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TECTONIC CONTROL ON GEOTHERMAL SITES WITH TECTONIC CONTROL ON GEOTHERMAL SITES WITH SPECIFIC REFERENCE TO THE ALBERTINE GRABENSPECIFIC REFERENCE TO THE ALBERTINE GRABEN
DozithDozith AbeinomugishaAbeinomugisha
Structural GeologistStructural Geologist
Petroleum Exploration and Production Department,Petroleum Exploration and Production Department,
At theAt the
SECOND AFRICAN RIFT GEOTHERMAL CONFERENCE
Imperial resort Beach Hotel 24Imperial resort Beach Hotel 24thth –– 2525thth November 2008.November 2008.
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TOPICS TO COVER.
1.1. INTRODUCTIONINTRODUCTION
2.2. REGIONAL SETTING OF THE EARSREGIONAL SETTING OF THE EARS
3.3. GEOTHERMAL POTENTIAL OF UGANDAGEOTHERMAL POTENTIAL OF UGANDA
4.4. CONCLUSIONSCONCLUSIONS
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1. INTRODUCTION: Location of Geothermal Sites1. INTRODUCTION: Location of Geothermal Sites
Geothermal Sites influenced by Plate Boundaries
•Divergent-Extension
•Convergent-Compression
•Conservative -Strike Slip
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1. INTRODUCTION: Location of Geothermal Sites1. INTRODUCTION: Location of Geothermal Sites
Convection of the mantle is the major drive for plate tectonics and thinning of the crust
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1.1. INTRODUCTIONINTRODUCTION Source of Geothermal EnergySource of Geothermal Energy
Geothermal fields Associated with active plate boundaries
•Convergent Zones
•Divergent Zones
•Strike slip Zones
Water circulation along deep seated faults
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1. INTRODUCTION: Surface expression of Geothermal Energy1. INTRODUCTION: Surface expression of Geothermal Energy
Deildartunguhver, Iceland: the highest flow hot spring in Europe
Common Surface Expression of Geothermal energy are Hot springs, Geysers, fumaroles
A hot spring is a spring that is produced by the emergence of geothermally heated ground water from the earth's crust.
Source of heat: from the Earth’s interior
•Tectonically active areas; Through deep seated faults
•Volcanic areas; Contact with Magma
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1. INTRODUCTION: Location of Geothermal Sites1. INTRODUCTION: Location of Geothermal Sites
Tectonic setting of Gila hot springs region, New Mexico, USA.
•Springs associated with deep seated extensional faults
GHC Bulletin, December 2002
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1. INTRODUCTION: Location of Geothermal Sites1. INTRODUCTION: Location of Geothermal Sites
Geologic cross section across Gila hot springs. The hot springs are associated with deep seated faults
GHC Bulletin, December 2002
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Tertiary rift
Rifting avoided the stable Cratons. Utilised the mobile belts.
Pre-Cambrian fabric influenced rift geometry
Extension direction is nearly E-W
Albertine graben forms the northern most termination of the Western branch of EARS
Source of map: ftp://e0srp01u.ecs.nasa.gov/
Legend
2. TECTONIC SETTING OF EARS2. TECTONIC SETTING OF EARS
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Albertine Graben
Malawi Rift
East Africa DEM
Ethiopian rift
Tanzania craton
2.2. TECTONIC SETTING OF EARSTECTONIC SETTING OF EARS
Tanganyika Rift
Kenya Rift
Red Sea
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Deep Seated Faults
General Trends
Northern trends in a NNE-SSWCentral trends in a NE-SWSouthern trends in a NNE-SSW
Highly segmented faults
Limited volcanism from the southern Limited volcanism from the southern partpart
3. GEOTHERMAL POTENTIAL OF UGANDA: structural setting of Albert 3. GEOTHERMAL POTENTIAL OF UGANDA: structural setting of Albert RiftRift
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3. GEOTHERMAL POTENTIAL OF UGANDA: Hot spring occurrence3. GEOTHERMAL POTENTIAL OF UGANDA: Hot spring occurrence
Hot Springs aligned along the AlbertineGraben
Over 40 hot springs studied
Three with highest potential
•Katwe - Kikorongo•Buranga
•Kibiro
Courtesy: Godfrey Bahati
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3.3. GEOTHERMAL POTENTIAL OF UGANDA: GEOTHERMAL POTENTIAL OF UGANDA: KatweKatwe AreaArea
Katwe -Kikorongo and Bunyaruguruvolcanic provinces
Volcanic line trend same as the basin margin faults
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3.3. GEOTHERMAL POTENTIAL OF UGANDA: GEOTHERMAL POTENTIAL OF UGANDA: KatweKatwe AreaArea
KitagataHotspringsKatwe-kikorongoarea
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3.3. GEOTHERMAL POTENTIAL OF UGANDA: GEOTHERMAL POTENTIAL OF UGANDA: KatweKatwe AreaArea
The Katwe KikorongoGeothermal Potential related to a thinned crust
The thinned crust responsible for the volcanic province
Located in the Accommodation zone of the Lake Edward and Semlki basins
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3.3. GEOTHERMAL POTENTIAL OF UGANDA: GEOTHERMAL POTENTIAL OF UGANDA: KatweKatwe AreaArea
Muhokya Hot springs
Eastern flanks of the Rwenzori Mountains
The tufa limestone deposits in the area related to hot springs along the NNE –SSW trending faults
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3.3. GEOTHERMAL POTENTIAL OF UGANDA: GEOTHERMAL POTENTIAL OF UGANDA: SempayaSempaya AreaArea
Buranga Hot Springs
Highest surface temperature
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3.03.0 GEOTHERMAL POTENTIAL OF UGANDA: GEOTHERMAL POTENTIAL OF UGANDA: SempayaSempaya AreaArea
5 km
Rwenzori nose underneath Semliki Basin
•Probably Volcanic intrusion
•Gas Chimney above the structuring
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0.00
0.50
1.00
1.50
2.00
2.50
3.00
2km
Buranga Hot springs could be associated with deep seated faults
Rw
enzo
rino
se3.03.0 GEOTHERMAL POTENTIAL OF UGANDA: GEOTHERMAL POTENTIAL OF UGANDA: SempayaSempaya AreaArea
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Turaco wells drilled in Semlikibasin encountered Carbon Dioxide
•Probably from a volcanic body
Geothermal Gradient 30oC –40oC
3.03.0 GEOTHERMAL POTENTIAL OF UGANDA: GEOTHERMAL POTENTIAL OF UGANDA: SempayaSempaya AreaArea
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3.3. GEOTHERMAL POTENTIAL OF UGANDA: GEOTHERMAL POTENTIAL OF UGANDA: KibiroKibiro AreaArea
Kibiro hot springs associated with deep seated faults
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Deep seated faults close to Kibiro
3.03.0 GEOTHERMAL POTENTIAL OF UGANDA: GEOTHERMAL POTENTIAL OF UGANDA: KibiroKibiro AreaArea
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An Oil Drilling Rig at Taitai, a few km north of Kibiro
•Geothermal Gradient in the Butiaba – Wanseko area: 60oC –70oC
3.03.0 GEOTHERMAL POTENTIAL OF UGANDA: GEOTHERMAL POTENTIAL OF UGANDA: KibiroKibiro AreaArea
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4. CONCLUSIONS
Geothermal potential manifested by presence of hot springs
Source of heat is the mantle due to a thinned crust
Water circulation through deep seated faults
Accommodation zones have indicated high potential. Therefore wanseko area with high geothermal gradient needs follow up
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Diversity of wildlife in the Albertine Graben
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