Paul Sylvester
@depts.ttu.edu
Professor, Geosciences
TEXAS TECH UNIVERSITY
RESEARCH, TEACHING, or OTHER INTERESTS
Geochemistry and Petrology, Earth and Planetary Sciences, Geology
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Alex M. Washburn, Paul J. Sylvester, and Kathryn E. Snell
Elsevier BV
Paul Sylvester
MDPI AG
I was appointed Editor-in-Chief of Minerals (ISSN 2075-163X) on June 1, 2016, by Dr [...]
C. A. Partin and P. J. Sylvester
University of Chicago Press
Paul J. Sylvester, A. Kate Souders, and Rui Liu
Geological Society of America
Abstract Detrital zircon U-Pb studies of mudstone provenance are rare but may preferentially fingerprint distal zircon sources. To examine this issue, Pierre Shale and Trinidad Sandstone deposited in a Late Cretaceous deltaic environment in the Raton Basin, Colorado (USA), were measured for detrital zircon U-Pb age by laser ablation–inductively coupled plasma–mass spectrometry. Two major detrital zircon age peaks at ca. 70 and 1690 Ma are found in both Pierre Shale and Trinidad Sandstone but in inversely varying proportions: 68% and 16%, respectively, for the finest zircon fraction (~15–35 μm) in the shale, and 25% and 32%, respectively, for the coarsest zircon fraction (~60–80 μm) in the sandstone. Proximal sources in the Sangre de Cristo Mountains, directly west of the Raton Basin, contain coarse-grained, ca. 1690 Ma zircon, whereas distal sources in Laramide uplifts and basins in Colorado, New Mexico, and Arizona contain fine-grained, ca. 70 Ma zircon. The results indicate that U-Pb zircon provenance of mudstone reflects availability of volcanic and other fine-grained source rocks rather than simply distal sources. U-Pb zircon provenance studies should routinely include mudstone units because these units may identify fine-grained zircon sources more reliably than sandstones alone.
Alcina M.F. Barreto, Anelise L. Bertotti, Paul J. Sylvester, Ludmila A.C. do Prado, Rilda C. Araripe, David H. de Oliveira, Maria E.T.R. Tomé, Flávia A.P. Lemos, Luis R.L. do Nascimento, Priscilla A. Pereira,et al.
Elsevier BV
Thomas M. Lehman, Jacob Cobb, Paul Sylvester, and A. Kate Souders
Geological Society of America
Abstract The Cretaceous-Paleogene (K-Pg) contact interval is constrained by vertebrate fossil sites at seven sites in the Tornillo Group and lies within an 80–100-m stratigraphic section between the top of the Javelina Formation and the base of the “log jam sandstone” marker bed in the Black Peaks Formation. In western exposures of this interval, the highest occurrence of in situ dinosaur specimens and the lowest occurrence of Paleocene mammal specimens are separated by an unusual conglomerate bed. This thin conglomerate bed coincides with the contact between Cretaceous and Paleogene strata and contains reworked Cretaceous fossils. It is superficially similar to conglomerate beds elsewhere attributed to the effects of tsunamis generated by the Chicxulub impact; however, the maximum depositional age of ca. 63 Ma based on detrital zircons indicates that the conglomerate was deposited about three million years after the K-Pg boundary event. Paleocene mammalian fossils from immediately above the conglomerate bed represent a fauna that can be no older than the middle Torrejonian (To2 interval zone). The contact between Cretaceous and Paleocene strata is therefore disconformal and represents a hiatus of at least three million years. A condensed section occurs at the westernmost exposure of the K-Pg contact, where at least 80 m of strata are absent below the conglomerate bed; these strata are present in exposures farther east. This condensed section likely records an erosional event resulting from uplift and deformation of the nearby Terlingua monocline. Although the 80 m of strata below the conglomerate bed are poorly fossiliferous, several clearly in situ dinosaur specimens indicate that this entire interval is Late Cretaceous in age. There is no compelling evidence for preservation of the K-Pg boundary event horizon at any of the seven sites in the Tornillo Group, and so the hiatus represented at the Cretaceous/Paleocene contact here likely also includes some part of latest Cretaceous time. Mammalian specimens from sites in the “log jam sandstone,” ~40 m above the middle Torrejonian sites, represent an early Tiffanian fauna (Ti1 interval zone). Latest Torrejonian (To3) sites have not been recognized, and therefore a second disconformity likely coincides with the base of the “log jam sandstone” marker horizon in the Black Peaks Formation.
Matthew Scott, Paul J. Sylvester, and Derek H. C. Wilton
MDPI AG
A number of hydrocarbon discoveries have been made recently in the Flemish Pass Basin and Central Ridge, offshore Newfoundland, Canada, but there is only limited geological information available. The primary goal of this study was to determine the sedimentary provenance and paleodrainage patterns of mudstones and sandstones from the Upper Jurassic Rankin Formation, including the Upper and Lower Kimmeridgian Source Rock (organic-rich shale) members and Upper and Lower Tempest Sandstone Member reservoirs, in this area. A combination of heavy mineral analysis, whole-rock geochemistry and detrital zircon U-Pb geochronology was determined from cores and cuttings from four offshore wells in an attempt to decipher provenance. Detrital heavy minerals in 20 cuttings samples from the studied geologic units are dominated by either rutile + zircon + apatite ± chromite or rutile + apatite + tourmaline, with minor zircon, indicating diverse source lithologies. Whole rock Zr-Th-Sc trends suggest significant zircon recycling in both mudstones and sandstones. Detrital zircon U-Pb ages were determined in two mudstone and four sandstone samples from the four wells. Five major U-Pb age groups of grains were found: A Late Jurassic group that represents an unknown source of syn-sedimentary magmatism, a Permian–Carboniferous age group which is interpreted to be derived from Iberia, a Cambrian–Devonian group derived from the Central Mobile Belt of the Newfoundland–Ireland conjugate margin, and two older age groups (late Neoproterozoic and >1 Ga) linked to Avalonia. The Iberian detritus is abundant in the Central Ridge and southern Flemish Pass region and units containing sizable populations of these grains are interpreted to be derived from the east whereas units lacking this population are interpreted to be sourced from the northeast and possibly also the west. The Upper Tempest Sandstone contains Mesozoic zircons, which constrain the depositional age of this unit to be no older than Late Tithonian.
Pulok K. Mukherjee, A. Kate Souders, and Paul J. Sylvester
Royal Society of Chemistry (RSC)
U–Pb zircon ages for 7, 10, 15 and 20 μm spots by laser ablation-ICP-single-collector-sector-field-mass spectrometry using short (∼50 pulse) integrations.
N. Kastek, R.E. Ernst, B.L. Cousens, S.L. Kamo, W. Bleeker, U. Söderlund, W.R.A. Baragar, and P. Sylvester
Elsevier BV
D. C. Grant, D. J. Goudie, C. Voisey, M. Shaffer, and P. Sylvester
Informa UK Limited
ABSTRACT Scanning Electron Microscope–Mineral Liberation Analysis (SEM–MLA) can be used to discriminate between hematite and magnetite in iron ores. However, achieving backscattered electron (BSE) segmentation between the two minerals is difficult for particles ≤75 µm using typical preparation and analysis methods for the MLA method based on a tungsten filament SEM (Quanta 400) with 25 kV high voltage. Preparing iron ore sample mounts using a slow-speed polishing method, and conducting the experiment on a field emission gun SEM–MLA (Quanta 650) with the high voltage setting lowered to 15 kV reduces instrument noise and results in very clean BSE images and segmentation. This method requires new X-ray standards for each mineral at 15 kV because of major changes in the spectra at lower kV. However, once these X-ray spectra are added to the mineral reference list, effective segmentation can be achieved and an accurate analysis obtained.
Kathryn L. Linge, L. Paul Bédard, Roxana Bugoi, Jacinta Enzweiler, Klaus Peter Jochum, Rüdiger Kilian, Jingao Liu, Johanna Marin-Carbonne, Silke Merchel, Frans Munnik,et al.
Wiley
This GGR biennial critical review covers developments and innovations in key analytical methods published since
January 2014, relevant to the chemical, isotopic and crystallographic characterisation of geological and
environmental materials. In nine selected analytical fields, publications considered to be of wide significance are
summarised, background information is provided and their importance evaluated. In addition to instrumental
technologies, this review also presents a summary of new developments in the preparation and characterisation of
rock, microanalytical and isotopic reference materials, including a precis of recent changes and revisions to ISO
guidelines for reference material characterisation and reporting. Selected reports are provided of isotope ratio
determinations by both solution nebulisation MC-ICP-MS and laser ablation-ICP-MS, as well as of radioactive isotope
geochronology by LA-ICP-MS. Most of the analytical techniques elaborated continue to provide new applications for
geochemical analysis; however, it is noted that instrumental neutron activation analysis has become less popular in
recent years, mostly due to the reduced availability of nuclear reactors to act as a neutron source. Many of the newer
applications reported here provide analysis at increasingly finer resolution. Examples include atom probe
tomography, a very sensitive method providing atomic scale information, nanoscale SIMS, for isotopic imaging of
geological and biological samples,
Tiago Jalowitzki, Fernanda Gervasoni, Rommulo V. Conceição, Yuji Orihashi, Gustavo W. Bertotto, Hirochika Sumino, Manuel E. Schilling, Keisuke Nagao, Diego Morata, and Paul Sylvester
Elsevier BV
Paul J. Sylvester and Simon E. Jackson
Mineralogical Society of America
Laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) has been used for more than 30 years to determine the elemental composition of natural and synthesized objects. A focused laser beam ablates a small volume of target material, and the aerosol produced is transferred in a gas stream to an ICP–MS for elemental and/or isotopic analysis. Through the increasing use of deep ultraviolet lasers and ultra-sensitive mass spectrometers, the technique has evolved towards higher sampling resolution and to generating 2-D (and 3-D) images of compositional variations. The future is likely to see femtosecond lasers and simultaneous mass spectrometers in common use, making new research areas possible.
Matthew S. A. Horstwood, Jan Košler, George Gehrels, Simon E. Jackson, Noah M. McLean, Chad Paton, Norman J. Pearson, Keith Sircombe, Paul Sylvester, Pieter Vermeesch,et al.
Wiley
The LA-ICP-MS U-(Th-)Pb geochronology international community has defined new standards for the determination of U-(Th-)Pb ages. A new workflow defines the appropriate propagation of uncertainties for these data, identifying random and systematic components. Only data with uncertainties relating to random error should be used in weighted mean calculations of population ages; uncertainty components for systematic errors are propagated after this stage, preventing their erroneous reduction. Following this improved uncertainty propagation protocol, data can be compared at different uncertainty levels to better resolve age differences. New reference values for commonly used zircon, monazite and titanite reference materials are defined (based on ID-TIMS) after removing corrections for common lead and the effects of excess 230Th. These values more accurately reflect the material sampled during the determination of calibration factors by LA-ICP-MS analysis. Recommendations are made to graphically represent data only with uncertainty ellipses at 2s and to submit or cite validation data with sample data when submitting data for publication. New data-reporting standards are defined to help improve the peer-review process. With these improvements, LA-ICP-MS U-(Th-)Pb data can be considered more robust, accurate, better documented and quantified, directly contributing to their improved scientific interpretation.
C.A. Partin and P.J. Sylvester
Elsevier BV
D. C. Grant, D. J. Goudie, M. Shaffer, and P. Sylvester
Informa UK Limited
A novel approach to creating a trans-vertical grain mount embedded in epoxy has been demonstrated through the creation of a new mounting mould, as well as a polisher adapter and sample holder for the Quanta 400 SEM. These rectangular moulds result in a sample that is 30 mm long × 10 mm high × 17 mm wide, thus leading to the ability to polish 10 samples at once. Up to 14 samples may fit in the SEM holder for analysis. This represents an increase in efficiency of over 50%, and with a slow-speed polishing method, the consumables used are reduced by at least a factor of 4. This has the potential to lead to significant financial savings. A comparison of mounting techniques using a −100+200 mesh size fraction of an iron-ore sample from Labrador demonstrates that this new mounting system removes any bias in analysis resulting from density stratification during the sample preparation. These moulds yield similar modal mineralogy abundances and standard deviation as the two-step trans-vertical method, but they are less labour-intensive to make and more efficient to analyse.
Stefanie M. Brueckner, Stephen J. Piercey, Jean-Luc Pilote, Graham D. Layne, and Paul J. Sylvester
Elsevier BV
M. E. Varela, P. Sylvester, F. Brandstätter, and A. Engler
Wiley
Fil: Varela, Maria Eugenia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico San Juan. Instituto de Ciencias Astronomicas de la Tierra y del Espacio; Argentina
Stefanie M. Brueckner, Stephen J. Piercey, Graham D. Layne, Glenn Piercey, and Paul J. Sylvester
Springer Science and Business Media LLC
The Ming deposit is an early Ordovician, bimodal-mafic Cu–Au volcanogenic massive sulphide (VMS) deposit in the Newfoundland Appalachians that was metamorphosed to upper greenschist/lower amphibolite facies conditions and deformed in the Silurian and Devonian. The Ming deposit consists of several spatially proximal ore bodies of which the 1806 Zone, 1807 Zone, Ming South Up Plunge and Down Plunge and the Lower Footwall Zone are the focus of this paper. The ore bodies have similar stratigraphic sequences. The ore bodies can be divided into (1) a silicified horizon that caps the massive sulphides, (2) semi-massive to massive sulphides and (3) sulphide mineralization in a rhyodacitic footwall. Sulphide mineralization in a rhyodacitic footwall includes (a) sulphide stringers immediately below the semi-massive to massive sulphides and (b) chalcopyrite–pyrrhotite–pyrite stringers distally from semi-massive to massive sulphides in the Lower Footwall Zone. Pyrite, chalcopyrite, pyrrhotite, arsenopyrite and galena were analysed by in situ secondary ion mass spectrometry (SIMS) for sulphur isotope compositions. The isotopic signatures of pyrite, chalcopyrite, pyrrhotite and arsenopyrite fall within a limited range of 2.8 to 12.0 ‰ for semi-massive to massive sulphides and sulphide mineralization in the footwall. The silicified horizon capping the semi-massive to massive sulphides has higher δ34S (5.8–19.6 ‰), especially for pyrrhotite (mean, 17.2 ± 2.2 ‰, n = 8). The sulphur isotope composition of galena is more heterogeneous, especially within semi-massive to massive sulphides and sulphide stringers, ranging from 0.8 to 17.3 ‰ (mean, 6.1 ± 4.3 ‰, n = 35) and 7.6 to 17.1 ‰ (mean, 13.7 ± 5.3 ‰, n = 3), respectively. Geothermometric calculations give insufficient formation and metamorphism temperatures for neighbouring mineral pairs, because sulphides were not in isotopic equilibrium while deposited in early Ordovician or re-equilibrated during Silurian–Devonian metamorphism, respectively. Therefore, original isotopic compositions of sulphides at the Ming deposit have been preserved. Modelling of the source of sulphur shows that: (1) reduced seawater sulphate and (2) sulphur leached from igneous wall rock and/or derived from magmatic fluids are the main sources of sulphur in the Ming deposit. The influence of igneous sulphur (igneous wall rock/magmatic fluids) increases with temperature and is an important sulphur source for the semi-massive to massive sulphides and footwall mineralization, in addition to a contribution from thermochemical sulphate reduction (TSR) of seawater. It is difficult to distinguish between sulphur leached from igneous rocks and magmatic fluid-related sulphur, and it is possible that both sources contributed to the ores at the Ming deposit. In addition to igneous sulphur, the heavy isotopes of the silicified horizon are consistent with the sulphur in this horizon being derived only from thermochemical sulphate reduction of early Ordovician seawater sulphate.
Stefanie M. Brueckner, Stephen J. Piercey, Graham D. Layne, Glenn Piercey, and Paul J. Sylvester
Springer Science and Business Media LLC
The Ming deposit is an early Ordovician, bimodal-mafic Cu–Au volcanogenic massive sulphide (VMS) deposit in the Newfoundland Appalachians that was metamorphosed to upper greenschist/lower amphibolite facies conditions and deformed in the Silurian and Devonian. The Ming deposit consists of several spatially proximal ore bodies of which the 1806 Zone, 1807 Zone, Ming South Up Plunge and Down Plunge and the Lower Footwall Zone are the focus of this paper. The ore bodies have similar stratigraphic sequences. The ore bodies can be divided into (1) a silicified horizon that caps the massive sulphides, (2) semi-massive to massive sulphides and (3) sulphide mineralization in a rhyodacitic footwall. Sulphide mineralization in a rhyodacitic footwall includes (a) sulphide stringers immediately below the semi-massive to massive sulphides and (b) chalcopyrite–pyrrhotite–pyrite stringers distally from semi-massive to massive sulphides in the Lower Footwall Zone. Pyrite, chalcopyrite, pyrrhotite, arsenopyrite and galena were analysed by in situ secondary ion mass spectrometry (SIMS) for sulphur isotope compositions. The isotopic signatures of pyrite, chalcopyrite, pyrrhotite and arsenopyrite fall within a limited range of 2.8 to 12.0 ‰ for semi-massive to massive sulphides and sulphide mineralization in the footwall. The silicified horizon capping the semi-massive to massive sulphides has higher δ 34S (5.8–19.6 ‰), especially for pyrrhotite (mean, 17.2 ± 2.2 ‰, n = 8). The sulphur isotope composition of galena is more heterogeneous, especially within semi-massive to massive sulphides and sulphide stringers, ranging from 0.8 to 17.3 ‰ (mean, 6.1 ± 4.3 ‰, n = 35) and 7.6 to 17.1 ‰ (mean, 13.7 ± 5.3 ‰, n = 3), respectively. Geothermometric calculations give insufficient formation and metamorphism temperatures for neighbouring mineral pairs, because sulphides were not in isotopic equilibrium while deposited in early Ordovician or re-equilibrated during Silurian–Devonian metamorphism, respectively. Therefore, original isotopic compositions of sulphides at the Ming deposit have been preserved. Modelling of the source of sulphur shows that: (1) reduced seawater sulphate and (2) sulphur leached from igneous wall rock and/or derived from magmatic fluids are the main sources of sulphur in the Ming deposit. The influence of igneous sulphur (igneous wall rock/magmatic fluids) increases with temperature and is an important sulphur source for the semi-massive to massive sulphides and footwall mineralization, in addition to a contribution from thermochemical sulphate reduction (TSR) of seawater. It is difficult to distinguish between sulphur leached from igneous rocks and magmatic fluid-related sulphur, and it is possible that both sources contributed to the ores at the Ming deposit. In addition to igneous sulphur, the heavy isotopes of the silicified horizon are consistent with the sulphur in this horizon being derived only from thermochemical sulphate reduction of early Ordovician seawater sulphate.
Gwenaël Hervé, Stuart A. Gilder, Cassandra L. Marion, Gordon R. Osinski, Jean Pohl, Nikolai Petersen, and Paul J. Sylvester
Elsevier BV
J.C. Pollock, P.J. Sylvester, and S.M. Barr
Canadian Science Publishing
Avalonia, the largest accreted crustal block in the Appalachian orogen, consists of Neoproterozoic magmatic arc sequences that represent protracted and episodic subduction-related magmatism before deposition of an Ediacaran–Ordovician cover sequence including siliciclastic rocks. Zircon crystals were obtained from arc-related magmatic rocks and from clastic sedimentary sequences and analyzed in situ for their Hf-isotope composition. The majority of magmatic and detrital zircons are dominated by initial 176Hf/177Hf values that are more radiogenic than chondritic uniform reservoir (CHUR) with calculated crust formation Hf–TDM model ages that range from 0.84 to 1.30 Ga. These results suggest formation by partial melting of juvenile mantle in a Neoproterozoic continental arc. Some zircons have Hf–TDM model ages ca. 1.39–3.09 Ga with εHf values of –33.9 to –0.5 and more clearly indicate involvement of older lithosphere in their petrogenesis. Whole-rock Sm–Nd isotopic compositions from felsic volcanic rocks are characterized by positive initial εNd values with Mesoproterozoic depleted mantle model ages consistent with juvenile extraction. Results suggest a dominant mantle component with long-term light rare earth element (LREE) depletion mixed with an older crustal component with long-term LREE enrichment. The pattern of TDM model ages and variations in Lu–Hf and Sm–Nd isotopic character are compatible with a ca. 1.0–1.2 Ga igneous tectonomagmatic event that formed basement to Neoproterozoic magmatic arcs in Avalonia. The presence of evolved isotopic signatures, however, indicates that significant older Proterozoic crust is present locally beneath Avalonia, suggesting that Avalonia formed in a single Neoproterozoic arc system that generated juvenile mantle-derived crust, coupled with lesser anatectic reworking of significantly older crust.
Michael Wiedenbeck, L. Paul Bédard, Roxana Bugoi, Mary Horan, Kathryn Linge, Silke Merchel, Luiz F. G. Morales, Dany Savard, A. Kate Souders, and Paul Sylvester
Wiley
Advances in the chemical, crystallographic and isotopic characterisation of geological and environmental materials can often be ascribed to technological improvements in analytical hardware or to innovative approaches to data acquisition and/or its interpretation. This biennial review addresses key laboratory methods that form much of the foundation for analytical geochemistry; again, this contribution is presented as a compendium of laboratory techniques. We highlight advances that have appeared since January 2012 and that are of particular significance for the chemical and isotopic characterisation of geomaterials. Prominent scientists from the selected analytical fields present publications they judge to be particular noteworthy, providing background information about the method and assessing where further opportunities might be anticipated. In addition to the well-established technologies such as thermal ionisation mass spectrometry and plasma emission spectroscopy, this publication also presents new or rapidly growing methods such as electron backscattered diffraction analysis and atom probe tomography – a very sensitive method providing atomic scale information.