Gary J. Long

Missouri University of Science and Technology

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Fernande Grandjean

Missouri University of Science and Technology

Brooks B. Ellwood

Louisiana State University

Burke Burkart

The University of Texas at Arlington

Margaret L. Buhl

Missouri University of Science and Technology

William Balsam

Dartmouth College

Raphaël P. Hermann

Oak Ridge National Laboratory

André-Mathieu Fransolet

University of Liège

Francis B. Harrold

St. Cloud State University

J. Delwiche

University of Liège

Ari B. Turkiewicz

Harvard University

Cooperative Institutions

University of California, Berkeley

University of Liège

Lawrence Berkeley National Laboratory

Centre National de la Recherche Scientifique

Missouri University of Science and Technology

University of California System

Berkeley College

The University of Texas at Arlington

University of California, Davis

Max Planck Institute for Chemical Energy Conversion

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Iron mineralogy in sediments. A Mössbauer study

Geochimica et Cosmochimica Acta (1986)

J. Hilton Gary J. Long Jenna Chapman J.P. Lishman

10.1016/0016-7037(86)90069-4

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Citations (33)

Bis(μ-alkoxo)-bridged dinuclear iron(III) complexes of pyrazole-based ligands as models for iron-oxo proteins

Polyhedron (2004)

Stefania Tanase Elisabeth Bouwman Gary J. Long A.M. Shahin R. De Gelder

Pyrazole

Hydroxylation

10.1016/j.poly.2004.07.026

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Citations (16)

Ti substitution mechanisms in phlogopites from the Suwalki massif-type anorthosite, NE Poland

European Journal of Mineralogy (2009)

Olivier Namur Frédéric Hatert Gary J. Long Natacha Krins André-Mathieu Fransolet

Anorthosite

Massif

Substitution (logic)

10.1127/0935-1221/2009/0021-1894

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Citations (8)

Confinement of atomically defined metal halide sheets in a metal–organic framework

Nature (2019)

Miguel I. Gonzalez Ari B. Turkiewicz Lucy E. Darago Julia Oktawiec Karen C. Bustillo

10.1038/s41586-019-1776-0

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Citations (99)

Anomalous magnetic properties in rocks containing the mineral siderite: Paleomagnetic implications

Journal of Geophysical Research Atmospheres (1986)

Brooks B. Ellwood William Balsam Burke Burkart Gary J. Long Margaret L. Buhl

Sampling and magnetic measurement of a 1‐m bed in a new road cut of the Upper Cretaceous Austin Chalk (northeastern Texas) has yielded anomalous magnetic results. Initial measurement of the anisotropy of magnetic susceptibility (AMS) indicated unusually high anisotropies and low bulk susceptibilities characteristic of a magnetocrystalline anisotropy which might be expected for siderite (FeCO 3 ). Natural remanent moments (NRM) for these samples were low (<1 × 10 −4 A m 2 ), and directions were typical for samples which had acquired a normal geomagnetic field overprint at the site. Periodic remeasurement of the NRM yielded an increase in moment for some samples and periodic reversals of RM in a direction parallel or antiparallel to the ambient field in the laboratory. Isothermal remanent moments of these samples saturates at low induction values (∼200 mT). AMS remeasurement over a period of weeks to months revealed a general decrease in the anisotropy magnitudes, an increase in susceptibility, and a change in principal axis orientations. These data were compared with heating (oxidation) experiments on Austin Chalk, siderite ore, and clastic sediments with siderite cements. All of these results are consistent with the X‐ray diffraction and Mössbauer data, which indicate the presence of siderite in the Austin Chalk samples. The Mössbauer spectra of the samples obtained at room temperature and 78°K indicate the presence of approximately 80% pyrite, 10% siderite, and 10% of a clay component (possibly chlorite) when only the iron‐bearing mineral components are considered. After sampling, exposure to the air, and subsequent oxidation in the laboratory, the siderite in Austin Chalk samples appears to have altered to γFe 2 O 3 (maghemite) or Fe 3 O 4 (magnetite), increasing the magnetic moment and changing the NRM and AMS directions in the samples. The continuing changes appear to reflect a conversion from the less stable γFe 2 O 3 to αFe 2 O 3 (hematite) or oxidation of Fe 3 O 4 to αFe 2 O 3 . We infer from our study that oxidation of siderite‐bearing limestone (e.g., during the formation of unconformities or due to low‐magnitude tectonic events) may produce a very stable secondary magnetic moment in the rock. Such changes may be very important when interpreting paleomagnetic data from limestones.

Natural remanent magnetization

Ankerite

10.1029/jb091ib12p12779

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Citations (68)

Synthesis, structure and magnetic properties of an unusual oligonuclear iron(III)-cobalt(III) compound with oxido-, sulfato- and cyanido-bridging ligands

Polyhedron (2018)

Fatima Setifi Zouaoui Setifi Piotr Konieczny Christopher Glidewell Samia Benmansour

Tripodal ligand

10.1016/j.poly.2018.10.021

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Citations (12)

A structural, infrared, and Mossbauer spectral study of rosemaryite, NaMnFe3+Al(PO4)3

European Journal of Mineralogy (2006)

Frédéric Hatert Raphaël P. Hermann André-Mathieu Fransolet Gary J. Long Fernande Grandjean

Quadrupole splitting

Triclinic crystal system

Crystal (programming language)

10.1127/0935-1221/2006/0018-0775

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Citations (12)

Production Profiles and Geologic Characteristics of the Wolfcamp and Bone Spring Plays of the Delaware Basin

Olga Popova Emily Geary April Patel Gary J. Long Jeffrey Little

Hot spring

10.1306/11238popova2019

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Citations (0)

The rockwall in rockwall, texas: A study of unusual natural magnetic effects in geoarcheological surveys produced by mineral oxidation

Geoarchaeology (1989)

Brooks B. Ellwood Jana Payne Gary J. Long

Abstract The city council of Rockwall, Texas, decided in 1985 to build a park containing an exposure of the “famed” rockwall after which the city and county of Rockwall derive their names. This wall, thought to be man‐made because of it's unusual brick‐like appearance, was first discovered in 1851. As a result of weathering, the wall has no surface exposure and crews working for the city had not been able to find it. Geological studies, published between 1927 and 1950, clearly demonstrate that the rockwall is one of a series of sandstone dikes with a carbonate cement and some unusual material constituents. Geoarchaeological methods, including magnetic and electrical resistivity surveys, and Mössbauer studies were used in identifying the precise location of the rockwall. This was possible because of strongly magnetic secondary minerals produced within the wall by weathering of two primary mineral constituents, siderite and marcasite. the resulting natural magnetic anomaly pattern made it possible to pinpoint the wall's location. This pattern closely resembles those identified in association with historic or prehistoric cultural activity. Our observations may help explain why some archeological excavations, at sites associated with well defined magnetic anomalies, do not yield clear sources for those anomalies, i.e., buried cultural material. These anomalies may result from weathering or from other natural processes, and in some cases interpretation of such ambiguities can be resolved using mineralogical and geochemical data.

Carbonate minerals

10.1002/gea.3340040202

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Citations (2)

Identification of the last glacial maximum in the Upper Paleolithic of Portugal using magnetic susceptibility measurements of Caldeirão Cave sediments

Geoarchaeology (1998)

Brooks B. Ellwood Joào Zilhão Francis B. Harrold William Balsam Burke Burkart

We have sampled Upper and Middle Paleolithic sediments in Caldeirão Cave, Portugal, for paleoclimatic analysis. This work involved measuring magnetic susceptibility (MS) on continuous vertical profiles of a series of ∼8 cc sediment samples, and using the MS data as a paleoclimate proxy. Previous work has shown that caves can be ideal recorders of paleoclimatic variations because they are protected environments. Pedogenesis outside the cave during time of cool climate produces sediments with low MS magnitudes, while warmer climates yield higher MS magnitudes. Eroded soils collect in caves in sediment sequences where futher pedogenesis and biological disturbance is minimal. Continuously sampled profiles of those sediments found in an archaeological context then allow paleoclimatic estimates for all archaeological levels. Results of our work here include identification of the last glacial maximum, at ca. 24,000–22,000 B.P. (calibrated), defined by very low MS values found in basal Solutrean levels in the cave. Distinctive ca. 2500 year Neo-glacial cycles, defined by the MS data within the Early Upper Paleolithic and Solutrean, are consistent with published 14C duration estimates for the Upper Paleolithic in Caldeirão Cave. © 1998 John Wiley & Sons, Inc.

Upper Paleolithic

Last Glacial Maximum

Paleoclimatology

10.1002/(sici)1520-6548(199801)13:1<55::aid-gea4>3.3.co;2-8

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Citations (2)