scholarly journals Using 87Sr/86Sr LA-MC-ICP-MS Transects within Modern and Ancient Calcite Crystals to Determine Fluid Flow Events in Deep Granite Fractures

Geosciences ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 345 ◽  
Author(s):  
Henrik Drake ◽  
Ellen Kooijman ◽  
Melanie Kielman-Schmitt
Keyword(s):  
Fluid Flow ◽  
Spatial Resolution ◽  
Inductively Coupled Plasma ◽  
High Spatial Resolution ◽  
Isotope Analysis ◽  
Growth Zone ◽  
Water Infiltration ◽  
Radiometric Dating ◽  
Fracture Networks ◽  
Icp Ms

The strontium isotope signature (87Sr/86Sr) of calcite precipitated in rock fractures and faults is a frequently used tool to trace paleofluid flow. However, bedrock fracture networks, such as in Precambrian cratons, have often undergone multiple fracture reactivations resulting in complex sequences of fracture mineral infillings. This includes numerous discrete calcite crystal overgrowths. Conventional 87Sr/86Sr analysis of dissolved bulk samples of such crystals is not feasible as they will result in mixed signatures of several growth zonations. In addition, the zonations are too fine-grained for sub-sampling using micro-drilling. Here, we apply high spatial resolution 87Sr/86Sr spot analysis (80 µm) in transects through zoned calcite crystals in deep Paleoproterozoic granitoid fractures using laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) to trace discrete signs of paleofluid flow events. We compare the outermost calcite growth zone with 87Sr/86Sr values of the present-day groundwater sampled in the same boreholes to distinguish potential modern precipitates. We then connect our results to previously reported radiometric dating and C and O isotope signatures to understand the temporal history and physicochemical evolution of fluid flow within the fractures. Comparisons of modern calcite precipitated in a borehole over a period of 17 years with modern waters prove the concept of using 87Sr/86Sr as a marker for fluid origin in this environment and for how 87Sr/86Sr changed during marine water infiltration. Intermittent calcite precipitation over very long time spans is indicated in calcite of the currently open fractures, showing an evolution of 87Sr/86Sr from ~0.705–0.707—a population dated to ~1.43 billion years—to crystal overgrowth values at ~0.715–0.717 that overlap with the present-day groundwater values. This shows that high spatial resolution Sr isotope analysis of fine-scaled growth zonation within single calcite crystals is applicable for tracing episodic fluid flow in fracture networks.

High spatial resolution in situ U–Pb dating using laser ablation multiple ion counting inductively coupled plasma mass spectrometry (LA-MIC-ICP-MS)

2017 ◽  
Vol 32 (5) ◽  
pp. 975-986 ◽  
Author(s):  
Lie-Wen Xie ◽  
Jin-Hui Yang ◽  
Qing-Zhu Yin ◽  
Yue-Heng Yang ◽  
Jing-Bo Liu ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Inductively Coupled Plasma ◽  
High Spatial Resolution ◽  
Zircon Age ◽  
Analytical Technique ◽  
Inductively Coupled ◽  
Rapid Measurement ◽  
Icp Ms ◽  
Plasma Mass Spectrometry

A new LA-MIC-ICP-MS analytical technique has been developed for the rapid measurement of 206Pb/238U zircon age (<1%, 2s) at a high spatial resolution. We show that this technique can be routinely employed to date U–Pb in small and/or complex zircons, providing a powerful tool for geochronology.

High spatial resolution quantitative elemental imaging of foraminifer by laser ablation-inductively coupled plasma-mass spectrometry

2019 ◽  
Vol 11 (16) ◽  
pp. 2129-2137 ◽  
Author(s):  
Yuqiu Ke ◽  
Jianzong Zhou ◽  
Lei Qiao ◽  
Muhui Zhang ◽  
Wei Guo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Spatial Resolution ◽  
Inductively Coupled Plasma ◽  
High Spatial Resolution ◽  
Elemental Imaging ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry

A methodology for high spatial resolution quantitative elemental imaging of foraminifer by LA-ICP-MS was developed.

scholarly journals High spatial resolution analysis of Pb and U isotopes for geochronology by laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS)

2009 ◽  
Vol 81 (1) ◽  
pp. 99-114 ◽  
Author(s):  
Bernhard Bühn ◽  
Márcio M. Pimentel ◽  
Massimo Matteini ◽  
Elton L. Dantas
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Spatial Resolution ◽  
Inductively Coupled Plasma ◽  
High Spatial Resolution ◽  
Isotopic Ratios ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Isotopic Analyses ◽  
Plasma Mass Spectrometry

Age determinations using the 235U and 238U radioactive decay series to the daughter isotopes 207Pb and 206Pb, respectively, using the mineral zircon (ZrSiO4), are widely used to decipher geological processes. A new method developed in the last couple of years, the laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS), overcomes previous laborious sample preparation, and yields isotopic ratios and age data with a high spatial resolution of ten of microns. The present study describes the analytical set-up and data reduction process as presently applied at the Laboratory for Geochronology of the University of Brasília. It explores the precision and accuracy of the method by cross-analysing three international zircon standards. We arrive at a precision of 1.9 to 3.7% (2σ SD) and an accuracy of 0.6 to 3.8% (2σ SD) for and U isotopic ratios of the standards. We also apply the method to two natural zircon samples, which have previously been dated by other analytical methods. A comparison of the results show a good conformity of the age data,being whitin the error limits. The data demonstrate the great analytical potential of the method for rapid, precise and accurate U-Pb isotopic analyses on the micron scale.

High-precision analysis of potassium isotopes by MC-ICP-MS without collision cell using cool plasma technique in low resolution mode

2021 ◽  
Author(s):  
Hai-Ou Gu ◽  
Sun He
Keyword(s):  
High Precision ◽  
Inductively Coupled Plasma ◽  
Isotope Analysis ◽  
Collision Cell ◽  
Low Resolution ◽  
Inductively Coupled ◽  
Plasma Technique ◽  
Icp Ms ◽  
Cool Plasma ◽  
Plasma Mass Spectrometry

This study presents a method for high-precision stable potassium (K) isotope analysis using Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) without collision cell in low resolution mode. Cold plasma technique...

Sensitive and rapid oxygen isotopic analysis of nephrite jade using large-geometry SIMS

2019 ◽  
Vol 34 (3) ◽  
pp. 561-569
Author(s):  
Axel K. Schmitt ◽  
Ming-Chang Liu ◽  
Issaku E. Kohl
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Isotope Analysis ◽  
Isotopic Analysis ◽  
Rapid Identification ◽  
Oxygen Isotopic ◽  
O Isotope ◽  
Oxygen Isotopic Analysis

High-spatial resolution O-isotope analysis of nephrite by SIMS allows rapid identification of provenance with applications in geology, archaeometry, and gemmology.

scholarly journals Extracting Reliable Paleo-Ocean Temperatures at Southern Mid-Latitudes During the Greenhouse to Icehouse Transition: a LA-ICP-MS Study of the Trace Element Chemistry of Eocene Foraminifera from New Zealand

2021 ◽  
Author(s):  
◽  
John Benjamin Creech
Keyword(s):  
New Zealand ◽  
Trace Element ◽  
Benthic Foraminifera ◽  
Inductively Coupled Plasma ◽  
Middle Eocene ◽  
Isotope Analysis ◽  
Time Interval ◽  
Northern Margin ◽  
Icp Ms ◽  
Fe And Mn

<p>Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been used to measure in situ elemental (Mg, Al, Mn, Zn, Sr, Ba/Ca) ratios of 13 species of variably preserved early to middle Eocene planktonic and benthic foraminifera from the mid-Waipara River section, north Canterbury, New Zealand. The sediments from Waipara River were deposited at bathyal depths (ca. 1000 m) on the northern margin of the east-facing Canterbury Basin at a paleo-latitude of ca. 55 dgrees S. LA-ICP-MS analysis yields trace element depth profiles through foraminifera test walls that can be used to identify and exclude zones of surficial contamination and infilling material resulting from diagenetic coatings, mineralisation and detrital sediment. Screened Mg/Ca ratios are used to calculate sea temperatures from late early to early middle Eocene (ca. 51 to 46.5 Ma), a time interval that appears to span the termination of the Early Eocene Climatic Optimum (EECO). During this time, sea surface temperatures (SST) varied from 30 to 24 degrees C and bottom water temperatures (BWT) from 21 to 14 degrees C. Comparison of Mg/Ca sea temperatures with published delta superscript 18 O and TEX subscript 86 temperature data from the same samples (Hollis et al., 2009) shows close correspondence, indicating that LA-ICP-MS can provide reliable Mg/Ca sea temperatures even where foraminiferal test preservation is less than ideal. Agreement between the three proxies also implies that Mg/Ca - temperature calibrations for modern planktonic and benthic foraminifera can generally be applied to Eocene species, although some species (e.g., V. marshalli) show significant calibration differences. The Mg/Ca ratio of the Eocene ocean is constrained by our data to be 35-50% lower than the modern ocean depending on which TEX86 - temperature calibration is used to compare with the Mg/Ca sea temperatures (Kim et al., 2008; Liu et al., 2009). Sea temperatures derived from oxygen isotope analysis of foraminifera from mid-Waipara show amplified variability relative to the Mg/Ca and TEX86 derived temperatures. While this difference might be attributed to the oxygen isotopes being more susceptible to diagenetic effects, the data may be consistent with the growth and collapse of significant global ice sheets during cool periods in the Eocene on timescales of ca. 0.5 Myr. The timing of the termination of the EECO in the reconstructed climate record from mid-Waipara is consistent with other published climate records (Tripati et al., 2003, 2005; Zachos et al., 2008).  A large decrease in foraminiferal Mn/Ca ratios up the mid-Waipara section is observed with the youngest samples having Mn/Ca ratios similar to modern foraminifera. This does not appear to be a diagenetic fingerprint as foraminiferal preservation is generally poorer up-section. Global cooling following the EECO may have led to enhanced biological productivity and uptake of Fe and Mn, thereafter producing an ocean with Mn concentrations more similar to the present ocean. This hypothesis is consistent with that proposed to explain changes in the thallium isotope ratios of Fe and Mn crusts observed at this time (Nielsen et al., 2009).</p>

New Insights Into the Control of Visible Gold Fineness and Deposition: A Case Study of the Sanshandao Gold Deposit, Jiaodong, China

2021 ◽  
Vol 106 (1) ◽  
pp. 135-149
Author(s):  
Hong-Wei Peng ◽  
Hong-Rui Fan ◽  
Xuan Liu ◽  
Bo-Jie Wen ◽  
Yong-Wen Zhang ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Inductively Coupled Plasma ◽  
Gold Mineralization ◽  
Isotope Analysis ◽  
Trace Element Analysis ◽  
Sulfide Minerals ◽  
Element Analysis ◽  
Rock Interaction ◽  
Inductively Coupled ◽  
Icp Ms

Abstract Mineralogical distribution, textures, electron probe microanalysis of visible gold, laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) trace element analysis of pyrite, and LA-multicollector (MC-)ICP-MS sulfur isotope analysis of sulfide minerals are examined in an ore zone extending obliquely to –4 km depth in the Sanshandao gold deposit Jiaodong, China. We relate these results to the temporal and spatial ore-forming processes in the deposit to further elucidate the controls on the deposition of visible Au and fineness variation. Two generations of Au mineralization are identified. The early generation is represented by beresitization and quartz-pyrite veins in which visible Au grains are associated with pyrite (Py1 and Py2) and are characterized by high fineness [729–961; fineness = 1000×Au/(Au+Ag)]. Py1 and Py2 are both enriched in Co, Ni, and Bi and depleted in As and Au. Texturally, gold and pyrite are pristine crystals, homogeneous in composition. These features are attributed to the sulfidation of the granitic wallrock (fluid/rock interaction) that effectively destabilizes Au in the ore-forming fluids during pyrite deposition. Fineness decreases continuously from 870 at –2650 m depth to 752 at –420 m depth. The Co and Ni contents of Py1 and Py2 decrease significantly from –4000 m to –420 m depth, whereas the As contents increase. The mean δ34S values of Py1 increase from 10.5 to 11.8‰. The spatial variations are interpreted to be related to gradual cooling, decompression, and an enhanced degree of fluid/rock interaction with decreasing depth, which facilitated the initiation of visible gold mineralization at ca. –2700 m depth. The late generation of Au mineralization is represented by quartz-polysulfide veins in which visible Au grains are associated with multiple sulfide minerals (Py3, galena, chalcopyrite, arsenopyrite, and sphalerite). It is characterized by low fineness (549–719), and heterogeneous textures with Ag-rich parts (218–421). Py3, occurring as the rim of pyrite grain, is interpreted to form by replacement via a dissolution-reprecipitation reaction. Py3 is distinctly enriched in As (median of 10 000 ppm) and Au (2.2 ppm), but depleted in Co, Ni, and Bi. The δ34S values of the polysulfide minerals decrease sharply by 4 to 5‰ at depths from –1909 to –1450 m. These features are interpreted to be generated by significant decompression and phase separation of fluid, where most ore elements (e.g., Au, Ag, As, and base metal elements) are destabilized. Our study suggests that remobilization did not affect the generation of visible Au mineralization at Sanshandao.

Triassic volcanic-sedimentary strata in the basement of Songliao Basin, discovered by International Continental Scientific Drilling Borehole, SK-2

2021 ◽  
Author(s):  
Yongkang Yin ◽  
Pujun Wang ◽  
Youfeng Gao ◽  
Haibo Liu
Keyword(s):  
Inductively Coupled Plasma ◽  
Oil And Gas ◽  
Songliao Basin ◽  
Radiometric Dating ◽  
Gas Reservoirs ◽  
Scientific Drilling ◽  
Oil And Gas Exploration ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Drilling Core

&lt;p&gt;In the Songliao Basin, the existence of lower Mesozoic strata remains a debatable issue. Previous studies indicated the absence of Triassic to Lower and Middle Jurassic strata in northeastern China because of uplift and erosion events associated with the return of geo-synclinal folds and orogenic movement during the Late Permian&amp;#8211;Early Jurassic. To date, geochronological studies of intrusive and metamorphic rocks in the basement of the Songliao Basin have also confirmed Carboniferous, Permian, and Late Jurassic ages for the basement formations in general. In the International Continental Scientific Drilling Project (ICDP) in the Songliao Basin, radiometric dating has been carried out for the entire drilling core of the SK-2 east borehole. As a result, we have discovered Triassic volcanic-sedimentary strata in the basement of the Songliao Basin. Laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U&amp;#8211;Pb geochronology was used in this research. Errors in individual analyses by LA-ICP-MS are given at the 1&amp;#963; level, whereas errors in pooled ages are given at the 95% (2&amp;#963;) confidence level. Triassic volcanic-sedimentary strata revealed by the SK-2 east borehole consist of andesitic volcanic breccias at the bottom; andesites, sandstones, and conglomerates in the middle; and andesites at the top. The total thickness of these strata is over 500 m. The formation age of the andesite at the depth of 6,031.9 m is 242.4 &amp;#177; 2.1 Ma (MSWD = 0.06, n = 7). The youngest peak age of the sandstone at the depth of 6,286.2 m is 242.2 Ma. The formation age of the andesite at the depth of 6,286.2 m is 242.6 &amp;#177; 1.5 Ma (MSWD = 1.02, n = 18). This study demonstrates that in the Songliao Basin, there are not only Carboniferous and Permian strata, but also a Triassic volcanic-sedimentary succession in the basement of the basin. The SK-2 drilling core reveals that this volcanic-sedimentary sequence has great thickness. These Triassic volcanic-sedimentary strata provide new clues for the study of the origin and development of the Songliao Basin. As both volcanic and sedimentary rocks can be oil and gas reservoirs, this discovery also provides a new target for oil and gas exploration deep in the Songliao Basin.&lt;/p&gt;

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