Connect with us

Archaeology

The Eye of the Sahara

Published

on

The Eye of the Sahara, also known as the Richat Structure and the Eye of Africa, is a geological feature in the Sahara Desert’s Adrar Plateau, located in west–central Islamic Republic of Mauritania.

The structure is an eroded elliptical dome of sedimentary rock, that ranges in age from the Proterozoic (2500 to 538.8 million years ago) within the centre, to Ordovician (488.3 to 443.7 million years ago) sandstone around its periphery.

The dome has a diameter of 40 kilometres (25 mi), with an interior comprised of intrusive and extrusive igneous rocks, including rhyolitic volcanic rocks, gabbros, carbonatites and kimberlites.

The rhyolitic rocks have been interpreted as lava flows that are part of two distinct eruptive centres formed from the remains of two maars, a low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion caused when groundwater comes into contact with hot lava or magma).

Eye of the Sahara – Image Credit : NASA – Public Domain

The gabbroic rocks form two concentric ring dikes, the inner ring dyke is 20 metres in width and lies 3 kilometres from the centre of the structure, while the outer ring dyke is 50 metres in width and is located 7 to 8 kilometres from the centre.

The processes that formed the structure has been theorised to be the result of either a meteoric impact, or a deep magmatic intrusion, the latter of which is supported with high-resolution airborne magnetic data and gravity data to reinforce the intrusion hypothesis.

The Eye of the Sahara was first identified during the 1950’s from aerial photographs, leading to ongoing studies by geologists until as recently as 2008. This latest study, explained that the ridges and valleys we see today are formed by the differential erosion of alternating hard and soft rock layers, uplifted as a dome by an underlying alkaline igneous complex of the Cretaceous age.

Archaeological research at the structure has revealed evidence of human activity, with numerous deposits of pre-Acheulian and Acheulian artefacts, characterised by the distinctive oval and pear-shaped “hand axes” normally associated with Homo erectus and derived species such as Homo heidelbergensis.

Acheulean tools were produced during the Lower Palaeolithic era across Africa and much of West Asia, South Asia, East Asia and Europe, first developed about 1.76 million years ago and derived from the more primitive Oldowan technology associated with Homo habilis.

Research by archaeologists have found Acheulean sites located along wadis that occupy the outermost annular depression of the structure, where outcrops of quartzite were sourced to provide the raw materials for tool manufacturing. Tool types found in Acheulean assemblages include pointed, cordate, ovate, ficron, and bout-coupé hand-axes (referring to the shapes of the final tool), cleavers, retouched flakes, scrapers, and segmental chopping tools.

The geographic distribution of Acheulean tools – and thus the peoples who made them – is often interpreted as being the result of palaeo-climatic and ecological factors, such as glaciation and the desertification of the Sahara Desert.

The climate of the region has undergone enormous variations between wet and dry periods over the last few hundred thousand years, believed to be caused by long-term changes in the North African climate cycle that alters the path of the North African Monsoon.

During the African humid period (AHP), much of the Sahara desert was covered by grasses, trees and lakes, where the people of the Lower Palaeolithic lived an existence as hunter-gatherers.

Evidence of Neolithic activity has also been found, with sparse, widely scattered spear points and other artefacts located northwest of the outer ring, although generally absent in its innermost depressions of the structure.

Due to the lack of middens or identifiable evidence of sustained occupation, this has led to the interpretation that the structure was only used for short-term hunting and stone tool manufacturing.

A pseudo theory by Fractal Source Research (FSR), proposes that the structure is the remnants of an advanced Antediluvian civilisation, namely the lost city of Atlantis, based on a comparison of measurements from the structure with the descriptions given by Plato.

Eye of the Sahara, taken by the Sentinel-2 Satellite – CC BY-SA 3.0 IGO

 

This content was originally published on www.heritagedaily.com – © 2023 – HeritageDaily

Continue Reading

Archaeology

Archaeologists may have discovered the lost city of Tu’am

Published

on

By

Excavations in the Umm Al Quwain area of the UAE have revealed 6th century ruins that could be the lost city of Tu’am.

The ruins are situated on Al Sinniyah Island, part of a collection of small islands on the western part of the Khor Al Bidiyah peninsula.

Previous studies on the island have revealed a pearling village and monastery, which has been the focus of the latest season of excavations.

Archaeologists have discovered evidence of a larger settlement, with the earliest signs of occupation dating back to the 4th century AD and peaking in the 5th or 6th century.

The team uncovered traces of large semi-urbanised tenement buildings measuring 30 square metres, which are tightly packed around narrow walkways. According to the researchers, the settlement could be the lost city of Tu’am as described in Ancient Arab texts.

Tu’am was a regional capital on the Gulf coast that was famed for its pearl fishing industry and trade in precious gems.

The population went into decline following a plague and regional tensions, and subsequently was abandoned. Mass graves in the vicinity support the historical account of plague, as the skeletal remains show no evidence of trauma or a violent death.

“Our archaeological work has discovered the largest settlement by far ever found on the Gulf coast of the Emirates,” said Prof Tim Power of UAE University.

“And it’s exactly the right period for the city described in the early Islamic geographical sources. It’s clearly a really important place. No one has ever found it.”

Professor Power explained that while they have not found irrefutable evidence (such as an inscription bearing the town’s name), no other major settlements from this period have been discovered on the coast, strengthening the argument that the settlement is Tu’am. “It’s a process of elimination,” he explained.

Header Image Credit : Umm Al Quwain Department of Tourism and Archaeology

Sources : NUAE

This content was originally published on www.heritagedaily.com – © 2023 – HeritageDaily

Continue Reading

Archaeology

New findings in North America’s first city

Published

on

By

Cahokia was the largest urban settlement of the Mississippian culture, a mound-building pre-Columbian civilisation that emerged in the Midwestern, Eastern, and South-eastern United States.

Archaeological evidence suggests that the city was founded around AD 1050 along the banks of the Mississippi River, located near present-day St. Louis, Missouri.

The city covered an area between six to nine square miles (notably larger than many contemporary European cities such as London) and was home to up to 20,000 inhabitants at its peak.

Following the tradition of the Mississippian culture, the people of Cahokia constructed large earthen mounds – ranging from raised platforms, conical, and ridge-top designs – involving the movement of 55 million cubic feet of earth over a period that lasted several decades.

The largest mound is known as “Monks Mound,” named after a group of Trappist monks, which rises to a height of 290 metres and was once the tallest building construction in North America.

Image Credit : MattGush – iStock

Archaeologists and students from Saint Louis University (SLU) have recently conducted a series of excavations on the western periphery of the Cahokia Mounds.

The team unearthed 900-year-old ceramics, microdrills, structures, and wall trenches dating from around AD 1100 to 1200, during the Sterling Phase of the Mississippian Period. According to the archaeologists, the finds offer new insights into a crucial period in the chiefdom’s development, coinciding with Cahokia’s rapid population growth.

The excavations follow an aerial survey by SLU and the National Geospatial-Intelligence Agency using Unmanned Aerial Systems (UAS) to conduct Light Detection and Ranging (LiDAR) to determine whether further mounds or archaeological features lie within the acres of thick forests and swampy land near the site’s main complex.

Header Image Credit : Alamy

Sources : KSDK

This content was originally published on www.heritagedaily.com – © 2023 – HeritageDaily

Continue Reading

Trending

Generated by Feedzy