Edaga Arbi Glacials

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Coordinates: 14°12′13″N 39°15′18″E / 14.2037°N 39.255°E / 14.2037; 39.255
Source: Wikipedia, the free encyclopedia.
Edaga Arbi Glacials
Late Carboniferous
Approximate paleocoordinates
0°N 0°E / 0°N 0°E / 0; 0
RegionTigray
Country Ethiopia  Eritrea
Extentcentral-south Eritrea, northeast Tigray
Type section
Named forTown of Idaga Arbi
Named byD.B. Dow
Edaga Arbi Glacials is located in Ethiopia
Edaga Arbi Glacials

The Edaga Arbi Glacials are a

Early Permian (~295 Ma) age.[1]

Name and definition

The name was coined by geologist D.B.Dow and colleagues[2] They referred to the wide outcrops surrounding the town of Idaga Arbi. So far the nomenclature has not been proposed for recognition to the International Commission on Stratigraphy.

Stratigraphic context

The Edaga Arbi Glacials fill the bottom of north-south oriented valleys, that were carved by glaciers, into the

Late Palaeozoic (Carboniferous-Permian; ~300 Ma). This has led to the presence of glacial sediments as well as erosional landforms in eastern Tigray. Over the last 30 million years the Ethiopian Highlands have been uplifted and the Edaga Arbi Glacials have been exposed as a result of the erosion of overlying rocks. This is one of the few places in the world where the Palaeozoic glacial deposits are well exposed and can be easily accessed.[3]

Environment

These glaciogenic sediments were deposited directly by the glacier as

fjords or pro-glacial lakes. The tillites have often been deformed by (underwater) slumping.[4]

Lithology

The Edaga Arbi Glacials may reach a thickness of 200 metres. Similar to most other tillites, they hold many different types of sediment. Generally, the sediments are rich in mud (clay and silt), in contrast to the

fluvioglacial deposits. Basal till that was deposited directly under the ice holds many rock fragments. In other places, the settling in water of suspended fine-grained sediment resulted in massive stratified mudstones. Still elsewhere, the underwater movement of sand by gravity resulted in sandstone lenses. As they were formed under water, the mudstone and the sandstone contain (sometimes very large) dropstones, deposited from melting ice rafts.[4]

Life

Pollen and spores have been found in the Edaga Arbi Glacials. Their age confirms that the Edaga Arbi Glacials date back to the Late Palaeozoic ice age.[5]

Geographical extent

The deposits are exposed locally as south as

Dogu’a Tembien massif.[3] They are widespread around Idaga Arbi and further north into Eritrea
.

Exposed glacial geomorphology

The

Glacial grooves within the Edaga Arbi Glacials were probably created by flowing meltwater under glaciers.[6]

References

  1. ^
    ISBN 978-3-030-04954-6
    .
  2. ^ Palaeozoic glacial rocks recently discovered in northern Ethiopia
  3. ^
    S2CID 199106886
    .
  4. ^
    doi:10.1016/j.jafrearsci.2014.04.005
    .
  5. doi:10.1016/j.jafrearsci.2007.09.003
    .
  6. doi:10.1016/j.gr.2009.10.009
    .
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