scholarly journals Dating Hydrothermal Alteration Attending IOCG Mineralization Along a Terrane Bounding Fault Zone: The Copper Lake Deposit, Nova Scotia

10.4138/10090 ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 146 ◽  
Author(s):  
Daniel. J. Kontak ◽  
Douglas A. Archibald ◽  
Robert A. Creaser ◽  
Larry M. Heaman
Keyword(s):  
Nova Scotia ◽  
Fault Zone ◽  
Hydrothermal Alteration

scholarly journals Hydrothermal alteration of fractured Carboniferous sedimentary rocks along the Cobequid Fault Zone, western Nova Scotia

2017 ◽  
Author(s):  
G Pe-Piper ◽  
D J W Piper ◽  
Y Zhang ◽  
C Sangster
Keyword(s):  
Nova Scotia ◽  
Fault Zone ◽  
Hydrothermal Alteration ◽  
Sedimentary Rocks

HEMATITE (U-TH)/HE CONSTRAINTS ON SYNCHRONOUS DEFORMATION, HYDROTHERMAL ALTERATION, AND SURFACE UPLIFT IN THE EASTERN DENALI FAULT ZONE, YUKON, CANADA

2019 ◽  
Author(s):  
Robert G. Mcdermott ◽  
◽  
Alexis K. Ault ◽  
Jonathan Saul Caine ◽  
Peter W. Reiners
Keyword(s):  
Fault Zone ◽  
Hydrothermal Alteration ◽  
Denali Fault ◽  
Surface Uplift

Early Carboniferous deformation and mineralization in the Cobequid shear zone, Nova Scotia: an 40Ar/39Ar geochronology study

2004 ◽  
Vol 41 (12) ◽  
pp. 1425-1436 ◽  
Author(s):  
Georgia Pe-Piper ◽  
Peter H Reynolds ◽  
Joe Nearing ◽  
David JW Piper
Keyword(s):  
Nova Scotia ◽  
Shear Zone ◽  
Hydrothermal Alteration ◽  
Early Carboniferous ◽  
Fault Zones ◽  
Igneous Rocks ◽  
Pluton Emplacement ◽  
History Of ◽  
Temperature Shear ◽  
Age Determinations

Latest Devonian to Early Carboniferous igneous rocks along the Cobequid shear zone of central Nova Scotia record a complex history of intrusion, volcanism, deformation, and hydrothermal alteration. Twenty new 40Ar/39Ar age determinations have been made on biotite and hornblende separates from rocks that constrain these events. The mafic plutons of the Cobequid shear zone are synchronous with the previously dated granitoid plutons (363–355 ± 4 Ma), with the exception of the younger Folly Lake gabbro (355–350 ± 4 Ma). High temperature shear deformation continued along the Cobequid shear zone during this entire period of pluton emplacement. Several samples from mylonitic and hydrothermally altered rocks with dates ca. 340 Ma indicate renewed movement along the Cobequid shear zone at this time, accompanied by minor magmatism. Younger ∼330–320 Ma ages reflect final movement along the Rockland Brook fault resulting in mid-Namurian uplift of the Cobequid Highlands. Following this regional Alleghenian event, there was no significant motion on the northern faults of the Cobequid shear zone and deformation moved southward to the Cobequid fault and its continuation in the Hollow and Chedabucto fault zones. Hydrothermal alteration, probably driven by a mid-crustal gabbro heat source, was widespread along the Cobequid and Rockland Brook faults in the early Carboniferous, resulting in albitization, potassic alteration, and iron mineralization.

Hydrothermal Alteration Mineralogy and Geochemistry of the Archean World-Class Canadian Malartic Disseminated-Stockwork Gold Deposit, Southern Abitibi Greenstone Belt, Quebec, Canada

2019 ◽  
Vol 114 (6) ◽  
pp. 1057-1094 ◽  
Author(s):  
Stéphane De Souza ◽  
Benoît Dubé ◽  
Patrick Mercier-Langevin ◽  
Vicki McNicoll ◽  
Céline Dupuis ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Fault Zone ◽  
Hydrothermal Alteration ◽  
Greenstone Belt ◽  
Gold Mineralization ◽  
Amphibolite Facies ◽  
Alteration Zone ◽  
Gold Deposition ◽  
Abitibi Greenstone Belt ◽  
World Class

Abstract The Canadian Malartic stockwork-disseminated gold deposit is an Archean world-class deposit located in the southern Abitibi greenstone belt. It contains over 332.8 tonnes (t; 10.7 Moz) of Au at a grade of 0.97 ppm, in addition to 160 t (5.14 Moz) of past production (1935–1981). Although the deposit is partly situated within the Larder Lake-Cadillac fault zone, most of the ore occurs up to ~1.5 km to the south of the fault zone. The main hosts of the mineralized zones are greenschist facies turbiditic graywacke and mudstone of the Pontiac Group (~2685–2682 Ma) and predominantly subalkaline ~2678 Ma porphyritic quartz monzodiorite and granodiorite. These intrusions were emplaced during an episode of clastic sedimentation and alkaline to subalkaline magmatism known as the Timiskaming assemblage (<2680–2670 Ma in the southern Abitibi). The orebodies define two main mineralized trends, which are oriented subparallel to the NW-striking S2 cleavage and the E-striking, S-dipping Sladen fault zone. This syn- to post-D2 ductile-brittle to brittle Sladen fault zone is mineralized for more than 3 km along strike. The ore mainly consists of disseminated pyrite in stockworks and replacement zones, with subordinate auriferous quartz veins and breccia. Gold is associated with pyrite and traces of tellurides defining an Au-Te-W ± Ag-Bi-Mo-Pb signature. The orebodies are zoned outward, and most of the higher-grade (>1 ppm Au) ore was deposited as a result of iron sulfidation from silicates and oxides and Na-K metasomatism in carbonatized rocks. The alteration footprint comprises a proximal alteration envelope (K- or Na-feldspar-dolomite-calcite-pyrite ± phlogopite). This proximal alteration zone transitions to an outer shell of altered rocks (biotite-calcite-phengitic white mica), which hosts sub-ppm gold grades and reflects decreasing carbonatization, sulfidation, and aNa+/aH+ or aK+/aH+ of the ore fluid. Gold mineralization, with an inferred age of ~2664 Ma (Re-Os molybdenite), was contemporaneous with syn- to late-D2 peak metamorphism in the Pontiac Group; it postdates sedimentation of the Timiskaming assemblage along the Larder Lake-Cadillac fault zone (~2680–2669 Ma) and crystallization of the quartz monzodiorite. These chronological relationships agree with a model of CO2-rich auriferous fluid generation in amphibolite facies rocks of the Pontiac Group and gold deposition in syn- to late-D2 structures in the upper greenschist to amphibolite facies. The variable geometry, rheology, and composition of the various intrusive and sedimentary rocks have provided strain heterogeneities and chemical gradients for the formation of structural and chemical traps that host the gold. The Canadian Malartic deposit corresponds to a mesozonal stockwork-disseminated replacement-type deposit formed within an orogenic setting. The predominance of disseminated replacement ore over fault-fill and extensional quartz-carbonate vein systems suggests that the mineralized fracture networks remained relatively permeable and that fluids circulated at a near-constant hydraulic gradient during the main phase of auriferous hydrothermal alteration.

Hydrothermal Alteration Along the Lisbon Valley Fault Zone, San Juan County, Utah

1965 ◽  
Vol 76 (4) ◽  
pp. 423 ◽  
Author(s):  
MARIAN B. JACOBS ◽  
PAUL F. KERR
Keyword(s):  
Fault Zone ◽  
Hydrothermal Alteration ◽  
San Juan ◽  
San Juan County

Hydrothermal alteration in an exhumed crustal fault zone: Testing geochemical mobility in the Caleta Coloso Fault, Atacama Fault System, Northern Chile

2014 ◽  
Vol 623 ◽  
pp. 147-168 ◽  
Author(s):  
Gloria Arancibia ◽  
Kazuna Fujita ◽  
Kenichi Hoshino ◽  
Thomas M. Mitchell ◽  
José Cembrano ◽  
...  
Keyword(s):  
Fault Zone ◽  
Hydrothermal Alteration ◽  
Fault System ◽  
Northern Chile ◽  
Atacama Fault System

Anatomy of a terrane boundary: an integrated structural, geographic information system, and remote sensing study of the late Paleozoic Avalon-Meguma terrane boundary, mainland Nova Scotia, Canada

1998 ◽  
Vol 35 (7) ◽  
pp. 787-801 ◽  
Author(s):  
T L Webster ◽  
J B Murphy ◽  
S M Barr
Keyword(s):  
Remote Sensing ◽  
Information System ◽  
Nova Scotia ◽  
Geographic Information System ◽  
Fault Zone ◽  
System Analysis ◽  
Geographic Information ◽  
Radar Images ◽  
Meguma Terrane ◽  
Shaded Relief

Remote sensing and geographic information system analysis complimented by geological mapping have resulted in a new interpretation of the Late Carboniferous evolution of the Avalon-Meguma terrane boundary (known as the Minas Fault Zone) in the Canadian Appalachian Orogen. Various images, including optical, radar, and shaded-relief elevation, have been integrated with magnetic and gravity data to compliment mapping in the vicinity of the exposed terrane boundary in mainland Nova Scotia. Throughout much of the region, the style of deformation is typical of dextral motion along the east-west Chedabucto Fault, the most prominent structure in the Minas Fault Zone. Lineament analysis of the shaded-relief elevation and radar images has identified an important lineament trending east-northeast which corresponds to the axial trace of folds that rotate clockwise into parallelism with the Chedabucto Fault. However, in eastern mainland Nova Scotia, the shaded-relief and geophysical images, together with field data, suggest that the Chedabucto Fault was offset by sinistral motion along the north-northwest-trending Country Harbour Fault. Following this event, the region in the vicinity of this offset became a restraining bend during renewed dextral motion along the Chedabucto Fault, resulting in the formation of a positive flower structure represented by the exposure of Early Devonian volcanic and sedimentary rocks in the Guysborough block. The processes described are probably typical of recurrent motions along terrane boundaries.

Fluids and hydrothermal alteration assemblages in a Devonian gold-bearing hot-spring system, Rhynie, Scotland

2003 ◽  
Vol 94 (4) ◽  
pp. 309-324 ◽  
Author(s):  
M. Baron ◽  
S. Hillier ◽  
C. M. Rice ◽  
K. Czapnik ◽  
J. Parnell
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Fault Zone ◽  
Hydrothermal Alteration ◽  
Hot Spring ◽  
Medium Temperature ◽  
Low Salinity ◽  
Major Fault ◽  
Spring System ◽  
Gold Bearing

ABSTRACTHydrothermal alteration at Rhynie, Aberdeenshire, Scotland, is concentrated along a fault zone, which juxtaposes surface deposits and the mineralised feeder zone to the Rhynie hotspring system. Mineralisation consists of breccias and veins filled with quartz, chert, calcite, K-feldspar and pyrite. Associated pervasive alteration comprises a high-temperature K-feldsparquartz-illite facies (formed at 250–350°C), a medium-temperature mixed layered illite/smectitequartz-K-feldspar-chlorite-calcite facies (formed at 150–200°C) and a low-temperature mixed layered illite/smectite-chlorite-calcite facies (formed at 100 to +150°C). The fluids responsible for mineralisation were mainly moderate- to high-temperature (Th =91–360°C), low-salinity (<0·2 to 2·9 wt.% NaCl eq.) H2O-NaCl-heated meteoric fluids comparable to modern and ancient hot-spring systems. The migration of these fluids was mainly restricted to a major fault zone bounding the Devonian basin. Fluids responsible for mineralisation, alteration and cementation elsewhere in the basin were low-temperature (Th 57 to 161°C), low- to high-salinity (<0·2 to 18 wt.% NaCl eq.) H2O-NaCl fluids, which resemble basinal brines.

scholarly journals Structural and Mineralogical Characterization of a Fossil Hydrothermal System Located at the Outermost Front of the Southern Apennines Fold-and-Thrust Belt

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Paolo Fulignati ◽  
Fabrizio Agosta ◽  
Claudia Belviso ◽  
Giacomo Prosser ◽  
Antonio Lettino ◽  
...  
Keyword(s):  
High Temperature ◽  
Fault Zone ◽  
Hydrothermal Alteration ◽  
Hydrothermal System ◽  
Positive Anomaly ◽  
Thrust Belt ◽  
Hydrothermal Circulation ◽  
Geothermal Resources ◽  
Mineralogical Characterization ◽  
Fold And Thrust Belt

Aiming at investigating the hydrothermal circulation along the eastern flank of the Vulture volcano, along the outermost edge of the southern Apennine fold-and-thrust belt (ftb), we studied the fossil hydrothermal alteration that mineralized a transtensional fault that crosscuts volcanoclastic rocks in the Rapolla area. On the basis of structural, mineralogical, and fluid inclusion data, three main stages of activity of the hydrothermal system are documented. Stage 1 was produced by the circulation of fluids having low-pH conditions (pH ≈ 3-4) and relatively high-SO42- activity, as testified by the hydrothermal alteration mainly carried out by the alunite group minerals (particularly jarosite), which is typical of an advanced argillic alteration facies. Hydrothermal fluids were characterized by a high temperature of about 200°-210°C. These hot fluids altered and mineralized the matrices of pyroclastic rocks and sealed both burial-related and fault-related fracture networks. Later hydrothermal circulation (Stage 2) was recorded by opal A-rich veins present both within and outside the fault zone. The fluids responsible of opal A precipitation were characterized by lower temperature conditions, probably lower than 100°C. Current goethite mineralization takes place along the main slip surfaces of the study high-angle fault zone due to low temperature (<30°C) underground water circulation. This study highlights that a high-temperature hydrothermal system developed in the past within the transtensional fault zone of the Rapolla area when a high thermal anomaly was present. If we take into account that this area is still affected by a heat flux positive anomaly (90 mW/m2), we may infer that it has the potentiality to be considered an interesting site for future exploration devoted to the finding of medium-enthalpy geothermal resources at depth.

Sign in / Sign up

Export Citation Format

Share Document