilometre-scale gentle folds with NE–SW-trending traces. Two primary aqueous fluid inclusion assemblages (FIA) are distinguished by salinity variation: 2–21 wt% NaCleq. in subhorizontal veins and 6–0 wt% NaCleq. in cleavage-parallel subvertical veins. Fluid inclusion thermometry and microstructural analysis suggest that veins crystallized between 250 and 270°C under fluid pressure fluctuating within a range of 50–500 MPa (subhorizontal veins) and 80–320 MPa (cleavage-parallel subvertical veins), evidencing fault-valve behaviour. Trends of coupled decreases in salinity and homogenization temperatures in both FIA indicate downward mixing of meteoric fluids, which was more effective in subvertical veins and was in both cases enhanced by fault-valve behaviour. Dominance of moderate salinity and absence of CO2 and CH4 indicate that the fluids are dominated by formation waters. The salinity signature is similar to those of formation waters and metamorphic fluids derived from rocks of shallow marine environments worldwide.Supplementary material: Details of samples and analytical data are available at https://doi.org/10.6084/m9.figshare.c.5275031

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