Ol Doinyo Lengai – The Mountain of God

Picture from Wikipedia. The 1966 eruption.

Ol Doinyo Lengai in Tanzania, approximately 20miles (30km) to the south of Lake Natron, is one of the most peculiar volcanoes.

Whereas all other volcanoes eject silicate based lava at a temperature of 1000°c plus, this gorgeous monster, at 2980metres (9780ft), ejects molten natrocarbonate at around 5-600°C. and is the only known active example of the type.

Picture taken from Volcanodiscovery. Erupting hornito at night.

Natrocarbonate is a mixure of sodium and potassium carbonates along with a minor quantity of silicate minerals and this type of lava and ejecta so produced are called Carbonatites. The silicate minerals are silica-undersaturated suites, as feldspathoids and nepheline along with olivine and pyroxenes ie minerals with ultra-basic affinities.

When newly erupted, these rocks are dark grey to black in colour and quickly weather to a pale grey to white. Unlike silicate high temperature lavas that are incandescent in daylight, the relatively low carbonatite temperatures give a lava that is black, glowing dull red at night.

Ol Doinyo is one of the volcanoes along the line of the African Rift Valley system. This rift system extends from the Mozambique coast opposite Madagascar in the south, northwards through Africa into the Red Sea by the Horn of Africa and extends past Sinai into the Dead Sea area. This rift system is the present day activity associated with the contunued break-up of the Gondwanaland super-continent and continental drift.

Picture by Nasa

An excellent suite of photos of Ol Doinyo volcano and landforms are found here:

http://www.photovolcanica.com/VolcanoInfo/Oldoinyo%20Lengai/Oldoinyo%20Lengai.html

Carbonatite intrusives are widespread, but very uncommon and include dykes, sills, pipes and veins.

Photograph taken by Eurico Zimbres. Jacupiranga, Brazil intrusive carbonatite: Calcite, Magnetite and Olivine.

Although rare, the presence of free carbon (rather than carbonates) is not unusual in igneous rocks, as evidenced by Diamonds in widespread, but rare, Kimberlite pipe intrusions, graphite in doleritic intrusions – eg the intrusion in Borrowdale (English Lake District, the original graphite source for the Cumberland Pencil Co. in Keswick) and in extra-terrestrial carbonaceous chondrite meteorites.

Diamond in Blue Ground Kimberlite.

Picture taken from http://www.eoearth.org/article/Diamond

Alan C

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190 thoughts on “Ol Doinyo Lengai – The Mountain of God

    • Probably magma moving.
      It is normal actions in a volcano preparing for a possible eruption. And it would most likely be a for Santorini normal eruption. And with normal I mean a VEI-2 that goes on for about a year.
      There will absolutly not be a new caldera forming event since the volcanic edifice is not developed enough yet. Also the magma chamber need to be rebuilt more after the last collaps.
      So no doom and gloom, there MIGHT be a fully normal small eruption there anytime from a month away to the next decade.

  1. A poetic license…

    Tera, the end of the Minoans

    Charles Pellegrino, author of The Mystery of Atlantis.

    110 km north of Crete is located on the island now known as Tera (fear) and that its inhabitants 4000 years ago called Kalliste (the very beautiful). A place came the splendor of one of the most impressive people of antiquity, Minoan, and today, thanks to people like Spyridon Marinatos, Christos Doumas and Charles Pellegrino, rescued from oblivion and give back the sun once lost.

    We speak of a civilization, the Minoan, which was the envy of kings and viziers of Egypt. They had the first fleet in the world and its authority in the Mediterranean stretching from the east to Tirrenia (Italy). Even hot water was available divided by the buildings of up to 4 stories high with a modern plumbing system.

    But in the late seventeenth century B.C. a terrible volcanic explosion caused more than 80 cubic kilometers of rock Teran rose into the air as vapor and instead be formed as a result of the invasion of the Mediterranean in the hole, a stunning waterfall more than a mile deep. A beautiful yet gruesome scene that was the beginning of the end for the Minoans and no doubt had a great response from the neighboring villages. So much so that a millennium later Plato wrote about what happened and called the Minoans, Atlantis?

    The Minoan empire

    We go back to the fourth millennium before a child, who was named Jesus, born in Bethlehem and changed the course of history. On the island of Crete began to emerge the Minoan civilization. No one knows for sure where it came from this town, but what is certain is that around 3500 BC they lived and the Aegean island (so far not been found pieces of pottery tools or before this date).

    Its technological development was brutal, comparable only to that which occurred in Egypt between the third and fourth dynasties when he went from simple mastabas build a funeral to erect the colossal pyramids. Around 2100 BCE Minoan Empire, or rather its navy, dominated much of the Mediterranean but it is not surprising since they were practically alone. And is that the Egyptians never became famous for possessing a powerful fleet.

    Map of the island of Thera, or rather we might say that what remains of it.

    It was a peaceful people, example of this is that left no sign of violence in their art. Its cities were fortified and not known to its setting, no evidence to suggest that suffered some kind of invasion or attack by other people. But anyway, is not too surprised because with such a fleet was hard enough that anyone could even approach them.

    One of its main sources of income was trade. Thus, when the twenty-second century BCE his ships reached the shores of Egypt and watched the magnificence of its monuments certainly opened their eyes wide and could not sleep for some nights thinking about all the business they could do. In fact there are many Egyptian records on Crete (or Keftiu as they called it) that have survived to this day. The inhabitants of the Nile always regarded the Minoans as a civilized and educated people and trade between the two was very important since its inception.

    The situation was idyllic until something happened. Suddenly, during the eighteenth Egyptian dynasty and the period of the reigns of Hatshepsut, Thutmose III and Amenhotep II, some representations of the Minoans in the tombs and temples were retouched by giving it a more Hellenistic. And it is in the tomb of Amenhotep II (also known as Amenhotep II) where the hieroglyphs refer Keftiu last time an image in which objects are strangers Minoans.

    Definitely something had changed. The Egyptians had to stop to receive visits from his friends the Minoans and instead began to reach people with other garments (Continental Greeks Minoans occupied territories after sunset). They noted that the power had changed hands and then touch up certain images. The Egyptian people has always been a very diplomatic and flattering people. But what led to this sudden change?. Always remember the words of Ipuwer when he says: “Today no one navigates to Byblos. What do we do about the cedar for our mummies? The priests are buried with their products, the nobles are embalmed with their corresponding oils up as far as Keftiu. But do not go. “.. and do not come, because something has happen …

    The explosion of Thera

    And indeed, something had happened. It’s time to head back we look to Tera, this small island north of Crete, and for this we will do the hand of renowned paleontologist Charles Pellegrino archaeological and data provided by Marinatos and Doumas, responsible for the excavations at Thera . In the center of the island a huge volcano 1600 meters did not stop some brave dwell there. They maintained close contact with the neighboring island of Crete and was wonderfully modern technology. But all this I leave for later, now let’s focus on Tera and its volcano.

    Effects of earthquakes on a ladder.

    It’s mid seventeenth century B.C. The volcano, calm and collected for many years decides to leave his lethargy causing terror among the inhabitants of Thera. A series of earthquakes of a certain size (even found a ladder cracked by earthquakes) forced people to flee to neighboring islands. As the excavations have allowed the march to find out was a controlled manner. No remains have been found in cattle, jewelry or valuables (except in a small area west of the island), suggesting that the Tyrants were given time to collect their belongings before leaving Tera. The ash given off by the volcano caused the formation of a thin layer of it in town but little else happened.

    Time passed, perhaps only a few months perhaps years, and the volcano returned to a resting state, enough for some to return to their homes (they have discovered repairs to certain parts of the city). But then came the fall of 1628 B.C. (An estimate of Pellegrino will explain at another time) and the volcano awoke again, this time with much more violence. The few people who decided to back out again and the volcano began to emanate so much ash that certain places were buried more than 60 feet from her, and this is what has allowed the city we found today almost as and as they left the Tyrants over 3500 years ago.

    But the worst was yet to come. In an instant the huge volcano erupted in a violent. The center of the island where it was, disappeared in a split second and in its place, where before there was a mountain of 1600 meters was now a huge hole of 125 cubic kilometers with a depth of more than 1.5 km where the Mediterranean water began to enter forming an immense waterfall.

    Excavations of the lost city, Tera

    To give you an idea, the force of the explosion of the volcano of Thera is comparable to that released by 150 hydrogen bombs exploding at once. Was 6 times more powerful than the explosion of Krakatoa in 1883 and remember that it was heard over 3200 km away and was strong enough to crack walls and windows to rattle more than 160 km.

    In Tera, after disappearing the volcano, immediately formed a huge cloud that covered the sky. It started to rain fire on the neighboring island of Melos, Naxos and Crete. While the cloud formed by a curtain of ash and steam that came and went at their edges, moving off an intense heat. Within an hour the shadow of death reached 300 km from sinking ships was on its way. He came to Turkey and Egypt turning day into night but the temperature and strength had diminished greatly. The shadow continued eastward over Syria and Iran and was dividing and smoothing while touring Asia. It is noteworthy that they have found remains of the ash layer Tehran in various parts of Egypt.

    And after the fire … water

    While the rain of fire and the ash cloud and intense heat were also important is certainly not enough to affect so catastrophic to the island of Crete, Minoan true center of power. Another far more devastating force had to be the culprit that the Minoans lost their hegemony in the Mediterranean and see helpless against the invasion of foreign peoples, in this case of the Greek mainland.

    The huge tsunami hit the northern island of Crete and caused chaos among the population.

    To see all this going to take us back to the summer of 1932 AD The archaeologist Spyridon Marinatos was working on the northern coast of Crete (the northern coast, facing Tera) at a place called Amnisos. There, in excavations, watched a few stone walls had collapsed in a somewhat strange. In one of the houses lacked the entire top of a vertical block and what was his surprise when the rest of the block was found more than 100 meters, fitted perfectly and weighed half a ton!.

    Be silly, and Marinatos was not, to think that any of the later invaders could devote to break and move a half ton block over 100 feet without any apparent cause. No, this block was swept away by the force of a great stream of water, the tsunami.

    Subsequent research has provided evidence about the tsunami that was triggered by the explosion of Thera. For example, we know that in the Gulf of Hermes (Turkey), more than 200 km east of Thera, the wave came with such force that through the holographic field, acting as a wedge, it rose to 250 meters and penetrated more than 50 km inland. Something similar happened in the west in the Gulf of Nauplis (Greece).

    Hard to imagine the devastating effects that occurred in the northern coast of Crete in the tsunami. The city of Knossos (north of the island) had to succumb to the force of water and most of the fleet (if not all) docked at the port of Heraklion should be reduced to splinters. Perhaps only a few boats that were at that time were saved at sea teran wave since the real destructive power of this lies in breaking against the shore, the sea inside its effects are greatly reduced. Although we must remember that many of these boats also suffered a cloud of ash and heat.

    The Minoan demise

    Lady Tiryns, Minoan art

    Within hours the important Cretan fleet was reduced considerably and what is worse, without the necessary infrastructure to rebuild quickly. With an island, Crete, virtually devastated the port and shipyards with little boats destroyed and the situation was very delicate. They were helpless and continental Greeks took advantage of it invading the island. The Minoans came to control the Mediterranean to be subjugated to Hellenistic power in just 50 years.

    No one knows exactly what happened to all the survivors, especially with teachers and craftspeople. Perhaps some were selected by the Greeks and the most valuable to Greece or Italy. It is believed that another party sailed south towards Tunisia and settled in the Atlas mountains. Others went south to Egypt, where the most talented apparently became a set of Egyptian nobles. And maybe the rest traveled to the east, bringing its unique architecture to the country called Philistia or Palestine.

    Earth 2000 years watched the journey of a peaceful, educated and intelligent. 2000 years of prosperity and technological advances. 2000 years of dreams interrupted by a pitiless nature and that even today reminds us that we can never master it.

    I would not write to finish without a quote from Charles Pellegrino .. an appointment for reflection on how the world might be today without the events of autumn 1628 BC …

    If Tera had not exploded, it could have come to television in the time of Christ. ”

    Author: José Hurtado

    http://historia-antigua.com/atlantida/tera-fin-de-los-minoicos/

      • Not an expert but if tEtruscan and Minoan art were contemporary, they would influence eachother as both are on trade routes.

        • No.. its still sound.

          It is very possible that the Villanova culture had direct contact with the culture that became known as “Minoan” (that’s not what they called themselves, it’s a later construct).

          As such, with an outlying colony (again, no evidence, just an idea), refugees from the Minoan culture would have fled to where ever was hospitable… be it Philistia, Egypt, or up along the future Italian coast.

    • Carlos – that was a super read; thanks very much for posting it.

      I watched a TV programme recently talking about how the designs on Minoan pottery had changed suddenly to depict many strange sea-creatures supporting the hypothesis that a tsunami had led to widespread destruction on Crete and incorporation into their culture.

  2. Avcan FB

    Eruptive surge in la Restinga. No, it is not now effusions of balls. It’s a surf spot, produced by the volcano, which must have earned meters in height and is approaching the surface lentísimamente. (JR)

  3. Avcan FB

    I can assure them that the phenomenon described as storm surge is real, we have seen that in the days of increased activity and lately is very common and it is real waves emerging from the center of the warhead on the submarine volcano sideways. What should happen now, is that to register output of steaming balls at the moment and match a strong wind to flush with water of more than 25 knots, shape in the ridges eddies white with foam, we see just in that area. We have seen waves of nearly two meters in some moments, what happens is that the images of the webcams are taken from positions with little azimuth and are almost flat and very distant. I think JR is very successful in his commentary.

    • It… looses something in translation.

      “Storm surge” is probably not an accurate description of something. A storm surge is caused by water pilling up in the NE quadrant of a tropical storm (northern hemisphere). In part, it is caused by wind rotation, and also by the sheer mass of the storm… the lift being in part from the low pressure.

      I’m pretty sure that is not what they are talking about.

  4. Avcan FB

    the “surge” is the result of convection currents, climbing the hot water from the vent, chinlock to the trade winds in the Rubberised, blowing SW. This shock causes small breaks or “surge”.
    about an hour ago · Like · 3

    • I don’t think it’s a quake anywhere.

      The spectral peak is around 14 Hz and there is almost not low end component at all. Could be that something fell nearby.

  5. Apologies if this has already been posted. Rapid Response picture of the stain published on ER (http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/)

    http://bbnet.gein.noa.gr/NOA_HL/

    As ER states the stain is intense. The stain is not however being carried far by the current (at least at the time of the picture), which is interesting given the wave patterns on the webcams shown earlier today. There may be two vents – but this is not clear.

  6. @KarenZ and Tor Hogne (from the previous page)

    About: The Mogi Model.

    Aside from the “geophys” package for the programing language “R”, which has a pretty understandable (okay, somewhat understandable) explanation, I found a power point presentation/student guide from carleton.edu that allowed me to build a spreadsheet that I can run various scenarios through.

    It is located here: http://serc.carleton.edu/sp/ssac/volcanology/examples/deformation.html

      • I can get the la Restinga Village webcam; but I guess that was not the cam you were referring to as the harbour wall is there. But there do seem to be a fair number of pyroclasts (seen as small white flashes).

      • Got the eruption site webcam now and I get the impression of a lot of activity (very dark blobs which could be stones and separate white flickers) – but the camera is too fuzzy to be sure what I am looking at. Certainly nothing to take a screen dump of at the moment but worth keeping an eye on if tyou have the time.

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