Discussion of the reply by R.L. Romer and U. Kroner on “Geochemical signature of Ordovician Mn-rich sedimentary rocks on the Avalonian shelf” 1Appears in Canadian Journal of Earth Sciences, 49(6): 775–780, 10.1139/e2012-006.

2012 ◽  
Vol 49 (11) ◽  
pp. 1372-1377
Author(s):  
David I. Schofield ◽  
John W.F. Waldron ◽  
Chris E. White ◽  
Sandra M. Barr
Keyword(s):  
Inductively Coupled Plasma ◽  
Sedimentary Rocks ◽  
Sediment Provenance ◽  
Inductively Coupled ◽  
Geochemical Signature ◽  
North Wales ◽  
Plasma Mass Spectrometry ◽  
History Of ◽  
Spectrometry Technique ◽  
Depositional Age

In their article ‘Reply to the discussion by J.W.F. Waldron and C.E. White on “Geochemical signature of Ordovician Mn-rich sedimentary rocks on the Avalonian shelf”’, R.L. Romer and U. Kroner reinterpret geochronological data presented by J.W.F. Waldron, D.I. Schofield, C.E. White, and S.M. Barr to imply an Ordovician, not a Cambrian, depositional age for the succession of the Harlech Dome, North Wales, and Meguma Supergroup, Nova Scotia. However, an extensive history of biostratigraphic and geological survey data refutes this interpretation and shows that the rocks are unequivocally Cambrian. Waldron et al. used the U–Pb zircon laser-ablation – multicollector – inductively coupled plasma – mass spectrometry technique primarily to provide information on sediment provenance and not depositional age. Investigation of anomalously young 206Pb/238U ages showed evidence of Pb loss. These data provide little constraint on depositional age and cannot be used to infer that the Harlech Grits Group is Ordovician.

Diagenetic and Epigenetic Mineralizing Events in the Kalahari Copperbelt, Botswana: Evidence from Re-Os Sulfide Dating and U-Th-Pb Xenotime Geochronology

2021 ◽  
Author(s):  
Wesley S. Hall ◽  
Holly J. Stein ◽  
Andrew R.C. Kylander-Clark ◽  
Murray W. Hitzman ◽  
Yvette D. Kuiper ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Wall Rock ◽  
Rock Fragment ◽  
Northern Margin ◽  
Inductively Coupled ◽  
Central African Copperbelt ◽  
Plasma Mass Spectrometry ◽  
History Of ◽  
Depositional Age ◽  
Host Rocks

Abstract The ages of sedimentation and copper-silver mineralization in the late Meso- to Neoproterozoic Kalahari Copperbelt in Botswana, an economically significant copper province, have previously been poorly constrained within a ~600 m.y. period that spans the Neoproterozoic from the assembly and breakup of Rodinia to the assembly of Gondwana. Rhenium-osmium geochronology of molybdenite and copper sulfide minerals and U-Th-Pb laser ablation split-stream inductively coupled plasma-mass spectrometry (LASS ICP-MS) analysis of xenotime grains are utilized to provide absolute and relative age data on the host rocks and mineralizing events within the Ghanzi Ridge region of the Kalahari Copperbelt. The data reveal a prolonged history of events, which is partially comparable with depositional and mineralizing events in the neighboring Central African Copperbelt. Abundant disseminated molybdenite is located within a shale layer near the base of the Proterozoic D’Kar Formation at the Northeast Mango Two deposit. Unusual molybdenite textures suggest organic matter may have been a precursor. Two molybdenite separates from a small calcite-molybdenite stringer in a wall-rock fragment that is enclosed within an epigenetic quartz-calcite-chalcopyrite vein with ill-defined and mismatched margins yielded Re-Os ages of 981 ± 3 and 981 ± 7 Ma. These ages indicate an early hydrothermal mineralizing event in the basin. A xenotime inclusion intergrown with molybdenite and chalcopyrite within the epigenetic vein yielded a younger U-Th-Pb age of 538 ± 8 Ma, suggesting two mineralizing events are preserved in a complex 6-cm-wide vein. Based on vein texture and alteration, the ages represent an ~981 Ma calcite-molybdenite mineralization event overprinted by an ~538 Ma quartz-chalcopyrite-molybdenite mineralization event, perhaps during reopening of the vein. Re-Os and U-Th-Pb geochronology were utilized at the Zone 6 deposit on minerals associated with a hydrothermal quartz-calcite-chalcocite-idaite-bornite vein. Several authigenic xenotime grains that occur along the margin of the vein yielded three concordant U-Th-Pb ages that indicate xenotime growth at ~950 to 925 Ma while other xenotime grains in a similar position yielded mostly discordant data, suggesting disturbance of the isotopic system in the xenotime grains. A coprecipitated chalcocite-idaite mixture within the hydrothermal vein produced an Re-Os age of 549.0 ± 11.2 Ma. Re-Os analysis obtained from a coprecipitated molybdenite-bornite mixture at the Northeast Fold deposit yielded an age of 515.9 ± 2 Ma. Together, the earliest Neoproterozoic Re-Os molybdenite and U-Th-Pb xenotime ages provide both a minimum depositional age constraint for the lowermost D’Kar Formation and clear evidence that diagenetic hydrothermal mineralizing events took place within the Ghanzi basin. The timing of this mineralizing event corresponds with a poorly documented regional thermal event that affected the northern margin of the Kalahari craton during the final stages of the assembly of Rodinia at ~980 Ma. The lower to middle Ghanzi Group of the Kalahari Copperbelt is at least 100 m.y. older than the host rocks within the neighboring Central African Copperbelt, which are associated with the breakup of Rodinia. The latest Neoproterozoic to Cambrian Re-Os and U-Th-Pb ages indicate that hydrothermal copper-silver mineralizing events occurred during the Pan-African (~600–480 Ma) fold-thrust evolution of the Ghanzi-Chobe zone and were broadly synchronous with widespread epigenetic hydrothermal copper-cobalt mineralizing events in the adjacent Central African Copperbelt.

scholarly journals The emplacement age of the Muntele Mare Variscan granite (Apuseni Mountains, Romania)

2009 ◽  
Vol 60 (6) ◽  
pp. 495-504 ◽  
Author(s):  
Ioan Balintoni ◽  
Constantin Balica ◽  
Monica Cliveţi ◽  
Li-Qiu Li ◽  
Horst Hann ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Variscan Orogeny ◽  
Weighted Mean ◽  
Apuseni Mountains ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
History Of ◽  
The Alps ◽  
Last Stage

The emplacement age of the Muntele Mare Variscan granite (Apuseni Mountains, Romania)Like the Alps and Western Carpathians, the Apuseni Mountains represent a fragment of the Variscan orogen involved in the Alpine crustal shortenings. Thus the more extensive Alpine tectonic unit in the Apuseni Mountains, the Bihor Autochthonous Unit is overlain by several nappe systems. During the Variscan orogeny, the Bihor Unit was a part of the Someş terrane involved as the upper plate in subduction, continental collision and finally in the orogen collapse and exhumation. The Variscan thermotectonic events were marked in the future Bihor Unit by the large Muntele Mare granitoid intrusion, an S-type anatectic body. Zircon U-Pb laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) dating yielded a weighted mean age of 290.9 ± 3.0 Ma and a concordia age of 291.1 ± 1.1 Ma. U-Pb isotope dilution zircon analyses yielded a lower intercept crystallization age of 296.6 + 5.7/-6.2 Ma. These two ages coincide in the error limits. Thus, the Muntele Mare granitoid pluton is a sign of the last stage in the Variscan history of the Apuseni Mountains. Many zircon grains show inheritance and/or Pb loss, typical for anatectic granitoid, overprinted by later thermotectonic events.

Experimental assessment of the effect of temperature and salinity on elemental composition of otoliths using solution-based ICPMS

1995 ◽  
Vol 52 (7) ◽  
pp. 1421-1430 ◽  
Author(s):  
Anthony J. Fowler ◽  
Steven E. Campana ◽  
Simon R. Thorrold ◽  
Cynthia M. Jones
Keyword(s):  
Elemental Composition ◽  
Inductively Coupled Plasma ◽  
Somatic Growth ◽  
Early Life History ◽  
Effect Of Temperature ◽  
Micropogonias Undulatus ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
History Of ◽  
Salinity Difference

Retrospective determination of the early life history of fish using the microelemental analysis of their otoliths is dependent upon understanding the factors that affect this elemental composition. Here, juvenile Atlantic croaker (Micropogonias undulatus) were reared under different treatments of temperature and salinity to determine their impacts on elemental inclusion rates in otoliths. Solution-based inductively coupled plasma mass spectrometry (ICPMS) was used to measure 21 isotopes in each otolith: isotopic concentrations ranged over seven orders of magnitude, and differed significantly amongst the temperature–salinity regimes. Univariate analyses identified 13 isotopes that contributed to these multivariate differences; the influence of temperature was stronger than that of salinity. Within each treatment there was a significant relationship between otolith microchemistry and otolith size. To some extent this confounded the interpretation of the between-treatment effect of temperature. In contrast, both the otolith and somatic growth rates were similar between the two salinity treatments, indicating that differences in elemental fingerprints were unambiguously related to the salinity difference, probably a response to the elemental concentrations in the tank water. Overall the study highlighted the current poor understanding of the mechanism of contamination of otoliths by trace elements and their incorporation into the otolith microstructure.

scholarly journals Supplemental Material: Recalibrating Rodinian rifting in the northwestern United States

2021 ◽  
Author(s):  
Daniel Brennan ◽  
et al.
Keyword(s):  
United States ◽  
Mass Spectrometry ◽  
Detrital Zircon ◽  
Inductively Coupled Plasma ◽  
Individual Sample ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Depositional Age ◽  
Conventional Laser

Individual sample detrital zircon results, alternative maximum depositional age calculations, conventional laser-ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) methodology, rapid LA-ICP-MS methodology, sample locations, and detrital zircon U-Pb/Lu-Hf results for all analyses and compiled U-Pb data.<br>

scholarly journals A Study of the Composition and Dissolution of Jianshui Purple Pottery in Yunnan, China

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1034
Author(s):  
Chang Liu ◽  
Heng Xie ◽  
Lei Nie ◽  
Hong Wang ◽  
Yuanyuan He
Keyword(s):  
Inductively Coupled Plasma ◽  
Theoretical Basis ◽  
Pottery Production ◽  
X Ray ◽  
Inductively Coupled ◽  
Dissolution Tests ◽  
Before And After ◽  
Plasma Mass Spectrometry ◽  
History Of ◽  
Composition Changes

Pottery is a gem in the history of human civilization and a crystallization of human wisdom. Yunnan Jianshui purple pottery is one of the four famous types of pottery in China, with a long history and superb craftsmanship. Used as tableware, research on the composition and element dissolution of pottery is extremely significant for production and health. This paper takes Jianshui purple pottery as its research object, samples its raw ores and finished products, and conducts X-ray fluorescence, scanning electron microscopy, inductively coupled plasma mass spectrometry experiments, and dissolution tests. The chemical composition, microstructure, and trace element concentrations of pottery before and after firing were measured. Results show that the dissolution of purple pottery under various use scenarios is low and meets health requirements. Combined with the characteristics of purple pottery, the composition changes and the mechanism of change before and after firing are discussed, which can be used as the theoretical basis for improving pottery production in the future.

Geochemical Characteristics of the Campano-Maastrictian Sediments of the Anambra Basin, Southeastern Nigeria - Implication For Provenance, Paleodepositional Environment, Maturity and Tectonic Setting

2021 ◽  
Author(s):  
Michael Edirin Okiotor ◽  
EDeh Desiree Ogueh
Keyword(s):  
Inductively Coupled Plasma ◽  
Tectonic Setting ◽  
Passive Margin ◽  
Source Rocks ◽  
Sediment Provenance ◽  
Southeastern Nigeria ◽  
Inductively Coupled ◽  
Anambra Basin ◽  
Plasma Mass Spectrometry ◽  
Chemical Index Of Alteration

Abstract The present study investigates the Anambra Basin shales to determine the provenance and maturity of the sediments using standard geochemical techniques. Twelve (12) representative samples recovered from shale sequences of The Mamu Formation and Nkporo Group of The Anambra Basin were studied to determine the sediment provenance, paleoenvironment, diagenetic conditions, maturity as well as the tectonic setting. To consider in detail and establish the inherent constituents of the Major minerals, Trace and Rare Earth elements, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analyses techniques was employed. The detrital minerals determined are Al2O3 (18.27% and 21.16%), TiO2 (1.73% and 1.63%) and Fe2O3 (2.78% \ and 2.85%), for Nkporo Group and Mamu Formation respectively. The enrichment of SiO2, Al2O3 and TiO2 (1.14, 1.94, 3.67 respectively) supported by Chemical Index of Alteration (CIA) of 93.54 & 39.55 and Rb/Sr ratio of 0.57 & 0.40, indicate that the Anambra Basin sediments are matured. TiO2/AL2O3 binary plots, Th/Co Vs La/Sc crossplots, Th-Sc-Zr triplots and Cr, Ni concentration suggest mixed provenance of felsic to mafic source rocks for these sediments. From the log (K2O/Na2O) Vs SiO2 crossplots, a passive margin tectonic setting was determined for these sediments.

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