Articles | Volume 3, issue 1
https://doi.org/10.5194/gchron-3-123-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/gchron-3-123-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
09 Mar 2021
Research article |
| 09 Mar 2021
| 09 Mar 2021
U − Pb geochronology of epidote by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) as a tool for dating hydrothermal-vein formation
Veronica Peverelli
CORRESPONDING AUTHOR
Institute of Geological Sciences, University of Bern, Bern, 3012,
Switzerland
Tanya Ewing
Institute of Geological Sciences, University of Bern, Bern, 3012,
Switzerland
Daniela Rubatto
Institute of Geological Sciences, University of Bern, Bern, 3012,
Switzerland
Institute of Earth Sciences, University of Lausanne, Lausanne, 1015, Switzerland
Martin Wille
Institute of Geological Sciences, University of Bern, Bern, 3012,
Switzerland
Alfons Berger
Institute of Geological Sciences, University of Bern, Bern, 3012,
Switzerland
Igor Maria Villa
Institute of Geological Sciences, University of Bern, Bern, 3012,
Switzerland
Dipartimento di Scienze dell'Ambiente e della Terra, University of
Milano-Bicocca, Milan, 20126, Italy
Pierre Lanari
Institute of Geological Sciences, University of Bern, Bern, 3012,
Switzerland
Thomas Pettke
Institute of Geological Sciences, University of Bern, Bern, 3012,
Switzerland
Marco Herwegh
Institute of Geological Sciences, University of Bern, Bern, 3012,
Switzerland
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Veronica Peverelli, Alfons Berger, Martin Wille, Thomas Pettke, Pierre Lanari, Igor Maria Villa, and Marco Herwegh
Solid Earth, 13, 1803–1821, https://doi.org/10.5194/se-13-1803-2022, https://doi.org/10.5194/se-13-1803-2022, 2022
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This work studies the interplay of epidote dissolution–precipitation and quartz dynamic recrystallization during viscous granular flow in a deforming epidote–quartz vein. Pb and Sr isotope data indicate that epidote dissolution–precipitation is mediated by internal/recycled fluids with an additional external fluid component. Microstructures and geochemical data show that the epidote material is redistributed and chemically homogenized within the deforming vein via a dynamic granular fluid pump.
Hugo Dominguez, Nicolas Riel, and Pierre Lanari
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2023-189, https://doi.org/10.5194/gmd-2023-189, 2023
Preprint under review for GMD
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Predicting the behaviour of magmatic systems is important for understanding Earth's matter and heat transport. Numerical modelling is a technique that can predict complex systems at different scales of space and time, by solving equations using various techniques. This study tests four algorithms to find the best way to transport the melt composition. The "Weighted Essentially Non-Oscillatory" algorithm emerges as the best choice, minimizing errors and preserving system mass.
Julien Reynes, Jörg Hermann, Pierre Lanari, and Thomas Bovay
Eur. J. Mineral., 35, 679–701, https://doi.org/10.5194/ejm-35-679-2023, https://doi.org/10.5194/ejm-35-679-2023, 2023
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Garnet is a high-pressure mineral that may incorporate very small amounts of water in its structure (tens to hundreds of micrograms per gram H2O). In this study, we show, based on analysis and modelling, that it can transport up to several hundred micrograms per gram of H2O at depths over 80 km in a subduction zone. The analysis of garnet from the various rock types present in a subducted slab allowed us to estimate the contribution of garnet in the deep cycling of water in the earth.
Chiara Montemagni, Stefano Zanchetta, Martina Rocca, Igor M. Villa, Corrado Morelli, Volkmar Mair, and Andrea Zanchi
Solid Earth, 14, 551–570, https://doi.org/10.5194/se-14-551-2023, https://doi.org/10.5194/se-14-551-2023, 2023
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The Vinschgau Shear Zone (VSZ) is one of the largest and most significant shear zones developed within the Late Cretaceous thrust stack in the Austroalpine domain of the eastern Alps. 40Ar / 39Ar geochronology constrains the activity of the VSZ between 97 and 80 Ma. The decreasing vorticity towards the core of the shear zone, coupled with the younging of mylonites, points to a shear thinning behavior. The deepest units of the Eo-Alpine orogenic wedge were exhumed along the VSZ.
Veronica Peverelli, Alfons Berger, Martin Wille, Thomas Pettke, Pierre Lanari, Igor Maria Villa, and Marco Herwegh
Solid Earth, 13, 1803–1821, https://doi.org/10.5194/se-13-1803-2022, https://doi.org/10.5194/se-13-1803-2022, 2022
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This work studies the interplay of epidote dissolution–precipitation and quartz dynamic recrystallization during viscous granular flow in a deforming epidote–quartz vein. Pb and Sr isotope data indicate that epidote dissolution–precipitation is mediated by internal/recycled fluids with an additional external fluid component. Microstructures and geochemical data show that the epidote material is redistributed and chemically homogenized within the deforming vein via a dynamic granular fluid pump.
James Gilgannon, Marius Waldvogel, Thomas Poulet, Florian Fusseis, Alfons Berger, Auke Barnhoorn, and Marco Herwegh
Solid Earth, 12, 405–420, https://doi.org/10.5194/se-12-405-2021, https://doi.org/10.5194/se-12-405-2021, 2021
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Using experiments that simulate deep tectonic interfaces, known as viscous shear zones, we found that these zones spontaneously develop periodic sheets of small pores. The presence of porous layers in deep rocks undergoing tectonic deformation is significant because it requires a change to the current model of how the Earth deforms. Emergent porous layers in viscous rocks will focus mineralising fluids and could lead to the seismic failure of rocks that are never supposed to have this occur.
Felix Hentschel, Emilie Janots, Claudia A. Trepmann, Valerie Magnin, and Pierre Lanari
Eur. J. Mineral., 32, 521–544, https://doi.org/10.5194/ejm-32-521-2020, https://doi.org/10.5194/ejm-32-521-2020, 2020
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We analysed apatite–allanite/epidote coronae around monazite and xenotime in deformed Permian pegmatites from the Austroalpine basement. Microscopy, chemical analysis and EBSD showed that these coronae formed by dissolution–precipitation processes during deformation of the host rocks. Dating of monazite and xenotime confirmed the magmatic origin of the corona cores, while LA-ICP-MS dating of allanite established a date of ~ 60 Ma for corona formation and deformation in the Austroalpine basement.
Samuel Mock, Christoph von Hagke, Fritz Schlunegger, István Dunkl, and Marco Herwegh
Solid Earth, 11, 1823–1847, https://doi.org/10.5194/se-11-1823-2020, https://doi.org/10.5194/se-11-1823-2020, 2020
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Based on thermochronological data, we infer thrusting along-strike the northern rim of the Central Alps between 12–4 Ma. While the lithology influences the pattern of thrusting at the local scale, we observe that thrusting in the foreland is a long-wavelength feature occurring between Lake Geneva and Salzburg. This coincides with the geometry and dynamics of the attached lithospheric slab at depth. Thus, thrusting in the foreland is at least partly linked to changes in slab dynamics.
Emmanuelle Ricchi, Christian A. Bergemann, Edwin Gnos, Alfons Berger, Daniela Rubatto, Martin J. Whitehouse, and Franz Walter
Solid Earth, 11, 437–467, https://doi.org/10.5194/se-11-437-2020, https://doi.org/10.5194/se-11-437-2020, 2020
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This study investigates Cenozoic deformation during cooling and exhumation of the Tauern metamorphic and structural dome, Eastern Alps, through Th–Pb dating of fissure monazite-(Ce). Fissure (or hydrothermal) monazite-(Ce) typically crystallizes in a temperature range of 400–200 °C. Three major episodes of monazite growth occurred at approximately 21, 17, and 12 Ma, corroborating previous crystallization and cooling ages.
Alice Vho, Pierre Lanari, Daniela Rubatto, and Jörg Hermann
Solid Earth, 11, 307–328, https://doi.org/10.5194/se-11-307-2020, https://doi.org/10.5194/se-11-307-2020, 2020
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This study presents an approach that combines equilibrium thermodynamic modelling with oxygen isotope fractionation modelling for investigating fluid–rock interaction in metamorphic systems. An application to subduction zones shows that chemical and isotopic zoning in minerals can be used to determine feasible fluid sources and the conditions of interaction. Slab-derived fluids can cause oxygen isotope variations in the mantle wedge that may result in anomalous isotopic signatures of arc lavas.
Christian A. Bergemann, Edwin Gnos, Alfons Berger, Emilie Janots, and Martin J. Whitehouse
Solid Earth, 11, 199–222, https://doi.org/10.5194/se-11-199-2020, https://doi.org/10.5194/se-11-199-2020, 2020
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Metamorphic domes are areas in a mountain chain that were unburied and where deeper parts of the crust rose to the surface. The Lepontine Dome in the Swiss and Italian Alps is such a place, and it is additionally bordered on two sides by shear zones where crustal blocks moved past each other. To determine when these tectonic movements happened, we measured the ages of monazite crystals that form in fluid-filled pockets inside the rocks during these movements of exhumation and deformation.
Laura Stutenbecker, Peter M. E. Tollan, Andrea Madella, and Pierre Lanari
Solid Earth, 10, 1581–1595, https://doi.org/10.5194/se-10-1581-2019, https://doi.org/10.5194/se-10-1581-2019, 2019
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The Aar and Mont Blanc regions in the Alps are large granitoid massifs characterized by high topography. We analyse when these granitoids were first exhumed to the surface. We test this by tracking specific garnet grains, which are exclusively found in the granitoid massifs, in the sediments contained in the alpine foreland basin. This research ties in with ongoing debates on the timing and mechanisms of mountain building.
Samuel Mock, Christoph von Hagke, Fritz Schlunegger, István Dunkl, and Marco Herwegh
Solid Earth Discuss., https://doi.org/10.5194/se-2019-56, https://doi.org/10.5194/se-2019-56, 2019
Revised manuscript not accepted
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Based on own and published age data, we can infer tectonic pulses along-strike the entire northern rim of the Central Alps between 12–4 million years. Although lithologic variations largely influence the local deformation pattern, the tectonic signal is remarkably consistent all the way from Lake Geneva to Salzburg. This might result from a deep-seated tectonic force and marks a change from dominantly vertical to large-scale horizontal tectonics in the late stage of Alpine orogeny.
Ismay Vénice Akker, Josef Kaufmann, Guillaume Desbois, Jop Klaver, Janos L. Urai, Alfons Berger, and Marco Herwegh
Solid Earth, 9, 1141–1156, https://doi.org/10.5194/se-9-1141-2018, https://doi.org/10.5194/se-9-1141-2018, 2018
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We studied porosity changes of slates from eastern Switzerland, which were deposited in an ocean in front of the emerging Alps during the Cenozoic. The Alpine collision between the European and African plates brought the rocks from this basin to today’s position in the Alps. From the basin to the surface, the porosity first decreased down to a small number of round cavities (<1 vol%) to microfractures, and once at the surface, the porosity increased again due to the formation of macro-fractures.
Francesco Giuntoli, Pierre Lanari, and Martin Engi
Solid Earth, 9, 167–189, https://doi.org/10.5194/se-9-167-2018, https://doi.org/10.5194/se-9-167-2018, 2018
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Continental high-pressure terranes in orogens offer insight into deep recycling and transformation processes that occur in subduction zones. These remain poorly understood, and currently debated ideas need testing. We document complex garnet zoning in eclogitic mica schists from the Sesia Zone (western Italian Alps). These retain evidence of two orogenic cycles and provide detailed insight into resorption, growth, and diffusion processes induced by fluid pulses under high-pressure conditions.
Francesco Giuntoli, Pierre Lanari, Marco Burn, Barbara Eva Kunz, and Martin Engi
Solid Earth, 9, 191–222, https://doi.org/10.5194/se-9-191-2018, https://doi.org/10.5194/se-9-191-2018, 2018
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Subducted continental terranes commonly comprise an assembly of subunits that reflect the different tectono-metamorphic histories they experienced in the subduction zone. Our challenge is to unravel how, when, and in which part of the subduction zone these subunits were juxtaposed. Our study documents when and in what conditions re-equilibration took place. Results constrain the main stages of mineral growth and deformation, associated with fluid influx that occurred in the subduction channel.
Raphael Schneeberger, Miguel de La Varga, Daniel Egli, Alfons Berger, Florian Kober, Florian Wellmann, and Marco Herwegh
Solid Earth, 8, 987–1002, https://doi.org/10.5194/se-8-987-2017, https://doi.org/10.5194/se-8-987-2017, 2017
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Structural 3-D modelling has become a widely used technique within applied projects. We performed a typical modelling workflow for a study site with the occurrence of an underground facility. This exceptional setting enabled us to test the surface-based extrapolation of faults with the mapped faults underground. We estimated the extrapolation-related uncertainty with probabilistic 2-D interpolation. This research was conducted to improve structural 3-D modelling in less-constrained areas.
Related subject area
SIMS, LA-ICP-MS
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Technical note: LA–ICP-MS U–Pb dating of unetched and etched apatites
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Chronological information on the evolution of the Namib Desert is scarce. We used U–Pb dating of silcretes formed by pressure solution during calcrete formation to track paleoclimate variability since the Late Miocene. Calcrete formation took place during the Pliocene with an abrupt cessation at 2.9 Ma. The end took place due to deep canyon incision which we dated using TCN exposure dating. With our data we correct and contribute to the Neogene history of the Namib Desert and its evolution.
Charles W. Magee Jr., Simon Bodorkos, Christopher J. Lewis, James L. Crowley, Corey J. Wall, and Richard M. Friedman
Geochronology, 5, 1–19, https://doi.org/10.5194/gchron-5-1-2023, https://doi.org/10.5194/gchron-5-1-2023, 2023
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SHRIMP (Sensitive High Resolution Ion MicroProbe) is an instrument that for decades has used the radioactive decay of uranium into lead to measure geologic time. The accuracy and precision of this instrument has not been seriously reviewed in almost 20 years. This paper compares several dozen SHRIMP ages in our database with more accurate and precise methods to assess SHRIMP accuracy and precision. Analytical and geological complications are addressed to try to improve the method.
Romain Tartèse and Ian C. Lyon
Geochronology, 4, 683–690, https://doi.org/10.5194/gchron-4-683-2022, https://doi.org/10.5194/gchron-4-683-2022, 2022
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Absolute chronological constraints are crucial in Earth and planetary sciences. In recent years, U–Pb dating of carbonates has provided information on the timing of, for example, diagenesis, faulting, or hydrothermalism. These studies have targeted relatively young terrestrial carbonates up to 300 million years old. By dating 3.9 billion-year-old martian carbonates in situ using the U–Pb chronometer, we show that this system is robust in ancient samples that have had a relatively simple history.
Darwinaji Subarkah, Angus L. Nixon, Monica Jimenez, Alan S. Collins, Morgan L. Blades, Juraj Farkaš, Sarah E. Gilbert, Simon Holford, and Amber Jarrett
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Advancements in technology have introduced new techniques to more quickly and cheaply date rocks with little sample preparation. A unique use of this method is to date shales and constrain when these rocks were first deposited. This approach can also time when such sequences were subsequently affected by heat or fluids after they were deposited. This is useful, as the formation of precious-metal-bearing systems or petroleum source rocks is commonly associated with such processes.
Daniil V. Popov
Geochronology, 4, 399–407, https://doi.org/10.5194/gchron-4-399-2022, https://doi.org/10.5194/gchron-4-399-2022, 2022
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This work provides equations allowing the use of minerals with variable concentrations of parent and daughter isotopes as primary standards to correct for elemental fractionation during the analysis by laser ablation inductively coupled plasma mass spectrometry.
Alexander Simpson, Stijn Glorie, Martin Hand, Carl Spandler, Sarah Gilbert, and Brad Cave
Geochronology, 4, 353–372, https://doi.org/10.5194/gchron-4-353-2022, https://doi.org/10.5194/gchron-4-353-2022, 2022
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The article demonstrates a new technique that can be used to determine the age of calcite crystallisation using the decay of 176Lu to 176Hf. The technique is novel because (a) Lu–Hf radiometric dating is rarely applied to calcite and (b) this is the first instance where analysis has been conducted by ablating the sample with a laser beam rather than bulk dissolution. By using laser ablation the original context of the sample is preserved.
Johannes Rembe, Renjie Zhou, Edward R. Sobel, Jonas Kley, Jie Chen, Jian-Xin Zhao, Yuexing Feng, and Daryl L. Howard
Geochronology, 4, 227–250, https://doi.org/10.5194/gchron-4-227-2022, https://doi.org/10.5194/gchron-4-227-2022, 2022
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Calcite is frequently formed during alteration processes in the basaltic, uppermost layer of juvenile oceanic crust. Weathered oceanic basalts are hard to date with conventional radiometric methods. We show in a case study from the North Pamir, Central Asia, that calcite U–Pb age data, supported by geochemistry and petrological microscopy, have potential to date sufficiently old oceanic basalts, if the time span between basalt extrusion and latest calcite precipitation (~ 25 Myr) is considered.
Bar Elisha, Perach Nuriel, Andrew Kylander-Clark, and Ram Weinberger
Geochronology, 3, 337–349, https://doi.org/10.5194/gchron-3-337-2021, https://doi.org/10.5194/gchron-3-337-2021, 2021
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Distinguishing between different dolomitization processes is challenging yet critical for resolving some of the issues and ambiguities related to the formation of dolomitic rocks. Accurate U–Pb absolute dating of dolomite by LA-ICP-MS could contribute to a better understanding of the dolomitization process by placing syngenetic, early diagenetic, and/or epigenetic events in the proper geological context.
Louise Lenoir, Thomas Blaise, Andréa Somogyi, Benjamin Brigaud, Jocelyn Barbarand, Claire Boukari, Julius Nouet, Aurore Brézard-Oudot, and Maurice Pagel
Geochronology, 3, 199–227, https://doi.org/10.5194/gchron-3-199-2021, https://doi.org/10.5194/gchron-3-199-2021, 2021
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To explore the U–Pb geochronometer in fluorite, the spatial distribution of uranium and other substituted elements in natural crystals is investigated using induced fission-track and synchrotron radiation X-ray fluorescence mapping. LA-ICP-MS U–Pb dating on four crystals, which preserve micrometer-scale variations in U concentrations, yields identical ages within analytical uncertainty. Our results show that fluorite U–Pb geochronology has potential for dating distinct crystal growth stages.
E. Troy Rasbury, Theodore M. Present, Paul Northrup, Ryan V. Tappero, Antonio Lanzirotti, Jennifer M. Cole, Kathleen M. Wooton, and Kevin Hatton
Geochronology, 3, 103–122, https://doi.org/10.5194/gchron-3-103-2021, https://doi.org/10.5194/gchron-3-103-2021, 2021
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We characterize three natural carbonate samples with elevated uranium/lead (U/Pb) ratios to demonstrate techniques improving the understanding of U incorporation in carbonates for U/Pb dating. With the rapidly accelerating application of laser ablation analyses, there is a great need for well-characterized reference materials that can serve multiple functions. Strontium (Sr) isotope analyses and U XANES demonstrate that these samples could be used as reference materials.
Guilhem Hoareau, Fanny Claverie, Christophe Pecheyran, Christian Paroissin, Pierre-Alexandre Grignard, Geoffrey Motte, Olivier Chailan, and Jean-Pierre Girard
Geochronology, 3, 67–87, https://doi.org/10.5194/gchron-3-67-2021, https://doi.org/10.5194/gchron-3-67-2021, 2021
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A new methodology for the micron-scale uranium–lead dating of carbonate minerals is proposed. It is based on the extraction of ages directly from pixel images (< 1 mm2) obtained by laser ablation coupled to a mass spectrometer. The ages are calculated with a robust linear regression through the pixel values. This methodology is compared to existing approaches.
Fanis Abdullin, Luigi A. Solari, Jesús Solé, and Carlos Ortega-Obregón
Geochronology, 3, 59–65, https://doi.org/10.5194/gchron-3-59-2021, https://doi.org/10.5194/gchron-3-59-2021, 2021
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Unetched and etched apatite grains from five samples were dated by U–Pb method using laser ablation inductively coupled plasma mass spectrometry. Our experiment indicates that etching needed for apatite fission track dating has insignificant effects on obtaining accurate U–Pb ages; thus, the laser ablation-based technique may be used for apatite fission track and U–Pb double dating.
Perach Nuriel, Jörn-Frederik Wotzlaw, Maria Ovtcharova, Anton Vaks, Ciprian Stremtan, Martin Šala, Nick M. W. Roberts, and Andrew R. C. Kylander-Clark
Geochronology, 3, 35–47, https://doi.org/10.5194/gchron-3-35-2021, https://doi.org/10.5194/gchron-3-35-2021, 2021
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This contribution presents a new reference material, ASH-15 flowstone with an age of 2.965 ± 0.011 Ma (95 % CI), to be used for in situ U–Pb dating of carbonate material. The new age analyses include the use of the EARTHTIME isotopic tracers and a large number of sub-samples (n = 37) with small aliquots (1–7 mg) each that are more representative of laser-ablation spot analysis. The new results could improve the propagated uncertainties on the final age with a minimal value of 0.4 %.
Andrew R. C. Kylander-Clark
Geochronology, 2, 343–354, https://doi.org/10.5194/gchron-2-343-2020, https://doi.org/10.5194/gchron-2-343-2020, 2020
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This paper serves as a guide to those interested in dating calcite by laser ablation. Within it are theoretical and practical limits of U and Pb concentrations (and U / Pb ratios), which would allow viable extraction of ages from calcite (and other minerals with moderate U / Pb ratios), and which type of instrumentation would be appropriate for any given sample. The method described uses a new detector array, allowing for lower detection limits and thereby expanding the range of viable samples.
Hugo K. H. Olierook, Kai Rankenburg, Stanislav Ulrich, Christopher L. Kirkland, Noreen J. Evans, Stephen Brown, Brent I. A. McInnes, Alexander Prent, Jack Gillespie, Bradley McDonald, and Miles Darragh
Geochronology, 2, 283–303, https://doi.org/10.5194/gchron-2-283-2020, https://doi.org/10.5194/gchron-2-283-2020, 2020
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Using a relatively new dating technique, in situ Rb–Sr geochronology, we constrain the ages of two generations of mineral assemblages from the Tropicana Zone, Western Australia. The first, dated at ca. 2535 Ma, is associated with exhumation of an Archean craton margin and gold mineralization. The second, dated at ca. 1210 Ma, has not been previously documented in the Tropicana Zone. It is probably associated with Stage II of the Albany–Fraser Orogeny and additional gold mineralization.
George Gehrels, Dominique Giesler, Paul Olsen, Dennis Kent, Adam Marsh, William Parker, Cornelia Rasmussen, Roland Mundil, Randall Irmis, John Geissman, and Christopher Lepre
Geochronology, 2, 257–282, https://doi.org/10.5194/gchron-2-257-2020, https://doi.org/10.5194/gchron-2-257-2020, 2020
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U–Pb ages of zircon crystals are used to determine the provenance and depositional age of strata of the Triassic Chinle and Moenkopi formations and the Permian Coconino Sandstone of northern Arizona. Primary source regions include the Ouachita orogen, local Precambrian basement rocks, and Permian–Triassic magmatic arcs to the south and west. Ages from fine-grained strata provide reliable depositional ages, whereas ages from sandstones are compromised by zircon grains recycled from older strata.
Marcel Guillong, Jörn-Frederik Wotzlaw, Nathan Looser, and Oscar Laurent
Geochronology, 2, 155–167, https://doi.org/10.5194/gchron-2-155-2020, https://doi.org/10.5194/gchron-2-155-2020, 2020
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The dating of carbonates by laser ablation inductively coupled plasma mass spectrometry is improved by an additional, newly characterised reference material and adapted data evaluation protocols: the shape (diameter to depth) of the ablation crater has to be as similar as possible in the reference material used and the unknown samples to avoid an offset. Different carbonates have different ablation rates per laser pulse. With robust uncertainty propagation, precision can be as good as 2–3 %.
Nick M. W. Roberts, Kerstin Drost, Matthew S. A. Horstwood, Daniel J. Condon, David Chew, Henrik Drake, Antoni E. Milodowski, Noah M. McLean, Andrew J. Smye, Richard J. Walker, Richard Haslam, Keith Hodson, Jonathan Imber, Nicolas Beaudoin, and Jack K. Lee
Geochronology, 2, 33–61, https://doi.org/10.5194/gchron-2-33-2020, https://doi.org/10.5194/gchron-2-33-2020, 2020
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Here we review current progress in LA-ICP-MS U–Pb carbonate geochronology and present strategies for acquisition and interpretation of carbonate U–Pb dates. We cover topics from imaging techniques and U and Pb incorporation into calcite to potential limitations of the method – disequilibrium and isotope mobility. We demonstrate the incorporation of imaging and compositional data to help refine and interpret U–Pb dates. We expect this paper to become a
go-toreference paper for years to come.
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Short summary
This work presents LA-ICP-MS U–Pb geochronology of epidote in hydrothermal veins. The challenges of epidote dating are addressed, and a protocol is proposed allowing us to obtain epidote U–Pb ages with a precision as good as 5 % in addition to the initial Pb isotopic composition of the epidote-forming fluid. Epidote demonstrates its potential to be used as a U–Pb geochronometer and as a fluid tracer, allowing us to reconstruct the timing of hydrothermal activity and the origin of the fluid(s).
This work presents LA-ICP-MS U–Pb geochronology of epidote in hydrothermal veins. The challenges...
