All this, and more, can be found sooner here, in our online version. Keep up to date with activities, news and events and find out how Fellows can get involved. The Geological Society of London is the UK's national society for geoscience, providing support to over 12, members in the UK and overseas.
Founded in , we are the oldest geological society in the world. The rifting on the EAR began in the Miocene around million years ago and continues today. It is thought that as the Nubian and Somalian plates continue to drift further away from each other, the lithosphere between them will grow thinner and drop below sea level.
New oceanic lithosphere may form along the centre of the rift, producing a narrow ocean basin with its own mid ocean ridge. This causes the brittle lithosphere to stretch and fracture and is accompanied by large outpourings of lava called flood basalts.
This rifting seen at the EAR is comparable to the opening up of the North Atlantic Ocean million years ago which resulted in huge flows of lava and associated volcanism across the Inner Hebrides. It is sometimes included as one of the Seven Summits, which are the highest mountain peaks on each continent. Puncak Jaya Carstensz Pyramid , a mountain in Indonesia, is considered the tallest mountain in Oceania.
Join our community of educators and receive the latest information on National Geographic's resources for you and your students. Skip to content. Twitter Facebook Pinterest Google Classroom. Encyclopedic Entry Vocabulary. Also known as a composite volcano. Media Credits The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.
Media If a media asset is downloadable, a download button appears in the corner of the media viewer. Text Text on this page is printable and can be used according to our Terms of Service. Interactives Any interactives on this page can only be played while you are visiting our website. Related Resources. Landforms and Landscapes. In addition, stratovolcanoes have a higher likelihood of landslides, avalanches, and mudflows, since they are generally comprised of ash and lava which can become easily dislodged by rain and earthquakes.
Sometimes, an entire side of a stratovolcano can collapse and cause massive destruction. Examples of other stratovolcanoes besides Mount Kilimanjaro include Mount St.
On Mount Kilimanjaro, Kibo is believed to have five main lava formations which created the towering mountain that stands today. The volcanic phases of Mount Kilimanjaro started about 2. About 1 million years ago, the volcanic activity migrated east to Mawenzi and Kibo. The oldest dated rocks on Kibo come from what is known as the Lava Tower group, a lava formation that resulted in a sheet of rock at m high. These rocks are mostly alkaline phonotephrites and tephriphonolites. The rocks found here date back to thousand years ago.
Two other lava formations represent the main period of volcanic activity on Kibo. These formations are the Rhomb Porphyry group and the Lent group. The Rhomb Porphyry group occurred between to thousand years ago and is characterized by tephriphonolite and phonolite lava, while the Lent group occurred between to thousand years ago and has aphyric phonolite lava with obsidian.
The Caldera Rim group lava phase took place between to thousand years ago and consists mostly of igneous rock such as quartz and feldspar. The final lava formation of Kibo is known as the Inner Crater group, which is comprised almost exclusively of aphyric phonolites, although there are occasional rare aegirine phenocrysts.
The first recorded climb of Mount Kilimanjaro was by Hans Meyer and Ludwig Purtscheller in , and ever since it has been a popular hiking destination for both locals and travelers alike. Mount Kilimanjaro is an appealing hike for many due to the fact it does not require any specialized gear or extensive amounts of experience in order to reach the summit. There are a number of routes available to reach the summit, meaning that you can select a path depending on your abilities and preferences.
To see a list of the paths and descriptions of each, there is a great guide located here. If you are hesitating about the idea of climbing Mount Kilimanjaro, you may be interested to know that one South African, Bernard Goosen, was able to reach the summit of Kibo while in a wheelchair. Goosen used a modified wheelchair but was still able to scale the mountain with barely any assistance.
Each year, about 25, people attempt to scale Mount Kilimanjaro, with about two-thirds of those trekkers successfully reaching the summit.
The most common reason hikers do not reach the peak is due to altitude sickness. On Kibo, the tallest peak of Kilimanjaro, there have been thick glaciers of ice more than meters thick. However, in recent decades, the icy cap of Mount Kilimanjaro has been shrinking. Due to global warming, the snows of Kilimanjaro are evaporating directly into gas. This is devastating to some local farmers, who count on the seasonal meltwater of the icy rivers to provide much-needed water for livestock and farming.
Kibo is also the one peak that really does look like a volcanic crater; indeed, there are not one but three concentric craters on Kibo. Within the inner Reusch Crater 1. The outer, Kibo Crater 1. There are gaps in the summit where the walls have been breached by lava flows; the most dramatic of these is the Western Breach see photo. Perhaps the most important feature of Kibo, however, is that its slopes are gentle. This feature means, of course, that trekkers as well as mountaineers are able to reach the summit.
Mawenzi is the second highest peak on Kilimanjaro. This is merely because its western side also happens to be its highest, and hides everything behind it.
Its sides too steep to hold glaciers, there is no permanent snow on Mawenzi, and the gradients are enough to dissuade all but the bravest and most technically accomplished climbers.
There are also two deep gorges, the Great Barranco and the Lesser Barranco , scarring its north-eastern face. The oldest and smallest summit on Kilimanjaro is known as the Shira Ridge, and lies on the western edge of the mountain.
This is the least impressive peak, being nothing more than a heavily eroded ridge, m tall at its highest point, Johnsell Point. This ridge is, in fact, merely the western and southern rims of the crater formed by the original volcanic eruption. Trekkers strolling across the Saddle of Kilimanjaro.
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