James Hein
zation
Geologist Emeritus with the USGS Pacific Coastal and Marine Science Center
Science and Products
Filter Total Items: 166
238U-234U-230Th chronometry of Fe-Mn crusts: Growth processes and recovery of thorium isotopic ratios of seawater
Comparison of (234U) excess⁄(238U) and (230Th⁄232Th) activity ratios in oceanic Fe-Mn deposits provides a method for assessing the closed-system behaviour of 238U-234U-230Th, as well as variations in the initial uranium and thorium isotopic ratios of the precipitated metal oxides. This approach is illustrated using a Fe-Mn crust from Lotab seamount (Marshall Islands, west equatorial Pacific). Here
Authors
F. Chabaux, A.S. Cohen, R. K. O'Nions, J. R. Hein
Chemically diverse, sporadic volcanism at seamounts offshore southern and Baja California
Compositions of lavas from seven small to medium-sized seamounts, between lat 34.0°N and 30.5°N offshore southern and Baja California, include low-K2O tholeiitic, transitional, and mildly to moderately alkalic basalt and their differentiates. The low-K2O tholeiites resemble primitive (>9% MgO) mid-oceanic-ridge basalt (MORB) with low incompatible element abundances and very depleted, concave-downw
Authors
A. S. Davis, S.H. Gunn, W. A. Bohrson, L.-B. Gray, J. R. Hein
Diagenesis of diatomite from the Kolubara Coal Basin, Baroševac, Serbia
Diatomite associated with the Kolubara Coal Basin was studied to better understand early stage silica diagenesis of shallow water deposits. The Kolubara Basin consists of Neogene siliciclastic rocks, diatomite, marlstone and rare carbonates. Palaeozoic metamorphic and Mesozoic sedimentary and igneous basement rocks are transgressively overlain by Upper Miocene sandstone, siltstone, shale and mudst
Authors
J. Obradović, James R. Hein, J. Djurdjević
Data and results from R.V. Aleksandr Vinogradov cruises 91-AV-19/1, North Pacific hydrochemistry transect; 91-AV-19/2, North Equatorial Pacific Karin Ridge Fe-Mn crust studies; and 91-AV-19/4, Northwest Pacific and Bering Sea sediment geochemistry and pal
No abstract available.
Authors
A.S. Bychkov, A. E. Gibbs
Composition and origin of hydrothermal ironstones from central Pacific seamounts
Ironstones recovered from five Late Cretaceous seamounts in the central Pacific region probably formed during late-stage edifice-building volcanism. Ironstones are dense and compact with the appearance of brown chert. The ironstones are characterized by a goethite mineralogy with FeOOH contents up to 88%, extreme fractionation of Fe and Mn, low trace-element and rare earth element abundances, low
Authors
J. R. Hein, Y. Hsueh-Wen, S.H. Gunn, A. E. Gibbs, W. Chung-ho
Two major Cenozoic episodes of phosphogenesis recorded in equatorial Pacific seamount deposits
The phosphorites occur in a wide variety of forms, but most commonly carbonate fluorapatite (CFA) replaced middle Eocene and older carbonate sediment in a deep water environment (>1000 m). Element ratios distinguish seamount phosphorites from continental margin, plateau, and insular phosphorites. Uranium and thorium contents are low and total rare earch element (REE) contents are generally high. T
Authors
J. R. Hein, Yeh Hsueh-Wen, S.H. Gunn, W.V. Sliter, L.M. Benninger, Wang Chung-Ho
Hydrothermal palygorskite and ferromanganese mineralization at a central California margin fracture zone
Ferromanganese oxyhydroxide crusts and nodules associated with palygorskite were recovered from the Santa Lucia Escarpment where the Morro Fracture Zone intersects the central California continental margin. Palygorskite was found in pure, high-Mg, low-Al, boxwork-textured veins, and disseminated in poorly consolidated palygorskite-rich mudstone. The purity of the palygorskite boxwork blades and th
Authors
A. E. Gibbs, J. R. Hein, S.D. Lewis, D. S. McCulloch
Variations in the fine-scale composition of a central Pacific ferromanganese crust: paleoceanographic implications
The crust represents 18.5 m.y. of growth of Fe and Mn oxyhydroxides. The crust is composed of alternating botryoidal and laminated layers. The botryoidal layers formed during the same time intervals that widespread Neogene deep-sea hiatuses were forming in bottom sediments. The botryoidal layers represent growth during times of intensified deepwater flow, whereas the laminated intervals represent
Authors
J. R. Hein, W. A. Bohrson, M. S. Schulz, M. Noble, D. A. Clague
Geochronology and subsurface stratigraphy of Pukapuka and Rakahanga atolls, Cook Islands: Late Quaternary reef growth and sea level history
Eustatic sea-level cycles superposed on thermal subsidence of an atoll produce layers of high sea-level reefs separated by erosional unconformities. Coral samples from these reefs from cores drilled to 50 m beneath the lagoons of Pukapuka and Rakahanga atolls, northern Cook Islands give electron spin resonance (ESR) and U-series ages ranging from the Holocene to 600,000 yr B.P. Subgroups of these
Authors
S.C. Gray, J. R. Hein, R. Hausmann, U. Radtke
Dolomitization of Quaternary reef limestones, Aitutaki, Cook Islands
The primary reef framework is considered to have been deposited during several highstands of sea level. Following partial to local recrystallization of the limestone, a signle episode of dolomitization occurred. Both tidal and thermal pumping drove large quantities of seawater through the porous rocks and perhaps maintained a wide mixing zone. However, the isotopic, geochemical and petrographic da
Authors
J. R. Hein, S.C. Gray, B. M. Richmond, L. D. White
Geology, geophysics, geochemistry, and deep-sea mineral deposits, Federated States of Micronesia: KORDI-USGS R.V. Farnella Cruise F11-90-CP
No abstract available.
Authors
James R. Hein, Jung-Ho Ahn, J.C. Wong, Jung-Keuk Kang, V. K. Smith, Suk-Hoon Yoon, W. M. d'Angelo, Sang-Ok Yoo, A. E. Gibbs, Han-Joon Kim, P. J. Quinterno, Moon-Young Jung, A. S. Davis, Byong-Kwon Park, J. R. Gillison, M. S. Marlow, M. S. Schulz, D. F. Siems, J. E. Taggart, Norma Rait, L. G. Pickthorn, M. J. Malcolm, M. G. Kavulak, Hsueh-Wen Yeh, D. M. Mann, M. A. Noble, G. O. Riddle, B. H. Roushey, Hezekiah Smith
Petrography and chemistry of hydrothermal manganese oxyhydroxides from the Mariana and Izu-Bonin Volcanic Arcs, West Pacific
No abstract available.
Authors
Marjorie S. Schulz, James R. Hein
Science and Products
Filter Total Items: 166
238U-234U-230Th chronometry of Fe-Mn crusts: Growth processes and recovery of thorium isotopic ratios of seawater
Comparison of (234U) excess⁄(238U) and (230Th⁄232Th) activity ratios in oceanic Fe-Mn deposits provides a method for assessing the closed-system behaviour of 238U-234U-230Th, as well as variations in the initial uranium and thorium isotopic ratios of the precipitated metal oxides. This approach is illustrated using a Fe-Mn crust from Lotab seamount (Marshall Islands, west equatorial Pacific). Here
Authors
F. Chabaux, A.S. Cohen, R. K. O'Nions, J. R. Hein
Chemically diverse, sporadic volcanism at seamounts offshore southern and Baja California
Compositions of lavas from seven small to medium-sized seamounts, between lat 34.0°N and 30.5°N offshore southern and Baja California, include low-K2O tholeiitic, transitional, and mildly to moderately alkalic basalt and their differentiates. The low-K2O tholeiites resemble primitive (>9% MgO) mid-oceanic-ridge basalt (MORB) with low incompatible element abundances and very depleted, concave-downw
Authors
A. S. Davis, S.H. Gunn, W. A. Bohrson, L.-B. Gray, J. R. Hein
Diagenesis of diatomite from the Kolubara Coal Basin, Baroševac, Serbia
Diatomite associated with the Kolubara Coal Basin was studied to better understand early stage silica diagenesis of shallow water deposits. The Kolubara Basin consists of Neogene siliciclastic rocks, diatomite, marlstone and rare carbonates. Palaeozoic metamorphic and Mesozoic sedimentary and igneous basement rocks are transgressively overlain by Upper Miocene sandstone, siltstone, shale and mudst
Authors
J. Obradović, James R. Hein, J. Djurdjević
Data and results from R.V. Aleksandr Vinogradov cruises 91-AV-19/1, North Pacific hydrochemistry transect; 91-AV-19/2, North Equatorial Pacific Karin Ridge Fe-Mn crust studies; and 91-AV-19/4, Northwest Pacific and Bering Sea sediment geochemistry and pal
No abstract available.
Authors
A.S. Bychkov, A. E. Gibbs
Composition and origin of hydrothermal ironstones from central Pacific seamounts
Ironstones recovered from five Late Cretaceous seamounts in the central Pacific region probably formed during late-stage edifice-building volcanism. Ironstones are dense and compact with the appearance of brown chert. The ironstones are characterized by a goethite mineralogy with FeOOH contents up to 88%, extreme fractionation of Fe and Mn, low trace-element and rare earth element abundances, low
Authors
J. R. Hein, Y. Hsueh-Wen, S.H. Gunn, A. E. Gibbs, W. Chung-ho
Two major Cenozoic episodes of phosphogenesis recorded in equatorial Pacific seamount deposits
The phosphorites occur in a wide variety of forms, but most commonly carbonate fluorapatite (CFA) replaced middle Eocene and older carbonate sediment in a deep water environment (>1000 m). Element ratios distinguish seamount phosphorites from continental margin, plateau, and insular phosphorites. Uranium and thorium contents are low and total rare earch element (REE) contents are generally high. T
Authors
J. R. Hein, Yeh Hsueh-Wen, S.H. Gunn, W.V. Sliter, L.M. Benninger, Wang Chung-Ho
Hydrothermal palygorskite and ferromanganese mineralization at a central California margin fracture zone
Ferromanganese oxyhydroxide crusts and nodules associated with palygorskite were recovered from the Santa Lucia Escarpment where the Morro Fracture Zone intersects the central California continental margin. Palygorskite was found in pure, high-Mg, low-Al, boxwork-textured veins, and disseminated in poorly consolidated palygorskite-rich mudstone. The purity of the palygorskite boxwork blades and th
Authors
A. E. Gibbs, J. R. Hein, S.D. Lewis, D. S. McCulloch
Variations in the fine-scale composition of a central Pacific ferromanganese crust: paleoceanographic implications
The crust represents 18.5 m.y. of growth of Fe and Mn oxyhydroxides. The crust is composed of alternating botryoidal and laminated layers. The botryoidal layers formed during the same time intervals that widespread Neogene deep-sea hiatuses were forming in bottom sediments. The botryoidal layers represent growth during times of intensified deepwater flow, whereas the laminated intervals represent
Authors
J. R. Hein, W. A. Bohrson, M. S. Schulz, M. Noble, D. A. Clague
Geochronology and subsurface stratigraphy of Pukapuka and Rakahanga atolls, Cook Islands: Late Quaternary reef growth and sea level history
Eustatic sea-level cycles superposed on thermal subsidence of an atoll produce layers of high sea-level reefs separated by erosional unconformities. Coral samples from these reefs from cores drilled to 50 m beneath the lagoons of Pukapuka and Rakahanga atolls, northern Cook Islands give electron spin resonance (ESR) and U-series ages ranging from the Holocene to 600,000 yr B.P. Subgroups of these
Authors
S.C. Gray, J. R. Hein, R. Hausmann, U. Radtke
Dolomitization of Quaternary reef limestones, Aitutaki, Cook Islands
The primary reef framework is considered to have been deposited during several highstands of sea level. Following partial to local recrystallization of the limestone, a signle episode of dolomitization occurred. Both tidal and thermal pumping drove large quantities of seawater through the porous rocks and perhaps maintained a wide mixing zone. However, the isotopic, geochemical and petrographic da
Authors
J. R. Hein, S.C. Gray, B. M. Richmond, L. D. White
Geology, geophysics, geochemistry, and deep-sea mineral deposits, Federated States of Micronesia: KORDI-USGS R.V. Farnella Cruise F11-90-CP
No abstract available.
Authors
James R. Hein, Jung-Ho Ahn, J.C. Wong, Jung-Keuk Kang, V. K. Smith, Suk-Hoon Yoon, W. M. d'Angelo, Sang-Ok Yoo, A. E. Gibbs, Han-Joon Kim, P. J. Quinterno, Moon-Young Jung, A. S. Davis, Byong-Kwon Park, J. R. Gillison, M. S. Marlow, M. S. Schulz, D. F. Siems, J. E. Taggart, Norma Rait, L. G. Pickthorn, M. J. Malcolm, M. G. Kavulak, Hsueh-Wen Yeh, D. M. Mann, M. A. Noble, G. O. Riddle, B. H. Roushey, Hezekiah Smith
Petrography and chemistry of hydrothermal manganese oxyhydroxides from the Mariana and Izu-Bonin Volcanic Arcs, West Pacific
No abstract available.
Authors
Marjorie S. Schulz, James R. Hein