Open AccessVejle Fjord Formation: Mineralogy and geochemistry
Author(s) -
Erik S. Rasmussen
Publication year - 1995
Publication title -
bulletin of the geological society of denmark
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.674
H-Index - 28
eISSN - 2245-7070
pISSN - 0011-6297
DOI - 10.37570/bgsd-1995-42-06
Subject(s) - siderite , pyrite , geology , fjord , illite , authigenic , geochemistry , diagenesis , detritus , clay minerals , sedimentary rock , sediment , anoxic waters , siliciclastic , organic matter , sedimentary depositional environment , geomorphology , oceanography , paleontology , chemistry , structural basin , organic chemistry
The Vejle Fjord Formation comprises three members; the Brejning Clay, the Vejle FjordClay, and the Vejle Fjord Sand (Late Oligocene-Early Miocene). The lower part of theBrejning Clay was laid down in a shelf environment with a reduced influx of siliciclasticdetritus. This resulted in deposition of clay minerals enriched in iron. The early diagenesiswas characterized by pyrite and siderite formation within an anoxic sedimentary environment which was established due to degradation of organic matter just below the water/sediment surface. The clay mineral assemblages of the upper part of the Brejning Clay,Vejle Fjord Clay and Vejle Fjord Sand, which were deposited in a lagoonal environment,reflect different stages in the development of the lagoon. When the lagoon was protectedfrom marine influence, the clay mineral assemblage was dominated by kaolinite. Duringperiods with open marine influence the smectite and illite content increased markedly.Authigenic mineral assemblages are characterized by pyrite and siderite in the lagoonaldeposits and pyrite in the tidal flats deposits. The absence of siderite from the latter is dueto insufficient reactive iron to form siderite