scholarly journals Project Seagull: a multi-disciplinary approach to revisional geological bedrock mapping along the Precambrian Shield Margin in the Flin Flon-Amisk Lake area

1995 ◽  
Author(s):  
B A Reilly ◽  
D J Thomas ◽  
W L Slimmon ◽  
K E Ashton ◽  
C T Harper
Keyword(s):  
Lake Area ◽  
Precambrian Shield ◽  
Flin Flon

Coeval sedimentation, magmatism, and fold-thrust belt development in the Trans-Hudson Orogen: geochronological evidence from the Wekusko Lake area, Manitoba, Canada

1999 ◽  
Vol 36 (2) ◽  
pp. 293-312 ◽  
Author(s):  
Kevin M Ansdell ◽  
Karen A Connors ◽  
Richard A Stern ◽  
Stephen B Lucas
Keyword(s):  
Regional Metamorphism ◽  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Detrital Zircons ◽  
Lake Area ◽  
Thrust Belt ◽  
Fold And Thrust Belt ◽  
Minimum Age ◽  
Flin Flon ◽  
Felsic Volcanic

Lithological and structural mapping in the east Wekusko Lake area of the Flin Flon Belt, Trans-Hudson Orogen, suggested an intimate relationship between magmatism, fluvial sedimentation, and initiation of fold and thrust belt deformation. Conventional U-Pb geochronology of volcanic rocks in fault-bounded assemblages provides a minimum age of 1876 ± 2 Ma for McCafferty Liftover back-arc basalts, and ages of between 1833 and 1836 Ma for the Herb Lake volcanic rocks. A rhyolite which unconformably overlies Western Missi Group fluvial sedimentary rocks has complex zircon systematics. This rock may be as old as about 1856 Ma or as young as 1830 Ma. The sedimentary rocks overlying this rhyolite are locally intercalated with 1834 Ma felsic volcanic rocks, and yield sensitive high resolution ion microprobe (SHRIMP) U-Pb and Pb-evaporation detrital zircon ages ranging from 1834 to 2004 Ma. The Eastern Missi Group is cut by an 1826 ± 4 Ma felsic dyke, and contains 1832-1911 Ma detrital zircons. The dominant source for detritus in the Missi Group was the Flin Flon accretionary collage and associated successor arc rocks. The fluvial sedimentary rocks and the Herb Lake volcanic rocks were essentially coeval, and were then incorporated into a southwest-directed fold and thrust belt which was initiated at about 1840 Ma and active until at least peak regional metamorphism.

Pressure and temperature conditions of metamorphism in the vicinity of three massive sulfide deposits, Flin Flon – Snow Lake belt, Manitoba

1987 ◽  
Vol 24 (11) ◽  
pp. 2305-2315 ◽  
Author(s):  
Pradeep K. Aggarwal ◽  
Bruce E. Nesbitt
Keyword(s):  
Experimental Studies ◽  
Massive Sulfide ◽  
Greenschist Facies ◽  
Maximum Pressure ◽  
Lake Area ◽  
Sulfide Deposits ◽  
Temperature Conditions ◽  
Massive Sulfide Deposits ◽  
Flin Flon ◽  
Temperature And Pressure

Estimates of pressure and temperature conditions of metamorphism in the vicinity of three massive sulfide deposits of the Flin Flon – Snow Lake, Manitoba, greenstone belt have been obtained using mineral assemblages in mafic and felsic metavolcanic rocks. The Flin Flon area around the Centennial deposit, in the western part of the belt, has been metamorphosed to low greenschist facies. Near the Spruce Point deposit, in the central part of the belt, the metamorphic conditions are estimated to be of the upper greenschist facies, with a temperature of 475 ± 75 °C at 2.6 ± 1.2 kbar pressure (1 kbar = 0.1 kPa). The Snow Lake area to the west, in the vicinity of the Anderson Lake deposit, has been metamorphosed to sillimanite grade. In the staurolite–biotite–sillimanite zone, the temperature and pressure conditions were 580 ± 25 °C and 5.25 + 0.75 kbar; in the biotite–sillimanite–almandine zone, the temperature was 620 ± 25 °C at a maximum pressure of 6.2 kbar. Based on the temperature and pressure estimates from the Snow Lake area, it is suggested that experimental studies of the upper stability of staurolite and quartz at low pressure indicate temperatures that are unusually high compared with those indicated by field assemblages.

Isotopic Studies of Ore-Leads in the Hanson Lake-Flin Flon-Snow Lake Mineral Belt Saskatchewan and Manitoba

1972 ◽  
Vol 9 (5) ◽  
pp. 500-513 ◽  
Author(s):  
D. F. Sangster
Keyword(s):  
Volcanic Rocks ◽  
Massive Sulfide ◽  
Good Evidence ◽  
Lake Area ◽  
Sulfide Ores ◽  
Geological Evidence ◽  
Isotopic Studies ◽  
Mineral Belt ◽  
Flin Flon ◽  
Host Rocks

Lead isotope abundances in 4 stratabound sulfide ores are presented and show characteristics of being single-stage lead deposits. Model ages based on these data range from 1780 ± 44 to 1900 ± 44 m.y. and are considered to be close approximations of the time of ore formation. Geological evidence in the massive sulfide deposits suggests they are coeval with their host rocks, which are predominantly volcanics of the Amisk Group. If this assumption is correct the average model lead age of the ores is essentially the age of the enclosing rocks. Within error limits the results are in good agreement with published Rb-Sr ages for Amisk rocks of the Flin Flon area, and with U-Pb ages in zircons of rhyolites, which also contain similar, massive sulfide ores in the Churchill Province of Arizona. This is considered to be good evidence that the Hanson Lake-Flin Flon-Snow Lake volcanic mineral belt, previously regarded as Archean, is Aphebian in part.A previously published Archean, Rb-Sr isochron for volcanic rocks in the Hanson Lake area may indicate that Amisk-type rocks are a folded complex of both Aphebian and Archean lithologies. The suggested Aphebian age of the Amisk-Missi Groups and their equivalents, indicates they are possibly eugeosynclinal equivalents of the miogeosynclinal Hurwitz sediments.

U–Pb geochronology of late Neoarchean tonalites in the Flin Flon Belt, Trans-Hudson Orogen: surprise at surface

1994 ◽  
Vol 31 (12) ◽  
pp. 1785-1790 ◽  
Author(s):  
J. David ◽  
E. C. Syme
Keyword(s):  
Shear Zone ◽  
Tectonic Evolution ◽  
Volcanic Belt ◽  
Lake Area ◽  
Magmatic Rocks ◽  
Flin Flon ◽  
First Time

The Flin Flon volcanic belt of the Trans-Hudson Orogen in northern Manitoba comprises magmatic rocks (1.88 – 1.90 Ga) generated in an intra-oceanic arc and identified as one of the best examples of juvenile Paleoproterozoic crust. In the Flin Flon – Athapapuskow Lake area, the belt consists of a series of fault-bounded blocks, each having distinct stratigraphic and magmatic affinities, juxtaposed to form an accretionary collage. Two tonalitic bodies within the Northeast Arm shear zone, a major deformation corridor separating two of the most important blocks in the area, have been dated by the U–Pb zircon method at [Formula: see text] and [Formula: see text]. These results indicate the presence of fragments of late Neoarchean crust within the Flin Flon belt, possibly related to ca. 2.5 Ga granitic bodies found in terranes beyond the western limit of the belt. The presence of ca. 2.5 Ga tonalites within the Flin Flon Belt, herein reported for the first time, has major implications for basement involvement in the early tectonic evolution of the Flin Flon Belt.

Crustacean Zooplankton Communities and Lake Morphometry in Precambrian Shield Lakes

1994 ◽  
Vol 51 (11) ◽  
pp. 2424-2434 ◽  
Author(s):  
W. Keller ◽  
M. Conlon
Keyword(s):  
Species Richness ◽  
Maximum Depth ◽  
Crustacean Zooplankton ◽  
Small Fish ◽  
Lake Area ◽  
Lake Depth ◽  
Lake Morphometry ◽  
Precambrian Shield ◽  
Zooplankton Communities ◽  
Shield Lakes

To investigate relationships between crustacean zooplankton communities and lake morphometry we sampled 60 near-neutral Precambrian Shield lakes, including many small, shallow lakes. Morphometry-related patterns in the distributions of many zooplankton species were evident. Lake depth determined the occurrence of hypolimnetic species, and lake depth, lake area, and watershed area were positively related to the species richness of zooplankton communities. Among lakes with fish, deeper (maximum depth >8 m) lakes were characterized by greater species richness, higher abundances of a number of species including Daphnia pulex, Daphnia galeata mendotae, Daphnia dubia, and Diacyclops bicuspidatus thomasi, and lower abundances of Leptodiaptomus minutus, than shallower (maximum depth <8 m) lakes. Increased predation pressure by small fish species in smaller, shallower lakes probably influenced the observed species distributions. Lakes inferred to be fishless based on the presence of Chaoborus americanus typically had relatively high abundances of D. pulex, Diaphanosoma brachyurum, and Aglaodiaptomus leptopus, and absences of D. g. mendotae and D. birgei, patterns attributable to intense invertebrate predation on zooplankton.

scholarly journals Airborne geophysical survey, Flin Flon-Hanson Lake area, Saskatchewan

1996 ◽  
Author(s):  
R B K Shives ◽  
R J Hetu ◽  
P B Holman
Keyword(s):  
Geophysical Survey ◽  
Lake Area ◽  
Flin Flon

Comportement du système U-Pb dans la monazite et chronologie de la déformation et du métamorphisme des metasédiments du domaine de Kisseynew, orogène trans-hudsonien (Manitoba, Canada)

1999 ◽  
Vol 36 (11) ◽  
pp. 1843-1857 ◽  
Author(s):  
Martin Parent ◽  
Nuno Machado ◽  
Herman Zwanzig
Keyword(s):  
Transition Zone ◽  
Lower Limit ◽  
Amphibolite Facies ◽  
Lake Area ◽  
Central Unit ◽  
Continuous Deformation ◽  
Minimum Age ◽  
Peak Metamorphism ◽  
Flin Flon ◽  
Southern Flank

The Kisseynew domain is the central unit of the Reindeer Zone of the Paleoproterozoic Trans-Hudson Orogen, in Manitoba and Saskatchewan. The southern flank of the domain is a transition zone between the greenschist facies of the volcano-plutonic assemblage of the Flin Flon - Snow Lake belt and the upper amphibolite facies of Kisseynew paragneisses. The Jungle Lake area, in the southern flank of the Kisseynew Domain, comprises mainly quartzofeldspathic gneisses representing continental clastic units of the Missi suite and migmatitic metagraywackes of the Burntwood suite. The area was affected by several phases of deformation, metamorphism, and migmatisation. Detailed mapping and U-Pb geochronology were carried out in order to establish the timing of the deformational and metamorphic phases. The oldest leucosome contains sillimanite formed during peak metamorphism and is associated with F2 folding and S2 fabric. Five single monazites from this leucosome yield ages between 1809 and 1803 Ma taken as the best estimate for the duration of peak metamorphism. Biotite schlieren in diatexites in the Burntwood suite show a S2 fabric folded by F3. Zircon from one of these diatexites yield a crystallization age of 1798+3-2 Ma, considered as the lower limit for the F2 event. Single monazites from the same rock yield ages between 1812 and 1789 Ma, the oldest of which are considered to be inherited. The youngest mobilisate is a pegmatite crosscutting F2 and F3 fabrics and yielded single monazite ages between 1875 and 1788 Ma. The youngest age is taken as the age of the pegmatite and is a minimum age for F3 fabrics. These results, together with those from other areas of the southern Kisseynew Domain, indicate a ca. 30 million year period (1818 and 1785 Ma) of continuous deformation and metamorphism. The data also show the presence of monazite crystals of different ages in the same rock illustrating the need to analyse single grains to obtain geologically meaningful ages.

Metamorphic and structural evolution of the Flin Flon – Athapapuskow Lake area, west-central Manitoba

2020 ◽  
Vol 57 (11) ◽  
pp. 1269-1288
Author(s):  
Manuele Lazzarotto ◽  
David R.M. Pattison ◽  
Simon Gagné ◽  
Paul G. Starr
Keyword(s):  
Regional Metamorphism ◽  
Equilibrium Phase ◽  
Structural Evolution ◽  
Geothermal Gradient ◽  
Island Arc ◽  
Amphibolite Facies ◽  
Ocean Floor ◽  
Lake Area ◽  
Modelling Techniques ◽  
Flin Flon

The Flin Flon – Athapapuskow Lake area, situated in the Flin Flon Greenstone Belt, Manitoba, consists of ocean-floor and island-arc assemblages, deformed and metamorphosed during the Trans-Hudson Orogeny (∼1.86–1.69 Ga). A new map of metamorphic mineral assemblages and isograds has been compiled that reveals a largely coherent regional metamorphic sequence increasing in metamorphic grade from prehnite–pumpellyite to amphibolite facies. Regional metamorphism postdates most of the deformation within the area, with the exception of the reactivation of major block-bounding faults. The regional prograde sequence has been subdivided into 10 metamorphic zones, separated by 9 isograds, that describe the transition from prehnite–pumpellyite to greenschist to amphibolite facies. The formation of contact metamorphic aureoles, pre-dating regional metamorphism, record conditions up to amphibolite facies. Equilibrium phase diagrams for the island-arc (low-Mg) and ocean-floor (high-Mg) assemblages were calculated and allow for the evaluation of the modelling techniques and determination of pressure–temperature conditions. Discrepancies between the modelling predictions and natural observations occur due to (1) limitations in the thermodynamic models for some of the complex minerals (e.g., amphibole); and (2) metastable persistence of some minerals to higher grade due to sluggish reaction kinetics. Notwithstanding these discrepancies, the modelling suggests that metamorphosed mafic rocks in the Flin Flon – Athapapuskow Lake area reached about 430–480 °C and 3.0–4.5 kbar. Peak metamorphic conditions within contact aureoles that preceded regional metamorphism did not exceed 500 °C (at a pressure between 2.7 and 4.4 kbar). The metamorphic field gradient records a transition from 250–300 °C/1.5–2.3 kbar to 430–480 °C/3–4.5 kbar (100–150 °C/kbar), defining a geothermal gradient of approximately 25–31 °C/km.

The Application of Seismic Reflection Techniques for Subsurface Mapping in the Precambrian Shield near Flin Flon, Manitoba

1975 ◽  
Vol 12 (12) ◽  
pp. 2036-2047 ◽  
Author(s):  
Z. Hajnal ◽  
Mel R. Stauffer
Keyword(s):  
Seismic Reflection ◽  
Complex Structure ◽  
Volcanic Rocks ◽  
Field Studies ◽  
Low Velocity ◽  
Near Surface ◽  
Precambrian Shield ◽  
Rock Types ◽  
Flin Flon ◽  
Subsurface Mapping

Some of the conditions necessary for the use of seismic reflection techniques for subsurface mapping in Precambrian Shield terranes have been determined from field studies carried out near Flin Flon, Manitoba.In areas of unconsolidated overburden, geoflex-type surface energy sources provide sufficient energy. However, in outcrop regions, boreholes have to be drilled to a minimum depth of 1.5 m, preferably in patterns of 2–6 holes. Explosives with a higher detonation velocity than those presently available would be useful.A near-surface, low velocity layer was discovered on top of all examined rock types, and appears to be the result of open fractures in the rock. The thickness of this layer varies from 20–44 m in the rocks studied.A velocity contrast of 783.3 m/s exists between the Amisk volcanic rocks and Missi sedimentary rocks, making reflection mapping possible. Seismic events which were interpreted as reflections were identified, near contacts between these formations in the subsurface. A fault contact between Amisk and Missi rocks has been mapped to a depth of about 1.6 km, and a normal stratigraphic contact between the Amisk and Missi Groups has been mapped to a depth of about 0.25 km.Because of the complex structure in most Precambrian Shield terranes, it is necessary to locate seismic lines carefully with respect to the geological features being studied. In particular, it is best to keep the line within a rock unit that has constant velocity throughout, and to use short lines, so that a limited number of structures are intersected.

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