Electronic Resource
Springer
Contributions to mineralogy and petrology
11 (1965), S. 614-620
ISSN:
1432-0967
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
Notes:
Abstract Some of the upper cretaceous sedimentary rocks near Regensburg, Germany, are rich in glauconite pellets of 63–200µ diameter. The clay fractions 〈 2µ ϕ of the same rocks are rich in glauconite-mica too. X-ray analysis, chemical analysis and petrographical tests show that, the glauconite pellets must be excrements of marine animals which took up glauconite-mica from sea-bottom. The glauconite materials from these rocks are 1M-micapolymorphs. A comparison of this glauconite with 1M-glauconites cited in literature by other authors shows close aggreement in K2O/MgO- and K2O/Fe2O3 ratios. Within the range of analytical errors the structure formulae of all these 1M-glauconites differ from one another only by the oxidation ratio of iron and — corresponding to this ratio — by the aluminum contents of the octahedral lattice layer. The differences of the 1M-glauconites in octahedral layer populations may due to different redox potentials during glauconite formation or to oxidation during rock diagenesis or rock weathering later on. In a similar manner 1Md-polymorphs of glauconite-mica may have developed from 1M-glauconite by oxidation of iron and corresponding removement of K+ and (H3O)+ ions from interlayer lattice positions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01110839
|
Location |
Call Number |
Expected |
Availability |
