Allen ein fröhliches und besinnliches Weihnachtsfest!
A Merry Christmas and Happy Holidays, enjoy the free days!
Feliz Navidad a todos mis amigos en todo el mundo y especialmente en sudamerica y Peru!
24 December, 2011
12 November, 2011
I'm reading plenty of papers these days about carbonate concretions, dolomite formation in terrestrial environments and paleosols. Here's of a collection of the papers that I personally find most interesting and informative. There is currently a lot of cool stuff happening regarding dolomite formation in low-temperature environments. These articles are on the cutting-edge in my opinion. Of course it is but a tiny collection...
- Precipitation of low-temperature dolomite from an anaerobic microbial consortium: the role of methanogenic Archaea (Kenward et al., 2009)
- Microbially mediated carbonates in the Holocene deposits from Sarlieve, a small ancient lake of the French Massif Central, testify to the evolution of a restricted environment (Breheret et al.; 2007)
- Pedogenic origin of dolomite in a basaltic weathering profile, Kohala peninsula, Hawaii (Capo et al., 2000)
- Microbial precipitation of dolomite in methanogenic groundwater (Robets et al., 2004)
- Presence of sulfate does not inhibit low-temperature dolomite precipitation (Sanchez-Roman et al., 2009)
- The role of biomineralization in the origin of sepiolite and dolomite (Leguey et al., 2010)
- Origin of magnesium in clays from the Amargosa desert, Nevada (Khoury et al., 1982)
30 August, 2011
I'm an economic geologist and sedimentologist by training. I search valuble minerals. But guess what keeps my mind going around and around? Issues that, at first hand, have nothing to do with mineral wealth. Today, another day in another open pit mine, and I am longing to be an expert in trace fossils (ichnofossils), soil science and palaeosols, calcretes and palustrine carbonates, diagenetic concretions, and the dolomite problem. And you ask, do they have something to do with mineral exploration and resources?
Well - yes. They do.
Am especially puzzled by the over-whelming amount of what I interprete to be trace fossils of some kind. Though I am no palaeontologist, especially no ichnologist (is that the right word even?). I should take some palaeontologist and soils scientist to the mines. They'd be amazed. Well, I am.
P.S. If you can recommend some superb trace fossils for dummies articles or books focusing on fluvial-limnic-lacustrine-palustrine-something depositional environments - let me know.
19 August, 2011
The last post demonstrated how we use big machines to dig deeper for science. Let me introduce one of the fruits that we could reap because of it: white bentonite. It is the lower most bentonite bed in the region. Roughly 2 - 5 cm thick and very, very pure montmorillonite. If it would be thicker and if it would not be coverered by 40 cm of sandy dirt it would be a real treasure. Mine workers are known to eat it when having problems with their stomach, i.e. pyrosis. A table spoon of white bentonite and it will pass after some minutes. The best way to describe its physical appearance is white chocolate. It's nearly in-distuigishable visually. We've been literally eating our way upwards in this pit. White bentonite has no taste but a pleasent consistency in the mouth - just like chocolate. It shows a conchoidal fracture and has a waxy feel.
Cream-white bentonite. Yummy!
P.S. Please bear with me for the superficial postings. Being a PhD and a teaching assistant eats all my time and most of the creativity. Writing high-quality post is unfortunately a time-consuming task. I don't have much time.
18 August, 2011
I've been sharing this image on facebook therefore I thought that I ought to show my loyal readers, as well. Thuesday I've been in the field north of Munich in one of the active bentonite pits that are currently in production. The big machinery just left the pit that morning but we still were fortunate enough to have the small excavator working in the pit which was of great help digging some holes for us to reach the lowest member of the bentonite. It's pretty awesome to direct the big machinery and tell them where to dig for you! I wish I'd always have one at hand for every field trip!
Digging deeper for science!
29 July, 2011
Just some photos taken during work which I am burried in. I am sorry for the lack of posts but writing interesting and quality stories takes a lot of time which I don't have much off. The PhD and teaching assistant position are full-time jobs. Volcanic ash, bentonite and carbonate concretions are piling in my office. That's all I can say. :-)
Friends from the industry.
A trace of history.
10 June, 2011
On May 27th I joined the first of two field trips this semester about industrial minerals in Bavaria. We saw several active open pits. The first location is an active clay pit (Fig. 1). Here relatively pure kaolinite and lignite that are closely inter-calated are being mined to produce chamotte. The clays and lignite are of pliocene age and were deposited in the glacial out-wash valley of the ancient Naab river. The mine is host to a large pond of acid mine drainage in the centre that is pumped out and neutralised with burned lime. Contrary to many acid mine drainage problems this is caused by the high organic content of the clay and lignite. The humic acids are also respondsible for the colors.
Fig. 1: Clay pit with acid mine drainage in center. Dark layers are lignite within kaolinite.
One of the pecularities of this clay pit are siderite concretions (Fig. 2). Peculiar as such as these clays are already very iron poor by nature. Siderite concretions are fairly common and can be the size of a football. What strikes in the field is that these concrections almost always have a small piece of coal or wood at their core. Not visible to the naked eye is that the clays are strongly iron depleted in the vicinity of the concretions. Sulphure isotope data points to the source of formation. Bacterial activity is to blame!
Fig. 2: Yellowish-brownish siderite concretion around wood chips in kaolinite.
The coal is not boring either. Below (Fig. 3) you can see a well preserved fossil leaf about 3 to 4 cm long. I have no idea what exactly this is but the pliocene coals of the region are known for their well preserved and rich plant fossils.
Fig. 3: Leaf on pliocene coal.
And finally a brief look (Fig. 4) into the oven! The sieved and prepaired clay is calcined at ca. 1200°C for a period of roughly 6 hours. The lignite supplies about 1/3 of the required energy, the remaining 2/3 supplied by natural gas. Fine-spread lignite within the kaolinite clay generates a high-porosity chamotte. Clay with few or no coal burns to a dense, low-porosity chamotte.
Fig. 4: Readily calcined and still glowing chamotte exiting the oven.
Thanks to my PhD supervisor for leading this interesting field trip and to
Rohstoffgesellschaft mbH Ponholz for showing us their mine and plant!
13 April, 2011
The dinosaurs probably got extinct more than once in the time of my online absence from blogging, however, this blog ain't dead - just in temporary hibernation that may end soon. Life threw a couple of more rocks at me that I had to handle in style suitable for a geologist. As things are going I have a job! Wohohooo!!! I didn't sign, yet, so I will delay the official celebration until later but as things are developing I will be moving to a large, wonderful city in Southern Germany soon to work at a reknown university and also persue a PhD related to industrial minerals. This also means that I finally have something to blog about and will be doing my own research - and behold: they will use me as a teaching assistant on the first year students! No idea who should be more scared: me or THEM! Haha... Stay tuned. The next weeks might be full with work here to move and organise but I promise once I get the time I will let you know and restart the geoblogging. :-D