Tuesday, November 18, 2008

Sequence Stratigraphy and Industrial Mineral Exploration - The Hauptrogenstein

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As announced in the introduction I will now post a very condensed summary of the Hauptrogenstein:

Studying the Hauptrogenstein in NW-Switzerland Gonzalez identified three shallowing-upward successions within the Hauptrogenstein-Formation and the underlying Rothenfluh Beds (Blagdeni Beds in SW-Germany).

The Rothenfluh/Blagdeni Beds consist of marls, interbedded mud- to wackestones and limestone nodules. They can contain a quartz content of up to 25%. The finegrained limestone beds become more frequent towards the hanging-wall and increasingly more bioclastic with intercalations of thin beds of ooid grainstones. This tendency increases into the Lower Acuminata Beds (Pentacrinus beds in SW-Germany) and the Lower Oolitic Series. The development to a high-energy shallow-marine environment continues with the appearance of thick layers of oblique and cross-stratified ooidal grainstones. In the top the oncolite rich "Mumienbank" is capped by an ommission surface. The Upper Oolitic Series essential follows the same composition with the Homomya Marls at the base, oolitic grainstones of the Upper Hauptrogenstein s. str. and Movelier Beds at the top forming the transition to the third shallowing-up succession composed of marls at the base and Ferrigineus-Oolith at the top.


Shallowing-up successions within the Hauptrogenstein-Formation (Gonzalez, 1996)

There is a trend of each sucession to become thinner with the Lower Oolitic Series the most massive and the iron-rich Ferrigineus-Oolith the thinnest (see Fig.). The water energy is increasing towards the top of each succession into a shoal or tidal-channel environment as supported by (bioclastic) oolitic grainstones.

You will see why this is important in the following parts of this mini-series...

References
  1. Ramon Gonzalez (1996): Response of shallow-marine carbonate facies to third-order and high-frequency sea-level fluctuations: Hauptrogenstein Formation, northern Switzerland, Sedimentary Geology, 102

2 comments :

Miguel Vera said...

Very interesting series. I think that most of us tend to relate sequence stratigraphy to the petroleum industry, but this application actually makes sense. Looking forward for the mineral exploration part.

Cheers.

Lost Geologist said...

Indeed an under-appreciated field I believe.

Please all accept my excuses that I am slow in continuing the series. My field work consumes most of my time. Once I get some time to breath I will compile the next episode.