Introduction to Geology

The oldest rocks in Ethiopia, found beneath other rocks, and subjected to pressure, heat, and earth movements. These are altered, metamorphic rocks.

The mountain-building process during the Precambrian Era, which resulted in gigantic mountain ranges in Ethiopia that eroded over time.

The major geologic process of the Paleozoic Era was denudation, the wearing down of mountains from the Precambrian orogeny.

Rarely found because of the limited deposition of sediments in Ethiopia during this era.

A time period (225-70 million years ago) in Earth's history characterized by alternating landmass rising and sinking (epeirogenesis), affecting the Horn of Africa.

The landmass tilted eastward during the Mesozoic Era, leading to lower areas in the southeast and higher areas in the northwest.

The Mesozoic Era saw sea invasions of the land in the Horn of Africa, beginning from Somalia and gradually spreading northwestward during the Triassic and Jurassic periods.

Rocks formed through the processes of pressure, heat, earth movements, and intrusive igneous activity. Minerals and crystals may be found in them.

Three major sedimentary formations (Adigrat sandstone, Hintalo limestone, and Upper sandstone) laid upon Precambrian rock in Ethiopia during the Mesozoic Era.

A sandstone layer, part of the Mesozoic sedimentary formations, older and thicker in the southeast, progressively decreasing in age and thickness northwestward.

A limestone layer, part of the Mesozoic sedimentary formations, formed from marine life remains.

The uppermost layer of Mesozoic sedimentary rocks in Ethiopia; thicker and younger (Upper Cretaceous) in the Southeast and thinner and older in the Northwest.

The movement of the sea towards (transgression) and away from (regression) the landmass, affecting the age and thickness of rock layers in a regional context.

The process of deposition of different sediments including sands, lime, mud, gypsum, and shale in the Mesozoic Era, shaping the sedimentary formations in the Horn of Africa and Ethiopia.

25% of Ethiopia's land mass is covered by Mesozoic sedimentary rock.

The age and thickness of Mesozoic sandstone layers vary across Ethiopia in a Southeast - Northwest direction due to tilting of the land and sea movement.

The slow rise of the Arabo-Ethiopian landmass, beginning in the Jurassic and Cretaceous periods, with a major uplift during the Eocene epoch, reaching a maximum height of 2,000 meters.

A widespread, gentle upward movement of the landmass, like a huge bulge.

The Ethiopian Plateau surface was formed by a massive outpouring of lava from volcanic activity during the Cenozoic Era, covering ancient sediments.

A type of lava flow that forms large, flat, layered formations of basalt, like a giant staircase.

The Rift Valley was formed as a result of the intense tectonic forces that caused the uplifting of the Arabo-Ethiopian landmass.

Where lava erupted through vents, it piled up to form towering volcanic mountains.

Volcanic activity continuing throughout the Quaternary period, forming volcanic mountains and deposits on the Ethiopian Plateau.

A large, flat, and nearly horizontal landmass in Ethiopia, formed by ancient Precambrian surfaces, Mesozoic sediment deposition, and volcanic lava flows.

A theory explaining the movement of Earth's crustal plates, which causes earthquakes, volcanic activity, and the formation of features like the Rift Valley.

Created by tensional forces causing fractures in Earth's crust, leading to the landmass collapsing and forming a depression.

A part of the larger East African Rift Valley, extending from Palestine-Jordan to Malawi-Mozambique.

The widest part of the Ethiopian Rift Valley, located in the Afar region.

Formed by rifting and faulting, connecting the Red Sea to the Gulf of Aden.

A down-faulted area filled with Red Sea water, later isolated and evaporated, leaving saline materials.

Uplifted mountains formed between the Red Sea and the Danakil Depression, from volcanic activity.

Regions in Ethiopia with a high concentration of minerals, formed from ancient volcanic and metamorphic rocks.

Locations where minerals are likely to be found, based on geological formations and past discoveries.

Three major greenstone belts in Ethiopia known for their mineral wealth: Western/South-western, Southern (Adola), and Northern (Tigray).

Significant gold deposits are found in various locations in Ethiopia, particularly within the greenstone belts.

Besides gold, Ethiopia has a diverse range of minerals including platinum, base metals (like copper and nickel), molybdenum, marble, and iron.

The most recent geological period, characterized by alternating warmer and colder periods, known as the 'Ice Age' in high latitudes and 'Pluvial Rains' in Africa.

Heavy rainfall that occurred in Africa during the Quaternary Period, impacting the Ethiopian landscape.

The sediments carried away by rivers and deposited in Rift Valley lakes during the Quaternary Period's heavy rains.

Sediments deposited in former lakebeds and swampy areas during the Quaternary Period's heavy rainfall.

Sediments deposited along river banks and floodplains during the Quaternary Period.

Sediments deposited by melted glacial ice on high mountains, like the Bale and Kaka Mountains.

Sediments deposited by wind, carried and dropped in various locations.

Sediments deposited in areas that were previously invaded by the sea.