Kate Rubingh - Academia.edu (original) (raw)

Papers by Kate Rubingh

Orogenic gold deposits in the Snow Lake area in the southeastern Trans Hudson Orogen, Manitoba, i... more Orogenic gold deposits in the Snow Lake area in the southeastern Trans Hudson Orogen, Manitoba, include the New Britannia deposit which, with a past production of a 1.4M oz Au (43 699 kg), is the largest Proterozoic gold deposit in Manitoba and Saskatchewan. The deposits are hosted by the ca. 1.89 Ga Paleoproterozoic Snow Lake arc (SLA) assemblage of the Flin Flon Glennie Complex (FFGC). The FFGC is bound by a sedimentary basin to the north, namely the Kisseynew Domain. It represents an oceanic protocontinent within an ancestral ocean, the Manikewan Ocean, which occupied the region between three Archean cratons (Hearne, Sask, Superior). The deposits occur within a sequence of explosive, submarine, bimodal volcanic rocks emplaced during an early episode of rifting and subsidence of the SLA. Deformation of these rocks began with their imbrication along brittle thrust faults during a D1 event. It continued during a ca. 1.84-1.82 Ga D2 event with thrusting of the Kisseynew basin and FFGC above the colliding Sask craton. The D2 event produced a penetrative regional foliation axial planar to map-scale isoclinal folds (NorAcme Anticline), sheath-like gneiss domes along the Kisseynew-FFGC boundary, and regional southwest-directed ductile thrust faults, such as the McLeod Road Thrust. Final collision of the FFGC and Sask craton with the Superior craton during a ca. 1.83-1.80 Ga D3 event reactivated the ductile thrust faults, folded the gneiss domes, and enabled the development of an orogen-parallel regional stretching lineation during lateral flow parallel to the cold Superior craton. The New Britannia deposit and nearby gold deposits were emplaced in the hinge of the Nor-Acme Anticline early during the D2 event, were folded during tightening of the fold, stretched parallel to the regional stretching lineation, and transposed along a late crosscutting shear zone, the Howe iv Sound fault, which formed as a transfer fault during thrusting. The deposits formed at amphibolite facies conditions during a prograde metamorphic event that culminated during the collision of the FFGC and Sask craton with the Superior craton during the D3 event. Thus, the deposits are atypical compare to most other Proterozoic and Archean orogenic gold deposits which typically form at greenschist facies conditions. Keywords Snow Lake arc assemblage, Flin Flon Glennie Complex, explosive submarine felsic volcanism, rifting, orogen-parallel stretching lineation, amphibolite facies orogenic gold deposits, thrusting, LA-ICP-MS mapping of arsenopyrite v Co-Authorship Statement This thesis consists of three manuscripts, which were prepared for publication in peer-reviewed scientific journals; one of which is published. The Appendix contains two "Report of Activity Papers", and one preliminary published map published by the Manitoba Geological Survey. Additionally, a field trip guide is included, which was presented to Hudbay Minerals Inc. Chapters two to four and the papers in the appendices were co-authored by the candidate and several collaborators, who provided constructive suggestions and edits. The candidate is the first author on all manuscripts. Chapter 2, 3 and 4 of this dissertation are co-authored with Drs. Bruno Lafrance and Harold Gibson. The candidate completed the field work and analytical work under the main guidance and supervision of Drs. Bruno Lafrance and Harold Gibson. Field work included mapping of outcrops, core-logging, and sample collection. Drill core was provided by Alexis Minerals Corporation and QMX Gold Corporation, and samples were chosen specifically by the candidate for further analytical work. Analytical work involved petrography, SEM analyses, data processing and subsequent interpretation. The geochemical, analyses discussed in Chapters 2 and 4 were completed by: i) the Activation Laboratories Ltd. in Ancaster, Ontario, ii) the Geoscience Laboratories of the Ministry of Northern Developments and Mines in Sudbury, Ontario, iii) ALS Limited, Sudbury, Ontario. The isotope analysis was conducted at the Pacific Centre for Isotopic

Geoscience Canada, Jan 24, 2013

International Conference on Multimedia Information Networking and Security, 2012

The New Britannia mine is a structurally controlled gold deposit hosted in mafic and felsic volca... more The New Britannia mine is a structurally controlled gold deposit hosted in mafic and felsic volcanic and volcaniclastic rocks. Mineralization is spatially associated with the hangingwall of the McLeod Road Thrust (MRT), and the gold deposits are located at stratigraphic contacts between units of contrasting competency at the intersection of a fault and a secondary structure, typically a fold hinge. Completion of the 2012 lithostratigraphic mapping of the McLeod Road-Birch Lake thrust panel (MB panel) has identified additional thrust faults, which repeat stratigraphic units of the panel. These structures appear to be truncated by the MRT and have been interpreted as early D 1 structures. The main foliation in the MB panel (S 1) is defined by the flattening of the clasts and is interpreted as a fabric formed during D 1 folding and thrust imbrication of the MB panel. The S 1 foliation is axial planar to the Nor-Acme anticline (F 1 fold) and is consistently parallel to the MRT (late D 1 thrust) contact. These D 1 structures are overprinted by a spaced cleavage (S 2), which overprints the Howe Sound Fault, the MRT and the Nor-Acme anticline. This fabric is correlative with the regional S 2 fabric in the Burntwood Group, and it is inferred that the S 2 fabric in the MB panel may be related to sinistral reactivation of the MRT. A spaced, steeply dipping, S 3 fracture cleavage related to the Threehouse synform (F 3 fold) consistently overprints all fabric elements. Gold mineralization is associated with D 1 structures and there is evidence to suggest that emplacement was late D 1 with later remobilization during D 2 .

Geophysical Prospecting, Dec 7, 2022

ABSTRACTA high‐resolution seismic reflection transect was acquired over a hard‐rock geological se... more ABSTRACTA high‐resolution seismic reflection transect was acquired over a hard‐rock geological setting along an existing roadway in the Larder Lake area of the Superior Craton of Canada for the Metal Earth project in 2017. This profile, as well as other Metal earth transects, primarily aims to enhance the knowledge and to better understand the subsurface geology of the Abitibi Greenstone Belt within the Canadian Shield. The complex geological settings of the study area as well as the tribulations caused by the survey geometry have made the imaging and velocity field estimation more challenging. A recently introduced 2.5D multifocusing stacking method is one potential solution for processing crooked‐line seismic data with a poor signal‐to‐noise ratio. The 2.5D multifocusing approach offers more realistic modelling of the zero‐offset wavefield by explicitly accounting for the midpoint dispersion and cross‐dip effects. The main practical problem of the 2.5D multifocusing implementation is the simultaneous determination of the optimal wavefield parameters for each image point and time location. We address this optimization problem using a multidimensional constrained differential evolution global optimization algorithm, as this improves the efficiency and accuracy of the estimation. We have also designed an efficient processing sequence for multifocusing seismic imaging. The performance of the 2.5D multifocusing procedure has been examined on a synthetic model, generated using the same real acquisition geometry. Numerical tests demonstrate that the 2.5D multifocusing technique can produce a more focused stack with the primary reflections appearing at their poststack correct locations, and the procedure can also provide reliable estimates of interface dips. Due to the importance and difficulty of imaging the data, several conventional and advanced processing strategies have been attempted on the transect, specifically: 2D phase‐shift time migration of a dip moveout corrected stack; 2D prestack Kirchhoff time migration; swath 3D poststack migration; and our 2.5D multifocusing imaging algorithm. We found that applying the 2.5D multifocusing stacking algorithm followed by a poststack time migration approach improved the resolution of the image significantly compared to all the conventional and advanced methods and identified new reflections. The 2.5D multifocusing method also focused the steeply dipping reflections more coherently, which resolved ambiguities in geological architecture by understanding the location and continuity of structures. The method also accurately extracts 3D structural information and results in an improved signal‐to‐noise ratio.

Geological Society of America eBooks, Jan 23, 2023

Canadian Journal of Earth Sciences, Jul 1, 2021

The Snow Lake gold camp is located within amphibolite facies volcanic rocks of the ca. 1.88–1.87 ... more The Snow Lake gold camp is located within amphibolite facies volcanic rocks of the ca. 1.88–1.87 Ga Flin Flon – Glennie Complex (FFGC) in the Trans-Hudson Orogen, Manitoba. During thrusting and collision with the Archean Sask craton, volcanic rocks were interleaved with turbidites of the ca. 1.855–1.84 Ga Burntwood Group and sandstone and conglomerate of the ca. 1.845–1.835 Ga Missi Group. The main cleavage in the turbidites was previously attributed to thrusting and used as a marker for correlating structures across the camp. A re-examination of this cleavage suggests that it overprints the thrust faults and formed during later collision between the FFGC and the Archean Superior craton. This has important implications as it further suggests that (1) previously unrecognized, early brittle thrust faults repeat volcanic stratigraphy and may have created the boundary conditions that enabled the formation of ductile thrust faults, fold nappes, and mega sheath folds; (2) shear sense indicators along ductile thrust faults formed during their reactivation as sinistral shear zones rather than during thrusting; and (3) peak metamorphic conditions were caused by thrusting and stacking during collision with the Sask craton but were attained later during collision with the Superior craton due to the time lag between orogenesis and the re-equilibration of regional isotherms. Results from this study may be applicable to other complexly deformed terranes where the dominant regional cleavage differs in expression in mixed volcanic and sedimentary successions and has been used as a marker for correlating structures.

Laurentia: Turning Points in the Evolution of a Continent

The Neoarchean is generally considered to have been the final era of major crust formation and ma... more The Neoarchean is generally considered to have been the final era of major crust formation and may have been characterized by the onset of modern plate tectonics. The Neoarchean may also have been the time interval during which subduction processes prevailed and became global. Evidence from individual cratons around the world suggests that this transition in geodynamic processes may have included diachronous and episodic major changes (i.e., turning points) and a more gradual evolution at the global scale, possibly largely driven by the secular cooling of the mantle and increasing stability of the lithosphere. The Superior craton, Canada, is the largest and best-preserved Archean craton in the world, making it an ideal location in which to investigate the occurrence (or absence) of turning points in the Neoarchean. This contribution examines the changes in geodynamic and magmatic processes that occurred during the Neoarchean, using geochemical data and new insights garnered from iso...

Passive seismic methods are considered as cost-effective and environmental-friendly alternatives ... more Passive seismic methods are considered as cost-effective and environmental-friendly alternatives to active (reflection) seismic methods. We have acquired co-located active and passive seismic surve...

Canadian Journal of Earth Sciences, 2021

Canadian Journal of Earth Sciences, 2017

The thrust-bounded McLeod Road – Birch Lake (MB) sequence occurs within the Paleoproterozoic Snow... more The thrust-bounded McLeod Road – Birch Lake (MB) sequence occurs within the Paleoproterozoic Snow Lake arc (SLA) assemblage of the Flin Flon belt. Stratigraphic correlation of volcanic strata of the MB sequence with strata of the thrust-bounded Chisel sequence indicates that distinctive, submarine, eruption-fed, pyroclastic flow deposits are more extensive and voluminous than previously recognized (>10 km3). These voluminous felsic pyroclastic deposits define a distinct magmatic and explosive volcanic event during bimodal volcanism that accompanied rifting of the SLA. The felsic pyroclastic deposits define the remnants of a basin, or of nested basins, that formed during arc rifting and subsidence, and their eruption immediately preceded formation of the Chisel sequence volcanogenic massive sulfide (VMS) deposits. Although the Chisel sequence ore interval is recognized in the MB sequence, the lack of VMS-related alteration indicates that VMS hydrothermal activity was restricted to...

Geophysical Prospecting