Dallol, Danakil Depression, Ethiopia

Dallol is a volcanic explosion crater, or maar, in the Danakil Depression in northeast Ethiopia. It is located approximately 50 meters below sea level and has been formed by the intrusion of magma underneath Miocene evaporite deposits in the Afar Triangle of the East African Rift system, followed by several eruptions. Subsequent hydrothermal activity has led to the formation of hot springs and brines in a landscape with striking red, yellow and green colors related to the presence of iron oxide, sulfur and microbes. Dallol is known as one of the hottest places on Earth, with average temperatures of 35 degrees Celsius throughout the year.


Information source: Smithsonian Institution National Museum of National History Global Volcanism Program

Image: Salt and sulfur deposits near the hot springs of Dallol in the Danakil Depression, Ethiopia. Credit: Ji-Elle, Wikimedia Commons.

Fossil remains of new hominin species Homo naledi discovered in South Africa

Paleontologists have discovered the fossil remains of a new hominin species in a dark cave system in South Africa and published their preliminary results in eLife. The new species has been named Homo naledi, which means “star man” in Sotho, after the Dinaledi Chamber of the Rising Star cave system where it was found. Homo naledi is characterized by a small body and brain size, but it also features several adaptations of the hands and feet that are relatively similar to modern humans. The age of Homo naledi and its position in the phylogenetic tree of hominins is still unresolved, but it is believed to be one of the more primitive ancestors of mankind. So far, an unprecedented 1550 remains of at least 15 individuals of Homo naledi have been unearthed, representing the largest fossil assemblage of a single hominin species ever found in Africa. Given the richness and exceptional preservation state of these fossils, it is speculated that Homo naledi may have been capable of performing primitive burial rites.


Journal references:

Berger, L. R., Hawks, J., de Ruiter, D. J., Churchill, S. E., Schmid, P., Delezene, L. K., … & Zipfel, B. (2015). Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa. eLife4, e09560.

Dirks, P. H., Berger, L. R., Roberts, E. M., Kramers, J. D., Hawks, J., Randolph-Quinney, P. S., … & Tucker, S. (2015). Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi Chamber, South Africa. eLife4, e09561.

Image: Fossil remains of Homo naledi, the new hominin species discovered in South Africa. Source: Lee Berger, Wikimedia Commons.

Mount Nyiragongo, Virunga Mountains, Democratic Republic of the Congo

Mount Nyiragongo is an active stratovolcano in the Virunga Mountains in the Democratic Republic of the Congo. The volcano has an elevation of 3470 meters and its main crater usually contains a large lava lake. Volcanism at Mount Nyiragongo is related to the presence of the Albertine Rift, the western branch of the East African Rift system, where the African tectonic plate is splitting into two.


Information source: Virunga National Park Service

Image: Lava lake in the crater of Mount Nyiragongo in the Virunga Mountains, Democratic Republic of the Congo. Credit: Caj Tjeenk Willink, Wikimedia Commons.

Cheetah

Cheetahs (Acinonyx jubatus) are the fastest land mammals on Earth and live in the open grasslands of most parts of sub-Saharan Africa and Iran. They are characterized by a golden fur covered with small, black spots and prey on smaller herbivores such as antelopes and hares. Because of their light and agile build, cheetahs are able to accelerate from 0 km/h to 100 km/h in 3 seconds and run at incredible speeds of up to 120 km/h over short distances. Chasing prey costs massive amounts of energy and requires so much of their bodies that cheetahs even risk brain damage at the end of a chase. As a result, they have to rest and recover in the shadow after each endeavor, during which they are mostly unable to defend themselves or their prey against other predators. Male cheetahs are often social and may live in groups to establish a territory and even hunt together, but female cheetahs are mostly solitary and hunt alone. Females raise their cubs on their own and leave them behind once the young become independent of their mother. Subsequently, female cubs leave the litter as well, but male cubs may remain together for the rest of their lives.


Information sources: National Geographic, WWF

Image: Cheetah in the savanna grasslands of Serengeti National Park, Tanzania. Credit: Tobias, Wikimedia Commons.

African Lion

African lions (Panthera leo) are apex predators that live in the barren savanna grasslands of most parts of sub-Saharan Africa, blending in well with the surroundings because of their golden fur. They feed on large herbivores such as wildebeest, zebras, buffalo, warthogs and gazelles, as well as smaller rodents. Lions are the only cats that live together in groups, called prides, which may consist of up to three males, ten lionesses and their young. They rest for most of the day, but are generally active at dusk and during the night. Male lions are known for their long manes and defend the territory of the pride against rivals, while the lionesses are the main hunters and stalk their prey in groups before closing in for a kill. As they grow, young males leave the pride to establish their own, while females often stay behind. Historically, the lion has been regarded as the king of beasts and is therefore still used as a symbol of courage, strength and royalty.


Information sources: National Geographic, WWF

Image: African lions feeding on a buffalo carcass in Kruger National Park, South Africa. Source: Luca Galuzzi, Wikimedia Commons.

Sahara desert may be older than previously thought

New findings of climatologists published in Nature reveal that the formation of the Sahara desert may have started up to 7 million years ago, more than twice as long ago as previously thought. Following the discovery of aeolian dune deposits that challenged the widely accepted age of approximately 2 – 3 million years for the Sahara desert, the scientists have used climate models to simulate the mechanisms behind the onset of aridification in northern Africa. Their results show that the origination of the Sahara desert may be related to shrinking of the Tethys Sea and the uplift of the Arabian Peninsula, associated with the northward movement of the African tectonic plate towards the Eurasian tectonic plate during the late Miocene. This reorganization of landmasses is thought to have significantly weakened the African summer monsoon, resulting in a reduced flow of moisture from the Atlantic Ocean and increasingly arid conditions in northern Africa. Until now, it was long believed that the desertification of northern Africa was related to the onset of glaciation on the Northern Hemisphere during the Pliocene and Pleistocene.


Journal reference: Zhang, Z., Ramstein, G., Schuster, M., Li, C., Contoux, C., & Yan, Q. (2014). Aridification of the Sahara desert caused by Tethys Sea shrinkage during the Late Miocene. Nature, 513(7518), 401-404.

Image: Sand dunes of the Sahara desert at sunset in Fezzan, Libya. Source: Luca Galuzzi, Wikimedia Commons.