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Earth of fire

Actualité volcanique, Articles de fond sur étude de volcan, tectonique, récits et photos de voyage

Articles avec #excursions et voyages catégorie

Publié le par Bernard Duyck
Publié dans : #Excursions et voyages
 The Messel Pit -  doc.Messel pit Wilson44691 derivative work Lampel

The Messel Pit - doc.Messel pit Wilson44691 derivative work Lampel

In addition to the series over the Vogelsberg and Rhön massive, the Messel pit, which is also of volcanic origin:

The Messel Pit Fossil Site is located 15 km. south of Darmstadt, Hesse Germany. This disused shale quarry is 60 meters deep and measures 1.000 m on 700, which is the extension of the deposit. It is the exploitation of this deposit in the late 1800s to the 1970s, which allowed a group of enthusiasts to discover these fossils.

 

Messel pit - shale outcrop - Photo Wilson44691

Messel pit - shale outcrop - Photo Wilson44691

The formation of the Messel site :

The volcanic history of Messel pit starts in the Eocene, there are about 48 million years. At this time, the European continent is not like what we see today : an archipelago, located 10° lower than today, is subjected to intense tectonic. The uplift of the Alps and the Rhine Graben subsidence favored magmatic lifts.

Deep drilling in 2001 established a maar structure as responsible for the formation of Messel pit. Gravimetric, magnetic and seismic reflection 
analyzes confirmed the hypothesis.

Under the bitumen formation (present to 190m), it was found, from 373 m. depth, a lapilli tuff, whose lower part was deposited at temperatures above 300° C. following a phreatomagmatic eruption.

 

The Messel pit : maar and fossils.
Diagram of passage of the maar stage to that of fossil oil shale deposit - doc. Senckenberg Forschungsintitute und Naturmuseum - A clic for a better vieuw

Diagram of passage of the maar stage to that of fossil oil shale deposit - doc. Senckenberg Forschungsintitute und Naturmuseum - A clic for a better vieuw

To theleft, localisationde Messel pit on the edge of the Rhine graben - to the right, Messel pit on the scale of geological time - doc. Senckenberg Forschungsintitute und naturmuseum - a clic to enlargeTo theleft, localisationde Messel pit on the edge of the Rhine graben - to the right, Messel pit on the scale of geological time - doc. Senckenberg Forschungsintitute und naturmuseum - a clic to enlarge

To theleft, localisationde Messel pit on the edge of the Rhine graben - to the right, Messel pit on the scale of geological time - doc. Senckenberg Forschungsintitute und naturmuseum - a clic to enlarge

The maar housed a lake,initially filled with volcanic debris, sand and pebbles. The lake formed in an area of ​​subsidence, has undergone a major tectonic activity.

Intermittent movements and / or  volcanism have released gas into the lake and the surrounding atmosphere, killing all living at that time. (many non-aquatic fossils are found: land animals, but also birds and bats). Vegetable and mineral substances there are also accumulated. Dead animals fell into the lake, were caught in the sapropel, a mud rich in decaying organic matter ... and the para-tropical climate of the time favored the fossilisation.

This brings to mind the episode of volcanic Lake Nyos in Cameroon in 1986, where CO2 emissions have killed all life within a few kilometers. High levels of siderite in the Messel oil shale also indicate that CO2 was present in high concentrations in the deep waters.

 

Messel pit - fossils of birds, insects and reptiles from the Eocene - doc. pasttime.org

Messel pit - fossils of birds, insects and reptiles from the Eocene - doc. pasttime.org

The fossils of Messel pit :

This site, due to its wealth of fossils, and geological and scientific importance, was ranked in 1995 as World Heritage by Unesco.

The layer of shale, with a maximum thickness of 190 meters, has a lenticular shape, and is between 2 layers of clastic rocks. This argillite, brown to olive green, contains 5-20% oil.

It is called a limnic deposit stagnation, and included a deposit-rich in smectite and algae from seasonal blooms. The ratio of sedimentation is estimated at only 0.1 mm / year.
 

Messel Pit Fossil - left, prehistoric crocodile discovered by miners in 1875 - photo Berthold Steinhilber - right, sweet water turtles - photo Jonathan Blair / Corbis / Smithsonian - a clic to enlargeMessel Pit Fossil - left, prehistoric crocodile discovered by miners in 1875 - photo Berthold Steinhilber - right, sweet water turtles - photo Jonathan Blair / Corbis / Smithsonian - a clic to enlarge

Messel Pit Fossil - left, prehistoric crocodile discovered by miners in 1875 - photo Berthold Steinhilber - right, sweet water turtles - photo Jonathan Blair / Corbis / Smithsonian - a clic to enlarge

Messel pit provides unique informations about the evolution of mammals, ranging from complete articulated skeleton, footprint skin and feathers, the stomach contents of animals at the time. Was able to reconstruct complex food chains, modes of reproduction, and even the evolution of echolocation with well-preserved fossils of bats; data on the evolution of early archaic horses also coming from the site.

More than a thousand species, especially plants and insects, provide an overview of lake ecosystems that have existed over an estimated one million years ... a real short period !

In the bird kingdom, a giant bird runner, Diatryma, the first large predator appeared after the extinction of the dinosaurs, certify an exchange of fauna between Western Europe and North America in the Eocene.

In May 2014, scientists at the Research Institute Senckenberg of Franfort, who care to search the site was granted in 1991, described the oldest fossil of a bird pollinator (hummingbird). The contents of the stomach well-preserved contained pollen from different plants, indicating a relationship between birds and flowers dating from at least 47 Ma.

The museum Senckerberg Frankfurt houses a splendid collection of these fossils.

 

Messel pit - fossil of a pollinator hummingbird, and its stomach contents - scale 10 mm - doc. Schenkerberg Institute

Messel pit - fossil of a pollinator hummingbird, and its stomach contents - scale 10 mm - doc. Schenkerberg Institute

Left, skeleton of a Diatryma / Gastornis from Wyoming - photo Vince Smith - right, restoring Diatryma / prédatio over a primitive equine - doc. dinozavrikus - a click to enlarge, and a better vieuw.Left, skeleton of a Diatryma / Gastornis from Wyoming - photo Vince Smith - right, restoring Diatryma / prédatio over a primitive equine - doc. dinozavrikus - a click to enlarge, and a better vieuw.

Left, skeleton of a Diatryma / Gastornis from Wyoming - photo Vince Smith - right, restoring Diatryma / prédatio over a primitive equine - doc. dinozavrikus - a click to enlarge, and a better vieuw.

Sources :

 - Leibniz Institute for Applied Geophysics – research drilling in Messel Pit  - link

- Messel, un écosyst ème éocène dans les schistes bitumineux allemands – par Stéphane Doyen  - link

- Smithsonian  Mag – The evolutionary secrets within the Messel pit - link

- Grube Messel - link

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Publié le par Bernard Duyck
Publié dans : #Excursions et voyages
Lanin volcano - photo Pedro Hauck / Summitpost.

Lanin volcano - photo Pedro Hauck / Summitpost.

 
Straddling the border between Chile and Argentina, with three-quarters of the massif in Patagonian Argentina, Lanin stratovolcano is part of a chain of three volcanoes aligned on a NW-SE fault, gathering Villarica, Lanin and the Quetrupillan, eroded remnants of 5 stratovolcanoes, more than 20 monogenetic volcanoes including 2 maars.
Left, border-Lanin volcanic chain Villarica; Villarrica-Lanin volcanic chain. CM: Cordillera El Mocho; H: Huililco; HM: Huelemolles; CB: Caburgua; LB: The Barda R: Relicura; CR: Cerro Redondo; PCH: Pichares; SJ: San Jorge; LZ: Lizan; EA: El Arenal; LA:. La Angostura - doc. Revista Geologica de Chile - right Simplified geological map Lanin - from a 1:50,000 scale map by Lara, in press / in Revista Geologica de Chile - click to enlarge the map. Left, border-Lanin volcanic chain Villarica; Villarrica-Lanin volcanic chain. CM: Cordillera El Mocho; H: Huililco; HM: Huelemolles; CB: Caburgua; LB: The Barda R: Relicura; CR: Cerro Redondo; PCH: Pichares; SJ: San Jorge; LZ: Lizan; EA: El Arenal; LA:. La Angostura - doc. Revista Geologica de Chile - right Simplified geological map Lanin - from a 1:50,000 scale map by Lara, in press / in Revista Geologica de Chile - click to enlarge the map.

Left, border-Lanin volcanic chain Villarica; Villarrica-Lanin volcanic chain. CM: Cordillera El Mocho; H: Huililco; HM: Huelemolles; CB: Caburgua; LB: The Barda R: Relicura; CR: Cerro Redondo; PCH: Pichares; SJ: San Jorge; LZ: Lizan; EA: El Arenal; LA:. La Angostura - doc. Revista Geologica de Chile - right Simplified geological map Lanin - from a 1:50,000 scale map by Lara, in press / in Revista Geologica de Chile - click to enlarge the map.

The top of 3,776 m., and dominant its base of 2,500 m., Lanin is a composite stratocône covering about 220 km ², at an estimated volume of 180 km ³ . A small summital lava dome  fed a lava blocks in a northerly direction, there 2,200 years. A post-glacial tuff ring, called Arenal Volcano, is located on the south-west flank. A young lava flow from Lanin covers the deposits of Arenal, and extends south into the lake Paimún.

To the altitude of 2,600 meters, and more visible on the side NO, slope failure coincides with the head of glacial cirques and seems to be the starting point of postglacial basalts.

Volcan Lanin - photo Terras Patagonicas

Volcan Lanin - photo Terras Patagonicas

Lanin - Photo John Davidson, University of Michigan (courtesy of Hugo Moreno (University of Chile).

Lanin - Photo John Davidson, University of Michigan (courtesy of Hugo Moreno (University of Chile).

Its structure can be divided into four different morphological units. The first is an ancient volcano; the three most recent formed the current cone from the Middle to Upper Pleistocene.

Lanin volcanic rocks have a composition that ranges from basalt to andesite and dacite. Effusive eruptive cycles are controlled by a short stay in a shallow magma chamber with a fast and equal evacuation of basalt and dacite. In recent eruptions, outbreaks of viscous magma sealed the main conduit, and induces a lateral drainage of the basalts, and a possible collapse of the upper part of the cone. The process of deterioration is however to be connected to erosion and ice cover of the cone.

Although no historical activity has been recorded since the year 560, the youthful appearance of emissions during the Holocene suggests that the volcano is still active and potentially dangerous. The main danger would be producing lahars in relation to the presence of summit glacier.

to the left, the volcano Quetrupillan - to the right, Lanin volcano - photo Ben Tubby

to the left, the volcano Quetrupillan - to the right, Lanin volcano - photo Ben Tubby

Sources :

- Global Volcanism Program - Lanin

- Sernageomin - Lanin

- Revista Geologica de Chile - Lanín volcano (39.5°S), Southern Andes: geology and morphostructural evolution – by  Luis E. Lara, José A. Naranjo,Hugo Moreno. - link

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Publié le par Bernard Duyck
Publié dans : #Excursions et voyages
Cavihue lake and volcano Copahue - photo Dangelin5

Cavihue lake and volcano Copahue - photo Dangelin5

The Copahue volcano is a composite cone (stratovolcano) andesitic elongated, located on the border of Chile and Argentina, the top covered with a large glacier.

The Copahue stood in Trapa-Trapa caldera, 8.5 km by 6.5, which is formed there between 400,000 to 600,000 years on the NW rim of the Cavihue caldera, large of 20 km by 15, dated Pleistocene.

The names Cavihue and Copahue come from Mapuche, meaning respectively "sacred place holiday or meeting", and "instead of sulfur."

 

Sulfur, snow and ice ... the Copahue - photo Thierry Dockx / Lave.be

Sulfur, snow and ice ... the Copahue - photo Thierry Dockx / Lave.be

Topographic map of Copahue-Cavihue complex - contours of the calderas, position of the active crater El Agrio

Topographic map of Copahue-Cavihue complex - contours of the calderas, position of the active crater El Agrio

 Copahue and his still smoking crater - photo-Alto Valle Valle Medio 10/05/2013

Copahue and his still smoking crater - photo-Alto Valle Valle Medio 10/05/2013

The area covered by the volcano is 57.5 km ², for an estimated 29 km ³ volume. It peaks at about 3,000 m.

Its summit crater the most eastern is part of a long line of 2 km of nine craters, oriented ENE-WSW. It contains a crater lake, acid and having an intense fumarolic activity, named El Agrio, or Del Agrio. El Agrio crater is the source of the historical activity: it is expressed through moderate explosive eruptions until the 18th century. The eruptions of the 20th century were ejected pyroclastic and liquid sulfur.

Hot and acids springs belong to the drainage of the crater lake, and contribute to the acidity of the waters of the Rio Agrio.

Copahue - the lake and the crater El Agrio in 2013 - photo Radio La Carretera

Copahue - the lake and the crater El Agrio in 2013 - photo Radio La Carretera

 Copahue - Las Maquinitas : a freedom Hydrotherapy area - photo Andarin2

Copahue - Las Maquinitas : a freedom Hydrotherapy area - photo Andarin2

Cavihue - The Salto del Agrio - 2012.12.27 - photo Secretaria Municipal de turismo Caviahue-Copahue

Cavihue - The Salto del Agrio - 2012.12.27 - photo Secretaria Municipal de turismo Caviahue-Copahue

Cavihue - volcanic organs on a sheet of pumice - photo Thierry Dockx / Lave.be

Cavihue - volcanic organs on a sheet of pumice - photo Thierry Dockx / Lave.be

The latest eruptive period is from December 2012 to June 2013 (in continuation).

After an increase of seismicity December 22, 2012, the first plumes are observed amount to 1000-1500 m above the crater, from a vent in the crater Del Agrio.

The 23.12, Strombolian activity increasing is responsible for the ejection of incandescent materials up to a height of 450 m, with a plume ash loaded. The eruption will continue, characterized by explosive activity, lava flows,and emission of plumes of steam and ash more or less important until June 2013.

Please note: the alert level of the volcano is still "amarillo / cambios en el comportamiento the actividad volcanica" (SERNAGEOMIN-OVDAS)

 

Copahue - eruptive plume 22.12.2012 - photo Antonio Huglich / AFP / NBC News

Copahue - eruptive plume 22.12.2012 - photo Antonio Huglich / AFP / NBC News

 Copahue - overhead view of the summit in December 2012 - doc Fasat Charlie SAF

Copahue - overhead view of the summit in December 2012 - doc Fasat Charlie SAF

Map of risk areas and evacuation 2013 - doc.Sernageomin

Map of risk areas and evacuation 2013 - doc.Sernageomin

Sources :

- Global Volcanism Program - Copahue

- Sernageomin-Ovdas - Copahue

- La Nacion  - Comienza en Chile la evacuación en los alrededores del volcán Copahue / mai 2013 - article et photos link

- CCAM - Parque Provincial Copahue Area protegida - link

- Lave.be - Copahue - link

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Publié le par Bernard Duyck
Publié dans : #Excursions et voyages

Located in Patagonia, on the border between Argentina and Chile, Batea Mahuida (not to be confused with Auca Mahuida) owes its name to its shape barrel reversed: Batea, meaning barrel, circular to oblong timber, without handles, used to wash in Mapuche -  Mahuida designating a mountain.

To the left, the situation of volcanic areas in the Argentine Province of Neuquen - right,  the Moquehue and Aluminé lakes, with north, Cerro Batea Mahuida - One click to see the cards. To the left, the situation of volcanic areas in the Argentine Province of Neuquen - right,  the Moquehue and Aluminé lakes, with north, Cerro Batea Mahuida - One click to see the cards.

To the left, the situation of volcanic areas in the Argentine Province of Neuquen - right, the Moquehue and Aluminé lakes, with north, Cerro Batea Mahuida - One click to see the cards.

Center, Cerro Batea Mahuida - down, the northern boundaries of lakes Moquehue and Aluminé - Doc. Atlas Neuquen

Center, Cerro Batea Mahuida - down, the northern boundaries of lakes Moquehue and Aluminé - Doc. Atlas Neuquen

The crater of the volcano Batea Mahuida, with a diameter of 5,000 meters, is occupied by a crystalline lake, which freezes in winter.

Dating of samples from the Cerro Batea Mahuida north gives a range between 5.2 and 4.9 Ma, a pre-glacial volcanism.

The last eruption of Batea Mahuida produced a lava flow forming a peninsula in the Aluminé lake, on which stood Villa Pehuenia (see map above). Volcanic sand beaches form along the lakes.

 Crater and Lake Batea Mahuida - photo Terras Patagonias

Crater and Lake Batea Mahuida - photo Terras Patagonias

Batea Mahuida: its name comes from its shape inverted barrels - photo Albasmalko

Batea Mahuida: its name comes from its shape inverted barrels - photo Albasmalko

The interest of the volcanic site became touristic : the crater and its lake are easily reachable by car. It became a place of excursions, as well as the summit, a wide panorama reveals near Moquehue and Aluminé lakes, and the border surrounding volcanoes: Villarica, Lanin, Callaqui, Lonquimay and Copahue. In winter, its gentle slopes promote learning to ski ... practiced throughout the region, La Angostura being a station set to the forefront by the ash fallout from the last eruption of Copahue.
 

From the summit of the volcano Batea Mahuida, a panorama over the lakes Moquehue and Aluminé - photo Jorge Spo.

From the summit of the volcano Batea Mahuida, a panorama over the lakes Moquehue and Aluminé - photo Jorge Spo.

Winter on the slopes of Batea Mahuida - photo WelcomArgentina

Winter on the slopes of Batea Mahuida - photo WelcomArgentina

Sources :

- Neuquen site

- Atlas Neuquen

- Geomorfología de la región de los lagos Moquehue y Aluminé: consideraciones acerca de las propuestas Calderas Meseta del Arco y Nacimientos del Aluminé (Neuquén) - Emilio F. González Díaz e Inés Di Tommaso

- Taringa – Los Volcanes in Argentina – link

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Publié le par Bernard Duyck
Publié dans : #Excursions et voyages

Located in the same volcanic province that Tromen, the Domuyo stratovolcano, also known as "El Techo de la Patagonia" (top of the Patagonia), is the highest point with 4.709 meters.

His name, of Mapuche origin, meaning "Who shakes and sounds" ... probably due to its geothermal activity.

 

Volcán Domuyo - photo Domingo Ferrayuolo

Volcán Domuyo - photo Domingo Ferrayuolo

The Domuyo volcanic complex :

At least 14 dacitic lava domes and other eruptive centers have been built within a large caldera 15 km. wide. Other eruptive centers are located outside caldera. The most important of them, the volcano Chanque-Mallin, located on the side ESE is truncated by a  caldera 4,000 meters wide, and contains a resurgent dome.

Brousse & Pesce (1982) reported that the volcanic rocks surrounding the Domuyo belong to two different magmatic series, from two separate magmas.

One of them, dated from the late Pliocene / early Pleistocene is calcoalcalin and gave andesites; the other, dated middle Pleistocene, is represented by both alkaline and shoshonitic series, which formed dacitic rocks and / or rhyolitic whose main expression is the Cerro Domo, located on the southern slopes of Domuyo . Age of Cerro Domo, calculated on a rhyolite flow is 0.72 Ma.

More recent volcanic products are dated between 550,000 and 110,000 years (JICA 1983), suggesting an activity Domuyo during the late Pleistocene.

 

Domuyo - photo Mountainduck

Domuyo - photo Mountainduck

In this photo of the ISS, the volcanic complex Domuyo area is covered with snow, located in the upper left corner. The elongate Laguna Valvarco, bottom right, sits near the western edge of the caldera Valvarco, dated of Pleistocene. (north is at the bottom right) - photo NASA Space Station image ISS008-E-7432, 2003

In this photo of the ISS, the volcanic complex Domuyo area is covered with snow, located in the upper left corner. The elongate Laguna Valvarco, bottom right, sits near the western edge of the caldera Valvarco, dated of Pleistocene. (north is at the bottom right) - photo NASA Space Station image ISS008-E-7432, 2003

The hydrothermal system of Domuyo :

Visit requires a local guide and access is by foot or horseback.

The site of Aguas Calientes (hot water) has waterfalls, fountains, pools of boiling water, colonized by thermophilic. The waters have healing properties for arthritis and skin problems.

Las Olletas sector is characterized by small geysers (> 1 m. High), and fumes of extreme high temperature steam.

Los Tachos has geysers emitting at 4 meters in height, and water up to 90 ° C.

 

The hydrothermal system Domuyo - photo site Neuquen

The hydrothermal system Domuyo - photo site Neuquen

Hydrothermal system Domuyo - warm waters are colored by thermophilic - photo alsurdemicalle.blogspot.com (other beautiful pictures on this blog)

Hydrothermal system Domuyo - warm waters are colored by thermophilic - photo alsurdemicalle.blogspot.com (other beautiful pictures on this blog)

Hydrothermal system Domuyo - Los Tachos site, where geysers reach 4 meters - photo website Neuquen

Hydrothermal system Domuyo - Los Tachos site, where geysers reach 4 meters - photo website Neuquen

This high temperature hydrothermal system does not match with magmatic intrusions dated to between 720,000 and 110,000 years. A study in 2013 analyzing the potential of the geothermal resource, suggesting the presence of a more recent volcanic activity, undocumented or a possible reactivation of Domuyo volcanic system, following a magmatic intrusion at shallow depth. (Chiodini and al.2013)

 

Sources :

- Global Volcanism Program - Domuyo

- Journal of Volcanology and Geothermal reseach - The Domuyo volcanic system: An enormous geothermal resource in Argentine Patagonia – by Giovanni Chiodini & al - link

- Termas del Domuyo o Aguas Calientes - link

- Blog Al sur de mi Calle / blogspot - link

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Publié le par Bernard Duyck
Publié dans : #Excursions et voyages

In search of  Gebirgsstein quarry, we borrowed various agricultural or quarry roads, to find ourselves in front of a disused quarry, does not correspond to our research, but photogenic and showing a wall where outcrops of basalt.




 

 "Unnamed" quarry in Scharzenberg - photo © Bernard Duyck 05.2014

"Unnamed" quarry in Scharzenberg - photo © Bernard Duyck 05.2014

Scharzenberg - walls of the "unnamed" quarry - photo © Bernard Duyck 05.2014

Scharzenberg - walls of the "unnamed" quarry - photo © Bernard Duyck 05.2014

Gebirgsstein quarry :

To get there directly, in the center of Oberbach, turn right towards Gefäll and find the parking lot after a rise of 4,700 meters. Take the road for about 400 meters and take the dirt road to the right towards the "Rhönklubhütte Oberbach" and the quarry.

The significance of this visit is to discover the eroded remnants of a cinder cone and basalt prisms.


 

 Geological map around Gebirgsstein - doc. Geotope Bayern - Ifu.bayer.de

Geological map around Gebirgsstein - doc. Geotope Bayern - Ifu.bayer.de

In the Gebirgsstein crater - photo © Bernard Duyck 05.2014

In the Gebirgsstein crater - photo © Bernard Duyck 05.2014

During a first phase of volcanism, there are some 20 million years, eruptions have formed a cone made of slag and bombs. A second phase is characterized by less explosive issue of basalt, which formed a lava lake inside the cone previously established. This lake of lava cooled and solidified by filling the crater.


 

 Site of Gebirgsstein Vulkankrater - Formation : 1. left, cinder cone - 2. right, formation of the lava lake - doc. Geotope Bayern Site of Gebirgsstein Vulkankrater - Formation : 1. left, cinder cone - 2. right, formation of the lava lake - doc. Geotope Bayern

Site of Gebirgsstein Vulkankrater - Formation : 1. left, cinder cone - 2. right, formation of the lava lake - doc. Geotope Bayern

Site of Gebirgsstein Vulkankrater -  3. left, before erosion - 4. right, today situation - doc. Geotope BayernSite of Gebirgsstein Vulkankrater -  3. left, before erosion - 4. right, today situation - doc. Geotope Bayern

Site of Gebirgsstein Vulkankrater - 3. left, before erosion - 4. right, today situation - doc. Geotope Bayern

Erosion has leveled the crater rim, and quarrying dug the center of the lava lake. Basalt there was exploited between 1937 and 1962, as railway ballast, making pavers and other construction materials for roads. The tuff or slag, forming the walls of the cone, less interesting, was not recovered.

The end of the operation left a wall of tuff, about 30 m high, on the banks of which fragments of basalt prism remain. Trees and shrubs were removed to make more readable the different layers. The fact that the heads of basaltic prisms are rotated in all directions toward the center of the quarry confirms the ancient topography.

 

 Crater Gebirgsstein - Tuff and basalt - photo © Bernard Duyck 05.2014

Crater Gebirgsstein - Tuff and basalt - photo © Bernard Duyck 05.2014

Crater Gebirgsstein - Detail on the wall of tuff (scoria and bombs) and basalt of the lava lake remains - Photo © Bernard Duyck 05.2014

Crater Gebirgsstein - Detail on the wall of tuff (scoria and bombs) and basalt of the lava lake remains - Photo © Bernard Duyck 05.2014

Crater Gebirgsstein - basalt columns - photo © Bernard Duyck 05.2014

Crater Gebirgsstein - basalt columns - photo © Bernard Duyck 05.2014

Crater Gebirgsstein - basalt columns - photo © Bernard Duyck 05.2014

Crater Gebirgsstein - basalt columns - photo © Bernard Duyck 05.2014

The DVG – Deutsche Vulkangeologische Gesellschaft - projecting to add the spot of Gebirgsstein in the Deutsche Vulkanstrasse. It is also planned to include the Gebirgsstein quarry in the Basaltweg Extratour - Extratour of "road basalt"

Sources :

- Geotope Bayern - Vulkan krater gebirgsstein  - link 

- Geocaching - Vulkankrater Gebirgsstein  - link

- Rhönklub Oberbach - link 

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Publié le par Bernard Duyck
Publié dans : #Excursions et voyages
 Gangolfsberg - a wall of basalt prism - photo © Bernard Duyck 05.2014

Gangolfsberg - a wall of basalt prism - photo © Bernard Duyck 05.2014

Located in a natural mixed forest (beech, oak and other hardwoods over 75 ha) northwest of Oberelsbach, Gangolfsberg, a basalt ridge placed on a underbody of limestone, houses a marvel: a wall of basalt prism.

Gangolfsberg - basalt staircase - photo © Bernard Duyck 05.2014

Gangolfsberg - basalt staircase - photo © Bernard Duyck 05.2014

You should run from the car park of the Schweinfurter Haus, a trail long of 2.5 km. to reach the foot of a staircase with steps of unequal height consisting of pieces of basalt columns. The forest trail is passable, but the end of the course, and access to the staircase wall, needs to be approached cautiously ... a misstep here can have significant consequences.

The cooling of basalt, issued during the second phase of volcanism of Rhön, left a wall of volcanic regular organs, medium diameter, placed almost horizontally (sign of basalt rising vertically).
 

Gangolfsberg - the basalt organs - photo © Bernard Duyck 05.2014

Gangolfsberg - the basalt organs - photo © Bernard Duyck 05.2014

Gangolfsberg - the basalt organs - photo © Bernard Duyck 05.2014

Gangolfsberg - the basalt organs - photo © Bernard Duyck 05.2014

Gangolfsberg - the basalt organs - photo © Bernard Duyck 05.2014

Gangolfsberg - the basalt organs - photo © Bernard Duyck 05.2014

Gangolfsberg - shrinkage cracks have left plolygones - Photo © Bernard Duyck 05.2014

Gangolfsberg - shrinkage cracks have left plolygones - Photo © Bernard Duyck 05.2014

Under the wall, a sea of ​​basalt blocks result, as in Schafstein but on a smaller scale, from the collapse of organs.
 

Gangolfsberg - Sea of blocks - photo © Bernard Duyck 05.2014

Gangolfsberg - Sea of blocks - photo © Bernard Duyck 05.2014

The walk continues, on the hillside, to get under a mass of basalt which houses the Teufelskeller, the cave of the devil.

The rock has a coarse prismation.

 

Gangolfsberg - the mass of basalt which houses the Teufelskeller - Photo © Bernard Duyck 05.2014

Gangolfsberg - the mass of basalt which houses the Teufelskeller - Photo © Bernard Duyck 05.2014

Gangolfsberg - Teufelskeller - coarse prismation - photo © Bernard Duyck 05.2014

Gangolfsberg - Teufelskeller - coarse prismation - photo © Bernard Duyck 05.2014

The legend tells that the Devil is hidden beneath the huge block of basalt at the entrance of a cave. He turned away from the path of unsuspecting farmers, loggers more or less drunk, to enlist in some plot. One day one of them confided to a priest to ease his conscience. The priest sprinkled holy water on the smelling sulfur cave ... the devil spring out the hole and reappeared never again. Since that day, the place is called Teufelskeller.
 

Gangolfsberg - the Teufelskeller, Devil's Cave ... a nice crack - Photo © Bernard Duyck 05.2014

Gangolfsberg - the Teufelskeller, Devil's Cave ... a nice crack - Photo © Bernard Duyck 05.2014

A chapel, now in ruins, is situated higher on Gangolfsberg; it is dedicated to Saint Gandolf. Died in the year 760, Gangolphus (Saint Gandolf of Avallon) is a military
Bourguignon venerated as a martyr. Its name comes from the Germanic Gangulf, meaning "wolf aggressive"
.

Sources :

Rhoentourist / Die besondere Tour – zu Prismenwand und Teufelskeller - link

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Publié le par Bernard Duyck
Publié dans : #Excursions et voyages

To the east of Wasserkuppe, located between the summit and the town of Ehrenberg we found - with difficulties - the site of Schafstein.

This high hill of 832 meters consists of basalt overlying the shelly limestone, covered by forest. As the region is classified as a forest reserve , no human intervention came disturb the growth, life and death of trees and bushes. In this natural area, two seas of basalt blocks completely bare form gray scars in the green ocean
.

 Aerial view of Schafstein - photo Wildchicken.net / geocaching

Aerial view of Schafstein - photo Wildchicken.net / geocaching

Schafstein - the top of the scree - Photo © Bernard Duyck 05.2014

Schafstein - the top of the scree - Photo © Bernard Duyck 05.2014

 Schafstein - a sea of basalt blocks - photo © Bernard Duyck 05.2014

Schafstein - a sea of basalt blocks - photo © Bernard Duyck 05.2014

These huge boulders are the remnants of the volcanic activity that marked Rhön Tertiary. Located in an area of ​​permafrost, between vast glaciers covering northern Europe and the Alps, the Massif of Rhön suffered extreme weather conditions ... the organs of alkali basalts from the top of Schafstein crashed and overturned forming a Sea of blocks covering the flanks at an elevation between 700 and 800 meters. These blocks form a layer 20-30 m thick, the interstices of which are filled with small fragments of basalt, humus and earth, and surmounted by a layer of 5 to 10 m thick formed only by blocks.

This sea of blocks covers not only his own basalt body, but also areas underbody made differently ... on approximately 3.6 hectares; it forms the greatest accumulation of blocks of the Rhön.

Schafstein -  schematic cross cup NW-SE - in the box to the right, schema of transformation of basaltic columns of the top into block - doc. in Die Hessische Rhön- Geotope im land der offenen fermen

Schafstein - schematic cross cup NW-SE - in the box to the right, schema of transformation of basaltic columns of the top into block - doc. in Die Hessische Rhön- Geotope im land der offenen fermen

Schafstein - Explanatory sign at the top - Photo © Bernard Duyck 05.2014

Schafstein - Explanatory sign at the top - Photo © Bernard Duyck 05.2014

This particular biotope allows only the installation of rare mosses or lichens. Specific climatic conditions are recorded : in summer, areas in front of the sea of ​​blocks can freeze, while in winter, there is the presence of hot air at the top. Measurements made by scientists suggest that ice can still keep today deep beneath the blocks.

Access: on the B284 between Gersfeld and Wüstensachen, turn left towards Reulbach, and find a small parking after 300 meters. From here a steep forest trail leads in zigzag to the top of  Schafstein, where we have a view of the sea of ​​basalt blocks.

GPS: 35 ° 69'250 - 96'730 55 °.


 

Schafstein - High of the scree - pieces of eroded basalt columns - photo © Bernard Duyck 05.2014

Schafstein - High of the scree - pieces of eroded basalt columns - photo © Bernard Duyck 05.2014

Sources :

- Die Hessische Rhön- Geotope im land der offenen fermen - Umwelt und Geologie - Hlug.de

- DVG – Rhön exkursion 2006 - link

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Publié le par Bernard Duyck
Publié dans : #Excursions et voyages

The relief o the Wasserkuppe reveals in a cross section a coverage of basalt and tuff overlying layers of sand, shell limestone and sandstone colored.



 

Schematic cross sectionof  Wasserkuppe - dark green : basalt and tuff - Light Green: vent at Fliegerdenkmal - Doc. Die in Hessische Rhön / Geotope im offenen land of fermentation / Hlug.de

Schematic cross sectionof Wasserkuppe - dark green : basalt and tuff - Light Green: vent at Fliegerdenkmal - Doc. Die in Hessische Rhön / Geotope im offenen land of fermentation / Hlug.de

Alkaline basalts at the top of Abtsrodaer Kuppe / Wasserkuppe - Photo Camp erna.de

Alkaline basalts at the top of Abtsrodaer Kuppe / Wasserkuppe - Photo Camp erna.de

The vent of  Fliegerdenkmal has a structure maar type.

Instead of being filled by a lake as are the maars in the Eifel, it was filled by lava flows, partly eroded, as the structure bordering originally.


 

Geological situation of Fliegerdenkmal / Wasserkuppe - the big black line marks the current level - Doc. Die in Hessische Rhön / Geotope im offenen land of fermentation / Hlug.de

Geological situation of Fliegerdenkmal / Wasserkuppe - the big black line marks the current level - Doc. Die in Hessische Rhön / Geotope im offenen land of fermentation / Hlug.de

One kilometer southwest of Wasserkuppe, the Pferdskopf leaves no guess its origin ... a deposition analysis revealed a highly explosive past: an explosive eruption produced a ring that has been eroded. From the trachyte dome extruded at the end of eruption is only one small part of which is the current top of Pferdskopf (875 m). Remains of a lava flow in blocks are also visible.

GPS: 50 ° 29'29 "N / 9 ° 55'16" E


The massive volcanic Rhön - 2 - Wasserkuppe.


The Pferdskopf - photo Geocaching


View from the top of Pferdskopf - photo VirtualTourist
Pferdskopf - trachyte - photo Kreuzschnabel

Pferdskopf - trachyte - photo Kreuzschnabel

Rhön volcanic massif - the Wasserkuppe.
The Pferdskopf - photo Geocaching

The Pferdskopf - photo Geocaching

View from the top of Pferdskopf - photo VirtualTourist

View from the top of Pferdskopf - photo VirtualTourist

Pferdskopf - trachyte - photo Kreuzschnabel

Pferdskopf - trachyte - photo Kreuzschnabel

Sources :

- Die Hessische Rhön- Geotope im land der offenen fermen - Umwelt und Geologie - Hlug.de

- Rhön-blog von Stefan Etzel - Géologie & vulkanismus der Rhön

- Rhön tourism portal

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Publié le par Bernard Duyck
Publié dans : #Excursions et voyages
Rhön / Wasserkuppe - the Pferdskopf - photo Rhönbilder

Rhön / Wasserkuppe - the Pferdskopf - photo Rhönbilder

Rhön form a territory shared between the Bundensländers Hesse, Thuringia and Bavaria,  east of the massif Vogelsberg. It covers approximately 3.500km ², with an oval shape 90 km. N-S, 50 km E-O.

This moderately hilly and heavily eroded massif has however a typical volcanic appearance. Its name comes from the Celtic Raino, meaning hilly. It rises to 950 meters at the top of Wasserkuppe (Hesse), the highest point in Bavaria is located in Kreuzberg, 927 meters.

The area is renowned for its thermal baths, as indicated by the names of several cities: Bad Kissingen, Bad Brückenau, Bad Neustadt, its winter sports and competitions of gliding.

 

Tertiary volcanism in Germany - doc in Die Hessische Rhön-im Land der Geotope offenen fermentation - Umwelt und Geologie

Tertiary volcanism in Germany - doc in Die Hessische Rhön-im Land der Geotope offenen fermentation - Umwelt und Geologie

At the Fliergerschule Wasserkuppe, towing gliders succeed at a high rate - Photo © Bernard Duyck 05.2014

At the Fliergerschule Wasserkuppe, towing gliders succeed at a high rate - Photo © Bernard Duyck 05.2014

Rhön / Wasserkuppe - semi-open landscape of the Hohe Rhön after Fliergerschule's take off - photo © Bernard Duyck 05.2014

Rhön / Wasserkuppe - semi-open landscape of the Hohe Rhön after Fliergerschule's take off - photo © Bernard Duyck 05.2014

Volcanism and geology are comparable to outline those describing the Vogelsberg, with a Tertiary activity mainly between 22 and 18 Ma. Unlike Vogelsberg where volcanism was mainly effusive, most gas-rich magmas produced Rhön more explosive volcanism, whose impact products have been eroded and leave flush basalt and phonolite only in places, especially in the south.

Phonolite, gray to greenish, consists of feldspar, feldspathoid and scarce glass paste. She debit in slab; as its name, derived from the Greek implies, it transmits well the sounds.
Basalts are declined in all varieties: basanite, népéhlinite, tephrite, trachyte, andesite, trachyandesite, alkali basalt.

Comparative scheme of the more effusive volcanic activity in Vogelsberg, and Rhön most explosive - Rhön was curved from Pliocene to Pleistocene in dome, which has contributed to the erosion of volcanic rocks giving the current reliefs - doc Geology & vulkanismus der Rhön / Rhön-blog Stefan von Etzel

Comparative scheme of the more effusive volcanic activity in Vogelsberg, and Rhön most explosive - Rhön was curved from Pliocene to Pleistocene in dome, which has contributed to the erosion of volcanic rocks giving the current reliefs - doc Geology & vulkanismus der Rhön / Rhön-blog Stefan von Etzel

Two major phases of activity can be distinguished:

An early phase characterized by relatively rich magmas in SiO2, mainly in the west and northwest of the Rhön, with production of tephrite, trachyte and phonolite. It is accompanied by pyroclastic flows and eruptions ignimbritic.

A second, more recent, phase, characterized by magmas with a lower proportion of SiO2 produced alkali basalts, basanite and nephelinite. The most effusive volcanism produced lava flows from which the plateau of the Hohe Rhön is built.

Exposed volcanic structures are numerous and I discuss here a few spots visited: Wasserkuppe Schafstein, Gangolfsberg and Gebirgsstein
.
 

Rhön - the top of Wasserkuppe with the radar dome - Photo © Bernard Duyck 05.2014

Rhön - the top of Wasserkuppe with the radar dome - Photo © Bernard Duyck 05.2014

Fliegerdenkmal, a memorial to fallen airmen during World War I, was built in 1923.

The base is made of basalt columns welded by concrete.; it is surmounted by an eagle sculpted by Augustus Gaul, initially set at the entrance to the garden of the villa of a Hamburg shipowner, and sold by his widow. Become part of Wasserkuppe, it serves as a benchmark.
 

Fliegerdenkmal das auf der Wasserkuppe - photo Rainer Lippert

Fliegerdenkmal das auf der Wasserkuppe - photo Rainer Lippert

Sources :

- Die Hessische Rhön- Geotope im land der offenen fermen - Umwelt und Geologie - Hlug.de

- Rhön-blog von Stefan Etzel - Géologie & vulkanismus der Rhön

-Rhön tourism portal

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