E4422 V3 Tanzania Energy Development and Access Project (TEDAP) P0101645 Environmental Assessment – Annex 2: Geological Investigations (EA) Part A (January 2005) E w 7 ,~~~1.4 .# t REINFORCEMENT AND UPGRADING OF DSM, KILIMANJARO AND ARUSHA TRANSMISSION UNES AND DISTRIBUTION SYSTEM PROJECT: Environmental Studies ANNEX 2: Geological Investigations Leonard B. Kassana Research & Development Department, Tanzania ElectricSupply Company Limited, P.O. Box 9024, Dares Salaam. Tanzania. January2005 I Reinforcement & Upgrading of Dar es Salaam, Kilimanjaro And Arusha Transmission ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL INVESTIGATIONS Lines LIST OF TABLES Table 1: Grain Size Distribution Table 2: Average PH levels Soil Properties LIST OF APPENDICES Appendix 6.1: Maps Appendix 6.2: Test pits logs Appendix 6.3: Laboratory Results Appendix 6.4: Photo Records of the Investigation Area Appendix 6.5: Other relevant literature and correspondence docs ACRONYMS AND ABBREVIATIONS CH Inorganic clays of high plasticity kv Kilo Volt MA Moshi-Arusha ND Non-Dispersive QDS Quarter Degree Sheet pH Negative decinal logarithm of the hydrogen ion activity Pi Plasticity Index TANESCO Tanzania Electric Supply Comnpany Limited Km Kilometers SM Silty sands and sand-clay rnixtures ToR Terms of Reference TP Test Pit USCS Unified Soil Classification System (American Society for Testing and Materials, 1985). Leonard B. Kassana Tanzania Electric Supply Company Limited iii 1/26/2005 And Arusha Transmission Lines Reinforcement & Upgrading of Dar es Salaam, Kilimanjaro INVESTIGATIONS ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL ACKNOWLEDGEMENT for the assistance in one-way or the other. Their The author is highly indebted to the following people helpful in carrying out this task: logistical support and comments as well, have been Dar es Salaam: * Mr. K.R. Abdulla - Tanesco, Director Corporate Planning & Research * Mr. D.E.P. Ngula - Tanesco, Manager Research & Development * Mr. M. Katyega - Tanesco, Chief Research & Investigation Engineer * Mr. K. Kabaka - Tanesco, Senior Geologist * Messrs Mansur, H & Lazimah, J - Tanesco Environmental Engineers Arusha: * Mr. C.J. Masasi - Tanesco Regional Manager Lines * Mrs. Dina Msuya - Tanesco Civil Engineer Technician, Transmission iv 1/26/2005 Leonard B. Kassana Tanzania Electnc Supply Company Limited Reinforcement & Upgrading of Dar es Salaam, Kilimanjaro ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL And Arusha Transmission Lines INVESTIGATIONS EXECUTIVE SUMMARY This document is an annex to the main report for Reinforcement & Upgrading of Dar es Salaam, Kilimanjaro And Arusha Transmission Lines ENVIRONMENTAL STUDIES. It deals with issues pertaining Geology and in particular soil conditions and its main objective is to obtain general overview of the geological/soil conditions of the project areas. * Ihe proposed corridors for the Moshi - Arusha 132 kV overhead transmission is approximatejy 70 km long and the Dar es Salaam transmnission routes are approximately 43 km long. Regionally, the Moshi - Arusha area lies within the Great Eastern African Rift Valley and is dominated by volcanic formations. The transmission corridor traverses east west through southern lower flat lying foot of the mounts Kilimanjaro and Meru. The proposed transmission corridor was selected to run parallel with the existing 132 kV transmission line from Moshi Kiyungi substation to Arusha Njiro substation. * The Moshi - Arusha transmission towers will be founded in volcanic sediments mainly consisting of Sandy Silty CLAY and few places have soils mainly composed of Sandy SILT/Silty SAND. * Soil samples taken from Moshi - Arusha Transmission line varying, a bit on the acidic side and largely on the alkaline corridor have pH values slightly side. About 80% of the tested soil samples have PH values greater than 7.0 indicating that the soils are alkaline in nature. Only 20 % of the tested soil samples show acidic nature. By these results, - Arusha Transmission line route are not acidic and therefore the ground conditions in the Moshi a very less corrosive threat to the transmission towers. it may be inferred that the site pose During the fieldwork, random visual inspection was conducted on the existing 132 kV transmission not observed on the towers. towers and corrosive effects were * The Dar Transmissions corridors are located in the coastal superficial sands of the flat, low lying coastal plain represented plain environment dominated by from the fault blocks. River alluviums consisting of sands by redistributed outwash material varying from off-white to buff-brown are also found in the corridors. Test on soil pH for the samples collected from Dar corridors show that the soils specimen are acidic, but the number of soil samples is too small to make a definitive conclusion. * Due to terrain nature of the transmission corridors and taken from the sites, it is apparently inferred that soil non-dispersive nature of the few samnples erosion Control measures for soil erosion will have to be determined along the transmission is not severe. design/construction phase. At this stage of this report on a tower-to-tower case during the we may not have a suitable blanket solution. * Due to the preliminary nature and time/budget constraints of the study, the Field Resistivity measurement for assessing electrical conductivity of the period and thus it is recommended to be done at later phaseground, was not conducted during this of the study/implementation. Leonard B. KIassana Tanzania Electnc Supply Company Limited v 1/2&62005 And Arusha Transmission Lines Reinforcement & Upgrading of Dar es Salaam, Kilimanjaro INVESTIGATIONS ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL 1. INTRODUCTION of Kilimanjaro-Arusha Transmission Lines and The field investigations for Reinforcement & Upgrading weeks no. 49 and 52 of 2004. This Dar es Salaam transmission lines took place between respect to geological/soil conditions of report gives an account of preliminary findings with the project area. of Tanzania for Moshi-Arusha and Dar es The project areas are situated in Northern and Eastern parts Transrnission Corridor lies between 30 Salaam Transmission routes respectively. The Moshi-Arusha Longitudes. The Dar es Salaam transrmission 22' S and 30 26' S Latitudes, 36°41'E and 370 19'E 6°43' and 6°56'S latitudes and 39°10' corridors lie between the following geographical coordinates: are shown in Figure 1. areas and 39021 'E longitudes. General locations of the project Lake ~- R ^^,, *Nawasha 0 150 km rr-ftw*a oLaa uru s Wbere R. \ Mimlagqwi R N -Tbora. *Songidao __ .Tanzania -- Wm1ilmR R-ib * Mpsd KJiQgo-R Tahg~nkaKIIOSO * Ruvu v A Sumb(wng F G,u RBuah ra i Ir. . ftfakra. . R u ;k-- Mibmbe, HL"o.A * PiorectAre.s 1o, LaKe Zambiea1 BEangweLIu X. 0i Malwr @i'g7 MAGELLAN GeographixRI Mozarbique v (805) 685-3100 www.maps.corn94 _ Figure 1: General location of the Project Area Leonard B. Kassana 1/26/2005 Page 1 of 8 Tanzania Electric Supply Company Limited Reinforcement & Upgrading of Dar es Salaam, Kilimanjaro And Arusha Transmission ENVIRONMENTAL STUDIES- ANNEX 2: GEOLOGICAL Lines INVESTIGATIONS 1.1 Scope of Work The scope of the assignment was to obtain general overview of the soil and general geological condition of the area so as to highlight preliminary effects of soil erosion with respect Environmental Impact Assessment. Specifically, to the scope included: * Scan and traverse along the proposed corridor documenting rock and soil types in general i.e. Overview Mapping. * Zoning and documenting different geomorphologic conditions along the proposed corridor * Spot soil investigations at few selected sites at locations to be determined at the site geologist. by the 1.2 Methods of Investigations Senior Geologist, Mr. Leonard B. Kassana of Research and Development Department, TANESCO Head Office, executed all investigations in accordance to the ToR. The field light investigations consisted of: * Carrying out soil investigations within the selected transmission corridors by test pitting. samples were collected for laboratory analysis Soil as well * Ground water measurements in the Investigation pits. * Overview Geological Mapping * Literature search relevant to the project. An overview mapping was based on: * Interpretation of topographic map at 1:50,000 and 1:100,000 scales * Interpretation of Geological maps, Quarter Degree Sheet (QDS) at a scale 1:125,000 * Walkover survey along the proposed transmission corridors Refer to Appendix 6.1 for maps locating investigation areas. 2. TOPOGRAPHY, REGIONAL GEOLOGY AND SITE GEOLOGICAL CONDITIONS 2.1 Kilimanjaro - Arusha Region 2.1.1 Topography The project area is dominantly covered by volcanic country at about 900 m.a.s.l For Arusha areas, mountain massifs rising abruptly from plateau mount Meru raises from about 900 m.a.s.l summit of about 4600 m.a.s.l. and Kilimanjaro to the rises from about 900 m.a.s.l to the highest peak 5895 m.a.s.l. of In general, the proposed transmission line runs parallel to both existing 132 KV Moshi Transmission line and the main Moshi - Arusha - Arusha road. The line runs almost east west direction of the high volcanic mountains in Africa, namely south Kilimanjaro and Meru. The transmission lines running parallel to the Moshi-Arusha road are in the south of the mountains. North of this terrain is of mounded topography formed by road, the Meru lahars while in the south of the road and our transmission proposal is running, outwashes where from the lahars form a more even plain. Wide spread topographical features are formed by the spread of 'lahars' or cold mudflow in south and southwest of mount Kilimanjaro emanating the from Kibo peak and mount Meru. For the further details of the topography the reader is kindly referred to the special QDS #42, 56 & 57 and QDS #55. covering Leonatd S. Kassana Tanzania Electnc Supply Company Limited Page 2 of 8 112612005 And Arusha Transmission Lines Reinforcement & Upgrading of Dar es Salaam, Kilimanjaro INVESTIGATIONS ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL 2.1.2 Regional Geology products of Pleistocene to Recent. According to Mt. Meru and Kilimanjaro are younger volcano essentially the geology of the QDS, Quarter Degree Sheets (QDS) # 55 and the KilimanjaroSpecial and some interbedded sediments of Neogene volcanic products area is consisting of a pile rocks. accumulated on eroded surface Precambrian metamorphic located on transverse branch of southern The two volcanoes together with other formations are African Rift System as shown in figure Gregory Rift, part Great Eastern Branch of the Great Eastern 2.1.2 . .assana av L. a3L1 E- Tanzana fbr2.1.t Sois i h PoetAre T2A N Z NA I As .. , - > Fiqu9e? nunaruwe an Ugd. of /s> X§tZ* --- s r,^,/ J lr Su3nm, Klflmeanjmro and Aruuh'a mnam.Ion and Olibulon l byan - EniTonment i UIy: Annex Geo - Iuestgoo ,d .... .~,.d b.~' i.~.. GENERA! STRtuCP4kf - d CA kOA'v -d.. c.... .. ,at - I S -. X -d9- -, ;' P>p t 12kVTanmssoWLn N iuIONeIgiaM ESoiarsaIan 0A20 N t..oy. 8611111&-k b Diecso.teof Oer... foapfto~ 1.0.~ohee, pA . 4 Mt eO C3 LCNsRd Scal 11 25 00 0 r 1Eic h 1I y D i o s mo o o d b y Ge o l o i c a l S . i , v I 3 5 7 S 9A SMS. - It 0 W!.!!. 'I b ii~ ~ ,.~.onof Ol MO~I5~ c LOA.. M!.! O,IIS .0 - ~., % - ~ - -. '~. -'2 7 C 2zc z ,, 2 r: -; ;-- I L - - - ; S~~o:c - TANESCO Grid Reinforcement Project 6Z New 132kV Transmission Line (parallel to existing 132 kV line) -I---- ' - 1 a'aa . t 9i40000 MTovo ' %s(,,Hjs L' a I . . J9E100 <-WERU 90XG ., : tc-r;. . ,, ' LS. . *~ . - - traw * r : *- -g **- ',a -n, WAT ' \ T ' ' , 'rl- -n -. a2E i - 1 j ',fl - : '0CS0 '4 .: 2 i-CSCC ,. ''a.a : 5,R2o aIa. N 1 -. -- -*~~ S. ;C-b .4nt xsig1J TLh;4 ;; .3 .tAJa x sc . - . - * - . twe ^ e ;i:......... Iew ,, hr N % -- .................. '......................... !-- t 96T00, E 5Xa~ ''" I * ,,~ A " 1 . :X Jaa ''a0 a,,, 9614' A0. \a - /S Pir .- ~ - :R'7 -, 7.d av " 5 ' Pr .x TP' I i'7c'1 . : Oaa km- 72---------- km 34 -k 58 a kn22 kn 4La' '/ "RI 3 m6~ 1 no ! -. -'' SNac-da , t' Inesiatiap. iure2 foM*;r I 2 seoctoo Tr'ans is L 1 ~e- s '- o -ne6^ .:Saei ANNXiGOOAL/SOIL INVSIATIN 66110000 X-I. 1 'ra~- .II4uaj /TANESCO :~; TANZANIA ELECTRIC SUPPLY COMPANY LIMITED 4~~~~~~r 6 *d .. Ca "~'a 3Renrcement * Upgrading Of Dar es Salaamn, Klamanjaro And Aru5ha I ' Y7 I.L -Tran5mi5siaon .-. L'ne5 -. ~ ~ aIc~ENVIRONMENTAL STUDIES _____________________ANNEX 2: GEOLOGICAL/SOIL INVEFSTIGATiOWS IPigre2:fr oshi Ar-usha 132kvTra'nsnm--i-jo-nLine 24 02oCCa.C 2~c-lrco 2700000 230000 .2900C0 30000 31 0C0 TANZANIA ELECTRIC SUPPLY COMPANY LIMITED ' temforcement 4 Upy adhn'3of Dar c5 5aWaM. V'- N ~Khmanjaroand Arusha T an5m*%cmo I-mes ANNEX IEALSO INVESTIGATIONS STUDOLO Fiigure 4: Dar es Salaamproposed 132 ky Transmission ,ed1 32 kV -50- IamrNyalats .DAWES SALAAM Reinforcement 4 Upgrading Of Dar e5 5alaam. Kilimarijaro And ArUsha Transmission Lbncs ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICALlSOIL INVESTIGATIONS APPENDIX 6.2: TEST PIT LOGS Kilimanjaro And Arusha Transmission Lines Reinforcement & Upgrading Of Dar es Salaam, rNVESTIGATIONS ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAIJSOIL APPENDIX 6.2: TEST PIT LOGS LINE AA: MOSHI - ARUSHA 132 KV TRANSMISSION Moshi - Arusha 132 KV Transmission NB: All test pits were excavated within the existing way leave TP 1 Sample Remarks Depth (m) Lithological Description from top 0.60 - 1.70 GW Dry 0.0 - 0.4 Dark Grey clayey SILT, with vegetation roots All soils are 0.4 -1.1 Brownish Grey clayey SILT volcanic sediments 1.1 - 1.7 Yellowish Brown SILT, hard clump TP 5 Sample Remarks Depth (m) Lithological Description from top #1:0.21-0.51 GW = Dry 0.0 - 0.3 Hard, Yellowish Grey clayey SILT #2: 0.0-0.21 All soils are 0.3 - 51 Consolidated soil - Yellowish grey hard volcanic crust with whitish spots sediments TP 6 Sample Remarks Depth (m) Lithological Description from top 2.0-2.5 River bank cut at 0.0 - 0.6 Yellowish grey, loose, clayey SILT Kiyungi S/S All soils are 0.6 - 1.20 Blackish grey, loose, fine SILT ALLUVIAL sediments 1.20 - 2.5 Slightly yellowish grey, very loose, clayey SILT TP 2 Lithological Description Sample Remarks Depth (m) from top 0.0- * Alluvial clay deposits 0.0 - 0.6 Cobles, gravels in black cotton soil 0.60 with cracks seen on matrix the surface. 0.4 - 1.0 Highly (grade IV) Weathered * Cobbles are volcanic rock subangular 1 of 3 1/2f2005 Leonard B Kassana Tanzania Electric Supply Company Limited Reinforcement & Upgrading Of Dar es Salaam, Kilimanjaro And Arusha Transmission ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICALUSOIL Lines INVESTIGATIONS TP 3: Located at 30 m north of angle tower # MA II I Depth (m) Lithological Description Sample Remarks from top 0.0 - 0.50 Dark Brown, medium dense clayey 0.0 - 50 * Rock lump in filled SILT with calcitic material 0.50 - 1.30 Highly weathered (grade [V) volcanic rock TP 4: Located 300 m west of River Sanya on the right hand side bank, flash flood area Depth (m) Lithological Description Sample Remarks from top 0.0 - 0.8 Grey, loose, dusty sandy SILT 0.0-0.8 * Gravels are sub angular 0.8 - 1.1 Gravel in Silty matrix TP 7: located 30 m north of tower # MA 12, top of a ridge Depth (m) Lithological Description Sample Remarks from top 0.0 - 1.30 Reddish Brown firm clayey SILT 0.0-1.30 (Lateritic Soil) Leonard B. Kassana Tanzania Electnc Supply Company Limited 2of 3 1/26/2005 And Arusha Transmission Lines Reinforcement & Upgrading Of Dar es Salaam, Kilimanjaro rNVESTIGATIONS ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICALUSOIL LINES BB: DAR ES SALAAM CITY 132 KV TRANSMISSION LINE BB1:FZIII - MBAGALA s/s 132 KV TRANSMISSION 14, logging done at the road cut of TPD 1: about 150 m west of the proposed angle tower TW TAZAMA pipe access road. Lithological Description Sample Remarks Depth (m) from top 0.0 - 1.80 Reddish Brown, sof to firm Silty CLAY kv substation TPD 2: located at the proposed Buza/Kipera (Yombo) 132/33 Depth (m) Lithological Description Sample Remarks from top 0.0 - 0.30 Grey silty SAND 0.30 - 1.0 Yellowish Grey silty SAND BB2: UBUNGO - MIKOCHENI 132 KV LINE Nujoma road bridge. All soils are TPD3: located on the left bank of Ubungo River at the Sam alluvial deposits Lithological Description Sample Remarks Depth (m) from top 0.00 - 0.25 Dark grey clayey SILT 0.25 - 1.00+ Grey, medium SAND site TPD4: Excavation pit of the Mlimani Holdings Project construction Depth (m) Lithological Description Sample Remarks from top 0.00 - 1.40 Yellowish Grey, clayey coarse SAND 1.40 - 2,00 Dark grey sandy clayey SILT Leonard B. Kassana 3 of 3 1/26/2005 Tanzania Electric Supply Company Limited Reinforcement 4 Upgrading Of Dar e5 Salaam. Kilimanjaro And Arusha Transmission Lines ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAJJSOIL INVESTIGATIONS APPENDIX 6.3: LABORATORY TEST RESULTS. SOIL pH TEST OF SOIL SCIENCES COMMITTEE OF THE INTERNATIONAL SOCIETY PROJECT:- Tanesco Power Lines Date:- 27 December, 2004 MLIMANI pit MBACALA TP4 TP6 TP7 SAMPLE TP I TP2 KIBURUGWA PIT 0.60 0.00 - 0.80 2.00 - 2.50 0.00 - 1.30 No. 0.60 - 1.70 0.00 - 0.00 -0.50 30 30 30 30 30 30 Mass ofsoil 30 used 75 75 75 75 75 75 Volume of 75 distilled water used mls 1:2.5 1:2.5 1:2.5 1:2.5 1:2.5 1:2.5 Soil to Water 1:2.5 RATIO 6. 7.17 7.03 7.15 7. 16 | 73 0 9.259.24 9 7631764| 7.3 6.1669 measured 6.3i 6.35 6.36 9.56 7.63 6.15 7.07 6.36 8.54 7.15 Average pH value 29.8 29.8 29.7 29.8 29.8 Temperature 29.7 29.8 degrees cngrde - -:c-, - PIN HOLE TEST. BS 1377: Part 5: 1990 SAMPLING DEPTH CLASSIFICATION FROM PIN HOLE SAMPLE No. TEST 0.00 - 0.60 ND4 PIT No.2 ND4 0.00 - 1.30 PIT No. 7 TESTED AND REPORTED BY: A J.MBUYAH i Dje of Tunpoabon& Gecmica- fa oCMh En& &The BLh Exvizonrnz _4c Colpf EWeznn & Thhual WUyivk of Dar-eU P O. Box 35131 - . %-. . C SILT IM 100 omws. COfaLn -i - |- 80 - T 00 2. w- 02 zX 0 mz 30.0 0.00 10 100.00 40~~ 0.oxx53 0PI0.0T 0.70 CH SAD lr LY 2 4 - -4 200 TP TO 6 2.50SM CLAYEY TICLE SI PAND - mm4 IN ta 5; - 4- TP1-ETH06 - 1.0meesT2DE H 0.0 - .6mts-A- T 4DPH00- 0.0 E ete - - - T6DET2.00-.0mte LOCATIONP UO. Cax CO51S3NC 3\^ SM- C.YYRVLYITSN O.30T00.6 - 1 8 -P COSZLIS WmC CzAY SILT 100 - 1 0 800 I o . - d6 NO, - .0 '1.0'100 01 0 0.0 ' EI- - 0 - ee .0O5mrSMAAA IIAIDPH EPH00 1.0C)e |-+ - P 20 ii 0 000.01 0.10 1.00 10.00 10.oo PARTICLE SIZE INmm - -MLIMANI DEPTH 00- 0.50mvetrs -- MBAGALA- metres. -4--TP7 DEPTHO.O00- 1.30memr Uc. CC.COSTEY l LOCATION DEPTH OF SAMPLING USCS SOIL DESCRIPTION 6 -de % %% SAND GRAVEL SAMPLE No. die dio .dw CLAY SILT SYMBOL No, GRAVELLY SANDY SIL TYCLAY 57 31 10 o 4P70.60 CH4 5 TO1.30 15 15 7PY tyot C* ft &I Buik 0 C14 GRAVELLYCLAYEYSILTYSAND - 6 MLMNI 0.50 TOc1 1 8 = O73 Su eLAYEY SILTY SAND 7 7iMBANG - B 35131 P 0esSaaa - Reinforcement 4 Upgrading Of Dar es 5alaam, Kilimanjaro And Aru5ha Transmt55ion Line5 ENVIRONMENTAL STDIES - ANNEX 2: GEOLOGICAJSOIL INVESTTGATIONS APPENDIX 6.4: PROJECT PHOTO ALBUM Kilimanjaro And Arusha Transmission Lines Reinforcement & Upgrading Of Dar es Salaam, INVESTIGATIONS ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAUSOIL APPENDIX 6.4: PROJECT PHOTO ALBUM AA: MOSHI - ARUSHA 132 KV Km 00: View showing LHS bank of the Moshi- Lukaranga River. In the background the Arusha tower no. I can be seen -,. - ., - Km 3.0: View to the East - Km 3.3: View to the East Leonard B. Kassana 1/26/2005 Tanzania Electric Suipply Company Limigted Reinforcement & Upgrading Of Dar es ENVIRONMENTAL STUDIES - ANNEX Salaam, Kilimanjaro And Arusha Transmission Lines 2: GEOLOGICAL/SOIL INVESTIGATIONS Km 6: View to the East - . -- .- ' , - -- Kmn 6: View showing a local lady collecting 'Magadi' - Soda : FBicarbonate - e -. Km 14: View to the East LAA6 Leonard B. Kassana Tanzania Electric Supply Company jj Limited 1/26/2005 Kilimanjaro And Arusha Transmission Lines Reinforcement & Upgrading Of Dar es Salaam, INVESTiGATIONS ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL/SOIL - - -- Km 24: View to the Southi AA7- .- !o ,X, - -~~ V'sS Km 24: View into TP 4 Km 24: View to the tower footing iii Leonard B. Kassana 1/2&2005 Tanzania Electnc Supply Company Linited Reinforcement & Upgrading Of Dar es Salaam, Kilimanjaro And Arusha Transmission ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICALUSOIL Lines INVESTIGATIONS -- Km 30: View to the West. IAAI Km 34: View to the West - L. - Km 34: View to the East AA12 Leonard B. Kassana Tanzania Electric Supply Company Limited iV 1/26/2005 And Arusha Transmission Lines Reinforcement & Upgrading Of Dar es Salaam, Kilimanjaro INVESTIGATIONS ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICALUSOIL Kin 34: View into the TP 3 Km 58: View to the West : - -- Km 58: View showing the expansive ground v 1/26/2005 Leonard B. Kassana Tanzania Electnc Supply Company Limited Reinforcement & Upgrading Of Dar es Salaam, Kilimanjaro And Arusha Transmission Lines ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL/SOIL INVESTIGATIONS "T Km 58: View into TP 2 L - .* ~416___ __ . & - ( W - Km 72: View to the East A 17 Km 72: View into TP I Leonard B.Kassana vi Tanzania Electnc SUPPIY ComPany Limrted 1/262005 And Arusha Transmission Lines Reinforcement & Upgrading Of Dar es Salaam, Kilimanjaro INVESTIGATIONS ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL/SOIL BB: DAR ES SALAAM TRANSMISSION LINE CORRIDORS BB 1: UBUNGO - MIKOCHENI LINE ~w-. Km 0.3: View showing the alluvial sand on the RHS of Sinza River , . , PlateBBI-1 - *" Km 3.3: View at Mlimani City Project construction pit showing ,.. erosive effects on the soil strata Kin 3.3: View as plate BB 1_2 l .- *F-, -~ showing a wide view of the ____ _construction pit Plate ; .K Vl Leonafd B. Kassan'. vii 1/2/2005 Tanzania E;ectrc Supply Company Limited Reinforcement & Upgrading Of Dar es Salaam, Kilimanjaro And Arusha Transmission Lines ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL/SOIL INVESTIGATIONS BB2: FZHI SS-MBAGALA SS LINE Km 0.0: View looking northerly .. -direction showing the Factory ~ ~Zone Eg 132/33 kV substation Plate BB2-1 -A:' w~~~;,~K * 1 n.0:0sS' View looking southerly direction showing the 132 kV Feeder outlet Factory Zone m 132/33 kV substation to Plate BB2-2 I ~ .-. Km 9.1: Looking southeast .- direction showing terrain and vegetation where the line traverses Plate BB2-3 Leonard B. Kassana Tanzania Electric Supply Cornpany Limited Vil12&2005 Arusha Transmission Lines Reinforcement & Upgrading Of Dar es Salaam, Kilimanjaro And ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICALUSOIL INVESTIGATIONS Km 9.1: Looking northwesterly direction showing terrain and J '3 -vegetation where the line traverses PlateBB24t View at kml10.0: Looking condition of the line traverse Plate BB2-5 : * (.. s~~~ ."t:!. ~ ~ -z ' ~< - - =Km 12.0: Looking west showing i . -. h1 . i terrain condition of the line -; - K. traverse Plate BB2 - - Leonard B. Kassana ix 1R6R005 Tanzania Electnc Supply Company Limited Reinforcement & Upgrading Of Dar es Salaam, Kilimanjaro And Arusha ENVIRONMENTAL Transmission Lines STUDIES - ANNEX 2: GEOLOGICALUSOIL INVESTIGATIONS . ~,/ I,/\/ hi 'View at Mbagala substation looking north showing the line traverse and terrain conditions Plat BB-7 View at Mbagala existing substation looking east direction Plate BB2 - 8 -- - Leonard B. Kassana X Tanzania Electric Supply Company Limited 1/26/2005 Transmis5ion Lines Reinforcement 4 Upgrading Of Dar es 5alaam, r.limanjaro And Aru5ha INVESTIGATIONS ENVIRONMENTAL STJDIES - ANNEX 2: GEOLOGICALVSOIL APPENDIX 6.5: OTHER RELEVANT LITERATURE 'I ~ ~Ie.s A It.} Vt 2Ministry of Iudtnstries, Mineral Resources and Power - (Geological Survey Division) ~k:~i~ IExplaiiatory Notes '. ''on tlle "* Geological Map of Kiliiiiaiijaro - , # ;- ; I ,, * * PREFACE The Sheffield University Kilimanjaro Expedition began the mapping e mountain in 1953 with the assistance of the Geological Survey of Tanganyika. and included N ' project was under thc leadership of Mr. W. H. Wilcockson Officers of the Geol, Wilkinson, Dr. C. Downie and Dr. D. W. Humphries. were N. J. Guest, G. P. Leedal and D. N. San- 1. Survey attached to the Expedition was carried out making u f -During the first season a general reconnaissance early German topographical maps of the mountain. on the mountain in 195, r The memnbrs of the Expedition continued workgeneral distribution of lava the preliminary -trological work bad.indicated the R. Neves then joinec from the volcanic centres. Prof. L. R. Moore and Dr. Expedition. 56 and 57 rapid m: 4 To complete the area of the quarter degree sheets 42. of Moshi was compl. n on the plains and lower slopes in the neighbourhood G. R. Orridge of the Geological Survey Division r - 1963 by E. W. Hanley and the extreme north-west by D. N. Sampson. The geological map has been prepared by Dr. C. Downie and Mr. P. Wilki The final completion of the map was held upcompilation until the 1:50,000 contoured from this scale and I based on air photographs were available. The H. E. Empson, Chief Draugh: draughting and checking has been carried out by of the Geological Survey Division. A full geological account is in the final stages Meanwhileof preparation by memb. it is felt apprn, the Geological Department of Sheffield University. in the 1:125,000 geological p that the results of the mapping should be issued series being published by the Tanganyika members Government. The following accour Mir. P. Wilkinson, Dr. C. Downie and other of the expedition provides a and summary of the history and petrography of this f. minary description supply aspects of the gi mountain. Brief descriptions of the economic and watcr have been added by officers of the Geological Survey. written on Kilimanjaro by memN i A number of papers have already been end of this account. They do not. hox' the Expedition and these are listed at the constitute a full bibliography of geological work done in this area. J. W. PALtisrER. Dodoma, April, 1964 Conmmisioner for Grologic,,I S CONTENTS- PHYSIOGRAPHY . ... .... ... ... . ... GLACIAL DEPOSITS . .. ... ... ... ... ... GEOLOGY ... ... .. . ... ... ... ... ... ... PRECAMBRIAN ... ... ... ... ... ... ... NEoENE ... ... .. ... ...-. Shi ... ... .. . .... .... - 01. Molog group ... ... ......- ... 3 Maweaizi ... ... ... ... ... ..... .. The Neumtann Tower group............ ... .. 3 The Mawenzi grouip 3 Kibo ... ... ... ... ... ... ... ... ... 3 The lower trachyandesite group ..... .... ... The Lava Tower trachyre group .... ........ The lower rectangle porphyry group ... ... ....... The upper trachyandesite group and the upper rectangle porpl group ..... ... .. .. ... The rhomb porphyry group ........ ... .... ... The Lent group ........ ... ... ... The small-rlornb porphyry group ... j Analcime syenite ... . . Kibo "lahar" . ... ... The Caldera Ri;m group . 5 The Inner Crater group Intrusions . . . . . .. Parasitic Cones ... ... ... ... ... ... The Saddle zone The Roinbo zone .. Kilema zone. ... Kibongoto zone ........ .. ... ... ... Shira and Lagun,ishera zones . . Present Volcanicity ...... ... ... .. ... ...... Meru "lahar" ... ... ... Alluvium ... ... ... Amboseli lake beds ......... ... ... Calcareous tulTaceous grit ... Red soils ... .. ... Wind.blown sands....... Rr,IONAL SIRUCIURAL FEA1URI.S VOLCANo-TrCTONIc Fr.ATUIRlS ECONOMic Gr.OLOGY SELECTED BinLIOGRAPIIY . ... ... PHYSIOGRA f Kilimanjaro, which occupies most of this sheet and spreads into adjoining ones, is a volcanic mountain massif rising abruptly from plateau country at about 3,000 to 4,000 feet above sea level to culminate on Kibo in Uhuru Peak, 19,340 feet, the highest point on the African continent. The plain-on which the volcanic pile accumulated is a warped and faulted erosion surface the age of which is still uncertain. Despite its near-equatorial position, the great height of the mountain has caused the glacierization of the Kibo peak above about 15,000 feet: Six glacial episodes have been recognized of which the third was the most extensive and included the glacierization of Mawenzi and to lesser extent of Shira as well as Kibo. The earlier of these glacial epi- sodes took place during the activity of the volcanoes as shown by the presence of tillites underlying lava or pyroclastics, and have continued since the centres became extinct. Terminal momines are found as low as 10.000 feet on Mawenzi and Kibo. Recent climatic change, however, has shifted the perrnanent snow-line above the summit level and the glaciers are now recedini rapidly, leaving lateral and terminal moraines which form a distinctive feature of the topography. The great altitude also leads to striking contrasts in vegetation. A rough zoning of the mountain is as follows: (a) Ice and Alpine Desert, above 13,500 feet; (b) Heath or Moorland Zone from about 10,000 to 14,000 feet with giant senecios, lobelias and Erica spp.; (c) Mountain Rain Forest Zone, 6,500 to 9,500 feet; (d) Cultivated Temperate Zone, from plain level to about 6,500 feet with coffee, bananas, wheat, maize; (e) Plain at 2,500 to 4,000 feet, semi-arid steppe. The drainage pattern is, in a general way, radial from the three major centres and rivers cut deep gorges into the flanks. Water-flow is seasonal in the north and east and passes, by way of the Tsavo River, into the Athi (Galana) River system. In the extreme north-west the intermittent drainage flows into the dischargeless basin of Lake Amboseli. The rivers of the west and south drain into the headwaters of the Pangani River. Widespread topographic features are formed by the spreads of "lahar" or cold mudflow in the south and south-west, emanating from Kibo and from Meru, a prominent extinct volcano which lies to the west. In the south, at heights of about 2,500 feet, lie the extensive alluvial plains of the Upper Pangani and its tributaries, and in the north the south-westem parts of the Amboseli Basin appear as widespread alluvial and lacustrine deposits at heights of about 3,700 feet. GLACIAL DEPOSITS Above the forest level and at heights between 11,000 and 14.000 feet, terminal moraines belonging to the last glaciation are conspicuous on the flanks of Kibo and Mawenzi. Behind them the corresponding lateral moraines follow the ridges up to about 15,000 feet. The enclosed area is richly endowed with glacial phenomena including cirques, glaciated pavements, boulder-trains, crag and tail, roches mo1ltonn&es. Outwash gravels, almost entirely cover the Saddle area. Sets of retreat moraines are sometimes present and more recent moraines exist near the glacier snouts on Kibo. Outwash sands and gravels cover wide areas of the flanks notably north-west and south of Kibo and south of the Saddle. In places they extend down to below 9,000 feet. GEOLOGY Essentially the geology consists of a pile of Neogene volcanic products and some interbedded sediments accumulated on an erodedl surface of Precambrian metamorphic rocks. Pxr.CAMNIRIAN Within the boundaries of the sheet therc are only a fesn restricted otut- crops of Precambrian rocks, all of whiichi have been assigned to the Usagaran of the the Mozambiquian orogenic belt. These outcrops represent the tops of inselbergs on and pre-volcanic surface and continue the topographic trends of the North Pare Lelatema Mountains in the south. *north-west comner of the sheet biotite gneiss forrr small hill and, east :rystalline limestone appears as a small outcrop. -. the south-west four ciAl Moo roup.-On- the north-western flanks of the mountain, belos, occurs a group of olivine basaltic and trachybasaltic lavas which appcar i present the northern foothills of the Lelatema Escarpment. High-grade one of the earliest eruptive episodes of the mountain and may havc been dl-t i.,nts are here exposed and include garnet-quartz-feldspar granulite, quartzite, the early Shira centre, iu'ianite granulite (khondalite), dolomitic marble, calcite-diopside marble and ..olite-homnblende-quartz 'granulfte. A small is-olated outcrop of crystalline- Mawenzi.-The highly eroded rocky mountain Mawenzi, with its binl crsin the foothills. H-ans Meyer Peak, 16,896 feet. is a complex erosion residual between ii -at :I troun ouh-est .cride and/the botcrops arouie he ~tcrps Kiumb incudequatzo-eldpatic ganuitecornies. The most important of ihese corries lies on the east at the bet- ndis aifnd iuncflude spartzafndsahomlnic grnuieg Great Barrancoi, a 4,000-foot gorge whith offers the longest and most continuo. .knde Land/or bidgotsite, o biotitegeis and quartz-feldspa andis biotitic quartzo- through the mountain. Mawenzi is a complex volcano with two majc heaeaRigcosssobittanhobedenes,visible, giving rise to two groups of volcanic rocks. Both centres have bCL r. %t, gneiss and smri-icalcareous gneiss. In the two hills north-west and north- since the early Pleistocene. Laterna, retrogressive homnblende-hyperthene gneisses and granulitesi showing- ipient migmatization are found. These -occur'rences in the south-east lie a -I The Niuman'n Tower group comprises a succession, mainly of lavas, stii :1 north of the North Pare Mountains, In general, the foliation of all these :.s NNW.-SS. with an inclination to the ENE. at 35-45'. )following range of rock type: ankaramite--olivine basat-asphyric and feld' r1. olivine trachybasalt and trachybacalt. The lavas dip out from a complex ! an agglomeratic infilling and intrusive bodies, situated at the Neumann Too't II NmEoNEe lavas represent the earliest visible activity of Mawenzi, and in the upper p. f: cieo h ocnct omneeto sucran ute ot nThree Kings' Valley and-in the Great Barranco, where they form the entire %s'.. cc o earles knowmnceogent o volcankicys haverbeen. da rthedrbisortopicn they are seen to be overlain by lavas of the Mawenzi group. To the sou .14 I. ealeto 3 'knillown. yeasold,e namely,icofv Mieene dage, The eriesotopi Great Barranco the Neumann Tower lavas occupy the whole south-east M; 13ol, o amey, 1 mllin f yariocneage Th erlistMawenzi but (heir full extent is much obscured by later parasitic I: n o volcanics can only be dated as Mio-Pliocene and activity has continued blanketing forest. Thus, although their distribution is probably extensive, i'csoeeinto Recent times with diminishing frequency and importance. with lavas below the forest line is conjectural, now limited to local fumnaroiles. The early history is little known because of The Mawenzi group is so named because all the principal peaks of Nft-. ve cover of younger extrusives. From an early stage, activity has been built of. its members. It is a sequence of effusions, including considerable a: .isd around three major centres, which now correspond to the three main .t~ pyroclastic rocks, showing the following range of types: olivine trachyt- I.:summits of Shira, Kibo and Mawenzi, The structures of these three trachybasalt--olivine trachyandesite and trachyandesite-basalt---andesite. i ~noes mutually interfere.to form a high massif with a pronounced WNW.- characteristic varieties are feldsparphyric and carry numerous phenocrysts of Si.L catin. umerusfrm araiticcons cnspcuou zoes longcerainbytownite with a thin platy habit (length/thickness ratio up to 20-1): they r. ~ I:ns.one inch across, In the central region the lavas are often con :C ;i-Shira, the oldest centre, is a relatively simple strato-volcanic cone with a brecciated by flow and may be mistaken for pyroclastic rocks. The lava-br, :d crater. Topographically, it forms a plateau 12,000 feet high, rimmed at tuffs, especially the latter, thin rapidly away from the centre. The vents resri margn rige b a nrthsout haf mles ongof wichthethese treeanda out-pourings have been identified as plugs of syeno-gabbro grouped asi -nt, Klure Peak, is 13,030 feet high. A shorter ridge bounds the south side. of the Great Barranco and in the South Peak. th and east the structure has been reduced by erosion and buried beneath :,ions from Kibo. Mawenzi and Neumann Tower lav'as extend down the slopes on to crossing' into Kenya and are exposed in the wsalls of Lake Chala;, the group, r; trne is built mainly of lavas, although some pyroclastics are present. The been separated in these regions. Ickasscitios ae een -A conspicuous feature of the structure is the occurrence of about 601" tmite < olivine basait-trachybasalt-trachyandesite compositions similar to the lavas. They average between two and three 1 basaitenephlinte.and are relatively hard and give rise to pinnacles and ridges. Two sets of *lower exposed part olivine basalts are important, but in the upper part arrangcd radially to the Neumann Tower and Mawen7i centres res;pectively * advanced differentiates predominate. Tue trachybasalts are of the cnrsfr oifratidcneti e.Ms ye.hwvr ' nrc -.ariety, similar to those of Mawenzi (q.v.) but with plienocrysts of panralel swarm, trending W Wiird . whcetich inesect.Mst tykes,two entre T: ,oLutcr dimnensions. prle wr,tedn N .EE,wihitrct tetv ete.Ti sout11hern part of the Shira Plateau rises the conical hill called Platzkegel. ntsonalteedksadaeol ceaial ersrtd .zcd remnant of a nmajor vent-infilling occupies a roughly central position '-kiho.-The central and largest of the Kilimanjaro centres is a"p -tto the Sliira structure. The vent-infilling is mainly composed of basaltic volcano thec dome of which has been obliquely truncated by collapsc resuilti 2,with some basic lavas, and is penetrated by intruIsions of doleriticanI formation of a caldera n. ntahl ie ndaee.Tehgetpr lr.Similar small intruisions occur at the eastern limit of the south ridge caldcra rim is on the south and culminates in Uhuru Peak (formerly Kaises i On ilic inner slope of the main Shiira Ridge a small subsidiary centre of Spitze). 19,340 feet high. From the floor of ithe caldera rises an Inner ( effuNicon became active at a late stage. A radial swvarm of (tykes, crater 000 yar(1s in diameter. Within the Inner Crater lies the Ash Cone cii: :!,, s.rmdar to the tava%, is conspicuously exposed on the ridges, and terme(l the "Ash Pit", the latter 370 yards in dliameter and 425 feet deep conccntric sheets of intrusive rocks, concordant with the lavas, are visible Cratler is the site of thie last activity of tlie mountain. The southern shijol I: arc dissected by glaciated vles but oneyrar thie Great Wet Ni --tst of the Shiira Plateau, in ithe upper parts of thec Kikafu Valley, th soutlisset Side doeis erosioni expose any considerahle section into thec %itri .itre" Sediments are exposed. ocn.Hre taotli00fe,te(isetO sdeet ii h dl Tlhese alluvial deposits contain a wide variety rocksnarc torbe ftaoun.Th more0 reent, ilc a havcio tendedps tod flis (oldi, incluiding ijolitic rocks not seen elsewhiere on the mountain. T'hey post-date ok and catoflaeksoand.in Thirego nothingeofnth oldvaer strcture( is seen dvi ivsity of Shira.an csfltkaninlisrgonoligo h iirsutreien 2 ...e upper rectangle porphyry group is developed a spect. l ifee: taaso Kb so srngakaie inan anefrmAbove -*ndesite, through trachyte to nepheline-rich phonolite. A wide range of these prhr ucsinmr hn300fe hc opiigterobp ecs occurs, and a detailed succession is well-established, especially in the the smnall-rhomb porphyry group and the Caldera Rim group. The n ~s.Near the centre dips approach tfice horizontal on the flanks they steepen popyyIa.be,sdesntal safil emt esrb aai Ps. The lava flows of Kibo flooded westwards almost completely over Shira - -composition- from trachytes to phonolites with mega-phenocrysts of ali pat "me cast they were strongly deflected to north and -south by the peak of Mawenzi. showing rhombic cross-sections; some varieties are very close to the type !h Oslo region, whilst others can be compared with those of Mount Kenya a1 in tcetions are available only on the south and west slopes and nmoraines and - phenocryst siz Erebus in -Antarctica. There is .considerable variation in mega-phenocrvy il t !nr; .ae~iial deposits conceal the lavas over considerable tracts. The maximum and also in the presence or absence of nepheline n ach f wich ay omprse core offrequency thckneso thesevral I avagrous, %-al flows, isg~iven in the following account. myc prs oof these features have proved stratigraphically significant. fJvashasben sicesson a folos: IThe rhomb porphyry grouip (2,000 feet). The lavas of this u, li,' dterind :es aahabendtrieasflos--characterized by abundant phenocrysts of alkali feldspar up to one and f. in length, sometimes comprising as much as half the volume of the isccsino tie l nner Crater group Caldera Rim group - matrix is usually dark grey and aphanitic to glassy, but locally it may i AVC There are no neipheline nmega-phenocrysts. It. must have been the .1~ SmLen hobpophr group- Rhom-pLent group r .distributed of all Kibo lavas since flows of this type pass off the sheet booir he north, north-west, and probably south of the mountain. Individual flov.-s. A) Uprhomb porphyry group- agl r I Upper tractyanglesporhyr group exceed 50 feet in thickness, are known to extend more than 25 miles from ti ti1 Lower rectangle porphyry grotup ' point of origin. They moved by characteristic tunnel-flow mechanis,m. Locally in the region of the snouts of the Penck and Crednter glacier I1 Lava Tower trtchyte group ynot divided on map. I-1 il, Lower trachyandesite group I porphyry is underlain by the distinctive Penck rhomb. porphyry (400 feeit I very sparse feldspar phenocrysts in a very basic matrix. Elsewhere :,o ta number of localities (and at certain well-defined stratigraphical horizons), S :et fluvio-glacial and alluvial deposits occur among the lavas of Kibo and in porphyry succession commences with the WVeru Weru agglomerate whicr -ey may reach thickness of over 200 feet, e.g. in the Karanga Valley but their thick in the Weru Weru Valley at 4,200 feet altitude. Neither of these t. ii; - as extensive outcrops and they have been included in the rhomb porphiyry -. i are to small to be shown. mp The Lent group (1,000 feet). In many parts of Kibo the lavas n-i . lb A;of the Kibo lavas seen belong to the earlier part of the Pleistocene but the i i.mmb porphyry group and Calder-a Rim group erupted in the latter half of the porphyry group were succeeded, after a lengthy erosion interval, in; trachyandesites. trachytes and phonolites. These form extensive flows on rn ne and the Inner Crater activity is Recent. lower trachyandesite group (200+ feet) is the oldest set of lavas exposed. It and southern flanks of the mountain, and appear to have originsted as flam v In from fissures and centres. The most prominent centre, the Lent Peak n, m. ,I I.tricted outcrop near the Lava Tower and in the Umbwe Valley at 13,500 feet Pfeet. Lithologically the lavas resemble the upper trachyandesites. Kibo, is an impressive collapsed dome. later In the regivii central the than (700 feet). it) Lav Th-r i sen eet tacyt nl i afewplce hih n heThe grup(30 LaTwe rhyerop(0fetisseonyiafeplcshgonteporphyry group rhaomb simall is succeeded by a groiup porphtyry group of lavas in age Lent .An are characterized by abundant, euhedral rhomb-sliaped phenocrysts of rek: vI 1 * c\t flanks of Kibo. Lithologically the lavas are green, fluidal, fissile and are ' -. 'sPicuously xenolithic. Petrographically the lavas are aegirine-rich trachytes. size, generally less than half an inch in length. Sparse, small rnega-phs t ovver rectangle porphyry group (2.000 feet) is also exposed in limitedI areas neplieline are also commionly present. ,uth-ivest flanks. Petrographically the lavas are trachyandesites, differing from Anakcinie sycnu'te 01,000+ feet). Within the central portion of Kiho. tI lower trachyandesites in the nature of the plagioclase mcga-plhenocrvs'ss. the Great West Notch show that the rhomb porphvry grouip is sucL -and lower rectangle porphyries the mega-phenocrysts are of andesine vithi a conisiderable thickness of analcime-sycnite, thie bottom of which has not becr aTcross-section showving a legth/thickness ratio in the range Ill to 4/I in syenite contains small rhombic plienocrysts of alkali feldspar, andi in otl A~ II with a more reguliar cross-section resembles closely small rhomb porphyry. It is, in fact, under thought to he a pu, traclhyandesites the feldspar is a labradorite to 5/1.s(nial rhomb porphyry magmia which was extrudled presumicd tni lengii/ticknssraioinherageSI subsidence proceeded. and cooled slowly by virtue of its large atioin he rnge5/I o I/I.cauldron lengh/iicknss inse of their restricted outcrops in the same area these earliest tliree groups of io'Isr.Abudrepitceralrgaeaftmelins Ahave been represented as one unit on this map. Mo%hi at lheighits of below 3,000 feet. In places it shows tlhe mounded upper/ trachlyande.sit- grou4p (200 feet) antd the upp,-r rectangIk porphyry *iroIIJp chmaracteristic of "lattar'. This deposit was formedi by enormous debris flu's development of thie Kibo Barranco which took pl-ice at some period sub-v I tl). Trhese two groups are similar in petrography to the loweer grOupsl- Of the .:,)e, buit have a much wider distribution, again mainly in thec west and south formantion of the small-rhomb porphyry group and before thec otitpotirinve Lavas on the nortlhern slopes of the mountain approaching the Anmhoseli Crater lavas. probably to be correalaed with the upper trachynndesite group. as are thiose Tlhe Caldera Rimp grouip (630 feet) is a grouip of rhomb porphryrics 551 I *eXPOSuire west of the Karanga River at the southern base of the miountain, large, well-formei niega-phenocrysts of alkali feld%par accompanied I'-. rrectangle porphyries extend westwvard on to the Shiira Plateau and are also abundant mega-phienocrysts of nepheline %hich may approachi one inichi' utteY sections in the 3,000 to 4,000 feet level east of Macharne and at thie These lavas formedI a series of flat-lying flows filling a caldfera uAhich f m: t . u and Kikafu rivers. small rhionb porphyry lavas. 1.ater they spilled over the sidecs formiing ' upper trachyandesite group is separated from thec underlying lower rectangle channel flows on the flanks of Kibo, especially on the north and north *groupl by an important erosion surface, btut it appears to gradle upward into wvhcre sonic extend to the edge of the map. The present summit ridlge ' memhcrs of this group. Nepheline rhiomb porphyries were also erupted Jr ! Irectangle porphyry groupthog lava-flowsshwn transitionalpleors separation of the two through h ss vrinrry osfreote ph cytparasitic centre on the Saddle. 4 !nner Crater group (425+ feet) comprises nepheli: ch aegirine-phonolite Shira at,. Laguimishera zones. From the west to the north of Shiri a Ismall rnega-phenocrysts of well-shaped nepheline and more irregular ones ofwihmrtan10cesgnrlymoedpredhninheR boe hsage. thei lowtcroneuils the preasento cavder which formped atd ar ina. widest range of petrogmaphic types known in the parasitic activity is fout i ,.,.-.ce i te agepesen cader whch frme attheboth -Teirlowconefils pre-rhomb porphyry and post-rhomb porphyry activity is known. ~ Caldera Rim group. They spill over the rim of the caldora and form - Shira zone forms a well-defined anid narrow maised linear zone extending fret . h *thlog, arro flws n noth-est,andare lsopresnt n te wet ad -Shira Plateau to the plains near Sinya. The lavas are chiefly andesites an . The groups of cones lying to the south and north of this zone have been :. . 'lions.. A number of dykes are present on the slopes of Kibo above 13000 ease of description, to an Engare Nairobi zone and a Lagumishera zone ci '. Y. )ly on the south-west and west, but a few are recorded high on the north. Presenit Volcanicity.lResidual volcanicity is now confined to Kibo, -c :I is *idial, from 1-8 feet wide. They comprise trachybasalts, rectangle porphyries, expressed by fumarolic activity associated with the Inner Crater ring frak *, ile rphyries and phonolites. fumaroles are believed to indicate waning activity, but they may represeni lo: -it *C d s-Associated with the Kilimanjaro volcanicity are small but staerinth volcaniciWety. hr h iimnaolvspssudrte ,dventitious cones. Two hundred and sixty-three of these ntinor volcanic grerat "Iaharfieldextenofn wshiara the iimnmroiaasp stMrubyn ss ode the Ja. i.been mapped on this sheet; generally they are situated on the lower - wa firreld irextendingmestad tobrybyn retlahar" colpeothe h atwlmt of the cra . i s *ending-in zones down to the plains, but they also occur on the Saddle "lhr a omdi eettmsb - h olpeo h atwl fteca .l Oi:,n 14,000 feet. The cones are usually-only a few hundred feet in diameter - In gene(al, north of the Arusha-Moshi road the Meru "lahar" formn, aithe same in height, but several reach a mile in diameter and over five topography whilst south of the road outwash from the lahar forms a more' ri - n. tcet in height. -They consist mainly of scoria aiid ash, but several have The "lahar"~deposit consists of boulder beds, over 80 feet of which are v.. , e lava flows forming extensive fields as in the Upper Rombo and North Sanya River sections. Al] the boulders are of types lava common on Meru. a. Rock-types identified are: ankaramite--oceanite--olivine basalt- Alluviu,ni.-Most of the valleys of Kilimanjaro have alluvial terraces ir' r r .te-phonolite-basalt-andesite--trachyte. However, these cones have not parts wvith boulder beds conspicuous among the deposits. These terraces -' n udied in detail and there may be an even wider petrographic range. At least the plains north and south of the mountain to form wide spreads o'f 2-. peiriods of parasitic eruption are known. The later post-dates the Caldera gravelly deposits. The Pangani deposits in the south consist mainly of IC and hence is the youngest activity on the mountain except for the Inner Kikuletwa and Sanya rivers have narrower alluvial plains, and stroI - f s. The older pre-dates the rhomb porphyry group but may post-date the lacustrine and alluvial deposits have formed west of Shira where the drai e .!.aiigle porphyry group. In addition much older centres have been identified Sanya River was temporarily blocked by the Meru "labar"'. Extensive allus: . lavas of Mawenzi, and other periods of parasitic activity certainly occur. gravel deposits surround the lacustrine deposits of Amboseli. ire mostly arranged in well-defined belts corresponding in some cases clearly Amiboseli lake beds.-The lacustrine beds in the Lake Amboseli * I;regional tectonic or volcano-tectonic lines. considered to be Neogene in age. The lowest strata are the Si,iya Beds ss a',ddle zone. This zone comprises eleven eruptive centres arranged in two of dolomitic limestones with some sepiolitic mudstones towards their he ain WNW-SE entes o Kio an MaeziTheitmestones inesbeteen are the main host-rocks for meerschaum, which is found WNW.iS,Einlpart pre-Cawerath Rmagopin and agntes KinclundeMawnkaaiThes sporadic bodies. The Sinya Beds are overlain unconformably by the Ain; *traclhyandesites. The southern line entirely post-dates the Caldera RimThsargen,epoicclywthmkdttxtricndwlinp includes ankaramites and basalts. An isolated centre betsveen the lines 01 Tuikai Beds which lie unconformably on thesc clays in this part of t c tasalt and nepheline rhomb porphyry. b constituted mainly of impure limestones with lesser marls and clays. I'anntbo zone. Ti zoneaper to cotnethe otenSdl ie toth Calcareous ituflaceouis grit.-Deposits of wvell-bedded Calcareous sat, of Mawenzi. Comprising more than a hundred cones it is the densestom selagyofavfrmntatinahckssfoer5 ,irasitic cones on the mountain, The upper part consists of lava and scoria south-west of Lake Chala. J2y ankaramitic in nature. Thei part within and below the forest, consists Red soils.-South of Kirua are extensive alluvial deposits of saw *.sh cones with ankaramitic and olivine basaltic affinities. All this activity conglomerate with secondary limestones, all distinctly red in colour. Sir: * g.Lake Chala lies isolated at the south-eastern extremity of the RombohaeawdsrdbuirglrocrenentelwesopsfKii ,iccupies a large caldera, some 300 feet deep, and is surrounded by *a of Slhira and east of Mawenzi but are not shown on this map. In placc! Wof agglomerate and tuff. The walls expose Mawenzi-derived lavas. It thicknesses of 200 feet. Outcrops of Precambrian rocks are all surrirunde, (tiat the large spread of water-deposited calcareous tutTaceous grits in this of duricrust which may be highly calcarcous in places. Surface hlme'ione I rner of the sheet wsas derived from the Clhala centre. some of the parasitic cones in the Shira Zone and locally elsewhere. zoc,Ths on i acnsicou ris(iaraemnain foma oitWind-blown sands.-Along the western edlge of Lake Amboseli there ai, it zoe. hiszon * cnspcuos isa rasedare emnatng roma pintdeposits of wind-blown material. The lake floor itself consists of flIne niL 2Saddle at 9.000 feet and running in thec general direction of the Pare places, contains crystals of gaylussite, becoming miore plentiftul as one tII. Somec twenty dissectedI basaltic scoriaccous cones overlie andi partlyeatrdinoKy. ''ick older series of basaltic to ultramnaric lavas whtich apparently form theeatrdinoK y. raiscd area. These older rocks appear to be overtain by lavas of the Although slhown on early topographical nmaps as s.aline, I.ake Ant1 o-kup on (heir eastern margin, and may prove to correlate with thie Neuimann particularly rich in either salt or soda. I.or to hc even oldcr. In the absence of poritive evidencc, the wh)oIe if RrrGI0NAL STP,UCTtIRA!. FEATU.RIS been miapped as parasitic lavas, which do, in fact form nmuch) of ilte ,sure. The stratigraphic position and petrographic claraicter aire citisely The Kilimanjaro massif appears to he SitUated at tlhe inter%ection ir *oseof tte01 (qv.)norh Mloggrop ofSttra.tectonic lines: the NNW.-SSE. faulted Pangani TroLugh, situated hetomc iofzone. B Mlog ruv (.. northanf areaaMountains and the Lelatema Mountains and an E.-W. trendling -lone . ine et f te eyod otte lns fStrai nextending from the Gregory Rift Valley 80 miles or so to the wcst. \ inefvr lland eroded cones occur, but their relationship to tlte faulting pre.dates the volcanic aclivity and wvittiin ttte hounds of it,. -unknown. 6 structures are buiried. 7 VOLCANO-TECToNIC FEATURES- VoLco-TcroNc -into FxruRs the wate,expiosi?on The large Chala whaich - Lake crater has accumulated as th extendsbelo°' waterof a result seepage of gc table . gnment of calderas, volcanic vents, parasitic cones, and dyke swarms is G Atab r m the map and these lines clearly have some form of structural control, BIBLIOGR -tber this is of purely volcanic origin or has regional significance is not DOWNIE, C. 1964. Glaciations of Mount Kilimanjaro, north-east T Bull. geol. Soc. Amer. Vol. 75, No. 1, pp. 1-16. ECONOMIC GEOLOGY D. W. HumpH_IEs, W. H. WILCOC_soN and P. WILKINSON. IC haum is mined at Sinya, north-west of Kilimanjaro. The deposits are of Kilimanjaro. Narure.Vol. 178. pp:828-830. n.custrine limestones, associated with green sepiolitic clays, which extend across HUMPHRIEs, D. W. 1959. Preliminary notes on the glaciology of K into Kenya along the south-eastern margin of Lake Amboseli. Meerschaum lour. Glciology. Vol. 3, pp. 475-478. . m pipes at a modern, well-equipped factory inArusha. Larger pieces are used Geology, volcanology and glaciology of Kl. nieerschaum pipes, smaller pieces for inserts in pipe bowlis and the fine Guidso-boDkNo Moun Key n-Kl,ajro h onanCu ir constituted into blocks (called "arcon" to distinguish it froma natural renya to Mouna Gude-book and-Kiattrnar The Mountain Club .;schaum) -from which pipes, with the excellent smoking characteristics of - N . .K. i rschaum, are made. -W-LCOCYsoN, W. H. 1956. Prelimiary notes on the geology of .w;r is forrning round the mouths 6f fumaroles in the Inner Crater of Kibo, eol. Mag. Vol. XCIII. No. 3, pp. 218-228. ,_conomic amounts. cs for building and road construction are in fairly plentiful supply but there tage of suitable sand for building purposes near Moshi and in the areas l-v volcanic rocks. Building sand is quarried in the Pangani alluvium near i Chini. r .Supply. Kilimanjaro is situated in the centre of an extensive arid area of ,C;t where the plains normally receive less than 20 inches of rain per annum. i, a increases on the mountain itself. The north and east sides of the mountain . short rains (November-early December) while the long rains (April-May) :1. on the south side. The highest rainfall (over 60 inches per annum) :lhe southern slopes of the mountain centred on Machame and Marangu. ih and north-east side of the mountain, rainfall is lower, usually between 30 clies. :.nent surface water is found mainly on the southern slopes of the mountain lie larger streams flow perennially. With the exception of the Karangal o and the Rau, all these usually dry up before reaching the plains in the dry I:l the north and east sides of the mnountain, permanent surface water is (he forest belt on the lower slopes and only the Lumwe stream flows below line in the dry season. On the upper mountain slopes, surface water is niols only at a few places (e.g. near Peters Hut) in the dry season. u h much of the rain falling on the mountain is dissipated in surface run-off. ,.: is readily absorbed by the pervious volcanic formations and tends to ,ihe botton of the volcanic pile, held up in some places by impervious lava v.crge as small springs which occur frequently in the forest belt. Most of .; > are utilised to feed pipe lines which serve the population on the lower ,.' mountain. -prings occur at the foot of the mountain near Moshi and at Miwaleni on .lc. On the south-east, east and north sides of the mountain, all the large . tovu, Taveta, Ziwani and Loitokitok) are located in Kenya. \ty borcholes have been drilled for water in the Kilimanjaro-Moshi area. horeliolcs drilled in volcanic formations around the foot of Kilimanjaro uccessful. Large quantities of ground water can be reached within 400 surfacc. s Boreholes drilled near Moshi and Sanya Juu have frequently of over 2.000 gallons per hour; some have given much higher yields. In !njaro (Engare Nairobi) area, boreholes have been less successful. On the k limanjaro several successful boreholes have been drilled on the southern ,r!lcular near Marangu. Uru and Machame where surface water is abundant ,d ground water horizons are struck at relatively shallow depth. Many .itesl5 have proved dry or ground water from levels near thc surface has iih continued drilling in attempts to increase water yield. On the eastern K.ilimanjaro, only one borehole, at Keni, has been successful; five other ,1 !led in NMkuu and Mashati areas were dry. 9 I I r 1. - i n | 3 X 5g - . . , E 6 .. , t jst i' Sm iiiisn aU"N owru -< t slowls Wm AO *c -ed't .. .. .i 1 fBO! 0 s e ! fl lStl1XM1031MGOILYMIJSS11123X111101 MIS eo ON1sSS Z101 O t'S 3S INS 't 0 ulm 1^]1 *a ssM SS titn ]Na 3MX > , A WM 3 SO SJ W Sil SlOIASThi 4 .' .. -I . . -Ca 1sl11i0MOLi1s1311mU IiSN *lLd%10 IA ,4 1Y 1) 1^Dwx n ,9 j3t3W: Y 0 JAIS 01O*S M38 WS ll W sw=4 -I3 Wl 'O N S OIN 01 d U SO f t l- S Ms *I JiArl J N ' IIte SNIdIiSo I h M3 3^315C 8C 'ON s5 d o1 s 10 $ U INIlNJ tljU ', 50 Tal 40 313 P20 10 4 ------ 0 100 0 10 20 30 40 C50 I0 70 90 KIM LIWt Si Table 4 Detail For classification of fine-grained soils and fine fraction of course-grained soils. Atterberg limits plotting in hatched area are borderline classifications requiring use of dual symbols. Equation of A-line: PI = 0.73 (LL-20) Notes: The above charts reprinted with permission from the Annual Book of ASTM Standards copyright the American Society for testing and Materials, Philadelphia, Pennsylvania. 0 1995 - 2002, Amerlcan Cast Iron Pipe Company Site Mao I Contact Us