Орчин үеийн геологийн судалгааны дэвшилтэт аргуудыг ашигласнаар Евразийн хамгийн эртний хүн амьдарч байсан бүс нутгуудын нэг болох ‘Убеидиягийн археологийн дурсгалт газрын насыг шинэчлэн тогтоожээ.
Иорданы хөндийд байрлах ‘Убеидия нь олон арван жилийн турш эртний хүмүүсийн чулуун зэвсэг болон амьтдын үлдэгдлийг агуулсан чухал бүс байсаар ирсэн. Өмнө нь энд амьдарч байсан хүмүүсийг 1.2–1.6 сая жилийн өмнө нүүдэллэн ирсэн гэж таамаглаж байсан ч Хайфагийн их сургуулийн Омри Барзилай, Талсагийн их сургуулийн Мириам Белмейкер болон Иерусалимын еврей их сургуулийн Ари Матмон нарын баг судалгааны үр дүнгээрээ энэ хугацааг 1.9 сая жил болгон урагшлууллаа. Энэхүү дүгнэлтийг Quaternary Science Reviews сэтгүүлд нийтэлжээ.
Судлаачид уг дурсгалт газрын насыг тогтоохдоо гурван дэвшилтэт аргыг хослуулан ашигласан байна. Эхнийх нь сансрын туяа чулуулаг дээр буухад үүсдэг ховор изотопуудын задралыг хэмжих замаар чулуулгийн дарагдсан хугацааг тогтоох арга юм. Хоёрдугаарт, хүн төрөлхтний үлдээсэн зэвсгүүдтэй ижил давхаргаас олдсон цэнгэг усны дунгийн бүрхүүлийг уран-хар тугалгын аргаар шинжилж, хамгийн бага насыг нь тодорхойлжээ. Гурав дахь арга нь тухайн үеийн дэлхийн соронзон орны чиглэлийг тунамал чулуулгаас тогтоож, соронзон орны эргэлтийн түүхэн бүртгэлтэй харьцуулсан явдал юм.
Эдгээр шинжилгээний үр дүн нь ‘Убеидия дахь суурин нь Гүржийн Дманисийн сууринтай ойролцоо настай болохыг харуулж байна. Судлаачид энд Олдован болон Ашелийн гэх хоёр өөр соёлын зэвсэг зэрэгцэн оршиж байсан байж болзошгүй гэж үзэж байгаа бөгөөд энэ нь Левантын бүс нутагт Ашелийн соёлын дэвшил таамаглаж байснаас эрт эхэлснийг илтгэж байна.
Энэхүү шинэчилсэн он цаг нь эртний хүмүүсийн нүүдлийн зам болон хугацааг ойлгоход чухал ач холбогдолтой юм. Судалгааны багийн үзэж буйгаар, уг олдвор нь Африкаас гарсан хүний нүүдэл олон давтамжтай эсвэл давхцсан үйл явц байсан байх магадлалыг дахин үнэлэх шаардлагатайг харуулж байна.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
The ‘Ubeidiya archaeological site in the Jordan Valley has been re-dated to 1.9 million years ago, placing it alongside the oldest known Eurasian settlements. Not far from the Sea of Galilee, in a sun-baked stretch of the Jordan Valley, ‘Ubeidiya has long produced hominin fossils. They were thought to belong to migrating populations that crossed what is now Israel between 1.2 and 1.6 million years ago. Remains and tools lay intermingled with the bones of other animals, many of them now extinct.
The site was already ancient, but it still had a surprise left. A re-analysis of its geological age, based on its rock layers, pushed the date back considerably. A team led by Omry Barzilai of the University of Haifa and Miriam Belmaker of the University of Tulsa, together with Ari Matmon of the Hebrew University of Jerusalem, published the results in Quaternary Science Reviews.
A Lake, A Stream And A Tilted Past
Long before it dried up, the area was a freshwater lake. A stream flowing into it left sediment containing hominin and animal fossils. Hominins living on the shore also left tools made of flint, basalt and limestone from the surrounding area. The sediment originally settled in even, horizontal layers, but they tilted when the center of the Jordan rift subsided.
A kibbutz member found the site by accident in 1959 while plowing, and excavations started the following year. Heavy machinery was needed to expose the strata. Only in 2021 did Barzilai and Belmaker begin to suspect that hominins had been there earlier than believed.
According to the study, the sediments had a more tangled history than once assumed. They were deposited and buried in the rift valley, later exhumed and eroded, then transported and redeposited along the paleo lake shoreline.
Three Ways to Find One Date
The team used three advanced methods that have proved effective on material long difficult to date. The first, cosmogenic isotope burial dating, establishes how long rocks were buried by measuring the decay of rare isotopes produced when cosmic rays strike rocks at the surface.
The second relied on fossilized shells of freshwater snails of the genus Melanopsis, found in the same layer as the hominin-made stone tools. Uranium-lead dating, which tracks the decay of uranium into lead, gave a minimum age for those tools.
The third came from Earth’s magnetic field. Its orientation was recorded in lake sediments that later turned to rock, and the researchers compared those records with documented geomagnetic reversals. The comparison placed the deposits in the Matuyama Chron, a period of reversed polarity that began at the dawn of the Quaternary.
The methods gave 1.9 million years, according to the paper, that is about the age of Dmanisi in Georgia, where Homo erectus settled before spreading through Eurasia and which has long been regarded as one of the oldest known settlements outside Africa.
Different Tools, Possibly the Same Time
The team suggest ‘Ubeidiya may once have hosted both Oldowan and Acheulean cultures. The oldest stone tools made by hominin hands come from African Oldowan sites up to 2.5 million years old, though some more debated sites in Ethiopia and Kenya go back 3.4 million years. By the time hominins reached ‘Ubeidiya, the flaking and fracturing involved in toolmaking had advanced.
Acheulean hominins refined it further and standardized the process, and their tools were strong enough to serve as weapons or to butcher animals for meat. The researchers think Oldowan and Acheulean hominins may have coexisted in the region. They also think Acheulean advances in the Levant came earlier than assumed.
“The revised age has significant implications for understanding the routes and timing of early human dispersal,” the authors said. “[This prompts] a reassessment of early Homo biogeography, dispersal pathways, and the possibility of multiple or overlapping migration events out of Africa.”
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