scholarly journals From Early Contraction to Post-Folding Fluid Evolution in the Frontal Part of the Bóixols Thrust Sheet (Southern Pyrenees) as Revealed by the Texture and Geochemistry of Calcite Cements

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 117 ◽  
Author(s):  
Nicholas Nardini ◽  
Daniel Muñoz-López ◽  
David Cruset ◽  
Irene Cantarero ◽  
Juan Martín-Martín ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Clumped Isotopes ◽  
Thrust Sheet ◽  
Frontal Part ◽  
Fracture Systems ◽  
Icp Ms ◽  
Flow Evolution ◽  
Calcite Cement ◽  
Fluid Flow Regimes ◽  
Host Rocks

Structural, petrological and geochemical (δ13C, δ18O, clumped isotopes, 87Sr/86Sr and ICP-MS) analyses of fracture-related calcite cements and host rocks are used to establish a fluid-flow evolution model for the frontal part of the Bóixols thrust sheet (Southern Pyrenees). Five fracture events associated with the growth of the thrust-related Bóixols anticline and Coll de Nargó syncline during the Alpine orogeny are distinguished. These fractures were cemented with four generations of calcite cements, revealing that such structures allowed the migration of different marine and meteoric fluids through time. During the early contraction stage, Lower Cretaceous seawater circulated and precipitated calcite cement Cc1, whereas during the main folding stage, the system opened to meteoric waters, which mixed with the connate seawater and precipitated calcite cement Cc2. Afterwards, during the post-folding stages, connate evaporated marine fluids circulated through newly formed NW-SE and NE-SW conjugate fractures and later through strike-slip faults and precipitated calcite cements Cc3 and Cc4. The overall paragenetic sequence reveals the progressive dewatering of Cretaceous marine host sediments during progressive burial, deformation and fold tightening and the input of meteoric waters only during the main folding stage. This study illustrates the changes of fracture systems and the associated fluid-flow regimes during the evolution of fault-associated folds during orogenic growth.

scholarly journals Fluid Dynamics in a Thrust Fault Inferred from Petrology and Geochemistry of Calcite Veins: An Example from the Southern Pyrenees

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-25 ◽  
Author(s):  
Daniel Muñoz-López ◽  
David Cruset ◽  
Irene Cantarero ◽  
Antonio Benedicto ◽  
Cédric M. John ◽  
...  
Keyword(s):  
Process Zone ◽  
Hanging Wall ◽  
Thrust Fault ◽  
Clumped Isotopes ◽  
Fracture Systems ◽  
Episodic Evolution ◽  
Calcite Veins ◽  
Thrust Zone ◽  
Calcite Cementation ◽  
Calcite Cement

Petrographic and geochemical analyses (δ18O, δ13C, 87Sr/86Sr, clumped isotopes, and elemental composition) coupled with field structural data of synkinematic calcite veins, fault rocks, and host rocks are used to reconstruct the episodic evolution of an outstanding exposed thrust zone in the Southern Pyrenees and to evaluate the fault behavior as a conduit or barrier to fluid migration. The selected thrust displaces the steeply dipping southern limb of the Sant Corneli-Bóixols anticline, juxtaposing a Cenomanian-Turonian carbonate unit against a Coniacian carbonate sequence. Successive deformation events are recorded by distinct fracture systems and related calcite veins, highlighting (i) an episodic evolution of the thrust zone, resulting from an upward migration of the fault tip (process zone development) before growth of the fault (thrust slip plane propagation), and (ii) compartmentalization of the thrust fault zone, leading to different structural and fluid flow histories in the footwall and hanging wall. Fractures within the footwall comprise three systematically oriented fracture sets (F1, F2, and F3), each sealed by a separate generation calcite cement, and a randomly oriented fracture system (mosaic to chaotic breccia), cemented by the same cements as fracture sets F1 and F2. The formation of fractures F1 and F2 and the mosaic to chaotic breccia is consistent with dilatant fracturing within the process zone (around the fault tip) during initial fault growth, whereas the formation of the latest fracture system points to hybrid shear-dilational failure during propagation of the fault. The continuous formation of different fracture systems and related calcite cementation phases evidences that the structural permeability in the footwall was transient and that the fluid pathways and regime evolved due to successive events of fracture opening and calcite cementation. Clumped isotopes evidence a progressive increase in precipitation temperatures from around 50°C to 117°C approximately, interpreted as burial increase linked to thrust sheet emplacement. During this period, the source of fluid changed from meteoric fluids to evolved meteoric fluids due to the water-rock interaction at increasing depths and temperatures. Contrary to the footwall, within the hanging wall, only randomly oriented fractures are recognized and the resulting crackle proto-breccia is sealed by a later and different calcite cement, which is also observed in the main fault plane and in the fault core. This cement precipitated from formation fluids, at around 95°C, that circulated along the fault core and in the hanging wall block, again supporting the interpretation of compartmentalization of the thrust structure. The integration of these data reveals that the studied thrust fault acted as a transverse barrier, dividing the thrust zone into two separate fluid compartments, and a longitudinal drain for migration of fluids. This study also highlights the similarity in deformation processes and mechanisms linked to the evolution of fault zones in compressional and extensional regimes involving carbonate rocks.

scholarly journals Geochemical signatures of mineralizing events in the Juomasuo Au–Co deposit, Kuusamo belt, northeastern Finland

2021 ◽  
Author(s):  
Mikael Vasilopoulos ◽  
Ferenc Molnár ◽  
Hugh O’Brien ◽  
Yann Lahaye ◽  
Marie Lefèbvre ◽  
...  
Keyword(s):  
Trace Element ◽  
Sulfur Isotope ◽  
Mineral Chemistry ◽  
Chemical Compositions ◽  
Metasedimentary Rocks ◽  
Metavolcanic Rocks ◽  
Icp Ms ◽  
Stage 1 ◽  
Host Rocks ◽  
Relationship Of

AbstractThe Juomasuo Au–Co deposit, currently classified as an orogenic gold deposit with atypical metal association, is located in the Paleoproterozoic Kuusamo belt in northeastern Finland. The volcano-sedimentary sequence that hosts the deposit was intensely altered, deformed, and metamorphosed to greenschist facies during the 1.93–1.76 Ga Svecofennian orogeny. In this study, we investigate the temporal relationship between Co and Au deposition and the relationship of metal enrichment with protolith composition and alteration mineralogy by utilizing lithogeochemical data and petrographic observations. We also investigate the nature of fluids involved in deposit formation based on sulfide trace element and sulfur isotope LA-ICP-MS data together with tourmaline mineral chemistry and boron isotopes. Classification of original protoliths was made on the basis of geochemically immobile elements; recognized lithologies are metasedimentary rocks, mafic, intermediate-composition, and felsic metavolcanic rocks, and an ultramafic sill. The composition of the host rocks does not control the type or intensity of mineralization. Sulfur isotope values (δ34S − 2.6 to + 7.1‰) and trace element data obtained for pyrite, chalcopyrite, and pyrrhotite indicate that the two geochemically distinct Au–Co and Co ore types formed from fluids of different compositions and origins. A reduced, metamorphic fluid was responsible for deposition of the pyrrhotite-dominant, Co-rich ore, whereas a relatively oxidized fluid deposited the pyrite-dominant Au–Co ore. The main alteration and mineralization stages at Juomasuo are as follows: (1) widespread albitization that predates both types of mineralization; (2) stage 1, Co-rich mineralization associated with chlorite (± biotite ± amphibole) alteration; (3) stage 2, Au–Co mineralization related to sericitization. Crystal-chemical compositions for tourmaline suggest the involvement of evaporite-related fluids in formation of the deposit; boron isotope data also allow for this conclusion. Results of our research indicate that the metal association in the Juomasuo Au–Co deposit was formed by spatially coincident and multiple hydrothermal processes.

scholarly journals Topological inversions in coalescing granular media control fluid-flow regimes

2017 ◽  
Vol 96 (3) ◽  
Author(s):  
Fabian B. Wadsworth ◽  
Jérémie Vasseur ◽  
Edward W. Llewellin ◽  
Katherine J. Dobson ◽  
Mathieu Colombier ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Granular Media ◽  
Flow Regimes ◽  
Media Control ◽  
Control Fluid ◽  
Fluid Flow Regimes

Petrogenesis of Silicic Rocks from the Phan Si Pan - Tu Le region of the Emeishan Large Igneous Province, Northwestern Vietnam

2021 ◽  
pp. SP518-2020-253
Author(s):  
Thuy Thanh Pham ◽  
J. Gregory Shellnutt ◽  
Tuan-Anh Tran ◽  
Steven W. Denyszyn ◽  
Yoshiyuki Iizuka
Keyword(s):  
Basaltic Magma ◽  
Red River ◽  
Granitic Rocks ◽  
Large Igneous Province ◽  
Weighted Mean ◽  
Emeishan Large Igneous Province ◽  
Icp Ms ◽  
Igneous Province ◽  
Single Grain ◽  
Host Rocks

AbstractThe Permian silicic rocks in the Phan Si Pan (PSP) uplift area and Tu Le (TL) basin of NW Vietnam (collectively the PSP-TL region) are associated with the Emeishan Large Igneous Province (ELIP). The Permian Muong Hum, Phu Sa Phin, and Nam Xe - Tam Duong granites, and Tu Le rhyolites are alkali ferroan A1-type granitic rocks, which likely formed by fractional crystallization of high-Ti basaltic magma that was contaminated by melts derived from the Neoproterozoic host rocks. Zircon U-Pb LA-ICP-MS geochronology yielded weighted-mean 206Pb/238U ages of 246 ± 3 Ma to 259 ± 3 Ma for granites, and 249 ± 3 Ma and 254 ± 2 Ma for rhyolites. This is contrasted with previously-published high precision U-Pb ages, obtained using CA-ID-TIMS method applied on the same zircon grains, which suggest that the calculated LA-ICP-MS U-Pb ages are variably inaccurate by up to 10 Ma, though at the single-grain level dates generally agree within uncertainty. The similarity of rock texture, whole-rock geochemistry, emplacement ages, and fractionation phases between the PSP-TL region and silicic rocks in the Inner Zone ELIP (i.e., Panzhihua, Binchuan) suggests they were spatially proximal before being sinistrally displaced along the Ailao Shan-Red River shear zone.

scholarly journals Multiple fluid flow events from salt‐related rifting to basin inversion (Upper Pedraforca thrust sheet, SE Pyrenees)

2021 ◽  
Author(s):  
David Cruset ◽  
Jaume Vergés ◽  
Antonio Benedicto ◽  
Enrique Gomez‐Rivas ◽  
Irene Cantarero ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Thrust Sheet ◽  
Basin Inversion

scholarly journals INTEGRATED MODEL «RESERVOIR - WELL - PUMP» FOR UNSTEADY FLUID FLOW REGIMES CALCULATING

2021 ◽  
Vol 19 (1) ◽  
pp. 33
Author(s):  
A.A. Pashali ◽  
R.S. Khalfin ◽  
D.V. Silnov ◽  
A.S. Topolnikov ◽  
B.M. Latypov ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Flow Regimes ◽  
Integrated Model ◽  
Unsteady Fluid Flow ◽  
Unsteady Fluid ◽  
Fluid Flow Regimes

scholarly journals Eclogite-like rocks from Southern Pirin Mountains – preliminary results about petrology and time of formation

2021 ◽  
Vol 82 (3) ◽  
pp. 61-63
Author(s):  
Lyubomirka Macheva ◽  
Philip Machev ◽  
Rossitsa Vassilevа ◽  
Yulia Plotkina
Keyword(s):  
Mineral Assemblage ◽  
Late Jurassic ◽  
Mineral Chemistry ◽  
Metasomatic Alteration ◽  
Preliminary Results ◽  
Icp Ms ◽  
Geological Map ◽  
Host Rocks ◽  
The Village

North-northeast of the village of Ilinden (Southern Pirin Mnt.) three eclogite boudins were separated on the geological map in scale 1:50 000 (Sarov, 2010). The rocks belong to the Slasten lithotectonic unit. The mineral assemblage and mineral chemistry do not allow these rocks to be classified as eclogites. They can be considered as eclogite-like ones, formed by postmagmatic-metasomatic alteration of the host rocks. Based on LA-ICP-MS sphene U-Pb dating, eclogite-like rocks yield a Late Jurassic age (160±19 Ma).

scholarly journals Trace element geochemistry of carbonates in the Jurassic Lusitanian Basin records mineral-fluid interactions

2019 ◽  
Vol 98 ◽  
pp. 01017
Author(s):  
Mário A. Gonçalves ◽  
Maja Vuckovic ◽  
Alfonso Fiorelli ◽  
Pedro Barrulas ◽  
José Mirão
Keyword(s):  
Trace Elements ◽  
Fluid Flow ◽  
Carbonate Rocks ◽  
Sedimentary Basins ◽  
Trace Element Geochemistry ◽  
Element Geochemistry ◽  
Chemical Signatures ◽  
Icp Ms ◽  
Mineral Interaction ◽  
Lusitanian Basin

Carbonate rocks in sedimentary basins are reactive and can record complex histories of events associated with fluid flow in these basins. These include processes of dolomitization and dedolomitization. In this work we provide some preliminary data where distinct calcite and dolomite generations in the Jurassic Lusitanian Basin were analysed by LA-ICP-MS for trace elements in order to characterize chemical signatures of fluid-mineral interaction. It was observed that different carbonate generations can preserve the range of certain trace metal concentrations, but later calcites have distinctly higher contents in REE, Th and U, and Ba. Dolomites also show distinct chemical signatures but lack of analytical and spatial resolution does not allow quantification of the precursor calcite relicts. However, these processes point to the action of basinal fluids triggered by distinct tectonic episodes and associated volcanic activity.

Nature and longevity of hydrothermal fluid flow and mineralisation in granites of the Bushveld Complex, South Africa

2000 ◽  
Vol 91 (1-2) ◽  
pp. 269-281 ◽  
Author(s):  
L. J. Robb ◽  
L. A. Freeman ◽  
R. A. Armstrong
Keyword(s):  
Fluid Flow ◽  
Bushveld Complex ◽  
Hydrothermal Activity ◽  
Incompatible Trace Element ◽  
Ore Deposits ◽  
Fluid Saturation ◽  
Fracture Systems ◽  
Sulphide Ores ◽  
Tin Deposit ◽  
Granite Suite

The Lebowa Granite Suite of the Bushveld Complex is a large, 2054 Ma old, A-type batholith, characterised by numerous relatively small magmato-hydrothermal, polymetallic ore deposits. The mineralisation is represented by a three-stage paragenetic sequence: early magmatic Sn-W-Mo-F ores (600°C > T > 400°C), followed by a Cu-Pb-Zn-As-Ag-Au paragenesis (400°C > T > 200°C) and then late-stage Fe-F-U mineralisation (< 200°C). The first stage of mineralisation (typified by the endogranitic Zaaiplaats tin deposit) is related to incompatible trace element concentration during crystal fractionation and subsequent fluid saturation of the magma. Evolution of the late magmatic fluids as they were channelled along fractures, as well as mingling with externally derived connate or meteoric fluids, resulted in the deposition of the second stage of mineralisation (typified by the fracture-related, endogranitic Spoedwel and Albert deposits and the exogranitic, sediment-hosted Rooiberg mine) which is dominated by polymetallic sulphide ores. As the externally derived fluid component became progressively more dominant, oxidation of the polymetallic sulphide assemblage and precipitation of hematite, pitchblende and fluorite occurred generally along the same fracture systems that hosted the earlier sulphide paragenesis.Small hydrothermal zircons trapped along quartz growth zones from the Spoedwel deposit yield a U-Pb concordia age of 1957 ± 15 Ma. Whole-rock Rb-Sr age determinations from the Lebowa Granite Suite fall in the range 1790 ± 114 Ma to 1604 ± 70 Ma and are interpreted to reflect alkali element mobility and isotopic resetting during exhumation of the Bushveld granite. In contrast to thermal modelling which indicates that hydrothermal activity should have ceased within 4 my of emplacement, isotopic evidence suggests that mineralisation was long-lived, but episodic, and that fluid flow events were linked to major periods of Palaeo- and Mesoproterozoic orogenic activity along the margins of the Kaapvaal Craton. During these orogenic episodes, fluid flow was enhanced by tectonically induced fluid over-pressuring and/or exhumation of the Bushveld Complex.

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