ISSN:
1437-3262
Keywords:
Geochemistry
;
Clay mineralogy
;
Weathering
;
Diagenesis
;
Rhine
;
Facies
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
Notes:
2 O contents, which can be attributed to the Alpine source supplying fresh, sodic plagioclase-rich material instead of the local, strongly weathered sediments. Increasing K2O/Al2O3 can be attributed to a similar decrease in degree of weathering. However, this trend is disturbed by the loss of K from clay minerals during weathering in organic-rich layers. Local high TiO2 anomalies, caused by preferential sorting and concentration, are found in most Pliocene sections, but they are absent in the Upper Pliocene and Lower Pleistocene Alpine-derived deposits. This change is probably due to a change in the energy of the fluvial system. Finally, (pyrite-) S contents drop (siderite-) Fe contents rise. Micromorphological observations indicate that the Pliocene pyrite was formed when freshwater deposits were flooded with seawater during short-term events. The decrease in S, and the increase in siderite-Fe, can be attributed to decreasing marine influence, as a result of the marine regression at the Pliocene–Pleistocene transition.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s005310050323
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