Immobile trace elements and Archean volcanic stratigraphy in the Timmins mining area, Ontario

1979 ◽  
Vol 16 (2) ◽  
pp. 305-311 ◽  
Author(s):  
J. F. Davies ◽  
R. W. E. Grant ◽  
R. E. S. Whitehead
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
No Value ◽  
Volcanic Rocks ◽  
Mining Area ◽  
Stratigraphic Correlation ◽  
Trace Element Data ◽  
Volcanic Stratigraphy ◽  
Lithostratigraphic Units ◽  
Hydrolysis Of

Carbonate alteration and hydrolysis of mafic volcanic rocks in the Timmins area have been accompanied by mobilization and redistribution of alkalies, CaO, MgO, and FeO. These major oxides are of dubious value in classifying the volcanic rocks, and are of no value in identifying and correlating lithostratigraphic units. The trace elements Y, Zr, TiO2, and Cr, whose fractionation tendencies parallel those of the alkalies, FeO and MgO, are relatively immobile and display characteristic patterns within different volcanic units. The trace-element patterns are highly diagnostic, and their distribution corresponds to the distribution of lithostratigraphic units. Immobile trace-element data represent a potentially valuable tool in stratigraphic correlation of Archean volcanic rocks, whether altered or unaltered.

Further immobile element data from altered volcanic rocks, Timmins mining area, Ontario

1980 ◽  
Vol 17 (3) ◽  
pp. 419-423 ◽  
Author(s):  
J. F. Da Vies ◽  
R. E. S. Whitehead
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Volcanic Rocks ◽  
Mining Area ◽  
Trace Element Data ◽  
Element Data ◽  
Lithostratigraphic Units

The relatively immobile trace elements TiO2, Zr, and Y prove useful for determining the original identity of, and for correlating, metamorphosed and metasomatized Archean volcanic rocks. More than 95% of 366 samples from the Timmins area were found to correspond to the lithostratigraphic units determined independently from structural and stratigraphic decisions based on lithology and top determinations. Trace-element data can be used for distinguishing volcanic units and as an aid in correlation regardless of any petrogenetic interpretations.

scholarly journals Pyrite Textures, Trace Elements and Sulfur Isotope Chemistry of Bijaigarh Shales, Vindhyan Basin, India and Their Implications

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 588
Author(s):  
Indrani Mukherjee ◽  
Mihir Deb ◽  
Ross R. Large ◽  
Jacqueline Halpin ◽  
Sebastien Meffre ◽  
...  
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Sulfur Isotope ◽  
Volcanic Rocks ◽  
Central India ◽  
High Energy ◽  
Vindhyan Basin ◽  
Mean Values ◽  
Fine Grained ◽  
Sedimentary Pyrite

The Vindhyan Basin in central India preserves a thick (~5 km) sequence of sedimentary and lesser volcanic rocks that provide a valuable archive of a part of the Proterozoic (~1800–900 Ma) in India. Here, we present an analysis of key sedimentary pyrite textures and their trace element and sulfur isotope compositions in the Bijaigarh Shale (1210 ± 52 Ma) in the Vindhyan Supergroup, using reflected light microscopy, LA-ICP-MS and SHRIMP-SI, respectively. A variety of sedimentary pyrite textures (fine-grained disseminated to aggregates, framboids, lags, and possibly microbial pyrite textures) are observed reflecting quiet and strongly anoxic water column conditions punctuated by occasional high-energy events (storm incursions). Key redox sensitive or sensitive to oxidative weathering trace elements (Co, Ni, Zn, Mo, Se) and ratios of (Se/Co, Mo/Co, Zn/Co) measured in sedimentary pyrites from the Bijaigarh Shale are used to infer atmospheric redox conditions during its deposition. Most trace elements are depleted relative to Proterozoic mean values. Sulfur isotope compositions of pyrite, measured using SHRIMP-SI, show an increase in δ34S as we move up stratigraphy with positive δ34S values ranging from 5.9‰ (lower) to 26.08‰ (upper). We propose limited sulphate supply caused the pyrites to incorporate the heavier isotope. Overall, we interpret these low trace element signatures and heavy sulfur isotope compositions to indicate relatively suppressed oxidative weathering on land during the deposition of the Bijaigarh Shale.

Geochemical contrasts between late Caledonian granitoid plutons of northern, central and southern Scotland

1984 ◽  
Vol 75 (2) ◽  
pp. 259-273 ◽  
Author(s):  
W. E. Stephens ◽  
A. N. Halliday
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Incompatible Element ◽  
Geochemical Data ◽  
Wide Sense ◽  
Trace Element Data ◽  
Isotopic Data ◽  
Element Data ◽  
High K ◽  
Mantle Component

ABSTRACTNew major- and trace-element data for granitoid plutons from the Grampian Highlands, the Midland Valley and the Southern Uplands of Scotland are presented and discussed. The study is restricted to ‘late granitoids’ (all younger than 430 Ma); the term ‘granitoid’ is used in a wide sense to encompass all plutonic components of a zoned intrusion of this age, sometimes including diorites and ultrabasic cumulate rocks. The data indicate that as a whole the province is chemically high-K calc-alkalic. Other notable enrichments are in Sr and Ba, and a marked geographical difference in these trace-elements is found between plutons of the SW Grampian Highlands and those of the Southern Highlands, the Midland Valley, and the Southern Uplands. Plutons of the NE Highlands tend to be more geochemically evolved than those further SW and those of the Midland Valley and Southern Uplands.When petrographical and geochemical data are considered, three plutonic suites are recognised: (1) the Cairngorm suite comprising plutons of the NE Highlands, (2) the Argyll suite comprising plutons from the SW Highlands, and (3) the S of Scotland suite comprising plutons from the Southern Highlands, Midland Valley and the Southern Uplands excluding Criffell and the Cairnsmore of Fleet. It is proposed that the more acidic granitoids are dominantly the products of I-type crustal sources, but certain diorites and the more basic members of zoned plutons have a substantial mantle component. The elevated Sr and Ba levels in granitoids of the Argyll suite may reflect the influence of incompatible-element-rich fluids from the mantle in the petrogenesis of this suite. The relatively anhydrous pyroxene-mica diorites of the S of Scotland suite are richer in Ni and Cr and appear to represent mantle-derived melts. The relationships between these data and already published isotopic data are discussed.

Mineralogical composition of and trace-element accumulation in lower Toarcian anoxic sediments: a case study from the Bilong Co. oil shale, eastern Tethys

2015 ◽  
Vol 153 (4) ◽  
pp. 618-634 ◽  
Author(s):  
XIUGEN FU ◽  
JIAN WANG ◽  
XINGLEI FENG ◽  
WENBIN CHEN ◽  
DONG WANG ◽  
...  
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Oil Shale ◽  
Volcanic Rocks ◽  
Mineralogical Composition ◽  
Geochemical Data ◽  
Anoxic Sediments ◽  
Marine Influence ◽  
High Concentrations ◽  
Element Enrichment

AbstractThe sediments of organic-rich oil shales in the Bilong Co. area can be correlated with those of the early Toarcian anoxic black-shale events in Europe. The Bilong Co. sediments are rich in trace elements Se, Mo, Cd, As and Ni, and, to a lesser extent, Li, F, V, Co, Cu, Cs, Hg and Bi, in comparison to the upper continental crust. Thirty-two oil shale samples were collected from the Bilong Co. oil shale to evaluate the controlling factors of trace-element enrichment in the lower Toarcian anoxic sediments. Minerals identified in the Bilong Co. oil shale include calcite, quartz, illite, feldspar and dolomite, and trace amounts of siderite, magnesite, halite, haematite, zeolite, amphibole, gypsum, anhydrite, apatite, pyrite, sphalerite, barite and mixed-layer illite/smectite. Mineralogical and geochemical data show that seawater and hydrothermal activities are the dominant influences on the mineralogical composition and elevated trace-element concentrations in the oil shale. The clay minerals, quartz and feldspar in the Bilong Co. oil shale were derived from the Nadi Kangri volcanic rocks. Input of sediment from this source may have led to enrichment of trace elements Li, Cr and Cs in the oil shale. Carbonate minerals and nodular- and framboidal-pyrite are authigenic phases formed from seawater. The enrichment of V, Co, Ni, Cu, Mo, As, Se, Bi and U in the oil shale was owing to marine influence. Barite, sphalerite and fracture-filling pyrites were derived from hydrothermal solutions. High concentrations of F, Zn and Cd were probably derived from hydrothermal fluids.

Revised stratigraphic nomenclature and age determinations for mid-Cretaceous volcanic rocks in southwestern British Columbia

1989 ◽  
Vol 26 (10) ◽  
pp. 2016-2031 ◽  
Author(s):  
Derek J. Thorkelson ◽  
Glenn E. Rouse
Keyword(s):  
British Columbia ◽  
Volcanic Rocks ◽  
Fault System ◽  
Volcanic Stratigraphy ◽  
Clastic Rocks ◽  
Lower Unit ◽  
Basement Rocks ◽  
Lithostratigraphic Units ◽  
Bridge Group ◽  
Stratigraphic Nomenclature

Mid-Cretaceous volcanic and volcaniclastic rocks in southwestern British Columbia, east of the Fraser Fault System, constitute two principal lithostratigraphic units. The lower unit, a composite succession of basaltic to rhyolitic lavas and various clastic rocks, is exposed in a 215 km linear belt from near Pavilion to south of Princeton. The upper unit, mostly amygdaloidal andesite, is restricted to the centre of the belt between Spences Bridge and Kingsvale, where it overlies the lower unit and contiguous basement rocks. Both units were deposited subaerially, concurrent with folding and faulting, and share a contact that varies from gradational, near Kingsvale, to unconformable, near Spences Bridge.The names "Spences Bridge Group" and "Kingsvale Group" were used by several authors for various parts of the volcanic stratigraphy. We suggest revision of nomenclature whereby the lower and upper units are named "Pimainus Formation" and "Spius Formation", respectively; together they constitute the Spences Bridge Group. The term "Kingsvale Group" is abandoned.Assemblages of fossil leaves and palynomorphs, collected from one Spius and seven Pimainus localities, include several species of early angiosperms. A late Albian age is thereby indicated for both formations; this is largely corroborated by isotopic dates from the volcanic strata and cross-cutting granitic plutons.

The geochemistry of carbonate cements in the Avalon Sand, Grand Banks of Newfoundland

1985 ◽  
Vol 49 (352) ◽  
pp. 457-467 ◽  
Author(s):  
Ian Hutcheon ◽  
Cynthia Nahnybida ◽  
H. R. Krouse
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Meteoric Water ◽  
Trace Element Data ◽  
Isotopic Data ◽  
Grand Banks ◽  
Carbonate Cements ◽  
Trace Element Contents ◽  
Oxygen Isotopic ◽  
Textural Evidence

AbstractCalcite cements from the Lower Cretaceous Avalon zone of the Hibernia field are, in places, extensively recrystallized, which complicates interpretation of the chemical and isotopic data. The oxygen isotopic data are widely scattered with δ18O ranging between +1.6 and −9.2 for calcite and siderite. Siderite has lower δ13C values (−6.6 to −13.2) than calcite +12.4 to −9.8. Typical trace element contents determined by ICP on acid-leached samples, range from 270 to 2100 ppm Sr and 180 to 2200 ppm Zn in calcite.The trace element data indicate that some of the calcite has been precipitated from, or recrystallized by meteoric water. The trace elements show trends related to variations in δ18O in such a way as to imply that not all the spread to low δ18O values can be attributed to meteoric water influence alone. The data are not well enough constrained to calculate meaningful temperatures, but the range of °18O values probably represents an elevated range of temperatures of precipitation or recrystallization.Microprobe analyses show that non-recrystallized fossils have a composition distinctly different from veins, cements, and recrystallized fossils, all of which are similar. The compositions of calcite cements are highly variable, with FeO (for example) ranging from 0.15 to 4.39 wt. %, but show no consistent patterns of zonation. Fossil fragments which show no textural evidence of recrystallization have low FeO contents (0.2 wt. %). Meteoric water, believed to be responsible for at least some of the cementation and recrystallization observed, probably entered the Avalon during and after formation of the mid-Cretaceous unconformity.

A tephrochronologic method based on apatite trace-element chemistry

2011 ◽  
Vol 76 (1) ◽  
pp. 157-166 ◽  
Author(s):  
Bryan Keith Sell ◽  
Scott Douglas Samson
Keyword(s):  
Trace Element ◽  
Electron Microprobe ◽  
Glass Composition ◽  
Volcanic Rocks ◽  
Trace Element Data ◽  
Element Data ◽  
Element Concentrations ◽  
Ash Fall ◽  
Trace Element Chemistry ◽  
Stratigraphic Record

AbstractGeochemical correlation of ash-fall beds with conventional tephrochronologic methods is not feasible when original glass composition is altered. Thus, alternative correlation methods may be required. Initial studies of heavily altered Paleozoic tephra (K-bentonites) have suggested the potential for employing trace-element concentrations in apatite as ash-fall bed discriminators. To further test the utility of apatite trace-element tephrochronology, we analyzed apatite phenocrysts from unaltered volcanic rocks with an electron microprobe: nine samples from rocks erupted during the Quaternary and one sample from a rock erupted during the Paleogene. The resulting apatite trace-element data provide unique bed discriminators despite within-crystal variability. Each of the volcanic rocks studied possesses unique trends in Mg, Cl, Mn, Fe, Ce and Y concentrations in apatite. The results from this study establish an important tephrochronologic method that can be applied to nearly all portions of the Phanerozoic stratigraphic record and greatly assist development of an advanced timescale. In addition to establishing a fingerprint for a particular eruption, apatite chemistry provides useful information about the source magma.

scholarly journals Magmatic affinity of modern and ancient subalkaline volcanic rocks determined from trace-element discriminant diagrams

2009 ◽  
Vol 46 (11) ◽  
pp. 823-839 ◽  
Author(s):  
Pierre-Simon Ross ◽  
Jean H. Bédard
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Volcanic Rocks ◽  
Total Iron ◽  
Calc Alkaline ◽  
Overall Performance

When dealing with ancient subalkaline volcanic rocks, the alkali – total iron – magnesium (AFM) diagram is of limited use in assigning a tholeiitic versus calc-alkaline affinity because these elements are often mobile during alteration and metamorphism. Classification diagrams using immobile trace elements are preferable but need to be tested and optimized on unaltered rocks. To this end, a geochemical database containing over a thousand, presumed unaltered, subalkaline volcanic samples from young oceanic arcs was assembled. The data were classified using both major and trace-element approaches, and the results were compared. If the calc-alkaline and tholeiitic fields on the AFM diagram are used to define magmatic affinity, then the commonly used Zr versus Y, La versus Yb, and Th versus Yb discriminant diagrams misclassify 39%, 24%, and 28% of samples, respectively. After optimization (using a number of criteria), all three trace-element classification diagrams produce results that are generally consistent with the AFM diagram. The optimized diagrams only misclassify 7%, 11%, and 12% of the samples, respectively. A new Th/Yb versus Zr/Y diagram has a better overall performance than any single ratio diagram and may prove helpful in assigning magmatic affinities to volcanic rocks in ancient successions.

Metabentonites in the Moffat Shale Group, Southern Uplands of Scotland: Geochemical evidence of ensialic marginal basin volcanism

1990 ◽  
Vol 127 (3) ◽  
pp. 259-271 ◽  
Author(s):  
R. J. Merriman ◽  
B. Roberts
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Late Ordovician ◽  
Trace Element Data ◽  
Geochemical Evidence ◽  
Sialic Crust ◽  
Element Data ◽  
High Concentrations ◽  
Arc Setting ◽  
Back Arc

AbstractMetabentonites occur extensively in the Moffat Shale Group of the Southern Uplands of Scotland. At Dob's Linn 135 metabentonite beds, 1–50 cm thick, occur in Ashgill to Llandovery strata, representing an aggregate thickness of 6 m of compacted ash accumulated over approximately 25 Ma. The metabentonites are characterized by relatively high concentrations of trace elements, including Ba, Cs, Hf, Nb, Rb, Ta, Th, U, Y, Zr and REEs, which were inherited from evolved vitric ash. Immobile trace element data indicate that a spectrum of silicic ash compositions accumulated, ranging from subalkaline to mildly peralkaline. In the late Ordovician N. gracilis to G. persculptus biozones, subalkaline ash falls predominated, whereas peralkaline ash falls predominated in the Llandovery (Silurian) P. acuminatus to M. convolutes biozones, giving way to predominantly subalkaline ash falls during accumulation of the M. sedgwickii to R. maximus biozones. Changeovers in the dominant ash types are marked by increased proportions of ash. The magmas from which the ash types evolved were generated in an ensialic arc transitional to a back-arc setting, and involved attenuated sialic crust and mantle characterized by variable depletion in HFS elements. Lithological, petrological and REE characteristics suggest that the Moffat Shale Group is not exclusively pelagic in origin and probably accumulated in a back-arc basin bordering an ensialic arc terrane.

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