TY - JOUR
T1 - Mineralogy and mineral chemistry of detrital heavy minerals from the Rhine River in Germany as evidence to their provenance, sedimentary and depositional history
T2 - focus on platinum-group minerals and remarks on cassiterite, columbite-group minerals and uraninite
AU - Oberthür, Thomas
AU - Melcher, Frank
AU - Goldmann, Simon
AU - Wotruba, Hermann
AU - Gerdes, Axel
AU - Dijkstra, A.
AU - Dale, Christopher W.
PY - 2016/3
Y1 - 2016/3
N2 - In the course of studying the gold-bearing heavy mineral spectrum of sediments from the upper Rhine River, a distinct suite of detrital grains comprising platinum-group minerals (PGM), cassiterite, columbite-group minerals and uraninite was identified and investigated using conventional and modern analytical methods. This study aimed to characterize the selected mineral groups mineralogically and geochemically in order to identify possible source areas and to reconstruct different aspects of the complex sedimentary history of the Rhine River sediments. The PGM assemblage is dominated by grains of Ru–Os–Ir alloys (~70 %), followed by Pt–Fe alloys, sperrylite and rare other PGM. Accordingly, this PGM assemblage represents highly mature, physically and chemically extremely resistant compounds which may have experienced and survived repeated reworking during their sedimentary history. Pt–Fe alloys and sperrylite may originate from various sources; however, the predominant Ru–Os–Ir alloy grains point to an origin from ophiolite sequences of unknown age (but likely pre-Alpine; Variscan or older). The exact locations of the primary sources and the complex, prolonged sedimentary history of the detrital PGM with possibly multiple intermittent storages remain unknown. Detrital cassiterite grains were dated by the U–Pb method using LA-ICP-MS. The age dates of cassiterite largely overlap with zircon age distributions by peaking distinctly at ca. 325 Ma (majority of ages), thereby implying a predominantly Variscan age of the cassiterite grains and possible derivation from mineralization in the Black Forest area. Columbite-group minerals are dominantly tapiolite originating from pegmatites. Rare uraninite grains attest that this mineral experienced rapid erosion, transport and deposition in a reducing environment.
AB - In the course of studying the gold-bearing heavy mineral spectrum of sediments from the upper Rhine River, a distinct suite of detrital grains comprising platinum-group minerals (PGM), cassiterite, columbite-group minerals and uraninite was identified and investigated using conventional and modern analytical methods. This study aimed to characterize the selected mineral groups mineralogically and geochemically in order to identify possible source areas and to reconstruct different aspects of the complex sedimentary history of the Rhine River sediments. The PGM assemblage is dominated by grains of Ru–Os–Ir alloys (~70 %), followed by Pt–Fe alloys, sperrylite and rare other PGM. Accordingly, this PGM assemblage represents highly mature, physically and chemically extremely resistant compounds which may have experienced and survived repeated reworking during their sedimentary history. Pt–Fe alloys and sperrylite may originate from various sources; however, the predominant Ru–Os–Ir alloy grains point to an origin from ophiolite sequences of unknown age (but likely pre-Alpine; Variscan or older). The exact locations of the primary sources and the complex, prolonged sedimentary history of the detrital PGM with possibly multiple intermittent storages remain unknown. Detrital cassiterite grains were dated by the U–Pb method using LA-ICP-MS. The age dates of cassiterite largely overlap with zircon age distributions by peaking distinctly at ca. 325 Ma (majority of ages), thereby implying a predominantly Variscan age of the cassiterite grains and possible derivation from mineralization in the Black Forest area. Columbite-group minerals are dominantly tapiolite originating from pegmatites. Rare uraninite grains attest that this mineral experienced rapid erosion, transport and deposition in a reducing environment.
KW - Cassiterite
KW - Gold
KW - Mineral chemistry
KW - Mineralogy
KW - Platinum-group minerals (PGM)
KW - Rhine River
KW - Tapiolite
KW - Uraninite
KW - U–Pb dating
KW - ITC-ISI-JOURNAL-ARTICLE
UR - https://ezproxy2.utwente.nl/login?url=https://doi.org/10.1007/s00531-015-1181-3
UR - https://ezproxy2.utwente.nl/login?url=https://library.itc.utwente.nl/login/2016/isi/dijkstra_min.pdf
U2 - 10.1007/s00531-015-1181-3
DO - 10.1007/s00531-015-1181-3
M3 - Article
AN - SCOPUS:84958052306
VL - 105
SP - 637
EP - 657
JO - Geologische Rundschau
JF - Geologische Rundschau
SN - 1437-3254
IS - 2
ER -