scholarly journals Retroarc Jurassic burial and exhumation of Barrovian metamorphic rocks dated by monazite petrochronology, Funeral Mountains, California

2022 ◽  
Author(s):  
Suzanne Craddock Affinati ◽  
Thomas D. Hoisch ◽  
Michael L. Wells ◽  
Samuel Wright
Keyword(s):  
Sierra Nevada ◽  
Inductively Coupled Plasma ◽  
North American Plate ◽  
Pressure Increase ◽  
Metamorphic Rocks ◽  
Lower Grade ◽  
Inductively Coupled ◽  
Plate Margin ◽  
The Matrix ◽  
T Path

ABSTRACT In this study, we determined the timing of burial and subsequent exhumation of Barrovian metamorphic rocks from the Chloride Cliff area of the Funeral Mountains in southeastern California by constraining the ages of different portions of a pressure-temperature (P-T) path. Using a split-stream laser-ablation inductively coupled plasma–mass spectrometry (ICP-MS) system, we analyzed 192 domains from 35 grains of monazite within five samples with a spot size of 8 µm to determine U-Pb ages and trace-element abundances from the same samples (same polished sections) that were analyzed to produce the P-T paths. Changes that took place within individual monazite grains reflect localized equilibrium and captured the changes in heavy rare earth element (HREE) abundances in the matrix reservoir that occurred as garnet grew, resorbed, and then regrew, thus constraining ages on different portions of the P-T path. The results show that garnet began growing ca. 168 Ma, began resorbing ca. 160 Ma, began retrograde regrowth ca. 157 Ma, and continued to regrow at least through ca. 143 Ma. The early garnet growth corresponds to a period of pressure increase along the P-T path. The subsequent partial resorption corresponds to the prograde crossing of a garnet-consuming reaction during decompression, and the retrograde garnet regrowth occurred when this same reaction was recrossed in the retrograde sense during further decompression. These results are consistent with previously determined ages, which include a Lu-Hf garnet age of 167.3 ± 0.72 Ma for the early pressure-increase portion of the P-T path, and 40Ar/39Ar muscovite cooling ages of 153 and 146 Ma in the lower-grade Indian Pass area 10 km southeast of Chloride Cliff. The 40Ar/39Ar muscovite ages document cooling at the same time as retrograde garnet regrowth was taking place at Chloride Cliff. The oldest monazite age obtained in this study, 176 ± 5 Ma, suggests that southeast-directed thrusting within the Jurassic retroarc was ongoing by this time along the California portion of the western North American plate margin, as a consequence of east-dipping subduction and/or arc collision. The Funeral Mountains were likely located on the east side of the northern Sierra Nevada range in the Jurassic, taking into account dextral strike-slip displacement along the Cretaceous Mojave–Snow Lake fault. The Late Jurassic timing of burial in the Funeral Mountains and its Jurassic location suggest burial was associated with the East Sierran thrust system. The timing of prograde garnet resorption during exhumation (160–157 Ma) corresponds to a change from regional dextral transpression to sinistral transtension along the Jurassic plate margin inferred to have occurred ca. 157 Ma. The recorded exhumation was concurrent with intrusion of the 148 Ma Independence dike swarm in the eastern Sierra Nevada and Mojave regions, which developed within a regime of northeast-southwest extension.

Pressure-temperature-time paths from the Funeral Mountains, California, reveal Jurassic retroarc underthrusting during early Sevier orogenesis

2019 ◽  
Vol 132 (5-6) ◽  
pp. 1047-1065 ◽  
Author(s):  
Suzanne Craddock Affinati ◽  
Thomas D. Hoisch ◽  
Michael L. Wells ◽  
Jeffrey D. Vervoort
Keyword(s):  
Sierra Nevada ◽  
Pressure Increase ◽  
Garnet Growth ◽  
Lower Grade ◽  
High Flux ◽  
Thrust Belt ◽  
Burial History ◽  
Metamorphic Belt ◽  
Pressure Decrease ◽  
T Path

Abstract New metamorphic pressure-temperature (P-T) paths and Lu-Hf garnet ages reveal a temporal correlation between Middle to Late Jurassic retroarc underthrusting and arc magmatism in southwestern North America. P-T paths were determined for 12 garnet porphyroblasts from six samples from the Chloride Cliff area of the Funeral Mountains in southeastern California. The composite path shows a pressure increase from 4.2 to 6.5 kbar as temperature increased from 550 to 575 °C, followed by a pressure decrease to 5.1 kbar during a further increase in temperature to 590 °C. Lu-Hf garnet ages from a pelitic schist (167.3 ± 0.7 Ma) and a garnet amphibolite (165.1 ± 9.2 Ma) place these P-T paths in the Middle Jurassic. We interpret the near-isothermal pressure increase portion of the P-T path to have developed during thrust-related burial, similar to lower grade rocks at Indian Pass, 8 km to the southeast, where garnet P-T paths show a pressure increase dated by the Lu-Hf method at 158.2 ± 2.6 Ma. We interpret the pressure decrease portion of the composite P-T path from the Chloride Cliff area to reflect exhumation contemporaneous with cooling in the Indian Pass area documented from muscovite 40Ar/39Ar step-heating ages of 152.6 ± 1.4 and 146 ± 1.1 Ma. The conditions and timing of metamorphism determined for the Indian Pass and Chloride Cliff areas, and isogradic surfaces that cut across stratigraphy, support the interpretation that the strata were dipping moderately NW during metamorphism, parallel to the thrust ramp that buried the rocks. Burial likely resulted from top-SE motion along the Funeral thrust, which was later reactivated as a low-angle normal fault with opposite motion to become the currently exposed Boundary Canyon detachment that was responsible for Miocene and possibly older exhumation. The part of the burial history captured by garnet growth occurred ∼6 m.y. before the 161 Ma peak of high-flux magmatism in the arc. Burial was contemporaneous with metamorphic ages from the western Sierra Nevada metamorphic belt, with the possible timing of accretion of arc terranes in northern California, and with the initiation of Franciscan subduction. Burial ages are also similar in timing with generally E-W crustal shortening in the retroarc that produced the East Sierra thrust system, the Luning-Fencemaker fold and thrust belt, the possible early history of the Central Nevada thrust belt, and the western thrusts of the southern Sevier belt. The timing of tectonic burial documented in this study and of high-flux magmatism in the arc supports the interpretation that the development of a coherent arc-trench system in the Early Jurassic resulted in the underthrusting of melt-fertile material beneath the arc along west- to northwest-dipping faults such as the Funeral thrust in the Jurassic, which penetrated the basement to the west as well as the roots of the magmatic arc, leading to increased magmatism.

Effect of the matrix in mass spectrometry using an inductively coupled plasma

1998 ◽  
Vol 65 (5) ◽  
pp. 804-811 ◽  
Author(s):  
A. A. Pupyshev ◽  
N. L. Vasil’eva ◽  
S. V. Golik
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Inductively Coupled ◽  
The Matrix

scholarly journals Isotope analysis of highly enriched “silicon-28” by high-resolution inductively coupled plasma mass spectrometry using an internal standard

2021 ◽  
Vol 25 (2) ◽  
pp. 98-109
Author(s):  
P. A. Otopkova ◽  
◽  
A. M. Potapov ◽  
A. I. Suchkov ◽  
A. D. Bulanov ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Matrix Element ◽  
High Resolution ◽  
Inductively Coupled Plasma ◽  
Internal Standard ◽  
Isotopic Analysis ◽  
Random Component ◽  
Inductively Coupled ◽  
The Matrix ◽  
Plasma Mass Spectrometry

In order to study the isotopic effects in semiconductor materials, single crystals of high chemical and isotopic purity are required. The reliability of the obtained data on the magnitude and the direction of isotopic shifts depends on the accuracy of determining the concentration of all stable isotopes. In the isotopic analysis of enriched “silicon-28” with a high degree of enrichment (> 99.99%), it is necessary to determine the impurities of 29Si and 30Si isotopes at the level of 10-3 ¸ 10-5 at. %. At this concentration level, these isotopes can be considered as impurities. It is difficult to achieve high measurement accuracy with simultaneous registration of the main and “impurity” isotopes in such a wide range of concentrations. The registration of analytical signals of silicon isotopes must be carried out in the solutions with different matrix concentrations. The use of the solutions with the high concentration of the matrix element requires the introduction of corrections for matrix noise and the drift of the instrument sensitivity during the measurement. It is possible to reduce the influence of the irreversible non-spectral interference and sensitivity drift by using the method of internal standardization. The inconsistency of the literature data on the selection criteria for the internal standard required studying the behavior of the signals of the “candidates for the internal standard” for the ELEMENT 2 single-collector high-resolution inductively coupled plasma mass spectrometer on the matrix element concentration and the nature of the solvent, as well as on the solution nebulizing time. Accounting for the irreversible non-spectral matrix noise and instrumental drift in isotopic analysis of enriched “silicon-28” and initial 28SiF4 by inductively coupled plasma mass spectrometry had allowed us to reduce by 3-5 times the random component and by more than an order of magnitude the systematic component of the measurement error in comparison with the external standard method. This made it possible to carry out, with sufficient accuracy, the operational control of the isotopic composition of enriched “silicon-28”, both in the form of silicon tetrafluoride and polycrystalline silicon obtained from it, using a single serial device in the range of isotopic concentrations 0.0001–99.999%.

Contact Metamorphic and Metasomatic Processes at the Kharaelakh Intrusion, Oktyabrsk Deposit, Norilsk-Talnakh Ore District: Application of LA-ICP-MS Dating of Perovskite, Apatite, Garnet, and Titanite

2020 ◽  
Vol 115 (6) ◽  
pp. 1213-1226 ◽  
Author(s):  
Alexander E. Marfin ◽  
Alexei V. Ivanov ◽  
Vadim S. Kamenetsky ◽  
Adam Abersteiner ◽  
Tamara Yu. Yakich ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Metamorphic Rocks ◽  
Complete Agreement ◽  
Ionization Mass ◽  
Pb Isotope ◽  
Inductively Coupled ◽  
Prolonged Duration ◽  
Plasma Mass Spectrometry ◽  
Ore District

Abstract The Norilsk-Talnakh ore district in the northwestern Siberian platform contains globally unique reserves of Cu-Ni-sulfides with Pt and, especially, Pd. The Oktyabrsk deposit, which is one of the largest in the district, is spatially and genetically associated with the Kharaelakh mafic-ultramafic intrusion and its exceptionally large metamorphic and metasomatic aureoles. In this study, we employed in situ laser ablation-inductively coupled plasma-mass spectrometry U-Pb isotope dating of apatite, titanite, garnet, and perovskite that cocrystallize with disseminated sulfides within the aureole of metasomatic and contact metamorphic rocks. The calculated isotopic ages for apatite (257.3 ± 4.5 and 248.9 ± 5.1 Ma), titanite (248.6 ± 6.8 and 249.1 ± 2.9 Ma), garnet (260.0 ± 11.0 Ma), and perovskite (247.3 ± 8.2 Ma), though with large uncertainties, indicate that sulfide mineralization within metasomatic and contact-metamorphic rocks is coeval with the emplacement of the Kharaelakh intrusion. These isotopic dates are in complete agreement with the published isotope dilution-thermal ionization mass spectrometry U-Pb zircon ages for the Norilsk intrusions and, at the same time, notably older than available Re-Os isochron ages of sulfides. The latter ages have been long interpreted as evidence for a prolonged duration of magmatic ore-forming processes; however, our data narrow their life span. Trace elements in titanite and garnet allow distinguishing late- and postmagmatic grains, which show indistinguishable U-Pb isotope ages.

Determination of trace elements in the Pb–Bi-eutectic system by inductively coupled plasma-quadrupole mass spectrometry after sequential removal of the matrix by precipitation

2014 ◽  
Vol 29 (9) ◽  
pp. 1720-1725 ◽  
Author(s):  
Krishnan Chandrasekaran ◽  
Dheram Karunasagar
Keyword(s):  
Inductively Coupled Plasma ◽  
Eutectic System ◽  
Inductively Coupled ◽  
Icp Ms ◽  
The Matrix ◽  
Sensitive Determination ◽  
P Matrix ◽  
Matrix Precipitation ◽  
Determination Of Impurities

Matrix precipitation for the sensitive determination of impurities in the Pb–Bi eutectic system by ICP-MS.

Determination of the Matrix Element Vanadium in the Potassium Metavanadate by Inductively Coupled Plasma Atomic Emission Spectrometry

2013 ◽  
Vol 740 ◽  
pp. 665-669
Author(s):  
Yong Cheng ◽  
Hui Xian Peng ◽  
Jin Hong Yuan
Keyword(s):  
Inductively Coupled Plasma ◽  
Atomic Emission ◽  
Atomic Emission Spectrometry ◽  
Emission Spectrometry ◽  
High Concentration ◽  
Plasma Atomic Emission Spectrometry ◽  
Inductively Coupled ◽  
The Matrix ◽  
Standard Solution

The potassium metavanadate samples were digested by hydrochloric acid and diluted with water to a constant volume, then the inductively coupled plasma atomic emission spectrometry (ICP-OES) was used to directly determine the content of 10 to 45% matrix vanadium. The matrix effects, spectral interference, background noise and other interference factors in the high concentration of potassium ions coexistence system were all examined in the paper. The results showed that although the coexisting alkali metal potassium significantly increased the ICP flame, the 1g/L potassium standard solution did not produce peaks in the scanning window of analysis line which substantially coincide with the reagent blank signal line, i.e., the 28% (or 0.28g/L) potassium contained in the potassium metavanadate did not interfere with the determination. Therefore, only the standard solution of vanadium was used to draw a calibration curve without the need of potassium matrix matching. In order to obtain a wide linear range and improve the detection precision and the accuracy of the matrix element vanadium, the sample dilution ratio and ICP spectrometer detection parameters were optimized, and the suitable sensitivity spectral lines and their detection integral and background correction regional were selected, the detection signal intensity of the high concentration vanadium is effectively regulated moderate, the detection range is covered from 10 to 45%, which fully meet the need for determination of vanadium in the potassium metavanadate (qualified products containing 37% vanadium). The results also showed that the background equivalent concentration is less than 5 μg/L, the relative standard deviation (RSD) is less than 1.0%, the detection results consistent with the redox titration method. The method is simple and fast, accurate and reliable, the precision is high. The inspection cycle is 10 to 15 minutes, which is greatly shorter than the chemical titration that takes 2 to 3 hours, so that the method meet the requirements of fast-paced production site of the potassium metavanadate product quality inspection and control.

A practical approach to non-spectral interferences elimination in inductively coupled plasma optical emission spectrometry

2016 ◽  
Vol 70 (6) ◽  
Author(s):  
Anna Krejčová ◽  
Tomáš Černohorský ◽  
Lenka Bendakovská
Keyword(s):  
Inductively Coupled Plasma ◽  
Matrix Effects ◽  
Optical Emission ◽  
Optical Emission Spectrometry ◽  
Emission Spectrometry ◽  
Spectral Interferences ◽  
Inductively Coupled ◽  
The Matrix ◽  
Plasma Optical Emission Spectrometry ◽  
Matrix Concentration

AbstractMatrix effects and practical possibilities of reducing accompanying non-spectral interferences in inductively coupled plasma optical emission spectrometry (ICP-OES) were studied for microconcentric Micromist, concentric and V-groove nebulizers (VGN) coupled with two cyclonic spray chambers of different sizes. The effect of a wide scale of interferents and mixtures thereof in the concentration range of up to 2 mass % (Na, Ca, Ba, La, urea) or up to 20 vol. % (nitric acid) on the analysis of Cd, Cu, K, Mg, Mn, Pb and Zn was investigated in terms of their analytical recovery and Mg(II) 280.27 nm/Mg(I) 285.29 nm line intensity ratio. Recoveries of ionic lines were lower than those of atomic lines (37–102 %) depending on the matrix concentration. The Mg(II)/Mg(I) ratios were found to be 12–15 and they slightly decreased as the matrix load increased. Exceptional behavior of pure La matrix, steeply lowering the recoveries and Mg(II)/Mg(I) ratios was observed. A Micromist nebulizer coupled with a small inner volume spray chamber provided the highest recoveries (94–102 %), lowest matrix effects across the matrix loads and, compared to others, the least significant dependence without worsening of the analytical characteristics (recoveries, signal background ratios and the Mg(II)/Mg(I) ratios) across the studied matrices.

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