#fossilfrdiay

The Cradle of Humankind

Located 65 Km south west of South Africa’s capital city, Pretoria, is The Cradle of Humankind. The site includes the Sterkfontein Caves, where the famous 2.3 million year old fossil “Mrs. Ples” was discovered. The discovery was made by Dr Robert Broom and John T Robinson. Prior to 2010, the Sterkfontein Caves produced over 30% of hominid fossils ever found.

Including the Sterkfontein Caves and a massive complex of limestone caves, the site currently occupies over 45 000 hectares. There are close to 40 fossil-bearing caves across the site.

A massive number of homonin fossils have thus far been excavated from the many sites comprising the Cradle of Humankind, including some of the oldest ever discovered. A few of these fossils have been found to be almost 3.5 million years old.

It is theorized that hominins may have lived all across the African continent, but their fossils can only be found where the conditions for fossil formation are optimal. The hominin fossils found in dolomitic caves at the Cradle are often enclosed in a blend of limestone and breccia.

hominid – “group consisting of all modern and extinct Great Apes”

hominin- “the group consisting of modern humans, extinct human species and all our immediate ancestors”

Breccia – clastic sedimentary rocks made up of angular fragments. Often there are gaps between the angular fragments. These gaps are filled with a medium consisting of smaller particles that binds the rock together.

Renesh T

Image Source:

https://commons.wikimedia.org/wiki/File:Copy-of.mrs-ples-maropeng.jpg

References/Further Reading:

Kashmira Raghu BSc. Hons. MSc http://bit.ly/1lyU3b6 http://bit.ly/1IpOH9d http://bbc.in/1LSB6Nd http://bit.ly/1EN4f5U http://bit.ly/19hfUyi http://bit.ly/1xeqCAZ

A spectacular find and a geological puzzle

Items trapped in flowing tree sap and later fossilised in amber are normally insects, or more rarely small land animals such as lizards. In the chunk shown in the accompanying photos an unusual concatenation of circumstances has caught some 40 tiny critters (including mites, spiders, millipedes, beetles, flies and wasps), and much more exceptionally the first recorded ammonite shell to be discovered in frozen tree sap.

Dating from 99 million years ago and discovered in northern Burma, it measures 3.3cm by 2.9, and seems to be the shell of a juvenile, as revealed by CT scanning. Since ammonites are common time markers in sediments the find has helped constrain the age of the entire deposit more precisely as well as giving us a snapshot of a long gone ecosystem that lived around a forest.

The tree that exuded the resin in response to some injury to its bark must have lived by the beach on a long gone sea shore, since it entombed a mixture of terrestrial and marine organisms. Some sea snails and slaters (animals that resemble pillbugs, in this case near identical to modern examples) also grace the interior of the piece. None of the shells contain soft tissue and the ammonite shell is filled with sand (which also dots the entire piece of amber), implying that they were washed ashore by waves before being encapsulated. Other possible scenarios include tsunami or storm debris being washed into a more inland forest.

Burmese amber is somewhat problematic, since the mines are hard of access and in a warzone. Scientists have been forced to go and scour the gem markets in the country, or to rely on collaboration with private collectors who have bought the gems, as happened in this case. The dealers thought the shell was a land snail but the collector’s curiosity and hope that it might be an ammonite was sparked and the piece purchased before being shared with researchers.

This particular collector owns a private amber museum and has been collaborating with the Chinese research team for years and is a co author on several of their papers and has had a fossil insect genus named after him in recognition. One should remember that collectors are usually as passionate as scientists, and often willing to share specimens so the regular damnation that is heaped on their heads whenever an important specimen is auctioned should be tempered with this awareness.

A second ammonite is apparently now doing the tour of the gem markets, so we may have a further exciting tale to share. Other spectacular finds made in Burmese amber these last years include a pair of Cretaceous bird wings )http://bit.ly/2I5G242 http://bit.ly/2ZecGq3 ), a chunk of feathered dinosaur tail (http://bit.ly/2wM1nt2) and a variety of bird and dino feathers (http://bit.ly/1DTZQdF)

Loz