Sunday, December 20, 2009

End of the year reflections.

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The holiday season is very near and christmas just waiting around the corner. December has been pretty quiet here and will most likely continue to be so for the rest of 2009. In the year that is now passing I have been and still am very busy with my graduation work. All geological travel this year was directly related to it either for my diploma mapping project in the beginning of 2009 or thesis fieldwork closer to the end of 2009. The mapping project as been brought to a successful end and even though I am still waiting to receive my official grade both examiners have hinted that there is nothing I need to be worried about.

As my planing goes I will travel to the Southwest of Germany in January or February again. The regional geological survey offered me to examine two new cores of Jurassic limestone for my thesis. This will be a welcome supplement to highlight the regional aspects of my study which is so far focused on Eastern France. The coring will be done in January. So they'll be very fresh. The core locations are directly based on my diploma mapping work by the way.

I realise the activity here has been a bit low in the recent weeks or months. That is mainly due to my thesis stress which simply doesn't leave me with enough peace of mind to author high-quality blog-posts on geology. I tried filling the gaps with some interesting news and geological tools. Also, being engulfed in my thesis, I hardly find the time to read or write something that has not to do with my thesis. Because my thesis is company sponsored there are also some aspects and results which I cannot openly publish online. I hope you understand.

Next year, with the thin-section completed, I hope to make a few good posts on microfacies and diagenesis of limestones. The half-done sections already seem to promise good photographic illustrations. We will see.
 
As this will most likely be the last post for this year I already want to wish everyone of my readers a wonderful christmas time and a happy new year!


Thursday, December 10, 2009

Instructional video on how to use a Geologic Compass

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In my last post I showed you a geologic compass in the Freiberg version. Below is a link on how to use a geological compass in the field. The compass used in the video is a Breithaupt model but usage is basicly identical. The only difference is the location of the dip scale which is not located on the sides of the joint but on the inside above the compass circle, as you will see in the video. Unfortunately there is no such video in English language. The video here is exclusively in German.

How to use a geological compass (Gef├╝gekompass)

Friday, December 4, 2009

Early Christmas Gift

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Wednesday I ordered with my first, own, hard earned money (the Internship wages don't count as I was just standing in the way and being useless really) a high-quality geologist compass, a UV lamp and some boxes for thin-sections. To my great surprise the parcel arrived today already! Usually it takes up to two weeks! So today I had a bit of an early geologist's christmas feeling that resulted in running around the house and examining everything with the UV lamp and the compass (in lack of any near-by outcrops the kitchen was measured). I can now confirm that the walls are indeed all standing vertical and are well aligned. On the foto I added a simple description. The compass is a 360° compass after Clar, Freiberg Modell, that I learned with and still consider one of the best. Neither the Brunton (which broke after 1 day of use), nor some Breithaupt Models (which lacked some marks) or the recently used, cheap imitation (which resulted in daily injuries of my fingers because of the extremely sharp edges and lose screws) of the Freiberg version were able to convince me. This one should last a lifetime though.



I will post some instructions on how to correctly use it sometime soon.

Wednesday, December 2, 2009

Tools and Tricks of the Trade - the GPS

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Ahead of fieldwork for my thesis I asked what kind of GPS device is recommmendable. A number of fellow geobloggers replied with valuable advise. I actually went and bought a GPS ahead of fieldwork. Now I am a proud owner of a GPSmap 60CSx.  The device has fullfilled all expectations in terms of durability, endurance and accuracy under not perfect conditions. The batteries last for 3 days of work or more. Dropping it on rock doesn't cause a scratch and signal reception under dense tree cover is excellent. As a matter of fact I still had a signal when entering underground caves. Well, at least for the first two or three meters. But I don't want to make a commercial here. Fellow geobloggers will know, non-trained readers might wonder though what I do with a GPS device. The idea is pretty simple. It allows to rapidly map and document geological relationships in the field with sufficient accuracy. Mapping lithological borders i.e. becomes a piece of cake. Find the contact in 3 or 4 locations, take a measurement of Easting and Northing, if possible also take a dip measurement with your geologists compass, and you are done. At least in principle. You don't necessarily need the expensive GPS device I decided to buy. A price of 260 Euros is not cheap. There are cheaper alternatives or even more expensive ones with a great variety of additional gadgets.

 
The GPSmap 60CSx operating inside

Using a GPS is easy. If you do not get training at University the documentation should allow you to catch on easily. The basic steps are simple. When the accurate position is your main or only interest, as it may be for most geological fieldwork, there is not much to do. After activating the device give it a moment to acquire a satellite signal. Depending on the location and ground conditions this should not take longer than 1 minute with a good device. Next select the position format and map datum. Usually these are hidden in the units or settings options of your device. In the most simpliest sense the position format determines the way how you write down your coordinates. As the Earth is an irregular globe your need a projection to realistically depict the surface in a flat, 2D map. One of the most common formats is the UTM (Universal Transverse Mercator) format that devides the surface into boxes. The map datum is the reference system. Because our planet is not a perfect globe you need a different model of the surface depending on your position. A model that best fits the real shape of the planet. A commonly used datum is the WGS84. Depending on your location you may wish to use another format and datum. In Germany you will still frequently encounter the Gauss-Kr├╝ger-coordinate system combined with the Potsdam-Datum or the Bessel-Ellipsoid (Bessel 1841). It fits the Geoid in Europe exceptionally well.

Having decided on your position format and map datum you can start mapping. Either simply noting the coordinates into your fieldbook or saving way points for download in the evening. When using way points remember to always save the way point and not to forget one. When working on large areas way points will make it easier to track back your movements.