Woldegabriel, Giday, Aronson, James L., Walter, Robert C. (1990) Geology, geochronology, and rift basin development in the central sector of the Main Ethiopia Rift. Geological Society of America Bulletin, 102 (4) 439-458 doi:10.1130/0016-7606(1990)102<0439:ggarbd>2.3.co;2

Abebe, B., Boccaletti, M., Mazzuoli, R., Bonini, R., Tortorici, M., & TRUA, L. (1998). Geological map of the Lake Ziway-Asela region (Main Ethiopian Rift). 1: 50,000 scale.

ⓘ 'Alkali Feldspar'

Localities:

Badda Volcano, Arsi Zone, Oromia Region, Ethiopia
Alutu Volcanic Centre, Arsi Zone, Oromia Region, Ethiopia
Tullu Moje Volcano, Arsi Zone, Oromia Region, Ethiopia
Bora-Bericcio Volcanoes, Arsi Zone, Oromia Region, Ethiopia
Sagatu Ridge, Arsi Zone, Oromia Region, Ethiopia

ⓘ Augite

Formula: (Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆

Localities:

Alutu Volcanic Centre, Arsi Zone, Oromia Region, Ethiopia
Chilallo Volcano, Arsi Zone, Oromia Region, Ethiopia

ⓘ Augite var. Ferrohedenbergite

Formula: (Ca,Mg,Fe)(Fe,Mg)Si₂O₆

Locality: Alutu Volcanic Centre, Arsi Zone, Oromia Region, Ethiopia

References:

Dakin, G., & Gibson, I. L. (1971). A preliminary account of Alutu, a pantelleritic volcano in the Main Ethiopian Rift. Bull. Geophys. Obs. Addis Ababa, 13, 110-114.

Weaver, S. D., Sceal, J. S. C., & Gibson, I. L. (1972). Trace-element data relevant to the origin of trachytic and pantelleritic lavas in the East African rift system. Contributions to Mineralogy and Petrology, 36(3), 181-194. doi.org/10.1007/BF00371430

Abebe, B., Boccaletti, M., Mazzuoli, R., Bonini, R., Tortorici, M., & TRUA, L. (1998). Geological map of the Lake Ziway-Asela region (Main Ethiopian Rift). 1: 50,000 scale.

ⓘ 'Glass'

Localities:

Tullu Moje Volcano, Arsi Zone, Oromia Region, Ethiopia
Chilallo Volcano, Arsi Zone, Oromia Region, Ethiopia

ⓘ Magnetite

Formula: Fe²⁺Fe³⁺₂O₄

Localities:

Sagatu Ridge, Arsi Zone, Oromia Region, Ethiopia
Badda Volcano, Arsi Zone, Oromia Region, Ethiopia

ⓘ 'Pyroxene Group'

Formula: ADSi₂O₆

Localities:

Alutu Volcanic Centre, Arsi Zone, Oromia Region, Ethiopia
Chilallo Volcano, Arsi Zone, Oromia Region, Ethiopia

ⓘ Quartz

Formula: SiO₂

Localities:

ⓘ Riebeckite

Formula: ◻[Na₂][Fe²⁺₃Fe³⁺₂]Si₈O₂₂(OH)₂

Localities:

Sagatu Ridge, Arsi Zone, Oromia Region, Ethiopia
Badda Volcano, Arsi Zone, Oromia Region, Ethiopia

ⓘ Sanidine

Formula: K(AlSi₃O₈)

Locality: Chilallo Volcano, Arsi Zone, Oromia Region, Ethiopia

References:

Di Paola, G.M. 1973. The Ethiopian rift valley (between 7º00' and 8º40' lat.north). Bulletin Volcanologique, 36, 517-560.

Mohr, P. A. (1966). Geological report on the Lake Langano and adjacent plateau regions. Bull. Geophys. Obs. Addis Ababa, 9, 59-75.

Abebe, B., Boccaletti, M., Mazzuoli, R., Bonini, R., Tortorici, M., & TRUA, L. (1998). Geological map of the Lake Ziway-Asela region (Main Ethiopian Rift). 1: 50,000 scale.

ⓘ 'Sodic amphibole'

Locality: Alutu Volcanic Centre, Arsi Zone, Oromia Region, Ethiopia

References:

Dakin, G., & Gibson, I. L. (1971). A preliminary account of Alutu, a pantelleritic volcano in the Main Ethiopian Rift. Bull. Geophys. Obs. Addis Ababa, 13, 110-114.

Abebe, B., Boccaletti, M., Mazzuoli, R., Bonini, R., Tortorici, M., & TRUA, L. (1998). Geological map of the Lake Ziway-Asela region (Main Ethiopian Rift). 1: 50,000 scale.

Gallery:

List of minerals arranged by Strunz 10th Edition classification

Group 4 - Oxides and Hydroxides
ⓘ	Magnetite	4.BB.05	Fe²⁺Fe³⁺₂O₄
ⓘ	Quartz	4.DA.05	SiO₂
Group 9 - Silicates
ⓘ	Augite	9.DA.15	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
ⓘ	var. Ferrohedenbergite	9.DA.15	(Ca,Mg,Fe)(Fe,Mg)Si₂O₆
ⓘ	Aegirine-augite	9.DA.20	(Na_aCa_bFe²⁺_cMg_d)(Fe³⁺_eAl_fFe²⁺_gMg_h)Si₂O₆
ⓘ	Aegirine	9.DA.25	NaFe³⁺Si₂O₆
ⓘ	Riebeckite	9.DE.25	◻[Na₂][Fe²⁺₃Fe³⁺₂]Si₈O₂₂(OH)₂
ⓘ	Aenigmatite	9.DH.40	Na₄[Fe²⁺₁₀Ti₂]O₄[Si₁₂O₃₆]
ⓘ	Sanidine	9.FA.30	K(AlSi₃O₈)
ⓘ	Albite	9.FA.35	Na(AlSi₃O₈)
ⓘ	var. Anorthoclase	9.FA.35	(Na,K)AlSi₃O₈
ⓘ	var. Oligoclase	9.FA.35	(Na,Ca)[Al(Si,Al)Si₂O₈]
Unclassified
ⓘ	'Alkali Feldspar'	-
ⓘ	'Pyroxene Group'	-	ADSi₂O₆
ⓘ	'Glass'	-
ⓘ	'Sodic amphibole'	-

List of minerals for each chemical element

H	Hydrogen
H	ⓘ Riebeckite	◻[Na₂][Fe₃²⁺Fe₂³⁺]Si₈O₂₂(OH)₂
O	Oxygen
O	ⓘ Aegirine	NaFe³⁺Si₂O₆
O	ⓘ Aegirine-augite	(Na_aCa_bFe_c²⁺Mg_d)(Fe_e³⁺Al_fFe_g²⁺Mg_h)Si₂O₆
O	ⓘ Aenigmatite	Na₄[Fe₁₀²⁺Ti₂]O₄[Si₁₂O₃₆]
O	ⓘ Albite	Na(AlSi₃O₈)
O	ⓘ Albite var. Anorthoclase	(Na,K)AlSi₃O₈
O	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
O	ⓘ Magnetite	Fe²⁺Fe₂³⁺O₄
O	ⓘ Albite var. Oligoclase	(Na,Ca)[Al(Si,Al)Si₂O₈]
O	ⓘ Quartz	SiO₂
O	ⓘ Riebeckite	◻[Na₂][Fe₃²⁺Fe₂³⁺]Si₈O₂₂(OH)₂
O	ⓘ Sanidine	K(AlSi₃O₈)
O	ⓘ Pyroxene Group	ADSi₂O₆
O	ⓘ Augite var. Ferrohedenbergite	(Ca,Mg,Fe)(Fe,Mg)Si₂O₆
Na	Sodium
Na	ⓘ Aegirine	NaFe³⁺Si₂O₆
Na	ⓘ Aegirine-augite	(Na_aCa_bFe_c²⁺Mg_d)(Fe_e³⁺Al_fFe_g²⁺Mg_h)Si₂O₆
Na	ⓘ Aenigmatite	Na₄[Fe₁₀²⁺Ti₂]O₄[Si₁₂O₃₆]
Na	ⓘ Albite	Na(AlSi₃O₈)
Na	ⓘ Albite var. Anorthoclase	(Na,K)AlSi₃O₈
Na	ⓘ Albite var. Oligoclase	(Na,Ca)[Al(Si,Al)Si₂O₈]
Na	ⓘ Riebeckite	◻[Na₂][Fe₃²⁺Fe₂³⁺]Si₈O₂₂(OH)₂
Mg	Magnesium
Mg	ⓘ Aegirine-augite	(Na_aCa_bFe_c²⁺Mg_d)(Fe_e³⁺Al_fFe_g²⁺Mg_h)Si₂O₆
Mg	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Mg	ⓘ Augite var. Ferrohedenbergite	(Ca,Mg,Fe)(Fe,Mg)Si₂O₆
Al	Aluminium
Al	ⓘ Aegirine-augite	(Na_aCa_bFe_c²⁺Mg_d)(Fe_e³⁺Al_fFe_g²⁺Mg_h)Si₂O₆
Al	ⓘ Albite	Na(AlSi₃O₈)
Al	ⓘ Albite var. Anorthoclase	(Na,K)AlSi₃O₈
Al	ⓘ Albite var. Oligoclase	(Na,Ca)[Al(Si,Al)Si₂O₈]
Al	ⓘ Sanidine	K(AlSi₃O₈)
Si	Silicon
Si	ⓘ Aegirine	NaFe³⁺Si₂O₆
Si	ⓘ Aegirine-augite	(Na_aCa_bFe_c²⁺Mg_d)(Fe_e³⁺Al_fFe_g²⁺Mg_h)Si₂O₆
Si	ⓘ Aenigmatite	Na₄[Fe₁₀²⁺Ti₂]O₄[Si₁₂O₃₆]
Si	ⓘ Albite	Na(AlSi₃O₈)
Si	ⓘ Albite var. Anorthoclase	(Na,K)AlSi₃O₈
Si	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Si	ⓘ Albite var. Oligoclase	(Na,Ca)[Al(Si,Al)Si₂O₈]
Si	ⓘ Quartz	SiO₂
Si	ⓘ Riebeckite	◻[Na₂][Fe₃²⁺Fe₂³⁺]Si₈O₂₂(OH)₂
Si	ⓘ Sanidine	K(AlSi₃O₈)
Si	ⓘ Pyroxene Group	ADSi₂O₆
Si	ⓘ Augite var. Ferrohedenbergite	(Ca,Mg,Fe)(Fe,Mg)Si₂O₆
K	Potassium
K	ⓘ Albite var. Anorthoclase	(Na,K)AlSi₃O₈
K	ⓘ Sanidine	K(AlSi₃O₈)
Ca	Calcium
Ca	ⓘ Aegirine-augite	(Na_aCa_bFe_c²⁺Mg_d)(Fe_e³⁺Al_fFe_g²⁺Mg_h)Si₂O₆
Ca	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Ca	ⓘ Albite var. Oligoclase	(Na,Ca)[Al(Si,Al)Si₂O₈]
Ca	ⓘ Augite var. Ferrohedenbergite	(Ca,Mg,Fe)(Fe,Mg)Si₂O₆
Ti	Titanium
Ti	ⓘ Aenigmatite	Na₄[Fe₁₀²⁺Ti₂]O₄[Si₁₂O₃₆]
Fe	Iron
Fe	ⓘ Aegirine	NaFe³⁺Si₂O₆
Fe	ⓘ Aegirine-augite	(Na_aCa_bFe_c²⁺Mg_d)(Fe_e³⁺Al_fFe_g²⁺Mg_h)Si₂O₆
Fe	ⓘ Aenigmatite	Na₄[Fe₁₀²⁺Ti₂]O₄[Si₁₂O₃₆]
Fe	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Fe	ⓘ Magnetite	Fe²⁺Fe₂³⁺O₄
Fe	ⓘ Riebeckite	◻[Na₂][Fe₃²⁺Fe₂³⁺]Si₈O₂₂(OH)₂
Fe	ⓘ Augite var. Ferrohedenbergite	(Ca,Mg,Fe)(Fe,Mg)Si₂O₆

Geochronology

Mineralization age: Cenozoic : 3.4 ± 0.4 Ma to 1.74 Ma

Important note: This table is based only on rock and mineral ages recorded on mindat.org for this locality and is not necessarily a complete representation of the geochronology, but does give an indication of possible mineralization events relevant to this locality. As more age information is added this table may expand in the future. A break in the table simply indicates a lack of data entered here, not necessarily a break in the geologic sequence. Grey background entries are from different, related, localities.

Geologic Time

Rocks, Minerals and Events

ⓘ Trachybasalt	1.74 Ma	Chilallo Volcano, Arsi Zone, Oromia Region, Ethiopia
ⓘ Trachytic tuff	2.54 Ma	Chilallo Volcano, Arsi Zone, Oromia Region, Ethiopia

Neogene

Pliocene

ⓘ Trachyte	2.70 Ma	Cacca Volcano, Arsi Zone, Oromia Region, Ethiopia
ⓘ Soda trachyte	3.4 ± 0.4 Ma	Cacca Volcano, Arsi Zone, Oromia Region, Ethiopia

Fossils

There are 3 fossil localities from the PaleoBioDB database within this region.

These data are provided on an experimental basis and are taken from external databases. Mindat.org has no control currently over the accuracy of these data.

Occurrences

Youngest Fossil Listed

156 Ma (Jurassic)

Oldest Fossil Listed

161 Ma (Jurassic)

Fossils from Region

Click here to show the list.

Accepted Name	Hierarchy	Age
Lima genus	Animalia : Mollusca : Bivalvia : Limida : Limidae : *Lima*	161.2 - 155.7 Ma Jurassic
Somalirhynchia africana species	Animalia : Brachiopoda : Rhynchonellata : Rhynchonellida : Tetrarhynchiidae : Somalirhynchia : *Somalirhynchia africana*	161.2 - 155.7 Ma Jurassic
Nanogyra (Nanogyra) nana species	Animalia : Mollusca : Bivalvia : Ostreida : Gryphaeidae : Nanogyra : *Nanogyra (Nanogyra) nana*	161.2 - 155.7 Ma Jurassic

Fossil Localities

Click to show 1 fossil locality

Ethiopia

Oromia Region
- Jurassic🐚 Abul Casim

Other Databases

Wikipedia:	https://en.wikipedia.org/wiki/Arsi_Zone
Wikidata ID:	Q646859
GeoNames ID:	343450

Localities in this Region

Ethiopia

Oromia Region
- Arsi Zone

Other Regions, Features and Areas that Intersect

AfricaContinent

East African Rift System (EARS)Zone (Tectonic)

African Plate

Arabian-Nubian Shield
- Nakfa TerraneVolcanic Arc

Somali PlateTectonic Plate

This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.

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Detailed Mineral List:

Gallery:

List of minerals arranged by Strunz 10th Edition classification

List of minerals for each chemical element

Geochronology

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