Rodderberg Vulkan

Der Rundweg
Falls ihr etwas Zeit habt empfehlen wir euch wärmstens den schönen Rundweg am Kraterrand. Den Rundweg könnt ihr auf Google Maps oder GPSies anschauen. Wir haben eine kleine Auswahl an Eindrücken in einer kleinen Rodderberg Vulkan Galerie zusammengestellt.

Die Fragen
Bitte begebt euch an die oben genannte Koordinate. In der Nähe befindet sich eine Informationstafel (siehe Wegpunkt). Lest euch die Tafel bitte sorgfältig durch und beantwortet folgende Fragen:

1. Bis wann wurde die Schlacke an diesem Ort abgebaut?
2. Zu welchem Zweck wurde die Schlacke verwendet?
3. In welcher erdgeschichtlichen Epoche ereignete sich eine gewaltige Explosion?
4. Nenne die Anzahl der Bilder auf der Tafel und beschreibe kurz was du auf ihnen siehst.
5. In welchem großräumigen Zusammenhang steht der Rodderberg?

Die Log-Bedingungen

1. Bitte schickt uns eine E-Mail an "earthcache [at] me.com" mit den Antworten für die Fragen. Bitte wartet dann auf die Log-Freigabe bevor ihr euren Log-Eintrag macht.
2. Bitte macht ein Bild von euch und eurem GPS vor dem Basaltgang und fügt es eurem Log-Eintrag hinzu. Solltet ihr alleine unterwegs sein genügt ein Bild von eurem GPS mit sichtbaren Koordinaten.

Logs ohne Bild oder vorherige Log-Freigabe werden kommentarlos gelöscht!

Wir hoffen euch macht dieser EarthCache und der Rundweg genau so viel Spaß wie uns! Wir danken euch für euren Besuch und freuen uns auf eure E-Mails!

Liebe Grüße Tona & Yo!

Waymarking
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EarthCache Bonus (virtuell) Geocoin
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  Rodderberg Volcano

The Rodderberg is the most northern and with an age of a little less than 800.000 years also the latest volcano of the region. Located in the South of Bonn, directly above the Rhine Valley it stretches over the town borders till the Rhein-Sieg-Kreis and to Rhineland-Palatinate. With its impressive, more than 50-m-deep perfectly circular crater with its slopes from basaltic tuff and slag it is a unique geologic monument. From several vantage points one has a wonderful round view on the directly subtending dragon's rock, the city of Bonn and in good weather to the Cologne Cathedral.

History
About 500.000 years ago, hot magma rose from deeper regions. When it reached ground water close to surface, it came to an immense phreatic eruption which formed the maar crater, nowadays about 50 m deep. The crater is approx. 800 m in diameter and is still well visible from the aerial perspective.

 

 

About 300,000 years later the Rodderberg awoke once more to life. This time with a series of slag eruptions. An especially well visible report of one of these later eruptions is a column full with lava, that forced its way into slag deposits in the northern pit. The slag was degraded and the basaltic dike persisted by reason of its bigger hardness. It can still be admired in this place.

 

 

Phreatic Eruption
A phreatic explosion can take place if water gets in direct contact with magma, lava or hot pyroklastic density streams. The abrupt arising steam with the about thousandfold water volume smashes the surrounding rock and bursts a crater into the rocky subsoil. Being in some cases almost totally from smashed non-volcanic adjoining rock, the ejected tuff material is deposited all around the crater as an embankment. This eruption type is recognized as the typical formation mechanism of maars.

 

 

The loop road
If you have some time we highly recommend the pleasant walk on the loop road at the edge of the crater. You can watch it on Google Maps or GPSies. We have arranged a small choice of the impressions in a little Rodderberg Vulcano Gallery.

 

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Questions
Please, head for coordinate mentioned above. Thereabouts is an information board (watch out for the waypoint). Read the board carefully by and answers the following questions:

1. Until when was the slag diminished at this place?
2. What was the slag used for?
3. In which geological epoch happened an immense explosion?
4. Name the number of the pictures on the board and describe shortly what you can see on them.
5. In which extensive connection over whide areas stands the Rodderberg?

Attention! The precise details are required, provided on the board! Unfortunately, solutions found in the internet cannot be accepted.

Log terms

1. Please send us an e-mail to "earthcache [at] me.com" with the answers to the questions. Please wait for approval e-mail before you make your log.
2. Please take a picture of you and your GPS in front of the basaltic dyke and add it to your log. If you’re alone on the move, a picture of your GPS with visible coordinates is enough.

Logs without approval e-mail or picture will be deleted without comment.

 

We hope you will enjoy this EarthCache and the loop road as much as we do. We thank you for your visit and are looking forward to your e-mails!

Kind regards, Tona & Yo!

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Waymarking
In combination with this cache you can log Waymark WM6TDF.

EarthCache Bonus (virtuell) Geocoin
If you like.... you can discover our EarthCache Bonus (virtuell) Geocoin. Just give us a hint in your e-mail.

 

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Statistik / Statistics

 

 

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Historie / History

• 21.06.2009 Listing erstellt. / Listing created.
• 29.06.2009 OpenCaching Link hinzugefügt. / OpenCaching link added.
• 19.07.2009 Waymarking Hinweis hinzugefügt. / Waymarking info added.
• 19.07.2009 Log-Bedingungen geändert. / Log terms changed.

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