Rare earth element concentrations in Quaternary volcanic rocks of southwestern British Columbia

1984 ◽  
Vol 21 (6) ◽  
pp. 731-736 ◽  
Author(s):  
Nathan L. Green ◽  
Paul Henderson
Keyword(s):  
British Columbia ◽  
Earth Element ◽  
Volcanic Rocks ◽  
Crustal Contamination ◽  
Lake Area ◽  
Calc Alkaline ◽  
Lower Light ◽  
The Individual ◽  
High Level ◽  
Ree Patterns

A suite of hy-normative hawaiites, ne-normative mugearite, and calc-alkaline andesitic rocks from the Garibaldi Lake area exhibits fractionated, slightly concave-upward REE patterns (CeN/YbN = 4.5–15), heavy REE contents about 5–10 times the chondritic abundances, and no Eu anomalies. It is unlikely that the REE patterns provide information concerning partial melting conditions beneath southwestern British Columbia because they have probably been modified substantially by upper crustal processes including crustal contamination and (or) crystal fractionation. The REE contents of the Garibaldi Lake lavas are not incompatible with previous interpretations that (1) the hawaiites have undergone considerable fractionation of olivine, plagioclase, and clinopyroxene; and (2) the individual andesitic suites were derived from separate batches of chemically distinct magma that evolved along different high-level crystallization trends. In general, however, the andesites are characterized by lower light REE contents than the basaltic andesites. These differences in LREE abundances may reflect different amounts of LREE-rich accessory phases, such as apatite, sphene, or allanite, assimilated from the underlying quartz diorites.

Eocene Challis-Kamloops volcanism in central British Columbia: an example from the Buck Creek basin

1998 ◽  
Vol 35 (8) ◽  
pp. 951-963 ◽  
Author(s):  
J Dostal ◽  
D A Robichaud ◽  
B N Church ◽  
P H Reynolds
Keyword(s):  
British Columbia ◽  
Rare Earth ◽  
Rare Earth Element ◽  
Fractional Crystallization ◽  
Earth Element ◽  
Volcanic Rocks ◽  
Volcanic Belt ◽  
The United States ◽  
Calc Alkaline ◽  
Heavy Rare Earth Element

Eocene volcanic rocks of the Buck Creek basin in central British Columbia are part of the Challis-Kamloops volcanic belt extending from the United States across British Columbia to central Yukon. The volcanic rocks include two units, the Buck Creek Formation, composed of high-K calc-alkaline rocks with predominant andesitic composition, and the overlying Swans Lake unit made up of intraplate tholeiitic basalts. Whole rock 40Ar/39Ar data for both units show that they were emplaced at 50 Ma. They have similar mantle-normalized trace element patterns characterized by a large-ion lithophile element enrichment and Nb-Ta depletion, similar chondrite-normalized rare earth element patterns with (La/Yb)n ~4-14 and heavy rare earth element fractionation, and overlapping epsilonNd values (2.4-3.1) and initial Sr-isotope ratios ( ~ 0.704). These features suggest derivation of these two units from a similar mantle source, probably garnet-bearing subcontinental lithosphere. The differences between tholeiitic and calc-alkaline suites can be due, in part, to differences in the depth of fractional crystallization and the crystallizing mineral assemblage. Fractional crystallization of the calc-alkaline magmas began at a greater (mid-crustal) depth and included fractionation of Fe-Ti oxides. The volcanic rocks are probably related to subduction of the Farallon plate under the North American continent in a regime characterized by transcurrent movements and strike-slip faulting.

Quantitative trace-element modelling of the crystallization history of the Kinojévis and Blake River groups, Abitibi Greenstone Belt, Ontario

1989 ◽  
Vol 26 (7) ◽  
pp. 1356-1367 ◽  
Author(s):  
A. D. Fowler ◽  
L. S. Jensen
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Fractional Crystallization ◽  
Earth Element ◽  
Calc Alkaline ◽  
Quantitative Modelling ◽  
Ti Oxides ◽  
History Of ◽  
High Level ◽  
Ree Patterns

The Archean tholeiitic Kinojévis suite is characterized by an iron-enrichment trend and abundant Fe–Ti oxides in its evolved basalts, andesites, and rhyolites. The rare-earth-element (REE) patterns of the suite remain flat from the basalts through to the rhyolites, with the development of small, negative Eu anomalies. Quantitative modelling of the trace elements from little-altered samples is consistent with the mineralogy, suggesting that the suite was produced through fractional crystallization of olivine, pyroxene, plagioclase, and Fe–Ti oxides. The evolved rhyolites are interpreted as having developed by greater than 90% fractional crystallization in a high-level magma chamber.The calc-alkaline Blake River Group conformably overlies the Kinojévis rocks and is characterized by enrichment in alkalis and silica. The REE patterns are light rare-earth-element (LREE) enriched, and the felsic rocks have prominent negative Eu anomalies. Geochemical modelling shows that the suite could have developed either through fractional crystallization dominated by plagioclase and clinopyroxene or by assimilation of tonalite, coupled with fractional crystallization.

Stratigraphy and geochemistry of the igneous rocks in the Elu Link between Hope Bay and Elu greenstone belts, northeast Slave craton: tectonic setting and implications for gold mineralization

2013 ◽  
Vol 50 (2) ◽  
pp. 148-170 ◽  
Author(s):  
H. Mvondo ◽  
D. Lentz ◽  
M. Bardoux
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Tectonic Setting ◽  
Crustal Contamination ◽  
Primitive Mantle ◽  
Lake Area ◽  
Calc Alkaline ◽  
Greenstone Belts ◽  
Hope Bay

Geological investigation of the rocks in the Elu Link has provided new information on the geodynamic origin of the Neoarchean (ca. 2716–2663 Ma) Hope Bay and Elu granite–greenstone belts. Stratigraphic and geochemical features of these rocks and those of the nearby Flake Lake area in the Hope Bay belt suggest that the two greenstone belts are contiguous, having similar mafic-dominated bimodal rocks comprising abundant basalts to andesites and less common dacites and rhyolites hosting gabbroic and trondhjemite–tonalite–granodiorite (TTG) intrusions. The corresponding parental magmas, whose evolution likely occurred via fractional crystallization and juvenile crustal contamination, formed from both deep and shallow mantle sources. The basalts, andesites, gabbros, and felsic volcanic rocks are variably tholeiitic to calc-alkaline. Chondrite- and primitive mantle-normalized profiles demonstrate (1) flat to slightly fractionated heavy rare-earth element (HREE) patterns with a weak negative Eu anomaly and (2) light rare-earth element (LREE) enriched and strongly fractionated HREE patterns with variable negative to positive Eu anomalies. In contrast, TTG rocks are calc-alkaline, with strong LREE enrichment, HREE depletion, and variable positive Eu anomalies. Altogether, the rocks exhibit Nb and Ti troughs, and variable Nb/Ta, La/Ta, and Zr/Hf ratios indicative of crustal contamination. Chalcophile elements and related ore deposits in the area are inferred to be formed from hydrothermal fluids mobilized during emplacement and after crystallization of their host rocks. An extensional, high-heat-flow back-arc tectonic environment is proposed to explain the stratigraphic and geochemical characteristics and the presence of large gold resources in these greenstone belts.

Sr and O isotope constraints on source and crustal contamination in the high-K calc-alkaline and shoshonitic neogene volcanic rocks of SE Spain

Lithos ◽  
1999 ◽  
Vol 46 (4) ◽  
pp. 773-802 ◽  
Author(s):  
R. Benito ◽  
J. López-Ruiz ◽  
J.M. Cebriá ◽  
J. Hertogen ◽  
M. Doblas ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Crustal Contamination ◽  
Calc Alkaline ◽  
Se Spain ◽  
High K ◽  
O Isotope

Petrochemistry of late Aphebian (~ 1.8 Ga) calc-alkaline diorites from the East Arm of Great Slave Lake, N.W.T., Canada

1981 ◽  
Vol 18 (6) ◽  
pp. 1018-1028 ◽  
Author(s):  
J. P. N. Badham
Keyword(s):  
Subduction Zone ◽  
Volcanic Rocks ◽  
Entire Length ◽  
Calc Alkaline ◽  
Slave Craton ◽  
Great Slave Lake ◽  
High Level ◽  
Chemical Trends

The East Arm of Great Slave Lake is a 2.5–1.7 Ga graben connected to the contemporaneous Wopmay Orogen on the margins of the Archean (2.5 Ga) Slave craton. It contains three major groups of sedimentary and volcanic rocks. The two earlier ones are cut by ~ 1.79 Ga diorites, which outcrop over 220 km along the graben.The diorites were preferentially emplaced as laccoliths into a horizon of megabreccia thought to be the product of evaporite solution and collapse. The diorites are similar down the entire length of the East Arm. Main phases are usually plagioclase–hornblende poryphyritic, but younger and possibly high level phases contain biotite and quartz. The diorites are calc-alkaline but show no obvious chemical trends along the graben. They cannot be related directly to the proposed easterly dipping, late Aphebian subduction zone that generated the Wopmay Orogen.

Regional implications of Upper Triassic metavolcanic and metasedimentary rocks on the Chilkat Peninsula, southeastern Alaska

1980 ◽  
Vol 17 (6) ◽  
pp. 681-689 ◽  
Author(s):  
George Plafker ◽  
Travis Hudson
Keyword(s):  
British Columbia ◽  
Volcanic Rocks ◽  
Upper Triassic ◽  
Late Triassic ◽  
Low Grade ◽  
Lake Area ◽  
Metasedimentary Rocks

A low-grade metamorphic sequence consisting of thick mafic volcanic rocks overlain by calcareous flysch with very minor limestone underlies much of the Chilkat Peninsula. Fossils collected from both units are of Triassic age, probably late Karnian. This sequence appears to be part of the Taku terrane, a linear tectono-stratigraphic belt that now can be traced for almost 700 km through southeastern Alaska to the Kelsall Lake area of British Columbia. The age and gross lithology of the Chilkat Peninsula sequence are comparable to Upper Triassic rocks that characterize the allochthonous tectono-stratigraphic terrane named Wrangellia. This suggests either that the two terranes are related in their history or that they are allochthonous with respect to one another and coincidentally evolved somewhat similar sequences in Late Triassic time.

scholarly journals Study of Petrogenesis and Tectonomagmatic Environments of Eocene Calc-Alkaline Volcanic Units in South and Southeast of Beroni Village in Southwest Ardestan (Isfahan)

2015 ◽  
Vol 10 (Special-Issue1) ◽  
pp. 719-726
Author(s):  
Sayyed Roshan ◽  
Ali Khan Nasr Esfahani
Keyword(s):  
Volcanic Rocks ◽  
Crustal Contamination ◽  
Hydrothermal Solution ◽  
Hydrothermal Solutions ◽  
Calc Alkaline ◽  
Silica Rocks ◽  
Calcium Magnesium ◽  
Alkaline Magmas ◽  
Host Rocks ◽  
Lateral Segregation

The study area is located in south and southeast of Beroni Village. It contains volcanic rocks including andesitic-basaltic, pyroxene-bearing andesite, andesite, dacite, rhyodacite, rhyolites and Eocene-Oligocene ignimbrites. The volcanic rocks are cut by an intrusive mass with great spreading in the region. According to lithological studies, the calc-alkaline magmas in continental margin arcs are comprised of mantle and fluid crust. The basic elements in the volcanic rocks were studied in terms of petrological indices. According to the results, the metaluminous rocks underwent crustal contamination. Due to chemical reactions between the hydrothermal solution and volcanic host rocks, hydrothermal solutions in volcanic rocks penetrate the surrounding silica rocks and thus some elements such as zinc and barium diffuse in the rocks. In addition, calcium, magnesium and iron have been drawn inwards from the surrounding rocks causing lateral segregation.

A petrological and geochemical study of the volcanic rocks of the Crowsnest Formation, southwestern Alberta, and of the Howell Creek suite, British Columbia

2006 ◽  
Vol 43 (11) ◽  
pp. 1621-1637 ◽  
Author(s):  
Melissa Bowerman ◽  
Amy Christianson ◽  
Robert A Creaser ◽  
Robert W Luth
Keyword(s):  
British Columbia ◽  
Trace Element ◽  
Isotope Geochemistry ◽  
Source Region ◽  
Volcanic Rocks ◽  
Trace Element Geochemistry ◽  
Element Geochemistry ◽  
Geochemical Study ◽  
Geological Sciences ◽  
Ree Patterns

Alkaline igneous rocks of the Crowsnest Formation in southwestern Alberta and in the Howell Creek area in southeastern British Columbia have been suggested previously to be cogenetic. To test this hypothesis, samples of both suites were characterized petrographically and their major and trace element geochemistry was determined. A subset of the samples was analyzed for whole-rock Sr and Nd isotope geochemistry. The samples of the two suites are latites, trachytes, and phonolites based on the International Union of Geological Sciences (IUGS) total alkalis versus silica (TAS) diagram. Samples from both suites show similar patterns on mantle-normalized trace element diagrams, being enriched relative to mantle values but depleted in the high field-strength elements Nb, Ta, and Ti relative to the large-ion lithophile elements. The chondrite-normalized rare-earth element (REE) patterns for both suites are light REE enriched, with no Eu anomaly and flat heavy REE. The isotope geochemistry of both suites is characterized by low initial 87Sr/86Sr (SrT = 0.704 to 0.706) and low εNdT (–7 to –16). The Howell Creek samples have lower εNdT and higher SrT than do the Crowsnest samples. Based on the intra- and intersuite differences in the isotope geochemistry, we conclude that these samples are not cogenetic, but rather represent samples that have experienced similar evolutionary histories from a heterogeneous source region in the subcontinental lithospheric mantle.

Mid-Tertiary volcanic rocks of the Cascade Mountains, southwestern British Columbia, ages and correlations

1981 ◽  
Vol 18 (3) ◽  
pp. 662-664 ◽  
Author(s):  
W. H. Mathews ◽  
R. G. Berman ◽  
J. E. Harakal
Keyword(s):  
British Columbia ◽  
Late Miocene ◽  
Volcanic Rocks ◽  
Early Miocene ◽  
Chemical Data ◽  
Volcanic Centre ◽  
Calc Alkaline ◽  
Cascade Mountains

Potassium–argon dates and chemical data have been obtained from three mid-Tertiary volcanic centres in the Hope area of the Cascade Mountains, southwestern British Columbia. Two of these, the Coquihalla volcanic centre and the Podunk Creek body, prove to be of early Miocene age (ca. 22 Ma), whereas the Skagit Formation is mid- to late Miocene (ca. 12.5 Ma). All three bodies are calc-alkaline.

Late Cenozoic volcanic rocks of the Clearwater – Wells Gray area, British Columbia

1984 ◽  
Vol 21 (3) ◽  
pp. 267-277 ◽  
Author(s):  
Catherine J. Hickson ◽  
J. G. Souther
Keyword(s):  
British Columbia ◽  
Volcanic Activity ◽  
Olivine Basalt ◽  
Volcanic Rocks ◽  
Volcanic Belt ◽  
Pillow Lava ◽  
Late Cenozoic ◽  
Gray Area ◽  
High Level ◽  
Tuff Breccia

The Clearwater – Wells Gray area of east-central British Columbia includes a succession of late Cenozoic, alkali olivine basalt flows that lie east of the extensive Chilcotin lavas and define the eastern end of the Anahim Volcanic Belt. The rocks are petrographically similar to but less altered than the Chilcotin basalts. The volcanic activity spanned at least two episodes of glacial advance and produced both subaerial flows and a subaqueous facies comprising pillow lava, pillow breccia, and tuff breccia, locally intercalated with fluvial gravels and sand. Four morphological assemblages have been recognized. An early glacial assemblage, characterized by tuyalike forms, gives K – Ar dates of 0.27 – 3.5 Ma. These circular features are surrounded by a deeply dissected valley-filling assemblage of subaerial and minor subaqueous flows and tuff breccia that rest locally on lag gravel and till. Subaerial flows in this assemblage give K – Ar dates of 0.15 – 0.56 Ma. Whitehorse Bluffs, a volcanic centre composed of crudely laminated tuff cut by high-level dykes, may be a source of some of these valley-filling flows. A late interglacial assemblage is composed of subaerial pyroclastic material, transitional deposits, and deposits that are clearly subaqueous. Volcanic activity in the area culminated with the formation of pyroclastic cones, blocky lava flows, and pit craters that postdate the last Cordilleran glaciation.

Sign in / Sign up

Export Citation Format

Share Document