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Geology and geothermal resource Geology and geothermal resource utilization options at Arusutilization options at Arus--Lake Bogoria Lake Bogoria

prospect, northern Kenya riftprospect, northern Kenya rift

John LagatJohn Lagat

ARGeoARGeo--C2 Conference Entebbe UgandaC2 Conference Entebbe Uganda2424--2828thth November 2008November 2008

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Blowout well close to L. Baringo•90 m borehole drilled for domestic water produced hot water 92°C (local BP) .

•Self discharged sprouting to a height of 50 m.

Introduction

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Objectives

1. Investigate and examine/report all geologic features that may be associated with development, and occurrence of geothermal potential in Arus-Lake Bogoria.

2. Determine whether the prospect deserves further exploration by drilling and if so, recommend targets and sites for exploration drilling sites.

3. Recommend how best the geothermal resource could be utilized.

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Location

• Northern Kenya rift.

• North of Menengai prospect and south of Lake Baringo prospects.

• Area extend more than 2000 km2

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Geology...1

• Miocene; represented by Samburu basalts to

• Recent; represented by Alluvial and fluvial sediments

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Geology....2

• Area has no young volcanic centre; the youngest eruptions dated about 2 Ma BP.

-Lake Bogoria trachytes• Manifested by wonderful

surface manifestations;-Existence of a geothermal

system

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Ololbutot comendite dated at ~200 yrs BP

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Structures

Main structures:

• Rift flanks on E & W

• NNE-SSW and N-S faults.

• NW-SE & NE-SW lineaments

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Structures

0 5 km

0°20'

0°10'

LakeBogoria

Lake Bogoria

Escarpment

Emso

s

Escarpment

Solai E

scarpment

Chui E

scarp

ment

Fissure opened up to a maximumof 2.4 m MARMANET

Marmanet Escarpment

Inguamiti Gorge

Lariak Forest

Epicentre

36°10' 36°20'

Fissure opened

up 0.6-0.9 m

Earthquake of Jan 28th 1928 indicate continuation of activityFissure opening of up to 2.4 m were recorded.

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Geothermal manifestations 1

Occur in forms of: Fumaroles, hot and steaming grounds, anomalous boreholes, hot springs, steam jets, altered grounds and sulphur, calcite, travertine and calcite deposits

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Geothermal manifestations 2

1 KM

Emsos

T T

T

T

T

T

T

T

T

T

T

T

T

Maji Moto

Ndo

loita

-Lob

oi

2 KM

Lake Bogoria

Mwanasis

Kwaibeipei

Emsos

Kipkongor

Kipongwe

Ngairus

Losaramat

Kibwui

KipongweKipkongorKwaibeipei

MaweMoto

Losaramat*

*

Loburu

Rongat

Ndigirui

Ndigirut

Loboi

Mwanasis

LEGEND

T

*

Hot springsWarm springsTravertine depositsGeysers

Clusters of fumarolesor steam vents

S Sulphur deposits

s

River or stream

LakeBogoria

•Manifestations mainly occur on the southern parts of the lake•Occur in a linear arrangement indicating structural control•Temps range from 85-98˚C

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Geothermal manifestations

Steaming fumaroles at ArusSteaming fumaroles at Arus

Silica veins near Arus Silica veins near Arus

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Geothermal manifestations

Steaming fumarole at ArusSteaming fumarole at Arus At a closer lookAt a closer look

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Geothermal model

Heat source;Heat source;Thin crust and shallow intrusives.Thin crust and shallow intrusives.Recharge; Meteoric water Recharge; Meteoric water --Kenya Rift Meteoric lineKenya Rift Meteoric lineReservoir rocks; Reservoir rocks; Flood PlioFlood Plio--Pleistocene trachytesPleistocene trachytesReservoir Temps; Reservoir Temps; <200<200ººC from gas geothermometryC from gas geothermometry

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Hot water at 38°C from a near by hot spring used to heat the spa pool

Hot spring

Curent utilization..1

Spa pool at L. Bogoria Hotel

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Tourist attraction

• Hot springs and flamingos add value to Lake Bogoria game reserve

Curent utilization..2

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1. Binary cycle electricity generation.

Utilization options..1

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2. Swimming pools, bathing and balneology using natural springs.

3. Greenhouse heating in flowers and vegetables growing

Utilization options…2

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4. Aquaculture.

Study on effects of temp. on animal and fish Require certain temperature for optimum growth.

Utilization options…3

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5. Residential cooling by use of heat pumps-Ground coupled closed loops

Utilization options…3

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6. Drying of agricultural produce:1. Drying of sisal2. Drying of fruits and vegetables3. Raw wool washing and drying

Utilization options…4

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7. Industrial applications.1. CO2 mining2. Wood industry

Utilization options…5

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Conclusions

1. Several low to intermediate fault controlled geothermal systems exist in the prospect area.

2. A huge potential of untapped low enthalpy energy resource is available in Arus-Lake Bogoria prospect area.

3. The geothermal resource in the prospect area can be utilized for electricity generation using binary and direct uses.

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