ryan mathur
Juniata College, Geology, Faculty Member
Numerous geochemical anomalies exist at the K-Pg boundary that indicate the addition of extraterrestrial materials; however, none fingerprint volatilization, a key process that occurs during large bolide impacts. Stable Zn isotopes are an... more
Numerous geochemical anomalies exist at the K-Pg boundary that indicate the addition of extraterrestrial materials; however, none fingerprint volatilization, a key process that occurs during large bolide impacts. Stable Zn isotopes are an exceptional indicator of volatility-related processes, where partial vaporization of Zn leaves the residuum enriched in its heavy isotopes. Here, we present Zn isotope data for sedimentary rock layers of the K-Pg boundary, which display heavier Zn isotope compositions and lower Zn concentrations relative to surrounding sedimentary rocks, the carbonate platform at the impact site, and most carbonaceous chondrites. Neither volcanic events nor secondary alteration during weathering and diagenesis can explain the Zn concentration and isotope signatures present. The systematically higher Zn isotope values within the boundary layer sediments provide an isotopic fingerprint of partially evaporated material within the K-Pg boundary layer, thus earmarking Z...
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Since its discovery in 1987, the Early Bronze Kestel Mine has been a topic of archaeological and geological controversy. The initial interpretation of the extensive marble-hosted galleries as the oldest known tin mine was challenged due... more
Since its discovery in 1987, the Early Bronze Kestel Mine has been a topic of archaeological and geological controversy. The initial interpretation of the extensive marble-hosted galleries as the oldest known tin mine was challenged due to the low tin grade in remaining hematite-quartz veins, and it was suggested that Kestel was more likely mined for gold. Mineralogical analysis of the remaining mineralization was compared to a heavy mineral concentrate extracted from the soil preserved within the mine. The compositionally complex, arsenate-rich mineral assemblage from the mine sediment, contrasts with that of the remaining surface mineralization. Thus, the outcropping veins do not represent the nature of the extracted ore. Only one grain of gold was found in the heavy mineral concentrate, whereas cassiterite composed 1.5% of the sample. Cassiterite occurs in complex assemblages with arsenates, clays, hematite, quartz, and dolomite, bearing resemblance to hematite-arsenate tin miner...
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Research Interests: Geology and Geochemistry
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Iron (Fe) isotope compositions of prehistoric stone tools and geological sources were compared to evaluate the robustness of this isotopic fingerprinting technique. Artefacts and source materials were collected from the Hatch site in... more
Iron (Fe) isotope compositions of prehistoric stone tools and geological sources were compared to evaluate the robustness of this isotopic fingerprinting technique. Artefacts and source materials were collected from the Hatch site in central Pennsylvania, United States, where both veined chert (Bald Eagle chert) and stone tools coexist within several metres. Yellow artefacts (δ 56 Fe = 0.38 ± 0.1, n = 7) and source materials (δ 56 Fe = 0.42 ± 0.1, n = 8) isotopically matched within error. The source values also overlap yellow chert samples from three other Bald Eagle chert locations in the area. These values are different from six other chert locations in the northeastern United States. These data suggest that the Fe isotope composition of chert artefacts reflect distinct geological sources. To enhance the mechanical characteristics of the stone tools, the chert experienced heat treatment, which induced a phase shift of the Fe oxide mineral goethite to hematite. This phase shift changes the colour of the chert to red. The red chert artefacts and source material also have overlapping Fe isotope values, but are 0.2‰ higher than the initial yellow chert. Experimental work where cherts were heated with different clays shows that Fe exchange with site soils induces the +0.2 fractionation. These data demonstrate that predictable Fe isotope fractionation occurs during heating, resulting in isotopically distinct artefacts.
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The genesis of the Zhaxikang Sb-Pb-Zn-Ag deposit remains controversial. Three different geological environments have been proposed to model mineralization: a hot spring, a magmatic-hydrothermal fluid, and a sedimentary exhalative (SEDEX)... more
The genesis of the Zhaxikang Sb-Pb-Zn-Ag deposit remains controversial. Three different geological environments have been proposed to model mineralization: a hot spring, a magmatic-hydrothermal fluid, and a sedimentary exhalative (SEDEX) overprinted by a hot spring. Here, we present the electron probe microanalysis (EPMA) and Fe-Zn isotopic data (microsampled) of four samples from the first pulse of mineralization that show annular textures to constrain ore genesis. The Zn/Cd ratios from the EPMA data of sphalerite range from 296 to 399 and overlap the range of exhalative systems. The δ56Fe values of Mn-Fe carbonate and δ66Zn values of sphalerite gradually decrease from early to late stages in three samples. A combination of the EPMA and isotopic data shows the Fe-Zn contents also have different correlations with δ66Zn values in sphalerite from these samples. Rayleigh distillation models this isotope and concentration data with the cause of fractionation related to vapour-liquid par...
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The origin of chalcocite is explored through a comparison of the copper isotope values of this mineral from supergene enrichment, sedimentary copper/red bed, and high-temperature hypogene mineralization around the world. Data from the... more
The origin of chalcocite is explored through a comparison of the copper isotope values of this mineral from supergene enrichment, sedimentary copper/red bed, and high-temperature hypogene mineralization around the world. Data from the literature and the data presented here (n=361) reveal that chalcocite from high-temperature mineralization has the tightest cluster of values of δCu65=0±0.6 in comparison to sedimentary copper/red bed δCu65=-0.9±1.0 and supergene enrichment δCu65=+1.9±1.8. Although the errors of the means overlap, large portions of the data lie in different values, allowing for distinguishing ranges for δCu65 of <−1‰ for sedimentary copper/red bed, between -1 and +1 for high-temperature hypogene, and >+1 for supergene enrichment chalcocite. The copper isotope values of sedimentary copper/red bed and supergene enrichment chalcocite are caused by redox reactions associated with the dissolution and transport of copper, whereas the tighter range of copper isotope val...
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We appreciate the opportunity to respond to Brown’s [...]
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Increased interest in the fractionation of Sn isotopes has led to the development of several techniques for preparing cassiterite (SnO 2 , the primary ore of Sn) for isotopic analysis. Two distinct methods have been applied in recent... more
Increased interest in the fractionation of Sn isotopes has led to the development of several techniques for preparing cassiterite (SnO 2 , the primary ore of Sn) for isotopic analysis. Two distinct methods have been applied in recent isotopic studies of cassiterite: (a) reduction to tin metal with potassium cyanide (KCN) at high temperature (800 °C), with subsequent dissolution in HCl, and (b) reduction to a Sn solution with hydriodic acid (HI) at low temperature (100 °C). This study compares the effectiveness and accuracy of these two methods and contributes additional methodological details. The KCN method consistently yielded more Sn (&gt; 70% in comparison with &lt; 5%), does not appear to fractionate Sn isotopes at high temperatures over a 2-hour period and produced consistent Sn isotope values at flux mass ratios of ≥ 4:1 (flux to mineral) with a minimum reduction time of 40 min. By means of a distillation experiment, it was demonstrated that HI could volatilise Sn, explaining the consistently low yields by this method. Furthermore, the distillation generated Sn vapour, which is up to 0.38‰ per mass unit different from the starting material, the largest induced Sn fractionation reported to date. Accordingly, the HI method is not recommended for cassiterite preparation for Sn isotopic analysis.
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Research Interests: Geology and Geochemistry
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Previous studies have shown that copper is fractionated in the environment. However, the mechanisms for isotope fractionation and the role of organic and inorganic processes in the fractionation are not well understood. Here we used the... more
Previous studies have shown that copper is fractionated in the environment. However, the mechanisms for isotope fractionation and the role of organic and inorganic processes in the fractionation are not well understood. Here we used the well controlled experiments used by Phelps Dodge Corporation aimed at leaching copper from their ore deposits to constrain the mechanism of copper isotope fractionation
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... SAUNDERS, James A. 1 , KAMENOV, GD 2 , BRUESEKE, Matthew E. 3 , HAMES, Willis E. 1 , and MATHUR, Ryan 4 , (1) Department of Geology and Geography, Auburn University, 210 Petrie Hall, Auburn, AL 36849, saundja@auburn.edu, (2)... more
... SAUNDERS, James A. 1 , KAMENOV, GD 2 , BRUESEKE, Matthew E. 3 , HAMES, Willis E. 1 , and MATHUR, Ryan 4 , (1) Department of Geology and Geography, Auburn University, 210 Petrie Hall, Auburn, AL 36849, saundja@auburn.edu, (2) Department of Geological ...
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Research Interests: Geology and Geochemistry
Research Interests: Geology and Geochemistry
GILMER, AK 1 , KYLE, JR 1 , CONNELLY, JN 1 , and MATHUR, RD 2 , (1) Department of Geological Sciences, The Univ of Texas at Austin ... 4--Booth# 1 General Geology and Rio Grande Rift (Posters) Sheraton Old Town Hotel: Alvarado DE 1:00... more
GILMER, AK 1 , KYLE, JR 1 , CONNELLY, JN 1 , and MATHUR, RD 2 , (1) Department of Geological Sciences, The Univ of Texas at Austin ... 4--Booth# 1 General Geology and Rio Grande Rift (Posters) Sheraton Old Town Hotel: Alvarado DE 1:00 PM-5:00 PM, Monday, April 30 ...
Abstract. – The important role of the Balkans in the origin and development of metallurgy is well established with respect to copper. In addition, Aleksandar Durman, in his 1997 paper “Tin in South-eastern Europe?”, essentially initiated... more
Abstract. – The important role of the Balkans in the origin and development of metallurgy is well established with respect to copper. In addition, Aleksandar Durman, in his 1997 paper “Tin in South-eastern Europe?”, essentially initiated studies into the
role of the Balkans in Europe’s Bronze Age tin economy. He identified six geologically favourable sites for tin mineralisation and associated fluvial placer deposits in the former Yugoslavian republics, and suggested that these may have added to the tin supply of the region. The viability of two of these sites has been confirmed (Mt Cer and Bukulja, Serbia) but the exploitation potential for the other locations has remained untested. River gravels from these four sites (Motajica and Prosara in Bosnia and Herzegovina; Bujanovac in Serbia; Ogražden in North Macedonia) were obtained by stream sluicing and panning. The sites of Prosara and Bujanovac were found to be barren with respect to cassiterite (SnO2). Streams flowing from Motajica and Ogražden were both found to contain cassiterite, but in amounts several orders of magnitude less than at Mt Cer and Bukulja. Although it is possible that minor tin recovery occurred at Motajica and Ogražden, it is unlikely that they could have contributed meaningfully to regional tin trade. This is supported by the fact that the isotopic signature (δ124Sn) of cassiterite from Motajica is highly enriched in light
isotopes of tin compared to that associated with Late Bronze Age artefacts of the region.
role of the Balkans in Europe’s Bronze Age tin economy. He identified six geologically favourable sites for tin mineralisation and associated fluvial placer deposits in the former Yugoslavian republics, and suggested that these may have added to the tin supply of the region. The viability of two of these sites has been confirmed (Mt Cer and Bukulja, Serbia) but the exploitation potential for the other locations has remained untested. River gravels from these four sites (Motajica and Prosara in Bosnia and Herzegovina; Bujanovac in Serbia; Ogražden in North Macedonia) were obtained by stream sluicing and panning. The sites of Prosara and Bujanovac were found to be barren with respect to cassiterite (SnO2). Streams flowing from Motajica and Ogražden were both found to contain cassiterite, but in amounts several orders of magnitude less than at Mt Cer and Bukulja. Although it is possible that minor tin recovery occurred at Motajica and Ogražden, it is unlikely that they could have contributed meaningfully to regional tin trade. This is supported by the fact that the isotopic signature (δ124Sn) of cassiterite from Motajica is highly enriched in light
isotopes of tin compared to that associated with Late Bronze Age artefacts of the region.
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Iron (Fe) isotope compositions of prehistoric stone tools and geological sources were compared to evaluate the robustness of this isotopic fingerprinting technique. Artefacts and source materials were collected from the Hatch site in... more
Iron (Fe) isotope compositions of prehistoric stone tools and geological sources were compared to evaluate the robustness of this isotopic fingerprinting technique. Artefacts and source materials were collected from the Hatch site in central Pennsylvania, United States, where both veined chert (Bald Eagle chert) and stone tools coexist within several metres. Yellow artefacts (δ 56 Fe = 0.38 ± 0.1, n = 7) and source materials (δ 56 Fe = 0.42 ± 0.1, n = 8) isotopically matched within error. The source values also overlap yellow chert samples from three other Bald Eagle chert locations in the area. These values are different from six other chert locations in the northeastern United States. These data suggest that the Fe isotope composition of chert artefacts reflect distinct geological sources. To enhance the mechanical characteristics of the stone tools, the chert experienced heat treatment, which induced a phase shift of the Fe oxide mineral goethite to hematite. This phase shift changes the colour of the chert to red. The red chert artefacts and source material also have overlapping Fe isotope values, but are 0.2‰ higher than the initial yellow chert. Experimental work where cherts were heated with different clays shows that Fe exchange with site soils induces the +0.2 fractionation. These data demonstrate that predictable Fe isotope fractionation occurs during heating, resulting in isotopically distinct artefacts.
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... Photoconductivity in amorphous thin films of Ge22Se68Bi10 (*) R. Mathur and A. Kumar Department of Physics, Harcourt Butler Technological Institute, Kanpur, 208002, India (Reçu le 10 octobre 1985, révisé le 14 avril 1986, accepté le... more
... Photoconductivity in amorphous thin films of Ge22Se68Bi10 (*) R. Mathur and A. Kumar Department of Physics, Harcourt Butler Technological Institute, Kanpur, 208002, India (Reçu le 10 octobre 1985, révisé le 14 avril 1986, accepté le 20 juin 1986) Résumé. ...
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The Aguablanca Ni-Cu ore deposit is hosted by subvertical magmatic breccia bodies in which fragments of pyroxenite are cemented by sulfides. It is located within the Aguablanca Stock, which includes diorite, gabbro, norite and... more
The Aguablanca Ni-Cu ore deposit is hosted by subvertical magmatic breccia bodies in which fragments of pyroxenite are cemented by sulfides. It is located within the Aguablanca Stock, which includes diorite, gabbro, norite and gabbronorite. Re-Os isotope data of magmatic pyrrhotite, chalcopyrite, and pentlandite and hydrothermal pyrite show that the Os has a mixed origin, derived from a juvenile mantle
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Adsorption of Copper, Zinc and Lead by Bed Sediments of River Ganges in India. DK Saikia, RP Mathur, SK Srivastava Environmental Technology Letters ETLEDB 8:33, 1987. The adsorption of Cu(2+), Zn(2+) and Pb(2+) from ...
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β-amyloid (Aβ) plaques are a key feature of Alzheimer's disease pathology but correlate poorly with dementia. They are associated with astrocytes which may modulate the effect of Aβ-deposition on the neuropil. This study characterised... more
β-amyloid (Aβ) plaques are a key feature of Alzheimer's disease pathology but correlate poorly with dementia. They are associated with astrocytes which may modulate the effect of Aβ-deposition on the neuropil. This study characterised the astrocyte response to Aβ plaque subtypes, and investigated their association with cognitive impairment. Aβ plaque subtypes were identified in the cingulate gyrus using dual labelling immunohistochemistry to Aβ and GFAP+ astrocytes, and quantitated in two cortical areas: the area of densest plaque burden and the deep cortex near the white matter border (layer VI). Three subtypes were defined for both diffuse and compact plaques (also known as classical or core-plaques): Aβ plaque with (1) no associated astrocytes, (2) focal astrogliosis or (3) circumferential astrogliosis. In the area of densest burden, diffuse plaques with no astrogliosis (β = -0.05, p = 0.001) and with focal astrogliosis (β = -0.27, p = 0.009) significantly associated with low...