Geochemistry and provenance of metasedimentary rocks from the Archean Golden Pond sequence (Casa Berardi mining district, Abitibi subprovince)

1996 ◽  
Vol 33 (5) ◽  
pp. 676-690 ◽  
Author(s):  
M. R. Flèche ◽  
G. Camiré
Keyword(s):  
Chemical Weathering ◽  
Volcanic Rocks ◽  
Source Area ◽  
Source Rocks ◽  
Iron Formation ◽  
Mining District ◽  
Metasedimentary Rocks ◽  
Clastic Rocks ◽  
The North ◽  
Volcanic Source

The Archean Golden Pond sequence is made up of deformed and metamorphosed conglomerates, greywackes, and mafic volcanic rocks, and is overlain by ferrugineous metasedimentary rocks of the North iron formation. The clastic rocks were derived mainly from a volcanic source that had undergone weak chemical weathering. Their source area was dominated by the presence of 60–80% high-Al2O3 felsic volcanics having strongly fractionated [La/Sm]N (= 3.7 ± 0.3) and very low Ta/Th ratios (= 0.09 ± 0.02), with lesser proportions of basaltic (10–30%) and ultramafic volcanic rocks (1–10%). The ferrugineous metasedimentary rocks can be modelled by mixing 20–40% siliciclastic material, of the composition of the average Golden Pond greywacke, with an Fe- and Si-rich precipitate (molecular Fe/Si = 0.6 ± 0.2). The high-Al2O3 felsic source rocks were most likely produced by subduction processes within an oceanic arc environment, but the mafic and ultramafic volcanic rocks were derived by different processes from an asthenospheric mantle source, possibly in an oceanic rift environment. Therefore, it is suggested that the ultramafic, mafic, and felsic volcanic rocks were brought to the same erosional level by dissection of the arc system and rapid exhumation of the felsic arc lithologies and the deeper ocean floor. Intrabasinal hydrothermal activity associated with contemporaneous mafic volcanism and (or) graben development may have also been responsible for the local production of the Fe-rich precipitates of the North iron formation.

Rb–Sr geochronology and metamorphic history of Proterozoic to early Archean rocks north of the Cape Smith Fold Belt, Quebec

1987 ◽  
Vol 24 (4) ◽  
pp. 813-825 ◽  
Author(s):  
Ronald Doig
Keyword(s):  
Volcanic Rocks ◽  
Granitic Rocks ◽  
Iron Formation ◽  
Fold Belt ◽  
Metasedimentary Rocks ◽  
Metamorphic History ◽  
The North ◽  
Basement Rocks ◽  
History Of ◽  
Wide Zone

The Churchill Province north of the Proterozoic Cape Smith volcanic fold belt of Quebec may be divided into two parts. The first is a broad antiform of migmatitic gneisses (Deception gneisses) extending north from the fold belt ~50 km to Sugluk Inlet. The second is a 20 km wide zone of high-grade metasedimentary rocks northwest of Sugluk Inlet. The Deception gneisses yield Rb–Sr isochron ages of 2600–2900 Ma and initial ratios of 0.701–0.703, showing that they are Archean basement to the Cape Smith Belt. The evidence that the basement rocks have been isoclinally refolded in the Proterozoic is clear at the contact with the fold belt. However, the gneisses also contain ubiquitous synclinal keels of metasiltstone with minor metapelite and marble that give isochron ages less than 2150 Ma. These ages, combined with low initial ratios of 0.7036, show that they are not part of the basement, as the average 87Sr/86Sr ratio for the basement rocks was about 0.718 at that time.The rocks west of Sugluk Inlet consist mainly of quartzo-feldspathic sediments, quartzites, para-amphibolites, marbles, and some pelite and iron formation. In contrast to the Proterozoic sediments in the Deception gneisses, these rocks yield dates of 3000–3200 Ma, with high initial ratios of 0.707–0.714. These initial ratios point to an age (or a provenance) much greater than that of the Archean Deception gneisses. The rocks of the Sugluk terrain are intruded by highly deformed sills of granitic rocks with ages of about 1830 Ma, demonstrating again the extent and severity of the Proterozoic overprint. The eastern margin of this possibly early Archean Sugluk block is a discontinuity in age, lithology, and geophysical character that could be a suture between two Archean cratons. It is not known if such a suturing event is of Archean age, or if it is related to the deformation of the Cape Smith Fold Belt.Models of evolution incorporating both the Cape Smith Belt and the Archean rocks to the north need to account for the internal structure of the fold belt, the continental affinity of many of the volcanic rocks, the continuity of basement around the eastern end of the belt, and the increase in metamorphism through the northern part of the belt into a broad area to the north. The Cape Smith volcanic rocks may have been extruded along a continental rift, parallel to a continental margin at Sugluk. Continental collison at Sugluk would have thrust the older and higher grade Sugluk rocks over the Deception gneisses, produced the broad Deception antiform, and displaced the Cape Smith rocks to the south in a series of north-dipping thrust slices.

scholarly journals Geochemistry and Petrography of the Sediments From the Marginal Areas of Qinghai Lake, Northern Tibet Plateau, China: Implications for Weathering and Provenance

2021 ◽  
Vol 9 ◽  
Author(s):  
Huifei Tao ◽  
Lewei Hao ◽  
Shutong Li ◽  
Tao Wu ◽  
Zhen Qin ◽  
...  
Keyword(s):  
Chemical Weathering ◽  
Volcanic Rocks ◽  
Source Rocks ◽  
Coarse Grained ◽  
Tibet Plateau ◽  
Qinghai Lake ◽  
Chemical Compositions ◽  
Geochemical Composition ◽  
Clastic Rocks ◽  
Felsic Volcanic

The provenance study of the sediments from Qinghai Lake is of great significance for the understanding of geological and climatic evolution processes of the Tibet Plateau on the one hand and for evaluating the controlling factors of the sediment components on the other hand. The samples were collected from five rivers, foreshore, beach, beach bar, and aeolian sand dune in the Qinghai Lake. The bulk geochemical composition, petrography, and mineralogy features of the samples are analyzed. The results show that: 1) Qinghai Lake sediments experienced low-intensity chemical weathering from the source areas to the deposition sites and were affected by some recycled detrital materials and 2) the source rocks for the sediments include felsic rocks (granite, granodiorite, and felsic volcanic rocks), carbonate, metamorphic rocks (marble and meta-volcanic rocks), and clastic rocks with the felsic source rocks to have the most important impact on the chemical compositions of the sediments. The geochemical indicator of Al2O3/TiO2 reflects that the provenance of fine-grained sediments from the center of Qinghai Lake is more mafic than the coarse-grained sediments from the margin of the Qinghai Lake, suggesting that the hydraulic sorting of grain size probably plays an important role in the geochemical compositions of the sediments. The mafic elements were probably preferentially enriched in muds.

Petrology and tectonic significance of Gates Formation (early Cretaceous) sediments in northeast British Columbia

1986 ◽  
Vol 23 (2) ◽  
pp. 129-141 ◽  
Author(s):  
Dale Leckie
Keyword(s):  
Mineral Content ◽  
Volcanic Rocks ◽  
Foreland Basin ◽  
Rocky Mountain ◽  
Source Area ◽  
Source Rocks ◽  
Sediment Sources ◽  
The North ◽  
Lake Formation ◽  
Tectonic Significance

Moosebar–Gates sandstones are predominantly litharenites, with some feldspathic litharenites. Both the light- and heavy-mineral suites indicate a mixed source characterized by clastic and carbonate sedimentary rocks, acidic to intermediate plutonic and volcanic igneous rocks, and metamorphic rocks. The sediment sources all fall within a recycled orogenic provenance grouping. Histograms showing stratigraphic variation of mineral content do not indicate any significant progressive unroofing of more deeply buried source rocks.The source area was very extensive regionally and extended well into the Omineca Crystalline Belt and eastern margins of the Intermontane Belt. Zebraic chalcedony was derived from evaporitic rocks of the Charlie Lake Formation, situated east of the Rocky Mountain Trench. Kyanite and almandine garnet were probably derived from the Omineca Crystalline Belt west of the Rocky Mountain Trench. Regional paleoslope dipped towards the north-northwest. Restoration of strike-slip on the Rocky Mountain Trench places potential source areas to the south of the depocentre; this supports paleoslope data. During Moosebar–Gates time the Tenakihi Group in the Omineca Crystalline Belt would have been hundreds of kilometres south of its present location and south of the study area, where it could have provided sediment. Volcanic rocks were derived from west of the Rocky Mountain Trench. Source rocks in the Omineca Crystalline Belt were being eroded as early as late early Albian and providing sediment into the foreland basin to the east.

A new volcanic province: evidence from glacial erratics in western North Greenland

2000 ◽  
pp. 35-41 ◽  
Author(s):  
Peter R. Dawes ◽  
Bjørn Thomassen ◽  
T.I. Hauge Andersson
Keyword(s):  
Volcanic Rocks ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Common Component ◽  
Volcanic Province ◽  
North West ◽  
North East ◽  
The North ◽  
Surficial Deposits ◽  
North Greenland

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Dawes, P. R., Thomassen, B., & Andersson, T. H. (2000). A new volcanic province: evidence from glacial erratics in western North Greenland. Geology of Greenland Survey Bulletin, 186, 35-41. https://doi.org/10.34194/ggub.v186.5213 _______________ Mapping and regional geological studies in northern Greenland were carried out during the project Kane Basin 1999 (see Dawes et al. 2000, this volume). During ore geological studies in Washington Land by one of us (B.T.), finds of erratics of banded iron formation (BIF) directed special attention to the till, glaciofluvial and fluvial sediments. This led to the discovery that in certain parts of Daugaard-Jensen Land and Washington Land volcanic rocks form a common component of the surficial deposits, with particularly colourful, red porphyries catching the eye. The presence of BIF is interesting but not altogether unexpected since BIF erratics have been reported from southern Hall Land just to the north-east (Kelly & Bennike 1992) and such rocks crop out in the Precambrian shield of North-West Greenland to the south (Fig. 1; Dawes 1991). On the other hand, the presence of volcanic erratics was unexpected and stimulated the work reported on here.

scholarly journals A missing link in the peri-Gondwanan terrane collage: the Precambrian basement of the Moroccan Meseta and its lower Paleozoic cover

2018 ◽  
Vol 55 (1) ◽  
pp. 33-51 ◽  
Author(s):  
Dominik Letsch ◽  
Mohamed El Houicha ◽  
Albrecht von Quadt ◽  
Wilfried Winkler
Keyword(s):  
Carbonate Platform ◽  
Source Area ◽  
Source Rocks ◽  
Lower Paleozoic ◽  
Northern Margin ◽  
Precambrian Geology ◽  
The North ◽  
Late Cambrian ◽  
Paleozoic Rocks ◽  
Rifted Margin

This article provides stratigraphic and geochronological data from a central part of Gondwana’s northern margin — the Moroccan Meseta Domain. This region, located to the north of the Anti-Atlas area with extensive outcrops of Precambrian and lower Paleozoic rocks, has hitherto not received much attention with regard to its Precambrian geology. Detrital and volcanic zircon ages have been used to constrain sedimentary depositional ages and crustal affinities of sedimentary source rocks in stratigraphic key sections. Based on this, a four-step paleotectonic evolution of the Meseta Domain from the Ediacaran until the Early Ordovician is proposed. This evolution documents the transition from a terrestrial volcanic setting during the Ediacaran to a short-lived carbonate platform setting during the early Cambrian. The latter then evolved into a rifted margin with deposition of thick siliciclastic successions in graben structures during the middle to late Cambrian. The detritus in these basins was of local origin, and a contribution from a broader source area (encompassing parts of the West African Craton) can only be demonstrated for postrifting, i.e., laterally extensive sandstone bodies that seal the former graben. In a broader paleotectonic context, it is suggested that this Cambrian rifting is linked to the opening of the Rheic Ocean, and that several peri-Gondwanan terranes (Meguma and Cadomia–Iberia) may have been close to the Meseta Domain before drifting, albeit some of them seem to have been constituted by a distinctly different basement.

Inversion of magnetic and frequency-domain electromagnetic data for investigating lithologies associated with gold mineralization in the Canadian Malartic area, Québec, Canada

2020 ◽  
pp. 1-20
Author(s):  
Mehrdad Darijani ◽  
Colin G. Farquharson
Keyword(s):  
Frequency Domain ◽  
Gold Mineralization ◽  
Volcanic Rocks ◽  
Tetrahedral Mesh ◽  
Iron Formation ◽  
Magnetic Data ◽  
Low Grade ◽  
Metasedimentary Rocks ◽  
Magnetic Inversion ◽  
Northern Edge

Canadian Malartic is an Archean low-grade bulk tonnage native gold deposit. The deposit is mostly located in altered clastic metasedimentary rocks, mafic–ultramafic dykes, and monzodioritic porphyry intrusions. Airborne magnetic and frequency-domain electromagnetic (EM) data were inverted to reconstruct the geological units associated with the mineralization, especially the intrusive masses. The 3-D inversion of magnetic data, which used a tetrahedral mesh to a depth of 2.4 km, shows that mafic volcanic rocks and iron formation rocks extend to depth in the area, more so than diabase dykes. The magnetic inversion also shows that the diorite and monzodiorite rocks of the Lac Fournière A pluton are dipping toward the south on its northern edge at the contact with the metasedimentary rocks. The 1-D inversion of the frequency-domain EM data, for both electrical conductivity and magnetic susceptibility, is able to reconstruct geological structures to a depth of approximately 100 m, providing more details and information about these features. The intrusive masses such as diabase dykes, diorite and monzodiorite rocks, and mafic volcanic rocks are reconstructed as electrically conductive structures in the inversion results. The metasedimentary rocks are resistive, and the overburden is conductive in most of the area. The geophysical data and inversion results suggest the presence of some features (such as diabase dykes and monzodiorite rocks) that are not yet present on some parts of the geology map. A comparison of the EM-derived susceptibility and the magnetic-derived susceptibility over the iron formations can reveal the effect of remanent magnetization.

scholarly journals Material composition of Lower Triassic sandstones from the northern areas of the Timan-Pechora oil and gas province

2020 ◽  
Vol 9 ◽  
pp. 26-36
Author(s):  
N. N. Timonina ◽  
Keyword(s):  
Oil And Gas ◽  
Chemical Properties ◽  
Source Area ◽  
Lower Triassic ◽  
Heavy Fraction ◽  
Clastic Rocks ◽  
The North ◽  
Northern Areas ◽  
Formation Conditions ◽  
Physical And Chemical

Recently various authors paid much attention to accessory minerals of clastic rocks to clarify the composition of the source area and formation conditions of terrigenous deposits. The paper describes some minerals of the heavy fraction of Triassic sandstones in the north of the Timan-Pechora oil and gas province (garnet, epidote, chromium spinels, ilmenite, etc.). We showed that the enrichment of sandstones with various mineral grains was controlled by not only the composition of the eroded rocks, but also by the hydrodynamics of the flow, as well as the method of transfer of clastic material. We noted that the features of heavy fraction minerals could be used to reconstruct sedimentation environments, taking into account their physical and chemical properties, distribution of minerals by fractions, and their stability during transportation.

scholarly journals Geochemistry of the Paleocene Clastic Rocks From the Southwestern Jianghan Basin, Central China Reveal Their Provenance, Tectonic Setting, and Palaeoenvironment

2021 ◽  
Author(s):  
Kai Yan ◽  
Chun-lian Wang ◽  
Jiu-yi Wang ◽  
Xiao-can Yu ◽  
Xiao-hua Teng ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Active Continental Margin ◽  
Source Area ◽  
Source Rocks ◽  
Central China ◽  
Clastic Rocks ◽  
Ree Distribution ◽  
C Value ◽  
Tectonic Settings ◽  
Jianghan Basin

Abstract This paper intends to learn about the provenance, tectonic setting and paleoenvironment of the Paleocene Shashi Formation in the southern Jianghan Basin by the bulk-rock geochemistry. The K2O/Al2O3 and SiO2/Al2O3 ratios indicate that the major proportion of samples are litharenite. The chondrite-normalized REE distribution pattern of the Shashi Formation’s mudstones are characterized by enriched LREE and flat HREE similar to those of UC with negative Eu anomalies. Combined with the geochemical element ratio discriminant diagram, such as Al2O3-TiO2, Zr-TiO2, La/Sc-Co/Th, and Hf-La/Th, so on, these samples were sourced from mixed felsic/basic rock. Moreover, the discriminant diagrams of K2O/Na2O-SiO2/Al2O3, La-Th-Sc, and Th-Co-Zr/10 suggest that the samples were formed under the tectonic settings of active continental margin and continental island arc. The values of CIA, CIW, PIA, ICV, Zr/Sc-Th/Sc, and ternary diagrams of A-(CN)-K and Al2O3-Zr-TiO2 indicate that weathering in the source area was weak and source rocks have not been reformed by depositional recirculation and hydraulic sorting. And the palaeoenvironmental indicators of C-value, Ni/Co, V/Cr, V/(V+Ni) and Sr/Cu, Ga/Rb indicate that the climate was cool and arid during the evaporite deposition period in the southern Jianghan Basin, and the water was in the condition of oxidation.

scholarly journals Geochemistry of Recent Brahmaputra River Sediments: Provenance, Tectonics, Source Area Weathering and Depositional Environment

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 813
Author(s):  
Md Aminur Rahman ◽  
Sudeb Chandra Das ◽  
Mark I. Pownceby ◽  
James Tardio ◽  
Md Sha Alam ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Chemical Weathering ◽  
Earth Element ◽  
Tectonic Setting ◽  
River Sediments ◽  
Source Area ◽  
Source Rocks ◽  
Heavy Minerals ◽  
Brahmaputra River

Sediments from stable sand bars along a 40 km section of the Brahmaputra River in northern Bangladesh were analyzed for their major, trace and rare earth element contents to determine their provenance, compositional maturity, source area weathering and tectonic setting. Geochemically, the sediments were classified as litharenites and the Index of Compositional Variability (ICV) varied between 1.4 and 2.0, indicating low compositional and mineralogical maturity. A high mean SiO2 concentration (72.9 wt.%) and low Al2O3 (11.1 wt.%) were consistent with a low abundance of shale and clay components. The depletion of the oxide components Na2O, CaO and K2O relative to average upper crustal compositions (UCC) reflected loss of feldspar during chemical weathering in the source region. Average TiO2 values for most samples were higher than average crustal levels, consistent with the northern section of the Brahmaputra River being a potential resource for valuable Fe-Ti oxide heavy minerals. Major and trace element ratios indicated the sediments represented erosional products from typical felsic upper continental crustal materials with contamination (30%–40%) from more intermediate/mafic compositions. The rare earth element patterns showed negative Eu anomalies (0.57–0.71), indicating they were derived mainly from fractionated felsic rocks. Resemblance of the sediment compositions to mean compositions from Higher Himalaya crystalline rocks pointed to these being potential source rocks but with components from a mafic source also present. Major element chemistries and low to intermediate weathering indices for all sediments indicated a lack of substantial chemical weathering. Evidence from tectonic discrimination diagrams suggested the Brahmaputra River sediments were derived from rock types that formed in a transitional tectonic setting ranging from an ancient passive margin to an active continental margin. Deposition occurred under cool to semi-arid climatic conditions in an oxic environment.

Mineralogy and origin of the upper Eastend and Whitemud Formations of south-central and southwestern Saskatchewan and southeastern Alberta

1969 ◽  
Vol 6 (2) ◽  
pp. 317-334 ◽  
Author(s):  
P. N. Byers
Keyword(s):  
Chemical Weathering ◽  
Upper Cretaceous ◽  
Volcanic Rocks ◽  
Source Area ◽  
Heavy Minerals ◽  
Major Constituent ◽  
Abrupt Decrease ◽  
South Central ◽  
Mechanical Weathering ◽  
Kaolinitic Clay

The Upper Cretaceous non-marine Whitemud Formation of south-central and southwestern Saskatchewan and southeastern Alberta consists of kaolinitic, metamorphic lithic sands and silts, and kaolinitic clays. The sands and silts are not highly feldspathic as was originally thought. The major constituent is metamorphic lithic grains with minor kaolinitic clay and vermicular kaolin, clear angular quartz, chert, muscovite, and minor volcanic lithic grains and feldspar. The upper part of the Upper Cretaceous Eastend Formation, which conformably underlies the Whitemud Formation, consists of non-marine sands, silts, and clays. Kaolin is very rare. The bulk of the sands are composed of volcanic lithic grains with minor metamorphic lithic grains, clear angular quartz, chert, feldspar, muscovite, and biotite.The contact is characterized by the following changes from the Eastend Formation upward into the Whitemud Formation: an abrupt decrease in volcanic lithic grains and increase in metamorphic lithic grains; the appearance of kaolin and the disappearance of biotite and apatite; a slight increase in clear angular quartz and muscovite and a decrease in feldspar; a general increase in metamorphic heavy minerals; and an increase in the percentage of ilmenite (both as solitary grains and intergrown with magnetite), which is altered to leucoxene.On the basis of mineralogy, the Whitemud Formation is definitely a correlative of the Colgate Member of the Fox Hills Formation in Montana and North Dakota.The upper Eastend and Whitemud Formations were derived from Upper Cretaceous volcanic rocks, Precambrian and Paleozoic metamorphic rocks, and Paleozoic carbonates all situated in Montana. Upper Eastend sediments represent fast mechanical weathering of mountains of freshly extruded volcanic rocks, whereas the Whitemud sediments represent slow chemical weathering and leaching, which predominated once the mountainous volcanic rocks were worn down. This deep chemical weathering altered the volcanic tuffs and flows into kaolinitic clay at the source area; the kaolin of the Whitemud Formation is not derived from the weathering of feldspars at the site of deposition.It is suggested that the Frenchman and Ravenscrag Formations were also derived from Upper Cretaceous and Lower Tertiary volcanic rocks in Montana.

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