Stone tools age Asia’s first Homo pres­ence

Oman Daily Observer - - OMAN/WORLD -

The re­mains of crudely fash­ioned stone tools un­earthed in China ad­vances the pres­ence of hu­man an­ces­tors in Asia by around 200 mil­len­nia to 2.1 mil­lion years ago, sci­en­tists said on Wed­nes­day.

If cor­rectly dated, the find means that ho­minins — the group of hu­mans and our ex­tinct fore­fa­ther species — left Africa ear­lier than ar­chae­ol­o­gists have been able to demon­strate thus far, a team re­ported in the sci­en­tific jour­nal

“Our dis­cov­ery means that it is nec­es­sary now to re­con­sider the tim­ing of when early hu­mans left Africa,” said study coau­thor Robin Den­nell of Ex­eter Univer­sity in Eng­land.

Ho­minins are be­lieved to have emerged in Africa more than six mil­lion years ago. They left the con­ti­nent in sev­eral mi­gra­tion waves start­ing about two mil­lion years ago.

The first mi­grants were likely mem­bers of the species Homo erec­tus (up­right man) or Homo er­gaster (work­ing man) — ex­tinct pre­de­ces­sors of our own group, Homo sapi­ens (wise man), which first emerged about 300,000 years ago.

The old­est known African fos­sil at­trib­uted to a mem­ber of the Homo fam­ily is a 2.8 mil­lionyear-old jaw­bone from Ethiopia.

Pre­vi­ously, the old­est ev­i­dence for ho­minins in Asia came from Ge­or­gia in the form of fos­silised skele­ton bits and arte­facts dated to be­tween 1.77 mil­lion and 1.85 mil­lion years ago.

WA­TER-TIGHT -

There have been other, un­proven, claims of even older fos­sil dis­cov­er­ies, the study au­thors said.

The lat­est find of 96 stone tools, mainly flakes made with rudi­men­tary ham­mers and likely used for cut­ting meat and other food, was ex­tracted from 17 lay­ers of sed­i­ment in the south­ern Chi­nese Loess Plateau.

The youngest layer was 1.26 mil­lion years old, and the old­est 2.12 mil­lion years.

There were no bones.

Den­nell and a team used a field of sci­ence known as “palaeo­mag­netism” to date the sed­i­ment lay­ers. These form when dust or mud set­tles be­fore be­ing capped by an­other new soil coat.

Any arte­fact found within a layer would be the same age as the soil around it.

Palaeo­mag­netism re­lies on shifts in the Earth’s mag­netic field, the his­toric dates of which are well known to sci­en­tists.

Den­nell and a team mea­sured the mag­netic prop­er­ties of min­er­als in the soil lay­ers to ho­minin de­ter­mine when de­posited.

This dated the tools, of a type known to have been man­u­fac­tured by Homo species in Africa since at least 3.3 mil­lion years ago.

The pa­per of­fers strong ev­i­dence for a ho­minin pres­ence in Asia fur­ther back than we thought, Den­nell said.

“There may be older ev­i­dence in places like In­dia and Pak­istan, but so far ... the ev­i­dence is not strong enough to con­vince most of the re­search com­mu­nity,” he said.

“With this type of claim, for an early hu­man pres­ence in a re­gion, the ev­i­dence has to be ab­so­lutely wa­ter-tight and bomb-proof.” Who made the tools? “Prob­a­bly an early form of our own genus Homo,” said Den­nell, though fur­ther re­search is needed to pin­point the species. —

AFP

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