Geochemistry and origin of Archean felsic metavolcanic rocks, central Noranda area, Quebec, Canada

1987 ◽  
Vol 24 (12) ◽  
pp. 2551-2567 ◽  
Author(s):  
Osamu Ujike ◽  
A. M. Goodwin
Keyword(s):  
Partial Melting ◽  
Fractional Crystallization ◽  
Volcanic Rocks ◽  
Primitive Mantle ◽  
X Ray ◽  
Tectonic Model ◽  
Metavolcanic Rocks ◽  
Felsic Volcanic ◽  
Back Arc ◽  
Felsic Volcanic Rocks

Felsic magma petrogenesis was studied by analyzing 24 stratigraphically controlled Archean andesite-to-rhyolite lava flows of both tholeiitic and calc-alkalic affinity from the upper Noranda Subgroup, Quebec, using instrumental neutron activation and X-ray fluorescence techniques. The lavas have moderate values of [La/Yb]N (0.9–3.8) and low values of 100 × Th/Zr (~1). According to calculations following batch partial melting and Rayleigh fractional crystallization models, both the calc-alkalic and tholeiitic felsic volcanic rocks are probably products of shallow-level fractional crystallization of mafic parental magmas formed respectively by lower (~7 % for calc-alkalic) and higher (~14% for tholeiitic) degrees of partial melting of a primitive mantle source.Contribution to the magma genesis from plausible crustal materials was negligible. A back-arc-type diapirism is geochemically suggested for the tectonic model of origin of Noranda felsic magmas, in conformity with geological observations. Felsic volcanic rocks with compositions analogous to the studied samples exist in several other Archean terrains of the Canadian Shield, suggesting thereby that the late Archean sialic crust was at least in part produced by volcanic rocks ultimately derived from the primitive mantle.

Geochemistry and isotope studies of the metavolcanic rocks of Shimoga greenstone belt, Western Dharwar craton - an effort to deduce the Petrogenesis.

2020 ◽  
Author(s):  
Anshuman Giri ◽  
Rajagopal Anand
Keyword(s):  
Fractional Crystallization ◽  
Greenstone Belt ◽  
Active Continental Margin ◽  
Volcanic Rocks ◽  
Crustal Contamination ◽  
Dharwar Craton ◽  
Metavolcanic Rocks ◽  
Depleted Mantle ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

<p>The archaean greenstone belts, dominated by mafic to felsic volcanic rocks followed by younger granitic intrusions occurs associated with volcano-sedimentary sequences. The Dharwar Super group (2600 to 2900 Ma) of rocks in western Dharwar craton, underlie the older TTG gneisses. The Shimoga greenstone belt (SGB) of WDC constitute the basal polymictic conglomerate along with quartzite, pyroclastic rocks, carbonaceous rocks, greywacke-argillite sequences with a thick pile of mafic and felsic metavolcanic rocks (BADR). These rocks are suffered from greenschist to lower amphibolite grade of metamorphism. The Medur metavolcanic volcanic rocks give an age of 2638 ± 66 Ma (1), whereas the Daginakatte felsic volcanic rocks give an age of 2601 ± 6 Ma (2). The present studied age of 2638 ± 66 Ma, tells about the cessation of mafic magmatism in WDC. The metavolcanic rocks of the Medur formation are tholeiitic to calc-alkaline in nature. These rocks show flat to LREE enriched REE pattern with negative europium anomaly. And also show enrichment in LILE and depletion in HFSE elements with significant Nb-Ta anomaly. The geochemical and the isotope data suggest the involvement of partial melting of the depleted mantle by the slab components and assimilation fractional crystallization (AFC) processes for the magma generation. The SGB metavolcanic rocks have 143Nd/144Nd ratios (0.511150 to .513076) and εNd values of -3.1 to -5.5 and the negative εNd values  for the rocks is due to the crustal contamination of the magma in a shallow marine subduction setting. The parental magmas were derived from melting in the mantle wedge fluxed by slab derived fluids and slab components followed by assimilation fractional crystallization (AFC) processes involving continental crust in an active continental margin.</p><ul><li>(1) Giri et al., 2019. Lithos, <strong>330-331</strong>, 177-193</li> <li>(2) Trendall et al., 1997a. J. Geol. Soc. India, <strong>50</strong>, 25-50.</li> </ul>

Geochemistry and age of the Aillik Group and associated plutonic rocks, Makkovik Bay area, Labrador: implications for tectonic development of the Makkovik Province

2002 ◽  
Vol 39 (5) ◽  
pp. 731-748 ◽  
Author(s):  
G S Sinclair ◽  
S M Barr ◽  
N G Culshaw ◽  
J W.F Ketchum
Keyword(s):  
Volcanic Rocks ◽  
Granitic Rocks ◽  
Metamorphic History ◽  
Bay Area ◽  
Metavolcanic Rocks ◽  
Show Evidence ◽  
Tectonic Development ◽  
Plutonic Rocks ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

The Aillik domain of the Makkovik Province is dominated by deformed and metamorphosed sedimentary and bimodal volcanic rocks of the redefined Aillik Group and abundant unfoliated late- to post-orogenic plutonic rocks. Mapping and petrological studies in the Makkovik Bay area of the Aillik domain showed that the upper part of the group, in addition to felsic volcanic rocks, also includes extensive areas of hypabyssal, foliated granitic rocks (Measles Point Granite). Although petrochemically similar to the spatially associated felsic volcanic rocks, a new U–Pb (zircon) age of 1929 Ma suggests that the Measles Point Granite may be about 70 million years older than the volcanic rocks of the Aillik Group, based on published U–Pb dates for the latter unit. The volcanic and granitic rocks show similar structural and metamorphic history, and both have characteristics of crust-derived A-type felsic rocks, although the granite shows less chemical variation than the felsic volcanic rocks. A within-plate setting is postulated, although the associated mafic metavolcanic rocks and amphibolite dykes show evidence of a volcanic-arc influence. Possible solutions of the paradox presented by the U–Pb ages imply that the Measles Point Granite either represents the juvenile basement to the Aillik Group or was derived from a basement with a large juvenile component. The setting for deposition of the Aillik Group that is consistent with current tectonic models for the Makkovik Province is a rifted arc built on a juvenile terrane accreted to Archean crust.

The nature of ‘ameletite’

1967 ◽  
Vol 36 (279) ◽  
pp. 438-443 ◽  
Author(s):  
D. S. Coombs ◽  
J. F. G. Wilkinson
Keyword(s):  
New Zealand ◽  
Volcanic Rocks ◽  
Chemical Data ◽  
X Ray ◽  
Type Area ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks ◽  
Aluminium Silicate

SummaryOriginally described in phonolitic rocks from the Dunedin district, New Zealand, ameletite was considered by Marshall (1929) to be a chlorine-bearing sodium aluminium silicate, probably a feldspathoid, and later, a zeolite of unspecified composition. Optical, X-ray, and chemical data on several ‘ameletite’-bearing felsic volcanic rocks from the type area indicate that material previously designated as ameletite is variously nepheline and mixtures of sodalite, analcime, phillipsite, and nepheline. Criteria thought to be characteristic of ameletite are discussed.

U–Pb zircon ages from the Lynn Lake and Rusty Lake metavolcanic belts, Manitoba: two ages of Proterozoic magmatism

1987 ◽  
Vol 24 (5) ◽  
pp. 1053-1063 ◽  
Author(s):  
D. A. Baldwin ◽  
E. C. Syme ◽  
H. V. Zwanzig ◽  
T. M. Gordon ◽  
P. A. Hunt ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Island Arc ◽  
Quartz Diorite ◽  
The North ◽  
Volcanic Sequence ◽  
Metavolcanic Rocks ◽  
Lynn Lake ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

Two ages of magmatism have been determined from zircon in felsic flows and plutons in the Churchill Province of Manitoba. A rhyolite flow from the Lynn Lake metavolcanic belt has a U–Pb age of [Formula: see text], and a rhyolite flow from the adjacent Rusty Lake metavolcanic belt has an age of [Formula: see text]. Tonalite and quartz diorite from two composite plutons emplaced into the volcanic rocks at Lynn Lake have ages of [Formula: see text] and [Formula: see text], indistinguishable from the age of the Rusty Lake belt rhyolite. The arcuate domain of metavolcanic rocks that includes the Rusty Lake belt in the southeast, the Lynn Lake belt in the north, and the La Ronge belt (Saskatchewan) in the southwest has previously been considered a single structural sub-province with similar ages throughout. Our results and published U–Pb ages from Saskatchewan indicate that an older magmatism is represented by volcanic rocks in the Lynn Lake belt; a younger magmatism, by volcanic rocks in the Rusty Lake and La Ronge belts and plutons in the Lynn Lake belt. At Lynn Lake the older magmatism (1910 Ma) produced mafic, intermediate, and felsic volcanic rocks and synvolcanic plutons. The volcanic rocks are geochemically similar to Cenozoic island-arc magmatic sequences. These rocks were isoclinally folded and subsequently intruded by the 1876 Ma plutons. The younger, dominantly subaerial, volcanism (1878 Ma) at Rusty Lake was predominantly felsic, and the coeval plutons were granitoid. The distribution of ages and the 8 km thickness of the younger volcanic sequence suggest that the older rock served as basement during the younger magmatism.

Crustal assimilation in the Burnt Lake metavolcanics, Grenville Province, southeastern Ontario, and its tectonic significance

1997 ◽  
Vol 34 (9) ◽  
pp. 1272-1285 ◽  
Author(s):  
T. E. Smith ◽  
P. E. Holm ◽  
N. M. Dennison ◽  
M. J. Harris
Keyword(s):  
Rare Earth ◽  
Trace Element ◽  
Partial Melting ◽  
Continental Crust ◽  
Fractional Crystallization ◽  
Volcanic Rocks ◽  
Lake Area ◽  
Depleted Mantle ◽  
Mafic Magmas ◽  
Back Arc

Three intimately interbedded suites of volcanic rocks are identified geochemically in the Burnt Lake area of the Belmont Domain in the Central Metasedimentary Belt, and their petrogenesis is evaluated. The Burnt Lake back-arc tholeiitic suite comprises basalts similar in trace element signature to tholeiitic basalts emplaced in back-arc basins formed in continental crust. The Burnt Lake continental tholeiitic suite comprises basalts and andésites similar in trace element composition to continental tholeiitic sequences. The Burnt Lake felsic pyroclastic suite comprises rhyolitic pyroclastics having major and trace element compositions that suggest that they were derived from crustal melts. Rare earth element models suggest that the Burnt Lake back-arc tholeiitic rocks were formed by fractional crystallization of mafic magmas derived by approximately 5% partial melting of an amphibole-bearing depleted mantle, enriched in light rare earth elements by a subduction component. The modelling also suggests that the Burnt Lake continental tholeiitic rocks were formed by contamination – fractional crystallization of mixtures of mafic magmas, derived by ~3% partial melting of the subduction-modified source, and rhyolitic crustal melts. These models are consistent with the suggestion that the Belmont Domain of the Central Metasedimentary Belt formed as a back-arc basin by attenuation of preexisting continental crust above a westerly dipping subduction zone.

Geochemical and isotopic (Nd, O) data from Ordovician felsic plutonic and volcanic rocks of the Miramichi Highlands: petrogenetic and metallogenic implications for the Bathurst Mining Camp

1998 ◽  
Vol 35 (3) ◽  
pp. 237-252 ◽  
Author(s):  
Joseph B Whalen ◽  
Neil Rogers ◽  
Cees R van Staal ◽  
Frederick J Longstaffe ◽  
George A Jenner ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Middle Ordovician ◽  
Basaltic Rocks ◽  
Volcanogenic Massive Sulphide ◽  
Vms Deposits ◽  
Bathurst Mining Camp ◽  
Felsic Volcanic ◽  
Back Arc ◽  
T Values ◽  
Felsic Volcanic Rocks

Middle Ordovician felsic magmatism contemporaneous with Bathurst Camp Pb-Zn volcanogenic massive sulphide(VMS) deposits consists of strongly altered volcanic to subvolcanic rocks, belonging to the Tetagouche Group, and relativelyunaltered granitoid plutons, which are divided into northern, central, and southern groups within the Miramichi Highlands.Calc-alkalic felsic volcanic rocks and northern plus central plutons have EpsilonNd(T) values ranging from -8.2 to -1.9 and -4.0 to +0.3, respectively. They exhibit within-plate-type volcanic and transitional I- to A-type granite geochemical characteristics.Granitoid rock Delta18O values range from +8.0 to +10.1‰. Published granitoid rock Pb isotopic compositions overlapunpublished galena data from Bathurst VMS deposits. Field, geochemical, and isotopic evidence indicate that these volcanicand granitoids rocks are consanguineous and mainly derived from Proterozoic orolder infracrustal sources. Alkalic felsic volcanic rocks, and associated alkaline basaltic rocks, are more juvenile (EpsilonNd(T) = +3.2 to +4.2) and were possibly derivedfrom slightly enriched mantle sources. Southern plutons exhibit continental arc-type features. The felsic magmatism and VMS deposits likely formed in an Okinawa-type back-arc basin developed from rifting the Early Ordovician Popelogan continentalarc, of which the southern plutons are remnants. Correlations between pluton groups and volcanic formations indicate that felsic magmatism was erupted through and onto the Miramichi Group. As most felsic volcanic formations lack plutonicequivalents, the Tetagouche Group probably does not represent disrupted slices of an originally conformable stratigraphic section. This supports a model in which thrust slices juxtapose remnants of volcanic centres erupted at different locationswithin a back-arc basin.

scholarly journals Generation of late Mesozoic felsic volcanic rocks in the Hailar Basin, northeastern China in response to overprinting of multiple tectonic regimes

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Zheng Ji ◽  
Qi-An Meng ◽  
Chuan-Biao Wan ◽  
De-Feng Zhu ◽  
Wen-Chun Ge ◽  
...  
Keyword(s):  
Partial Melting ◽  
Early Cretaceous ◽  
Lower Crust ◽  
Late Jurassic ◽  
Volcanic Rocks ◽  
Late Mesozoic ◽  
Hailar Basin ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks ◽  
Zircon Saturation

Abstract We performed zircon U–Pb age dating and geochemical analyses of late Mesozoic felsic volcanic rocks in the Hailar Basin, NE China, with the aim of eclucidating their emplacement ages, origin and geodynamic significance. The volcanic rocks consist of dacites, rhyolites and rhyolitic tuffs. Laser ablation–inductively coupled plasma–mass spectrometry zircon U–Pb dating results suggest that the rocks were erupted during the Late Jurassic–Early Cretaceous (161–117 Ma). They belong to the high-K calc-alkaline series and can be divided into two groups. Group I rocks are metaluminous to weakly peraluminous, contain low concentrations of heavy rare earth elements (HREEs) and high field strength elements (HFSEs), and have low zircon saturation temperatures (average 786 °C), all of which indicate an I-type affinity. In contrast, Group II rocks have higher HREE and HFSE concentrations and zircon saturation temperatures (average 918 °C), suggesting an A-type affinity. All the felsic volcanic rocks have positive εHf(t) values of 1.43–12.32 with two-stage model ages of 1110–401 Ma. Our data indicate that the I-type felsic volcanic rocks formed from magmas generated by partial melting of a dominantly juvenile mica-bearing K-rich basaltic lower crust, whereas the A-type felsic volcanic rocks originated from the partial melting of a dry mafic–intermediate middle–lower crust that was dehydrated but not melt depleted. Based on the present results and previous research, we propose that the Late Jurassic I- and A-type felsic volcanic rocks in the Hailar Basin were formed in a post-collisional environment related to break-off of the subducted oceanic slab of the Mongol–Okhotsk Ocean and the subsequent gravitational collapse of the orogenically-thickened crust after closure of the ocean. In contrast, the Early Cretaceous I- and A-type felsic volcanic rocks were erupted in an extensional setting related to rollback of the subducted Paleo-Pacific Plate.

Geochemistry and geodynamic constraint of volcanic and plutonic magmatism within the Banfora Belt (Burkina-Faso, West-Africa): contribution to mineral exploration

2020 ◽  
pp. SP502-2019-86
Author(s):  
Hermann Ilboudo ◽  
Sâga Sawadogo ◽  
Gounwendmanaghre Hubert Zongo ◽  
Seta Naba ◽  
Urbain Wenmenga ◽  
...  
Keyword(s):  
Fractional Crystallization ◽  
Mineral Exploration ◽  
Volcanic Rocks ◽  
Mafic Magma ◽  
Calc Alkaline ◽  
High K ◽  
Tectonic Settings ◽  
Arc Setting ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

AbstractPredominant volcano-plutonic (mafic–felsic) activity is expressed in the eastern Banfora Belt. The geochemical signature shows different geodynamic settings: (1) mafic rocks are tholeiitic, subalkaline and show high-Mg tendency, whereas pyroxenolite (MgO c. 15.4 wt%) has komatiite affinity; (2) felsic volcanic rocks are subalkaline; and (3) granitoids surrounding the Banfora Belt are alkaline to calc-alkaline, high K, peraluminous to metaluminous. The geochemistry of mafic volcanic rocks shows an unusual evolution from Mid Oceanic Ridge Basalt to Arc-related. The Western Granite and Eastern Granites were emplaced by fractional crystallization and partial melting, respectively, but sourced from igneous protolith (I-type magma) in a volcanic arc setting. The Sodingue granite was emplaced by fractional crystallization from A-type magma in a ‘within-plate setting’. Two-mica S-type granites located at the central portion of the belt relate to syn-collisional fractional crystallization. The paper highlights the complexity of the magma process through a diversity of sources, geochemical patterns and tectonic settings. An emphasis on the komatiite affinity of mafic magma is a challenge for related commodities, such as copper and gold resources.

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