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8 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Metalliferous Coals of Cretaceous Age: A Review

Critical elements in coal and coal-bearing sequences (e.g., Li, Sc, V, Ga, Ge, Se, Y and rare earth elements, Zr, Nb, Au, Ag, platinum group elements, Re, and U) have attracted great attention because their concentrations in some cases may be comparable to those of conventional ore deposits. The enrichment of critical elements in coals, particularly those of Carboniferous-Permian and Cenozoic ages, have generally been attributed to within-plate (plume-related) volcanism and associated hydrothermal activity. However, Cretaceous coals are not commonly rich in critical elements, with the exception of some (e.g., Ge and U) in localised areas. This paper globally reviewed metalliferous coals from Siberia, the Russian Far East, Mongolia, South America, the United States and Mexico, Canada (Alberta and British Columbia), China, Africa, and Australasia (Victoria, Queensland, New South Wales, South Australia, Northern Territory, New Zealand, Nelson, West Coast, Canterbury, Otago, and Southland). The world-class Ge-U or Ge deposits in North China, Mongolia, and Siberia are the only commercially significant representatives of the Cretaceous metalliferous coals, which are related to bio-chemical reduction of oxidized meteoric, hydrothermal, or sea waters by organic matter of the peat bogs. The common Cretaceous coals worldwide are generally not rich in critical elements because intensive igneous activity led to extensive acidification of terrestrial and marine waters, which are responsible for the low coal metallogenesis during the Cretaceous period, especially the Early Cretaceous time.

58 GEOSCIENCES↗
DOE OSTI2020

Materials Data on UGe2 by Materials Project

UGe2 is Zirconium Disilicide-like structured and crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. U is bonded in a 10-coordinate geometry to ten Ge atoms. There are a spread of U–Ge bond distances ranging from 2.92–3.20 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a distorted square co-planar geometry to four equivalent U and four equivalent Ge atoms. All Ge–Ge bond lengths are 2.93 Å. In the second Ge site, Ge is bonded in a distorted square co-planar geometry to four equivalent U and four equivalent Ge atoms. In the third Ge site, Ge is bonded in a 8-coordinate geometry to six equivalent U and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.77 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on UGe2 by Materials Project

UGe2 is Zirconium Disilicide structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. U is bonded in a 10-coordinate geometry to ten Ge atoms. There are a spread of U–Ge bond distances ranging from 2.95–3.19 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 8-coordinate geometry to six equivalent U and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.70 Å. In the second Ge site, Ge is bonded in a 8-coordinate geometry to four equivalent U and four equivalent Ge atoms. All Ge–Ge bond lengths are 2.89 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on UGe3 by Materials Project

UGe3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. U is bonded to twelve equivalent Ge atoms to form UGe12 cuboctahedra that share corners with twelve equivalent UGe12 cuboctahedra, edges with twenty-four equivalent GeU4Ge8 cuboctahedra, faces with six equivalent UGe12 cuboctahedra, and faces with twelve equivalent GeU4Ge8 cuboctahedra. All U–Ge bond lengths are 2.97 Å. Ge is bonded to four equivalent U and eight equivalent Ge atoms to form distorted GeU4Ge8 cuboctahedra that share corners with twelve equivalent GeU4Ge8 cuboctahedra, edges with eight equivalent UGe12 cuboctahedra, edges with sixteen equivalent GeU4Ge8 cuboctahedra, faces with four equivalent UGe12 cuboctahedra, and faces with fourteen equivalent GeU4Ge8 cuboctahedra. All Ge–Ge bond lengths are 2.97 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U5Ge4 by Materials Project

U5Ge4 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. there are two inequivalent U sites. In the first U site, U is bonded in a 8-coordinate geometry to two equivalent U and six equivalent Ge atoms. Both U–U bond lengths are 2.91 Å. All U–Ge bond lengths are 3.08 Å. In the second U site, U is bonded in a 7-coordinate geometry to seven Ge atoms. There are a spread of U–Ge bond distances ranging from 2.89–2.98 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded to six equivalent U atoms to form distorted face-sharing GeU6 octahedra. In the second Ge site, Ge is bonded in a 9-coordinate geometry to nine U atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U5Ge3 by Materials Project

U5Ge3 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. there are two inequivalent U sites. In the first U site, U is bonded in a 5-coordinate geometry to five equivalent Ge atoms. There are a spread of U–Ge bond distances ranging from 2.93–3.19 Å. In the second U site, U is bonded in a 8-coordinate geometry to two equivalent U and six equivalent Ge atoms. Both U–U bond lengths are 2.73 Å. All U–Ge bond lengths are 2.97 Å. Ge is bonded in a 9-coordinate geometry to nine U atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U3Ge by Materials Project

U3Ge is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. U is bonded to eight equivalent U and four equivalent Ge atoms to form distorted UU8Ge4 cuboctahedra that share corners with twelve equivalent UU8Ge4 cuboctahedra, edges with eight equivalent GeU12 cuboctahedra, edges with sixteen equivalent UU8Ge4 cuboctahedra, faces with four equivalent GeU12 cuboctahedra, and faces with fourteen equivalent UU8Ge4 cuboctahedra. All U–U bond lengths are 3.04 Å. All U–Ge bond lengths are 3.04 Å. Ge is bonded to twelve equivalent U atoms to form GeU12 cuboctahedra that share corners with twelve equivalent GeU12 cuboctahedra, edges with twenty-four equivalent UU8Ge4 cuboctahedra, faces with six equivalent GeU12 cuboctahedra, and faces with twelve equivalent UU8Ge4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U3Ge by Materials Project

U3Ge is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent U sites. In the first U site, U is bonded to eight U and four equivalent Ge atoms to form distorted UU8Ge4 cuboctahedra that share corners with twelve equivalent UU8Ge4 cuboctahedra, edges with eight equivalent GeU12 cuboctahedra, edges with sixteen UU8Ge4 cuboctahedra, faces with four equivalent GeU12 cuboctahedra, and faces with fourteen UU8Ge4 cuboctahedra. There are four shorter (3.02 Å) and four longer (3.06 Å) U–U bond lengths. All U–Ge bond lengths are 3.02 Å. In the second U site, U is bonded to eight equivalent U and four equivalent Ge atoms to form distorted UU8Ge4 cuboctahedra that share corners with four equivalent UU8Ge4 cuboctahedra, corners with eight equivalent GeU12 cuboctahedra, edges with twenty-four UU8Ge4 cuboctahedra, faces with six equivalent GeU12 cuboctahedra, and faces with twelve UU8Ge4 cuboctahedra. All U–Ge bond lengths are 3.06 Å. Ge is bonded to twelve U atoms to form GeU12 cuboctahedra that share corners with four equivalent GeU12 cuboctahedra, corners with eight equivalent UU8Ge4 cuboctahedra, edges with eight equivalent GeU12 cuboctahedra, edges with sixteen equivalent UU8Ge4 cuboctahedra, faces with four equivalent GeU12 cuboctahedra, and faces with fourteen UU8Ge4 cuboctahedra.

36 MATERIALS SCIENCE↗