The geochemistry of Arus & Bogoria geothermal prospects

1st EAST AFRICAN RIFT GEOTHERMAL CONFERENCE –ARGeo-C1

GEOLOGICAL SURVEY OF ETHIOPIA,24TH NOV– 2ND DECEMBER, 2006

C. Karingithi

2ARGeo-C1

Map of study area

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LOBOI

MAJI MOTO

LAKE BOGORIA

EMS0S SP

MUGURIN

ARUS STEAM JETS

MOLO SIRWEEMINING

KIMOSET

RADAD

LELEN SWAMP

Kapkun

Kimorock

Chepkoimet

Kailer

Kures

Marigat

Chebaral

Ebenezer

Tabarbangetuny

Noiwet

LegetetewetOldebes

Ngendalel

Nyalilpush

Ol Kokwe

Mogotio 1Mogotio 2Mogotio 3

LomolloKisanana

Tabarweche

Chemorongnion

Sosionte

Nyimbei

IlngaruaNgambo

Perekera

950

10001050

11001150

12001250

13001350

14001450

15001550

16501700

17501800

1850

masl

32 33 34 35 36 37 38 39 40 41 42Latitudes

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

Long

itude

s KENYA

Mt. Kenya

L. Magadi

SuswaLongonotOlkaria

Eburu

Menengai

Paka

Barrier

Silali

L. Victoria

Mt. Kilimanjaro

Emuruangogolak

Namarunu

KorosiL. Baringo

Bogoria

UGANDA

ETHIOPIA

SOM

AL

IA

TANZANIA

Shombole

Olorgesaille

South Island

Central Island

North Island

Nyanza

Nairobi

Legend: Rift FaultsVolcanic centres

3ARGeo-C1

Aerial Photo of BogoriaProspect

4ARGeo-C1

OBJECTIVE

Locate and map all geothermal surface manifestations.Establish the whether a geothermal resource exists in Arus and Bogoria prospects. Site exploration wells.

5ARGeo-C1

Locate, sample and analyse the springs, fumaroles, boreholes and gas holesSoil gas survey.Ground temperature.

Surface exploration Methodology

6ARGeo-C1

Arus steam jets

7ARGeo-C1

Bogoria geysers

8ARGeo-C1

Bogoria fumaroles

9ARGeo-C1

Work done to date

Located and Sampled EIGHTEEN (18) springsLocated and Sampled 31 boreholes338 radom radon and soil gas measurements Located and sampled ten fumaroles

10ARGeo-C1

Location of all sampling points

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LOBOI

MAJI MOTO

LAKE BOGORIA

EMS0S SP

MUGURIN

ARUS STEAM JETS

MOLO SIRWEEMINING

KIMOSET

RADAD

LELEN SWAMP

Kapkun

Kimorock

Chepkoimet

Kailer

Kures

Marigat

Chebaral

Ebenezer

Tabarbangetuny

Noiwet

LegetetewetOldebes

Ngendalel

Nyalilpush

Ol Kokwe

Mogotio 1Mogotio 2Mogotio 3Lomollo

Kisanana

Tabarweche

Chemorongnion

Sosionte

Nyimbei

IlngaruaNgamboPerekera

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10001050

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11ARGeo-C1

Boreholes and springs temperature distribution plot

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LOBOI

MAJI MOTO

LAKE BOGORIA

EMS0S SP

MUGURIN

ARUS STEAM JETS

MOLO SIRWEEMINING

KIMOSET

RADAD

LELEN SWAMP

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12ARGeo-C1

ResultsThe temperature of the boreholes varied between 24 °C for Seretion borehole to 40 °C at the Mogotio boreholes.The pH varied from 7.2 to 9.2, however, 22 out of 31 boreholes discharged water whose pH was between 6.5 and 8.0.With the exception of five samples, the conductivity of the water samples is less than 1000 µS/cm. None of the boreholes have silica concentration exceeding 100 ppm.

13ARGeo-C1

Chloride-Sulphate-Bicarbonate ternary diagram

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Cl

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0

SO4

14ARGeo-C1

ResultsThe pH of the spring samples varies from 7.3 to 9.8 Chloride concentration varies from 31 ppm (BS 5) to 3295 ppm (BS 15).Quartz geothermometer temperature range from 115 to 325 deg C, while the Na/K geothermometer temperature range from 122 to 377 deg C.

15ARGeo-C1

Arus & Bogoria Soil gas Radon 220 distribution plot

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Kapkun

Kimorock

Chepkoimet

Kailer

Kures

Marigat

Chebaral

Ebenezer

Tabarbangetuny

Noiwet

LegetetewetOldebes

Ngendalel

Nyalilpush

Ol Kokwe

Mogotio 1Mogotio 2Mogotio 3Lomollo

Kisanana

Tabarweche

Chemorongnion

Sosionte

Nyimbei

IlngaruaNgambo

Perekera

LOBOI

MAJI MOTO

LAKE BOGORIA

EMS0S SP

MUGURIN

ARUS STEAM JETS

MOLO SIRWEEMINING

KIMOSET

RADAD

LELEN SWAMP

0

200400

600800

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CPM

16ARGeo-C1

Arus & Bogoria Soil gas Radon 222 distribution plot

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Kapkun

Kimorock

Chepkoimet

Kailer

Kures

Marigat

Chebaral

Ebenezer

Tabarbangetuny

Noiwet

LegetetewetOldebes

Ngendalel

Nyalilpush

Ol Kokwe

Mogotio 1Mogotio 2Mogotio 3Lomollo

Kisanana

Tabarweche

Chemorongnion

Sosionte

Nyimbei

IlngaruaNgambo

Perekera

LOBOI

MAJI MOTO

LAKE BOGORIA

EMS0S SP

MUGURIN

ARUS STEAM JETS

MOLO SIRWEEMINING

KIMOSET

RADAD

LELEN SWAMP

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17ARGeo-C1

Arus & Bogoria Ground temperature distribution plot

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Kapkun

Kimorock

Chepkoimet

Kailer

Kures

Marigat

Chebaral

Ebenezer

Tabarbangetuny

Noiwet

LegetetewetOldebes

Ngendalel

Nyalilpush

Ol Kokwe

Mogotio 1Mogotio 2Mogotio 3

LomolloKisanana

Tabarweche

Chemorongnion

Sosionte

Nyimbei

IlngaruaNgambo

Perekera

LOBOI

MAJI MOTO

LAKE BOGORIA

EMS0S SP

MUGURIN

ARUS STEAM JETS

MOLO SIRWEEMINING

KIMOSET

RADAD

LELEN SWAMP

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deg C

18ARGeo-C1

Arus & Bogoria Soil gas CO2distribution plot

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Kapkun

Kimorock

Chepkoimet

Kailer

Kures

Marigat

Chebaral

Ebenezer

Tabarbangetuny

Noiwet

LegetetewetOldebes

Ngendalel

Nyalilpush

Ol Kokwe

Mogotio 1Mogotio 2Mogotio 3

LomolloKisanana

Tabarweche

Chemorongnion

Sosionte

Nyimbei

IlngaruaNgamboPerekera

LOBOI

MAJI MOTO

LAKE BOGORIA

EMS0S SP

MUGURIN

ARUS STEAM JETS

MOLO SIRWEEMINING

KIMOSET

RADAD

LELEN SWAMP

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0.10.2

0.30.4

0.50.6

0.80.9

11.5

2

2.53

3.54

4.510

% V/V

19ARGeo-C1

CONCLUSIONSA GEOTHERMAL RESOURCE EXISTS IN ARUS AND BOGORIA,145–325 deg CTHE UPFLOW MAY BE LOCATED IN THE AREA CLOSE TO THE ARUS STEAM JETS AND THE AREA NORTH OF MUGURIN. High radon and ground temperature.

20ARGeo-C1

AcknowledgementsSpecial thanks to the Management of Kengen for allowing us to publish this paper

Thank you very much

Have a wonderful WEEK