The Lost Geologist: November 2008

30 November, 2008

Field impressions #2

Thursday I spent all day with another Geologist practising how to quickly document a quarry. With some practise the documentation process for resource evaluation (overburden, thickness of useable rock, petrography, etc.) can take no more than 5 to 10 minutes. It can be quite fun to drive around all day and visit old quarries here and there. Before lunchtime we had one stop with a magnificent view across the Rhine Valley with the Vosges mountains at the horizon. I would like to share it.

The view west from close to the Tuniberg

29 November, 2008

Geopetal structure

During my first real field day I came across some very nice sedimentary structures that looked just like in the textbook. Unfortunately I forgot to take ma camera to the field. However, I could take home this nice example of geopetal structure within limestone.

(Click image to enlarge)

It can be nicely observed how the complete shell was infilled at the bottom with mud during deposition and subsequently calcite crystals formed after deposition or diagenesis. It is a wonderful example of how to tell palaeo-up from down especially in tilted sediments. The complete preservation of the shell leads me to assume that it was deposited either in-situ or without much transport. Long transport or strong wave and current action would have seperated the two shell parts.

22 November, 2008

Field impressions

To my great surprise the owners of the little vacation flat that I am renting during my mapping work provided me with internet access! I am very happy about it. It will make staying in touch with family and friends much easier and also gives me the chance to share a few, first field impressions with you. The real work will begin monday when I have an organisational meeting with my local supervisor. Thuesday should then be the first official day at field work. Anyhow, today I took a drive around and through my mapping area to gather first impressions and to orientate myself. The weather is very bad and it had some rain and snow showers even in the valleys. Some of the hills are completely white right now. The weather forecasts look good though and starting thuesday temperatures and weather should improve.

Closing in on the southern end of my mapping area

At the southern most tip I found this unused quarry.

Just a few km down the road: The wine in front still belongs to my area. The village and what's behind gladly not.

On the road back to town I passed through this fairy tale forrest.

As you can see conditions aren't really perfect but I think it'll do. Once the weather improves and once I have access to the drill core documents work should be easier. The few random pieces I picked-up today already contained a few fossils and oncolites/pellets/oolites which proved to be a bit hard to tell apart because they are so tiny. Perhaps I can demonstrate a few fotos of those in the coming weeks.

19 November, 2008

Fieldwork

I'm leaving for field work tomorrow morning and will be absent until christmas - unless I find internet access. The Southern Upper Rhine Graben between Freiburg and Basel will be my hunting ground. Check out some previous posts for more details. To prevent spam I activated the comment moderation. If your comments should not show-up then I didn't have a chance to access the internet.

18 November, 2008

Sequence Stratigraphy and Industrial Mineral Exploration - The Hauptrogenstein

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

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

14 November, 2008

Sequence Stratigraphy and Industrial Mineral Exploration - Introduction

While searching the literature for detailed information for my mapping project I came across two articles relating to sequence stratigraphy and mineral exploration. Both articles share the common theme of sequence stratigraphy: One focuses on the development of the Hauptrogenstein-Formation and the other focuses on how sequence stratigraphy can be use as a tool in the exploration for industrial minerals.

Gonzalez discussed in 1996 the response of shallow-marine carbonate facies of the Hauptrogenstein-Formation (N-Switzerland) to third-order and high-frequency sea-level fluctuations. Dynamic stratigraphy as a tool for economic mineral exploration was discussed by Pawellek and Aigner in 2004 using ultra-pure Upper Jurassic limestones as an example.

There will be no complete discussion of the articles I mention in this post but for anyone interested I will post the references at the end of the posts. I have to admit that I never considered sequence stratigraphy like it appeared to me only a short while ago after discovering both articles.

Looking ahead I will try to use the method described by Pawellek and Aigner on the Hauptrogenstein-Formation from Northern Switzerland. They showed what facies out of a sequence stratigraphic context are most prospective for ultra-pure limestones exploration. The Hauptrogenstein extends northerly into SW-Germany. The other articles provides sufficent information for my very relaxed hypotising and if I can identify ultra-pure limestones by their facies.

To not get distracted too much from my actuall work I have decided to turn this into a short series of 3 to 5 posts. This way I can write short contributions whenever my work allows. After todays introduction I will discuss next how the Hauptrogenstein responded to sea-level fluctuations.

References

Thomas Pawellek and Thomas Aigner (2004): Dynamic Stratigraphy as a tool in economic mineral exploration: ultra-pure limestones (Upper Jurassic, SW Germany), Marine and Petroleum Geology, 21
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

P.S. I do not know how frequent I have time to make thoughtfull contributions to this mini-series inbetween my work so please do not hold your breath till part 2!

11 November, 2008

The Hauptrogenstein-Formation

I recently noticed a number of visitors coming from Wikipedia. There are several posts on the Hauptrogenstein on my blog. Please click on the tags Carbonate Sedimentology and Germany to find most of them.

The majority of rocks and formations within my mapping area are from the Middle Jurassic. During the Bajocian (Middle Jurassic) a shallow-marine carbonate platform - the Burgundy Platform - stretched from France towards the SE and prograded slowly into modern Germany and Switzerland. It represents the so called Celtic facies realm that grades into the Swabian facies realm E of Strasbourg and Bern. In Germany this transition is not preserved. The platform carbonates are composed of the oolitic complex of the Hauptrogenstein-Formation and the uppermost Ostreenkalk-Formation.

Paleogeography

While the W is mostly dominated by the deposition of marls the E is dominated by N-S trending oolitic barries and tidal areas. Back barrier facies belts developed W of these. Off-barrier deposition is again characterised by marls and intercalated strom deposits. A good map says more than a 1000 words though:

Paleogeographic reconstruction of the late Bajocian (from Gonzales & Wetzel, 1996)

Three facies belt can be distinguished in the geological record. A shallow-marine, high-energy oolitic barrier system controlled by tidal currents. A backbarrier with calmer water and deposition of micrites, oncolites and patch reefes and a off-barrier dominated by marls and tempestites.

In SW-Germany, in the S edge of my own field area, the interfingering of marls at the bottom, oolitic sands in the middle and backbarrier patch reefes can be very nicely observed in several profiles also indicating the slow progradation of the different facies over time and the growth of the platform towards the NE and SE.

References:

Ramon Gonzales & Andreas Wetzel (1996): Stratigraphy and paleogeography of the Hauptrogenstein and Klingau Formations (middle Bajocian to late Bathonian), northern Switzerland, Eclogea. geol. Helv. 89/1
Martin Ernst (1991): Lithostratigraphische und fazielle Untersuchungen des Hauptrogensteins (Bajocium) im SE-Oberrheingraben, Jber. Mitt. oberrhein. geol. Ver., N.F. 73

07 November, 2008

If I could paint like this...

Below is a small painting my girlfriend made for me so I can remember our stay at the Black Sea this summer (that beach was so nice, sun, warmth, ocean and even nice rocks!). She did that all by herself. I have it on foto. I am so jealouse and proud of her at once. I wish I could paint like that.

Her painting

The foto

I think it is so great to be able to paint so well like that. She surely has to teach me!

06 November, 2008

Geology bookmarks 5

Today I want to share the last batch of geology related bookmarks with you. Today's version is about a lot of mining companies that I came across during the last years of studying. If you are looking for jobs perhaps some of these sites may be of help.

Mining and Georesource Companies

05 November, 2008

Geology bookmarks 4

While WoGE #154 is still waiting for the first replies (btw, I added volcanista's Magmalicious Blog to my Blogroll) I can continue with sharing my geology related bookmarks. Today I have a list of institutions and associations of geology and various state surveys.

Geological Institutions and Associations

04 November, 2008

Geology bookmarks 3

Here is the 3rd edition of my geology bookmarks. This time it is only a few palaeontology/biology links that I came across while preparing seminar papers or homework for university.

Palaeontology/Biology

03 November, 2008

WoGE #154

After a long time I have scored another win on the Where on Google Earth challenge and solved WoGE #153 (Jan Mayen volcanic island) hosted by volcanista on her Magmalicious Blog.

I will invoke the Schott Rule here because I want people who have not yet won a WoGE to get a chance. This means all those who have already won must wait one hour for each of their wins.

If you can identify the location of WoGE #154 please reply in the comments stating the exact location or coordinates and also some information about the geologic significance of this location. Simple stating the location without geology I will let not let count! If you are correct you get to host and select WoGE #155. If you do not have a blog you may designate someone to host it for you.

Here it is:

Good luck!

Posting time was 11:54PM CET (Central European Time) - that is UTC+1

02 November, 2008

Geology bookmarks 2

Here is the second batch of geology related bookmarks I want to share with you. These focus on mineral deposits, sedimentology and volcanology. There are more to come in the next days for Palaeontology, Geological Associations, Journals I often consult and a long list of mining companies if you want.

Mineral Deposits

Sedimentology

Volcanology

News on dimension stones

Geoberg has another post on newly found Geoblogs on his Geoberg-Blog. Among others there is the Naturstein Newslog - a newsblog of the German Naturstein Magazine on dimension stones in Germany. I decided to add their news section to my feed of German Geoblogs to increase its variety.

Geology bookmarks 1

I've been thinking of sharing my geology related bookmarks for a while. Finally I figured out how to copy & paste the links and names easily. Below you will find around 50 to 60 links to various geology sites taken from my "general geology" bookmarks. I will share other bookmarks later which may include sites of similiar topical range, however, most of my bookmarks are arranged by creative chaos which should also ensure that there is something for everybody. Don't spend too much time reading - some of those website are simply excellent and also all of these sites are completely free access and very educational!

P.S: I tried to only post working links but if there should still be dead links please let me know and I clean-up the list.

Update: Added numbering and removed a dead link

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