Oil in Uganda

CONTENTS

1

3

t722

25

27

29

29

History of Explomtionceology-

Stratigraphy

Oil and Gas Indicationsceophysical SurveysSummary aad ConclusionsAcknowledgmertsBibliogmphy

Appendices-L- Earl$ Mineral Oil Concessions

II . . List of Oil atrd Gas Indications (after \V.yland)31

32

Figules-1 ..2 _.3 ..4 ..5 ...J..

Sketch Map of Part ofthe Western Rift Depressioq East Africa.Kibuku Area, Toro.Kibiro Eutiaba Area, Bunyoro.Glavitr. Anomaly, Western Rift Depression.Boreholes in the Kibiro-Butiaba Area.Boreholes in the Kibuku Area.

SKETCH MAPOF

PART OF THE WESTERN RIFT DEPRESSIONEAST AFRICA

t-_1L,rr !"doldid., di6G

-',J.'",,',.,^,.-".",.:

'r-k,

sonne (lq49J, Ii11lc m(r,1ior' i" madr olorl ros:hilili's' ancl I'i' ttorl ti'l be referrcdrn orrh inso{ar as it bears (]" t"" 'ti'ip'loi"n 'i it" e'ut"sil.al fir'ding'

nn thc

Upard'a .ide ol rhc bord, r ' ,:rcd in rh. s.dr,l, fo- oil. The 1ir"r. and ari'to

-aln 'rca'

h'v'.be(n rrrr,]l't1,';1,;, "r,t"-.".,"r" shorco

ol LaLc AIL'ertrhe rim< rhe mo.r t-,..rnrs,rc ro(.,rrr\.,t,s(i,.tr",ivrijr"j-i,, iqz!. The s,cond areafil,ll}llii.ii: *it*i.,?; iiili',il.,",",.;r ii"*""io'iu"a on rhe nits soun or LlkcAlberl. 'l hc.'e !r'as.r'c rr orcirl(o orr r ;'''''ll .,"J t'ptr.r'rlv in F'gurrs 2 and 3

HISTORY OF EXPLORATION(N I-lARnIS)

Thc errly hi'ror]' of ec'rogi' :r' :Y :.il'^l Li',:f:,f,k.\Ci,';1.'ili 'ytill:],.il1 :irh. oranrins of oit uonrc.-,o-s ,"

"""ii;],;;.";;tiif,.j';i lo)s i*i..,nd cdirio.,,l lsa;da". M.rr. Nu. 1. G.',1. JL/ ilglut and unlorlur,rt(l)

"ot* o't "'"'"'": tftft" sercr;l parLics rho lrcclmr

rnldrcrled arE lisrcd rn Appcnorr -i '

'55.rr*t "iih 'nrot-.,rio" regardrne thtir

conuessions \\i1h thc 'lieprron ' 'tl'' ::'li''t uplion Jhq ct'a' o\:r shich rhe

\ariou' concc"'ions \, r( h' ld harc "';';: i;;fit;fu ro bc unJ' rlainty crr"tellincrocks relerred to thc Basemcnt t

" "li'l'' ;;l;i i"i;-t"tt oi t'ppo-.d Prc-ciml-'rion

"l'1"^.ir'i' ,-tiir" agr sLr(h aq rlre ltr'"vo-' uhcial Scrie- lr i- nnr surDrtsrns'

therciorc,thatnothingca'neot.thes'l":i"lr"ii,>i"""'l'iploi'"1't"oil in Ugrrrde

'w;;i;;j,t \u,k. as ,((ordcd I .ii,.l:1",,Y]l;"1n"*i,"oT,l"iiiio"i.o,:'/"1;';Hc c'"rabli.hed rhe 12cr .thrt itl,

-""l"-ii"ii. ,".r1 "i ,fr" B:rsrmenr- Cor"rpl,rlil':il1'i*'i"',,:';""1:::l:";:" ,:i lr",:;lii iijii"-ir''"' "",.r :"gri:"li? i"":l:iiiI"f,t""f."

'ii' ;a, J inro l(i"cgi Kri'" rrd EDi l(ai'u U'dsr rhc KIscgr i

"traL. $.r( rrcogniscd ,ls r'rrng oro ii"i+I'ii' o' 'h"llo" screr'ryp' and hcr'cc

ol hcsh\talcr origin; hc o'"o'"'"a "''t."

"'Iit'"i -"r if'" Kr"'si Uids round thcnorrhern tern'ination ol rh' ttut'''"zo''i" '"t'' '"i 'tt" s'clsgc of lighr

oil and gas

i;i'ih:,; ;i 'ii;r.',r, ;,, rr. s"mr;r';,v1ir"1r r* fililf,:ii ;i1,,'l&t.?',.n'""i{[flKibiro and the fas emanallons at lJ'l"'i xru;i-" ol,tl.,,-, "-,,1.":"' l;'.',,,'l'.1;::,9,"8 "1ii',ii:,ii.l'ifi"|'Jili:

lll i:Jililit"Jt::"1,1'J'li.Til'l'i,.' i"ple'^pi';.. rc'rLrr'" ir-rh-e,nrti c"urd bercsarded as lhe r.d'clron ot unot"tt'nd "trutiu|c :rr d' i" parricular' rl-at \Va(iriii ")"r""

'-ids' r-,,'.""n, e^,,;:"1",,1;J*ll:.",U:;';]..,.t"'.!,;::,'ii!nl"",iJ1,,

;'-".Yill ;'';''Jil':r",*i: I il n;:liiiil':l'.:l;^:'![jil;:."',]:'fl:-l';ff:',-:::iL fr:i;::lJ';l'Er'l-i,',"''r."^iiii,l, deic'i1'tion' or thc'e ar' ';m;fl.:i,'r." ,"*..ti"," seclions in rhis pro'r and in.AppcnJix lT Iote'hcr \\rth tor r n"'t

1l:-:::1".d: lri. scr-prrard dips in,rhr Kai-o..cctirncrrrs zrc no,r rcga-dcd as beingmarnlJ' ol d, posrlrunal or'rgrrr. arrd hi. c6n1-n11o,, rrr:r surlacc rupographiral Ierrurclarc the reflcction ol rnderground srructure has becn disprovJd 'b)'1"r", a;ih;,particularly in the Wahi Hili area.-, Y:-o], No. .1 rras lidcll urrculated among .commercial firms and one of these,llre,ALgIo f(rsre Url ( ornp-ny Ia. il \\as rlr(r. lnorrr,.; suLrmirre6l in jQZO anapprcdlton lor lh. g-ar,t ot ,\.tu:r!c gr.t. to (\pl^rc, prospecl a-d min< for oil.n..tLc orca.

_A snnior L:,ologi.r. B. K. \. \ jlli": ur" ",n,',o craminc thc LakcAlb_ert arta durmg 192E, but on consideration of his report, rvhich is not availablcin llgzndl, the Conrpanl npp;rtrtly came to the concllsion that at ihai time thevhad nrsufh.re,rr inlorn-,rlion lo ju..r.l). {,rrrh. I op, r.rliuns. Th, y *ern taccd u irithe chor(-r bLt\\c(rr r\lc.,,i\c ,\ploraror) drilling and prrl;m;n:ry geophlsical \!.ork1o elunrnxre,lhc mo'u sprcrrl.rr-r'c elcmc-r. in rhi ur"L,l.m. parri"uiarii i,irh r.gardlo, rlr( dcplh

.and lorarior ol pc."ihr.-. oil_b

IStructure contours draNn on the top of the "Big Sand" Horizol indicated thatthe axis of the dome is parallel to thc cscarpment, the closure being 85 feet and theclosed area occupying about ,150 acrcs in cxtent. The site for the first decp rvcll(B1) rvas located near test-hole No. 8 and s'as 1,280 yards WSW from thc top of\\raki Hill and 2,200 yards from the foot of the escarpment.

Since thc axis of the Waki "structure" does lot correspond t-ith thc topographichigh of Waki l-lill, they probably have no connection lr'ith each other and the latterhas merely bccn forncd by thc denudation of a vallcy running parallel to theescarpment belorv Bukumi.

The line of test-holes to$ards Butiaba u,as thcn continued, seven holes (Nos. 12to 18) being spread ovcr thc remaining nvo miles. No. 17 \vas actually near the endol the Butiaba sand-spit. Thc averaBe depth oI trienq test-holes \as 366 fect.No sign of oil or gas \\'as found in anv of thcm. Three holes 1Nos. 16, 17 and 18)were drilled at Butiaba to see if any lault or other disturbance of the strata occursthere which could accoult for thc manifcstations of gas and oil seen jn the wate.near the jett.v. No. 17 \,as driilcd to 632 fect. Thc strata could be correlated fromhole to hole and no abnormality rras fouDd.

Borehole 81 rvas drilled to 4,0,13 feet. It found thc "Big Sand" Hodzon frorn70 to about 240 fect, I{aiso I(iscgi Beds to 3.320 {cct undcrlain by a formation rvithoil-shales thought to be probably of Xlioccne age, and the borehole reachedcrystalline basement at ,1,008 feet. At abo\rt 3,850 feet, a sand u,ith traces ofasphaltic oil \iias encountered, but no frce oil rvas found.

The infolmation furnished by this \\'ell was most valuable for future guidance.The thickness of the sedimeni:rry bcds (4,008 feet) rvas more than ixpected,indicating a dou,nthrorv of the rift flrult of about 6,000 feet. I'he presence of oil-shale lyas quite unexpectcd. It pointed to the source of the oil seepagcs known inthe Albert Rift VzJley in the samc rray as the oil-shales of thc Lothians supply thefree oil found in the coal miles xnd $,e11s round Edinburgh. A fu her similarit.vin the t$,o districts is the fact that both oil-shale sedcs occur in fresh$'ater beds.Natural heat, e.g. supplied by undcrground volcanic intrusions, is required to liberatefree oil from the oil-shales, and thc fact that thc Waki boreholc u,as devoid of oilindicates that no such undergrourd sourcc of heat cxists in that area. Therempercture of the strata tlrillcd through at vaious depths was taken, and therempFrarure rr 4.000 feet \'2s or,i)'51'c (122'F), a rcrl small incrcasc in temp-rralure pcr foot oi depLh and quiI. inadcquetc ro di.til any oil-shaln.

The failure of this *.c11 to show any liquid oil, or even high gas pressure, suggestedthat future sites should be chosen under conditions difrerent from those near WakiHill. Trvo arcas suggested thenseh,cs: Butiaha Port and Kibiro. The former hasgas emanations and oil in the .ll,ater ncar the jetty, but the test-holes there shou.edahat therc is no faulting of the strata such as u'ould h|ing an oiJ-bearing bed nearto surface or a{ford an uplvard passage for gxs under pressure to reach the surfacefrom dcpth: furth.r. holc No. l7

"hor,.d that lrom 201 to 632 fect rhcrc is anunbroken series of tough shalrs and clays rvithout a trace of oil in them, throughrvhich gas and oil could not penctrate from belorv exccpt under very high pressure.Thcrefore, it rvas considered that the maDifestations of gas and oil in the water were

dcrited lrom the beds of lignitc and carbonaccous clay rvhich rere Iound fromabour J0 ro 60 f,tr dcprh jr r,rL-holcs No.. I0 Jnd t8.

The case foI the Kibiro aree is thar thetc js an oil s3nd outcrop and:r series ofhot saline springs near the foot of rhe escalpm(nt. As the fartuie of lVc1l 81 toproduce oil \1as considcrccl to be due to the absclcc of anv natural heat to distilthc o:l-sh.l.. rhc prcs...r ot rl r.c hut sprirE- en.ouraped rire I,cliel that iher

There rvas no trace of oil or gas in the rl,ell: cvidcntly the oil found near theKibiro seepage has not migrated laterally along thc rih fault plane as far as WellK1. Had any so migrated, traccs of it rouLd ha\e I)eLn apparsrt in the porous sandsurnrlrirg the Ba.nnlnr Corpler. i.,. Irorn 2.11j r,,2.211 le,r.

Thc tcmperature oI thc strata it Well K1 uas takel at 1,900 feet and was foundto be 51'C, r'hich is 16'lTigher than that fouid in \Vell 81 at the same depth, aDdconsiderably higher than the averagc- 'Ihe reason for this is that the area is one ofsubterrancan heat, as evidcnced by the hot springs. The oii irt testioles K,[ andK4a is assumcd to dcpcnd for its cxistencc ol the presence of oil-shales l,hich havebecn subjected to local hcating; the abscncc of oil-shales in \lrell I{1 is probablysulfici, nl .xplan.rtion for th, r.l'.".rcc ol oil. s c, c locil h.rr i\ pres(nl.'It thcrefore sccmcd that rhc only hopc of ol.taiLrine oil in the Kibiro area rvas

to drill quite nerr lh,: oil seepage. A location for a deep relJ, I{2, rvas thereforemade 960 yards south-u,cst of thc scepagc and 77il fcct from the foot of theescarpment. It \\,as on thc Butiaba sicle of thc fxult found betwecn test-holes K5and K6 so that it 1\'ould bc unafitctcd b,v any advcrsc influcncc of the fault on themigration of thc oil. lt rl,as caicul:rted thxt thc Bssclncnt Complex s,ould be.n...unt.r,d ar .rbout I,ljr-l l

't. z "\

;:,'lll;:i:t"li'1ff*c$:il;,'tii:gl) ir'-r o\vhere i' hi- Do.lion or rhe Lake Arber,\\ ere ir so.. rhe c +;;i;-r,. ".,i i #j-i"l,l;'"#.;;Ti,t Ji:ij,f%?.::i[::ii:tgas vents alung rhe iur,crion ol th-e scdrmenrary Lcd, at rlrc Bx.(--ncnt (.omDicr olthe escrrpmenr. .l,he Comoanv

s,'" ,p ,i; ;,.r,"i,il'r;$"iii;,s i::::i'i:l, f:'ior;[. *"'"", t,"r,"' a.iiiiig '",i1

r,)i**"1;'iil",3iJi ;*;lnll*', Fi,nanr irr pr"virion \\rs rhpr, m,d. ro.r (ixplorarory dri :if i"rri i,..iJi;.1" r'1 rlt" c'oloPical 5urrev 'o th.,r JddirionJlrrhich rhc e,.;.r'n r,,J nri"r"r," llt t" rh' prom:inga'ea oithcKibut u "."p"rs;unoerra\c. I hc u|climinrrt o;^t.], .'lu" '.r""t ('ompany had rror Le.'n ,Ui i6isr;;;;'",'ir"l,rib'i;'iil;i; H':.:flll''ur'c1 'lra' m*Jc bv R C Parqercr rn rareend oI rhe Rr,,";r;;i

-i,,rir;.'Y""t" rrr' m'rrr strucrur'l t",rr'". or itte no.ih"rn

lsc,Figuicii: af;;.i1ilji iil\ri Ir'ce ,sarn5' trhich rho l(iburu'cepascoccur..side oi rh. nr,,*)""; ],",,"i,i,i,'ron( Jcrc\\irq'ho\(nloIdrillirgonrh"iitr rrti"lfaulr zonc r,, ,"i-1l,"rrl.i,ii1rl l'ar'J] r'r rnr:(ipariun ot "n"ou,.r.r;nn rt".rii.u;a"n." r,o--,,lr,iir, ;;; ;i;;:,'lf"l't, Ihis I'ulelrole ''"" .'pn.,"J ro plovideano mrghr aroo irdicarr ,h.'n.".,.," IauiI roI ' could Lc mor ac'.rratclr d.t"i-nli,,eit;; i; ;;. ;:i' 1l:r::'' ffi::il':iir'.i j:,1".Ji.:r,1.;:l;.nn:'**:,lli.-l."f.uiling I500' rorrrl drilling-.-rnachir c, r,as r.ceireC in mid_lq4S. \o. 1;:.:"*ii;,:;',;'i:rt"oo-['","1"'f.^']:',d"".",r,"d ,r,o;; l; 1',rv.'"1wii. ,,,a *^lhroughout. e-," ,r," i.oi.n;"j(cemD( I lq46 .co'ing having bcerr undcrlakenamou,.t oj n.garirc i.r"i",il;.';.i'31"',ol.vre\'\' rhc va'u' ul riis hol' lie' in ih;.'ysull;n. iio8i oi h."rit,'i;.":f"''" \(rlher rhe F.,rrlr zon' ror rhE prcsumcd{eer lrom surface, irr. .,*,, ,r.l"aj,r9"untercd 'fo a d"oth of apnrorim*','ty t.lOo,lthorgt, un,riirtrt. i";];;#:r;"dl:.'' 1lv rrnp"';o" clav" '1n4 'un'1. ela,' uhiih.cap rocks. g.l"* r,zbo f."i,'ir,i",n"Yn o' otl ttould rrndouhtcdl) 'ir as excelJerir*l;ill"l;n*l :xi r*i"jr" _:;1t,ii i",llt o1:d6,i;,"iI ":i,,T,,b."ifl:and $outd t"r" 6"",i .i,-ili, :;.;[.t+'"'n n nlringhrmsh;re) oilfeld ol Blirain[r".enl, No-rraccs';i;;;:;i.;H';ip,%Xiii:,i]"r-."XJJ::::i l:J,rT ilr,f;:rJ::;;:",;::ff":iJ;],i;: iiyli,;i H::,ilr,.a l;J.'"t ii,ii,.iii"ri'.i

1'he most impo't:nr qucstiorr lc[r unannn^rcd n1 \n l borrhole,rtas Ihe (xacl,f"",i'rn r"t

" i]utr,o.". X.,.2 Lro-ehul< rrr., rh,ritnr,. 'ircJ hrltrr) hrtrre

l^i;ilill'1*,' Yiio':1,;i;"i:i::J mo'r or thc rocar:r,c" drscribcd originaryp-evrou.tv otserrbed. nirm sulrq ul thc surfacn manif.s,at;Jns oi^-Unlonunarelv,

Bottl -. gr..rv iry .r:-".I d,d, f,!r pruv;dc ,nu, h addirionat irrturmrrir)n. tocal taultrng jn ordcr to suihotes. sired ".,? ,r,. *.u.,-il;":,:i"^f'll119, l'iq--'n".. M",n"hrt" "r,,,r,1,cncuuntcred d;ffi.ri,,,.-i;-r:;;Ji idsr or r\roLri u 'o rn\'.tisate rh" miir, rl

fivc closely .prl"a i,"r..'"'l ;ill"f' houlde'-!rJ\cls ',,4 ."."".. pinnlry. , .,,scepage area to tcst rhe.trr"trrr,rt l!1"1,-"-"'t h-ve.miicq no'th-.n=t ot ti" rib,.,'paciag ol t,00 t"i ;;;.,';;;:ol:i;'cnrl''r'n' c or I lorn c'carpmcnr' In sp;tn oj

"r,cburd be 'sabr,sh,d

"i ir,I"'"i;lL: ]:-::,:l:' :g: drp-rl',or8'0 re'r' ro .-o'rnla'j':l'ii;"'i,:"fJ ''6fl),;,;;:1; :f:;,l"ilJi;''ii::;:',';i"fl i:lllJ,i:':115,"",';:.u.pendcd alf,..,.a oi --5- r '" i 'cnl '8r"rl sur\'y or L ga'.da" \\'erc rhcreJu

GEOLOGY

slraligraphy 'J \\' P"r'r r'rr:n),"0"1n'.'llli.?l :[-,il:ii,i,?;':]:rr L1 'po iriurr oI rh. rcrLiary ,o Rece. be.r,!cd-. o1]y rh. uptr.r;o |

";"'; ir;:t "?='1"lt rhe surl2c' \\ithi,r Il:. outcrop or rh..

reer. whiie ,r," -!jo,;ir r,iu" ol#o 1'n't ol" drirl hole h'r" p.nc,,arei ro 1.uihand. geophv;ic;i"'c,.lia",.J'i*iii"lt'"tid r,o onl,., zbour 1.0u0 ft(r. on rhc orL,

obrious. rheinrore. rrlri'1"","i.,jri ,.n ,iu'a' thjckn'-ss .ol rt Icrsr 8 000 lecL. lr lthe Io$er serie. ;. rri"""r, i'.iii;.'r lhr srraligraphJ is unlJ or|,rirl. Irr parricularrhar oil accumurariJr; l. I;iii"i"'r," r*,lhes' lo'\.r bed- rhri ir snem. moci probabr,SouTHEnN AnEA (l,-isure 2)^Wa1land. in l925iSa,, rhc Iollor.rrcpresslon:- r'tng succession for the beds in the Albert Rift

4. ,\ludorn Dcpo"ir.J. Red Earth -z. r

Kriso Beds is said by Wayland to bc seen in the course of the Ilisegi River being"indicated by the dilTerence in stLike and dip". Wayland recorded 30'dips in theKisegi Bcds though an e\Erage of 10'rvas morc common, rvhereas l(aiso Beds shorvdips of 7' or lcss, rapidly decreasing arvay from the bascment and tol'ards the lake.

Boulder bcds and gravels overlie and ol,crstcp tllc oldcr beds and pass up into redexrths at Kaiso and cquivalcnt bouldcr bcds are considcrcd to occur in the moresouthern arca. Dr.idence of age for thcsc r,arious groups is scanty; Waylandconsidcrcd thc Kiscgi to be possibly of N'Iioccnc agc, t ilc bone-beds in the upperpalt of thc Kaiso suggested late Plioccnc or carly Plcistoccrle age. 'l'he mammalianrcrnains rvere later identified by Hopn'ood (1929) and indicatcd a midclle Plcistoceneagc. 'lhis has subsequently been reviscd by thc samc author (1953) to 1o$.erPlcistocene. The overlying gravels \\:erc tcrmcd Epi-Kaiso Dtds b1' Wayland in1930, and ivere relatcd to ccrtain terrace gravcls elsc$Lrcrc in Ugrnda.

Thc dctailed mapping by Pargeter (19'19) and \trraldron (1951) in dre same areashes not materially altered Wayland's original dcscription; the uDConformitvsuggested to occur betleen Kaiso and Kisegi Beds js not sulllcicntly marked toform a sound stratjgraphical division, though Pargeter states "therc is no doubtthat progressi\.e overlap of clavs and soft sandstones over rrore consolidated gritsand hard sandstones has occurred. The division, therefore, betNecn the prc-dominantly areDaceous l(isegi Beds and the argillaceous lGiso Beds is a convenientbasis for mapping".

Thc Kiscgi Beds in the t_ype area are describcd in more detail by Pargeter asa "highly variable serjes of ill-sortcd grits, conglomeratic grits, hard sandstonesand ime soft sandstones $,ith subordinatr ch1. pertings. Beds nreiy rcacha thickncss of more than a fcw fect, except in the s,-,ft sandstnncs. rrhete thcy maybe 40 to 50 feet, Thcre is also considerable vrriation latcralll, so that useful markcrbeds are difficult to find . Thin partings of lignitic mineral [sra], gypsum, andgritty limestone are comrnon. Brorvn clavs u,ith calcareous concretions and iron-itonis become mole lrequent iear the top . . . 'Ih. sediments here rcacha lraximum thickness secn, rvhich is 300 400 fcct. The)' are sharply faultcd offinto the main rift vallev wcst of lCbuku and havc becn covered by iater sedimcnts(Kaiso)". It is not eniircly certain that thcsc otclll'ing be.ls can be cxactly cor-related $.ith those of th(] type area at Kaiso, but they are described by Pargcter as"ncarly all clays, generally very light in colour and contain abunclant calcareousconcretions There are subordinate beds of harder matcrial in the form ofsandstones, calcareous sandstones, grits and ironstones, but these are rarely morethan 2 or 3 feet in thickness These beds cover the rvhole of thc Rift ValleyDcpression. On the lvestern or Sernliki side of Ru\venzori, they form flat plains,and abut against the crystalline rocks of the mountain along the 2,200-foot contouralmost all the way between Sempaya and IGbuku. Thev then shelvc very gcntlynorth-eastNards ai far as Lake Alberi (2,028 feet) 25 miles'arvay . . . Thc thi&ncsiexposed above the Ki;egi River is approximately 400 feet, but tllis is near theextremity of the beds and must increase very considerably north-eastwards."

Waldrbn continued thc dctailed u,ork and lccordcd a numtrer of measuredsections. Neither he nor Pargeter found any fossils save a felv gastlopods andpelecypods in the overlying presumed Epi-Kaiso Beds.

l1

'I'hus, on the northern termination of Rurvcnzori altogcther about g00 fect ofvariable sediments are to be scen in conlinuous selluen ce, -resting on the crystalline!,."-,nr. lr i, obriou... l,or,ev,.r.. rhar il.-;-;i;1,;";; ,c"''.i lt;"', "."

i. i,.lound ar drplh orr rlr. do\n,hro\\.sirle 61. 11.,","rii, *ii , i3' fr""hli'ro* ,.d. rl,.::l::i":.: ,h.,.I,ii, ,Borcho,c trihut u No. I *.r. ", ir,-i" rr,. "[u ii ou,".op,;,",ulrscnDeo and passic, rhrough r serics of unconsolidatcd claycy sands ancl iaidvi,:L:^):,f^1.:1?iit. thrn harJ band_s *,ith catcarcou. ."-"l,t,",1a-"."Ii.;:ip"b;laTtll:l," ,": ror.,J rJl(An(sc ot 1.o60 h^r. Trre,irlrologv rtas ir.ufficiinrlr di"rir.cLircto oecrol. \\n.rnFr th.:eflri \.rs l(r;.. ur Kr.cg: ,rr h"ih. Thc mri,,

"eciion shorieJa high clay fraction which decreasect belor' r,zOO r".i'iirr"L"*#.il-.,;,*. ;;;unconsolidated sands are more common. (lrigure 6t. -' '''"-_Thc uncorforrnable j.nctior r'.ith bc,lioci ."ri'

"n.ount.r"d in both boreholesNos. I and 4, rnd thc irnncrtiar.rv o1.er1,vj1g b",1" .",i ilr;;"i;;" ;i"|y'#'r""i,rn"a ,oll",-rl,:iq:^T:::: blt .th r j unctron " iih'tt: ;;;r,_;'il;;'; ffi i .\',i"",t^i,,,,,,dIt rras rnerclore UeEn thr: I)lr.rr.. \ince then to use the tcrln Ilaiso I{isegi Beds inthnaL.e-ce-oJ a

'ccogni.atl" d \idir,g l;ne 1,",,,"",, ,h;i,,;;;;;;;." "' '.,llarns.1l95U) ..ummaris.d _rhc brds rr),uun1c,,d i- rhc"bo.rholes No". I 4 as::J,,,".'J";

-,1 ,,I" \irrh a \ariabrL .rnJ c,..r, nt rnd -rr,d. u.ua ) rr;rh a ctay h.n),,,,:,, "9,] rn, co

of the oil scePage athl drocarbons. 1hePlio-Pleistocene.

Of consiclerable significance is,estern side of the Albert Rift

Kibuku ancl adjoiling presurned faults' sho*ing -no traceof^g"-"i}r"." rr"h. ;.,

-lr-i indirect evrdcnce, considered to be

th( \\orl dorre b1 L"pc1-en1,' llql0l orl rh^Dcprc"si,-,r,. Hi. sLrc,,.'i 'rr ,';rt Lr ''rrnmTrr'ecl

,)

thus:-5. RDCENT4. LAcusTRINE SERIDS ..

Shore deposits and flood plain of Lalie Albettand the Sernliki River.

t,r;r,1". .rnds 3'i ql ''' .' cr'ion.r'lr 91p'i-feroui, t'ith calcareous concretifils i l)is-conformitv at basc.

Gr,rvels, s,rucls and claYs, o:cesirlal horizonsof iron-cemented sands.

Llpper Stilgc, fine sands ancl occasional clay

Mi,idL Stos?. plcLlomr-ant') .rr gilla(eous'",".it"-ri. 50mc dixt,,,nr,; .rnd bcd. olii,[r]ar lim"r,iri. irorr'ronn rrith fos-rls(gastropods and lamcllibranchs) and bonehcds.

La'a?i StaAP, all(rnaliun" r,l sand' lnd clels\iirlrorr iron"torres or ros-irs Unconformit]'

Coarse felspathic coDglomerate cemented inlrterite.

3.

1. BASAL L,ITERITIC FoRMATIoN '

Srulrrr StnttsLArso SERIES

'lhetotalthickncssofthesegroupsisestimatedasatleastl'300feetlncomparingt;.'.i,"."...1"""

',;,,r rt"i "*ri;",'dcscribrd I'r \v'r!land L'fcrso-rne does. "ol hnd

, ].ii .''* ii""l.., ,"",r.. ii'"gi s"a'-h'' Join'"o,''rhar ih' t(ai'o Bed' on rhes,srern :ide or rh. Depr('sron nrt" , fi,,ol,ll tacics rhat'rr1 *ell,bc cqurrcd sithii'.'?i."s;l ir'.'r,'"a'iiq3o, r,,,r. ;o'-u"' i,'CgT,:1,,:kil,."i:,,X[::l'#l]helreen thcse t\\o scres rna) nc purer) ro(4"' ' l'"i"'.""'.'l; "::'.::::":;rh;;;;il;;1., ue^rla" h"'u' bien encountered the.fossiliierous' ferrugrnousil:;: ;i'ii"";J;i; p t-& it'" r

thercfore. that $: I!"-"gt Bcds can be once again cstablished as a distinctlv earljerrormdlr,,n. plr.bl\ oi Vlio.,.nc rgc (a. \lallarrd 6rsr "ulpcsreJr

.11 r- \\orlh rrring rl,er L.p.r""rnc -desciit,. a l,,cal?.urrencc of a.cdimnrrar"lserlcs. underlying rle Brsal l_ate.tc rormation. ih" ;;;;;; ;;;il';;jprovides little means. of dating, but.it is provisionaliy ;;;.i,f;;;J;-;i Kr.."; ;;;rn rts generai resernblance to tho T.rrkuga Series aboui trueniy_nu. milis.uest it ttreIrumu Basin.

.

de Htirzclin has recertll (t{i55) pLlblished the lesuhs of dctailecl stratjgraphicalsludrc\ (Jfri(d ur.r on rt., .' ,u.. ..di-n, nr, of th" ulp,r. S,.i"Lii,;-rrli.., ,r,;. ,;r*lcar

of the Company:Err K^rso BrDs

(70 f(r)KArso IrDs Upper:

(1,650 feet)

S,1d) .. /s .."llig Sand", prcdominantly sand \'lth grits, clayey

"a.,1,n,1,'. ) i,r,,,dl,rior. .. ..Allernations of coarse sands, gravcls and some clays . .Gre\ gr..,l'\""r, la.s ..Altcnutions of sards aDd grc) b,own to grey-grccn

.1.,)rA'rr' a..r o,'. ^l s. nr..nr Ll,i. r i \ o I la.sBlue-green shalcs and oil-shales $ith subo inate

s-nddon.. . .Basal co!glomerate.

Krstrcr BIDS(1,600 feet)

I NlccENE BEDS(680 fee,

African and European Inlcstment Company Limited that kno*ledge of thestratigraph] in this region ',tes gained. 1'he first deep borehole drilled by thisComiani "at \Vlki, [,ll 81, protided the lollosing g(nerrlised succc:rion.summcriled from the more dctailld rcports by F. W. Penny, the Chief Geologist

X{iddlc:Upper:

Tor{L .. +,008 f.(t

170 fcct970 fcct510 feet

780 feet820 Ieet

Appro\imatel\ 600/" of rhe hole \\as corcd and the detailed core 1og lvas sup-pleminted by

irr rhofi1.1 11o'"no I-,rl\ h,,lc. I,rlr tlrc rnor, courl-er.l) urr,5 passed through.,grcyard 8r(en ,.Jays,..hal.i rrrrl ul,r1,y _srnds (onrdirinq chdracl(r.i"lrc srnd.ronesrnngrrs znd L,rnds .irnitrr ro rh"sc 'i ntor,. th" T;t S;":.:r i;,;"r'.1. 'ilu,,;. f_.*fcorrelation bet\yeeD the four ,ore

"",rtfr*11. L.f,rr,"aiiii"i a'"n'l{,i.ig" a"p,t., of450 feet, *'as based or a charact,:ris ic ;i .;.;,r";i'';.;. "uri'li'ry ir, ,"u.i'occurred sandsrones \\'ith oolitic "hr-o.it. _p"J.t.". No'"aa*itior"l l'i.aag."phicotinformation \\'as obtained from thcs.-test h"li;,;;;;" i,";;;;i,"*'i'J"i'.r

"l .".a"\Yas cncountcled in test-lloles l

stones in thc N{uzizi Va1ley at about tNcnty miles bevond the present }ilrrit of thcRrfl DEpressjor arrd rcsting unconiormabl\ on the crystalline baselncnt, mightrlell bc eorr.lated rrith Lasal bcds ln the dorvn-faulted trough, xnd he dcscribedsirnilarities bett'een thesc N,Iuzizi Sandstones and harcl bancls in the Kaiso Beds.The N{uzizi Sardstones are o\:crlain bv grar.els thich Wayland provisionallyidcntified as Epi-I(aiso Bcds. Pargcter (1950) examjned these beds in the NkusiVallev and described thcm thus: "'Ihc sedimcnts arc remarliably unifr-rrm inchara"cter, bcing ahrays 6nc grained -urd lamin.Lt.d. '1'he hmin.rtiuirs are thvalsthin and at no point \\'crc inteibedrled shale or grit bands seen. OccasiorallSrounded pebbles ar'e plcscnt, hut no real conglomerates occur cxccpt in thin bandsnear thE contact $ith the hills nI crystalline rocks and ncar the base of the group,ls exoov-d ncer I-el.e Alhen . '-the sandstoncs arc critrcmclv hard and there islille'jo'nti-g. Th.r .,re prrrric, llr n.r-r,(dJ(d or u.tlr r,11 .rnrll dip- . . . r;\e'to be d(tositional in oLigin 'l'ol.ards the Lake Albert scarp, the sandstonebecomes much coarser in grain sizc and is often red in colour. The sedimnts :rrcseeD to entend riglrt do\,n to thc riycr bed (Nkusi) et the edge of the scarp so thatthe thickness must be in the rcgion oI 300 feet. A massir.e corDpact conglomerateabout 20 feet thick can bc obscrvcd Iiossils rrould appear to be completelyabsent it is not possible to 6\ thc datc of the sandstoncs and so thc questionof coffelatioll nith either I(isegi or uppcr llaiso horizons rcmains opcn."Structure

There is a striking absencc of folding throughout the -lrourg sediments in the

Uganda part of the Albert Rift Dcprcssion. Dips ol 10' or more have been notcd,but in most cases can be interpreted as depositional. Thc occasional steeper dip isnomally associatcd n'ith faulting. In thc southern arca, Waldron (1951), on theevidence of surface mapping, records that "the cntirc arca covered sho\\s noevidence of anv 'closcd structures'. Xllonoclines and structural traps produced byfaulting, though not obscri'ed on the surface, may be prcsent at dcpth." On theKaiso flats, Wayland rcmarked oD one or t\\'o dips rvith an inclination towards theescarpment. Thcsc rvcrc cxamioed by Waldlon (1951) \\,ho came to the coDclusionthat sincc thc beds rrerc essenti.rlly cla-vs and unconsolidatcd sand having an"undisturbcd" and uncrushed appeararce, their dip suggested "lowcring of blocksof large sizc" rather tharr "side pressure".

In the northcrl area of young sedjments, Wayhnd rvas strongly of the opinionthat Waki Hill represented a structural dome and the first drilling opcrations bythe African and [uropeaD In\.cstment Company Limited \vere dirccted to test thiscontention. A total of eightccn holes, 300 to 400 fect deep for closc correlationpurposes, \'as drilled and a markcr horizon 1!as used at the top of thc "Big Sand".Iller.en holes rvcrc drilled, on r'.hich structure contour lines were bascd, and,according to Penny, delimited a domc lith closure ol cighty-fire Icct. Thisprovidcd- a sitc fol ihe first dccp test. It lrs bcrn sholn, hc,ivei er, that thc "BigSand", like all beds in the series, is lcnticular and passes into sands and clals $ithinthree miles. It is possible, thercfole, that, as pointed out by Davies (195i), thc"Big Sand" me1, be nothing morc thrn r sendbanl p,rralJel to xn old shore-linc,and that thc hill oNes its oiigin not to an rnticlinrl slructurE, but to diffcrcntial

17

erosion. Such sandbanlis are a feature of the prescnt shore_Lnc. On the coflelationsestablished in the shallon holcs drillcd ncar'lGbiro, d.viations c,i thJ strike fromparallel to the cscarlrr.cnt suggcsted

^slight folding, rhough Ir.r:. ,g"i. j.p*it;""^ivarlatrons may ralher be the cause. Structural dclormatir'n, the, cfJrc, muit be con_sidcred as targell'limircd ro faults. It is i-porr""f to ,rni;;;;" .r;,";h;;'i_.p"r.""""rrcord. po.r-hriso rolding on thc rrr"rern'sidt of tlc niii. ,,;,,l it,. froar.,ion o.diDs of as much as 40' -

FoI the .convenierce of description, faultrng may be scparatcd into the trvogroJps: mdJnr lracrure lirres dclimiring rhc Rrii Depressior..'an.l srruc,ur"- rrirhin

rr c uouno3nc( o th( vouna scdtm(rrls.NIAIN RITT FAULTS

A cor- d. rablc litrrarur. h." rciurnularerl around rlre sulric, r ul th< uounderrfaults ol rlrt,Alb"n Rirr Depre.sio,r as b.aring on rh. ,ilid;;,";t; "i'.riii,lili,,.rr gcn(rat. tr rs nol inlcrd(J lo dis(Lr.- thc c,,n1ro\(rsy rhiih hns derciopcd orirrheorics of.the modo ol origin oI rhc-c slruclulrs. \V,Llr'rceard ro rhe Imirecl rcpionhcre dc5(r,L,cd. rcicrrn., shuuld I'r made ro \Aallor d qto25. IqJOr. l,,itev Witrir(iqJ6)..Shand rtqJor. lJ-.1 {tal5)..Di\ey.r tslsi Xa.Con-.it it q5'ir."i..p'.r.;;;:(l94al j,.,hn"on and l\l,CorncIl (1q5t), Djvie- rt9!t).

_.1-\\o mrin zones of bourrdary laulring havr bccn invcsrigared. rriLh specialrelercnce to Dctrolerrm :..

(a) the system ot frults alung rhc \.estcrn cdge oI the northern termination ofRu\ enzotj, and(6) the faults foLming the escarpment over.looking Lakc Albert from Kibiroto \\r:rki.

In both systems it is o,ident that therc. has becn more than one pcriod of majormovem.rt. Tl e pre,er.r ..(arpm, nl: d:sphy a iompr,.irc .l"rrr.rl,r , un.irt;.g'ofan, uPp.r \\cll

calc-sinter deposited from old hot springs t'hich occur on both thc north-sorrthline and on tde approximately east-lvest stretch (sre Figure !)..

At Kibuku, thd'oil sccp is'in the nrighbourhood ol ihis fault system.-and drillinglyas undertakeD on both iides of thc fault in llolcholcs l(ibuku 1 4 '1'h'. fault l'asencountered in No. 2 at 920 fcet, thich implies a dip of 73' towards thcnorth\resL lHarrrs. 1949). Bedrock encountcred at 355 feet in No. 3 borehole rr':rsinterDre-ted as due to step-fxultjnq. A 1o\', though distiDct, scarp continues in theloul's sediments north north-eas'irrards from the ncighbourhood ol l(buku Aii,r" Sf.lostlv sDaced boreholes r,'as sited across this fcature live milcs north-eastof Kibuku t6 tist its strucrural signi{icance- No corrclation, horvever', could beefle, ted from thc corolo8..

The Daturc of this ivhole fault zotre liom thc neighbourhood of SempayaDorthwards to lllakoga M.T.S. {'as iDvestigated by a gravitl' survey described.l'cwhcre in this oaoe1. Thr int.rprc rtinrr imnli.s n Ioral lh'o 'ol nl lrast 10.u00leer rhrouphoul ri,e'"outhcrn parr. l'lr, rIon alJ di's out l,ir1y r:rpidll norrh oiXllufu ar-", no douhr, ro rlre cor binctl c1T. cr ul ind,-rccd rhro,r

',r,d rhe dimirurionul gravil) contrast ,( th. youngcr sedimt nts nv.r51(p thc. laulr .a.rrtard'.

,[ mirior b.ur,,1arv lauir ociut. un th. ea5t.iJe ol lhc norlhqrn lcrminaliun ol'Ruuenzori. Palg,tei.tlc": lt carr I'c sctn. rlring uffha'pl mcmLcrsofthr K;'egiItcd" iu"t aborelhc main east to nurrh.rtir! of th. I(is.gi RitLr. Thar the thro'r,. s,,hcient to L,un Ki*si Beds c,-rplctnl\ 'cems probr['lr"' Rcconnai's'jn(-cgrcritl

"urrel. inrd the \f,a.a cmbalmcr,t did rrot -evcrl xny rnarl'd slrrrcrrr-21hrerk ne:r the Rurvenzori massif.Further north the boundary fault adjoinjng Lalc Albtn is a mrrkrdly lcctilinear

fearrrre rrith onlr sl:pht local'odiustm,l,ts to-thc .truclural gra.n ol thc crl"tallrr ''bascm.nt, rihicli is "gcn.ralll ai a Jighr'y obliquc arrgle lo rhc- csuarpmcnr' Lrdetail. irrrpularitirs ai" noted ,ther" L:c liulring h.," mid. usn of r numher ol oldnl:ncs of iractur.. Thc goree of thc llluzizi River is controiled in its lowcl partir an ohliouc lr.rclure \hich offsers rhe mr:n lirr olthc cscarprr' nt (Pzllisrer. 1056)'Ii"re aeain, rhcrr is aLuDdant cvidcnc( ot early. morc d(.ep-s,:rrd comprc.cioneln'or,-Ent in the dctclopmenl ul nylonitr arrtl cpidosite ['.,m hiotrtc gneiqs's rndrmnhiholites. ln this oart of the m"in e'ca"pm.it therc i' also sornc

From rhe lir.ircd cvidrn"n o, ouL, rop anrl drilring, i1 see6. 16xs 16.of [,ounda1 tautr" ,onsisr< ot m"a.i.,i"r, ;;;,,j;i";: i;".i;;"':' ,iiil60-70'ror'trdo rhc rrougl,. Thc , ridcrr,e;.in,, ,o ,,".rnuiirufii,,.,. ""[hNoR F^ul-:rs

maln system

A.sociared tih rl'csc ,r:,in t.., n,lrr) l.,u1s rrr r ..,- Lr"r uf - iror c-osc.Jaulls.'l he." alc eriJ, rrr t,arri. rrl:rl, ,,., rt,, no111,.,n ,.._i"r,;r,, o."ii..Itu*"nrorirn.rs.i'. lhe, S.mp,jr g",g,. rblt,-,," ,r., "r,, h .futr. ii,..,"i ,1,",u,"i'rS .ri.u,fr,d pprne nanh. Ortr

(d) "Slorv but continuous subsi,l

OIL AND GAS INDICATIONSSutrrect Srrpecrs

-

The-oil seepage ne:rr liibiro earll Jrcrl atteDrion to rhe oil possibilities of theLaIc Aibcn ,ri-Bion. .lr i. tourrd orr rrr l.LLr L,ach

", ,frorr ,,,i-.nj r'l"lt

-;f"",orl'..:r..1 ot Krt,rro.rllap( r,rC c,,n"-.r. ot :.plrrlti, pirche\ ot nand ,pperrrng tromb.cn^cath. thc

.present *'hiic trcactr "r,,a qi",'. i",il,i- ;; ;ffi,;'d i!lr'" rv"ytu,ra

l]12-s] ,1," !:,;: ib:' rhr u.. u,icJ c, Th. 6111.16i6; ',.. """p,e". i,l""n ,n.o,.,"o,li se(r, lo ('or,:rsl nl , o.r,r' c.rJrd .rrrrrar, d rri h r ttri, L pclrolrutn. ln colo.rr it i.blccl o' (\r11 n,tr dar\ b.o,,rr ,rd rtrl;r,h, .r;i;".:-A t;i i";h;.';;i;,,';h;

surfacc, howevc'r,'it. is bright ancl gI"t-ri"g i;,tfr"iiiriJ p","rf"r#"iiri **-U*rn appearance lrcshlv made tannacada.rD. Attcrnpts to dig iDto this deposit, theIareral cucrr',,,i 'rhiilr r- rrnInn,,n. rrsr.tr .o rf,. i,-i,",- f-ir.. ," iriirrl: ,"., r"*r/.(l ao\\n.

,ln. :lrcl() n, lrolcunr -ozn.. our '.rpidl) rnd ,.ovnr- rv.r\lhi!g in l\\rcrnrl) \\rth a !rn.ri,l.\ bl.rnk rn.rs.,,. p.r,rlc,rm ar.d oil_sorLqd "rid. Wh". n,,

:ll.TPI":, ":'" 'c.-lr'anLru'.r.1. p.rrul, u,,r 2.curnul2rcs irr ir a,.d gas buLrLIes uprnrouBlr llr( ltqurd. (op. ,//. pp. 2q J0).,

Thr sceprgc has bein ririicd ,,n r irumber of occasions and little dilierence hasDccn no1i.L1. \- a.rpl\5,, nradc.l th. Tmp,.r,xl 1151;1u1" is gircn bt Warlard rrithcomm.nrs f,\ 'ullu*r:" Arr an;lrsr-. m:rrlc';r ,t" t",p"rLi-f3.i,,r,i'oi',-(. o,1 ,.ornrne r\rorro asnha rc ne,.p r" rc lullo\,.s:-lnt..ol, u- tmr,,, - ,olul'le in acnr.,ncl 5r,.g perccnt.qsplrarr,rn,lm.rll,rsoluhlcirrchlLrrotoln) 425 perrcnr.Ash anu non-brLrltnllrous.rgpnr,.ma ,.r 0.7 p.rccnr.lu]lhgr .. 0 31 irerce,t,

. Cabrilicvduc 10 322 small calor ies or 18.598 British therr";i";i;""

.fli:lil.rrhen dri"d.,rr" tor.r,d ro ha,, a,pccinc g.,;i,j "i0.sJr';, rs C,,"a\rncn suDJ(fl(d lu lraclr,,nal drjr.llirtio|h i.ldcd lhc lol[,rrinp re.u]rs:_

L;ght pctroleumKerosencLubricatnrs Oils a.d solid

Hydroca,bons

Rcsidue (coke and Pn.h)

Boiling poirts15'C

0.8351.1

12. +60.542.5

Upto150"C..150 300.c ..Abovc 300'C at

The high calorific value and the lorv sulphur content are of interest.,, (o2. .r.Pp. 31-32).

Th"r orhrr.:mporra.r uil srcpage is rhar ar.lriLrrLu. vi,irrd by \Valland,n l9l9an{l lrcqu(rrll) rxllmi-qd ,irrcr.rlrar d

i,t

tr

to the preseDce of iron phosphate, and rhcir ririnitl.is marl,ed b1' r srrong odourvery closeiy approximeting that of paralin (i.elrscne). I'hrre rrc somc small rockypools on the outcrop of the iol,er pcbl.lc L,cJ. lhrsc support chrLrctcristic oilfilms, rvhilc ycllou,, vellolish-red arcl r,hite precipitates oI flocculcnt sulphur cor.ermany of thc stoncs and sonetimes the sidcs of the smallcr pools. Some of the rocksabove the general level of the rratcr are covered \\'ith a thick greasy fi1m of yellotish-brorvn oil.

J- trro ol tlre pool". ga' huLbl,- ul) tro " ,r: ,'\. rrr th. r'orl; irr orrc,a.u rrpidll.T'r,' botrl.s nl this rrr, r,,ll,,r.,l ..r upr,r,l li.1,rrc,m,,rr .., '' "arn.,

znd s"ntro Enrebbe tor e\i:rminrrio.l. TI .r prnrrl ,,; 1:',1,. f',1,i"i if,",ei.,

"rrior"ltcnnugh. t\e1 gav" diflrrenr ^bsorfr "n.. rh,n ;l rc,d o\cr' :,r.rg L1u,ri( sod:sohitions. No. 1 (volume: 770 ee.) absorbed 18$cc. o1'solution; No. 2 (r,olume:

8Q0 uc.) ebsorbed 400 cc. 'l'hc Lilusric soda, on tcsting, shos.ed the prescncc of SO,and CO.. The tcsts rcr. pcrlormcd by X,lr. \\t. C. Sin-rmons. 'l'he Iack of pr.operappli:nuL" rcndcrcd rhem.

"r ',.u,.,it). .,, ,rrr'rr cludc. L,rr rhc rn,rin r.suh riasthe proof of the presence of a high pcrcentage of sulphul dioxide and carbondioxide, a little cthane, ard soDre inelt gas, prr:sumablf nitrogen. The presenceor absence of hclium could not be cletermincd. As rnay be expected, the ivater inthe pools is slightly acid.It is impossible tu sJy ho\ tar the petrolilirous pehble beds are to be regardedrs true oil holiznns, fur thrrc is thc possibility that they may represent 'secondaryhorizons', so to speal

countr! wherc rhe Alber.tine T) cn rr5-sj6n .

p155s5 intu thc Scmlili Rift. In adclitionl? lffli,ill"""i),f ;l;;;:::';,|;l.*"1ii "r'i' "i 'r'" i"r"" lii'ii^;"'lili',.", *"0"n"Sur-sutrrecr INotcarroNs

As rEcorJed elscrvhcrc. uil_shal,,szsoo recr ,nj.ri:o:i"i r""rl;ll'i,i.i'i"i,ilji::l;,;lo,: ili:"ll A:,.y,X"I:l:i:lrrith tlre.e chu.olr,c-,,r.or,n',,,,r.t.1.1 g1,.1 if fr"l..-,,,,." i;i; .;:i;*"^

", g*foand*ron. ri l.02+ t.(.r ro J.;lo l,,r sorn, oi rrhirlr.ho,red rrr,.es.t ,rcc orl onresrins \1ilh rl.lor,,ro'm. qt.,,.,r t x_0. r.^(.r.

" f,t*t oir_.1 |.,,.tij,"ro",,,r",..,rrith chlorulorm ir.n l.ELq r,,ir,,.J.S(2,"",.. ..,,..fr,,n.,,.r.'i"lj'*f.,,t,*""

rmprcgnar(d r,irh 5.,roo t,\ \\,jgr r ,,f i. ...t,..r,1. ,,it ,,f,ll sf,"\l.a",]" ""-nsr:rurr,r- ,nd u,, .rrr,,,'i.,, ,,i, o,., j ,"* t'.. ,,n ;;i;r;:;:"ilJ. |ii..",";:",l,1:,,1of vrsrline. T\\.(r rrsts \ith a form.-t.,"J"ir," i,;i;. "i:r;l;'i*J"i:ilJr"':.:::::i ':ii:,-i*" ;lil:'.,,",*t*:, ;:.:toccurred in th< shrlc, but ther

-roo.'"*g,,;,. ie",n1. io.r;, i i",ili j,ljrl:lj i;liI.": ii::,'J ::]l ;li xl, l;:, *;Lroup eJ\e rlre lultor,irr rc.,,lr . r,;,it.,f, ir.--,,t", r "j.'S,,0'i'"i', ,0."1

.

".g"r;.rratt.r. s.mc rxlrflctaL,lc ii.c uil c.rr,air.ine Q 7o. .urphui..:,

ln.shaJlo\ rccr.lrnl,* l(4 i,nd l(ti irr rt,i KiLiro i,"jt,l.r.tro"l,.arrds rnore oric"\ rmpr(qlrr.d rrirh ort r,.r, ,.r,,,t 11 m,.1l) ro,i,on"i i, -i

GEOPHYSICAL SURVEYS(J. N,I. BRow\-)

fhe first sturly nf thc rariation of gravity in Uganda rvas uldcltaken by E. C.B,,jl1rd Il9.lb). Bctr,ctn l9J,l ar,J I9lt,. l'r u..rrurrd Fltrcr

'it,s,nd d.termincdrl. qlrriry ralu.- tt .rringing 1,.n lulurn". ln ubs.qu.r L !ur\c):ir rrhich a NorthAmiricar,-erarirt m,r.r r,i. u..J ro m,Jsu-, grurr,' dilT.rcnccs. a rrum[,.r oI hi.strtions \"ere re-occupicd; this fcnnitted riduction of the mcasuremerlts toabsolute values. Thc originai pendulum values \!c're Dodified by Bullard andHors6,:ld (1937), sh., crlclrlatEd a positir,c corrcction of 3 45 milligals, and againbv Duclaux rnd MiJtjn (195{), lho dctcrmirred a lurther correction of 4 60;iiligals. The moclified Bullard values \\'erc thosc adopted during thc gravity

Bctl,cen June :rnd Septcmber, 1950, ll. ll. tl,ld undert,,ok a gravity surveyol pa|t of Lh( Rilr. Tha obi(cr :r' r\\o lu'J: arslll. ru.l'rain I J.triled gra\ir)'nici,,rc orer Lh. Serrrlili flct' and in rhc r,, i:l,l'uu-huuJ nf rh" feultccl terminarion^l rh. nonh(n, nirr ul thL Rur.rrzori. t i',' 1,1'66 thar rhi'rroultl guidc rhelocation ol drillin,a in thc scarch fnr hiddco lault structures. Thc second objectol thc

"urr"y se- io begin a gcn, r;l inro+igrt.un ol riit !.:ctunics.Altogethei about 4O0-graviiy stations \\crc ohscr\cd. fhc majoriq of these wereon tra\irse lines betrueen the main boundarv lault and the Scmliki River, and acrossrh. Dresumcd L,uIi.d r'or'rhcIrr l.rmlnrtri4n ol rh( cr\'tr'lirre nrc." ol l(urenzori,rnd'r'.re a",omp.r,i..l 1,1 prc.i.c lrv

absolute veltrcsand I-Io1sfieldand X4a1tin.

An analysisuncertainty of

zduprcd Iol rhc punduturrr stari.rs \.rc thn5q d...ri[,( d l_rv Bullard{Lp. .//.) plus t1'o 4 60 rlilligal uunicriur dcLermir

)L

il'

I

iit

tl

escarpment near ]Jutiaba. Sirce thc Bougucr \elucs continuc tc, LJrop for. somemiles belond thc borehole site, jt is n,,r unreasonrhle to infcl that a thickness rvellin excess of,1,000 lcct obtains near thc axis of the basin.

The va-rietion Jn the Bougucr \alues olel thc escarpment is, on ar.erage, of theorder ol 50 milligals. Th;s re-iar'or' ir conlir Ld [rq.ly to a

'r.ip ot .rbour 5 ro l0miles in u'idth, normal to the directior r,1 thc escarpmenr. Throushout theseinvesligatior'-. rh, vrlr rrrrkqd rs-o.iJti.rr ot rhc rrpid chcrge in Botfiuer rarue

lascerlc; , d Ly .lrillinq rlr|ouel. Lhcrn ir,ro rh, undIrlying rrlsrailine roc\s. Dlillingp'ugra.nmp. havc be,n crr.,ied urr i,r rhrcc r*r. i,,,fi;ri er;l',"'' '""(r) Ar \Vri,i .,..r1 Br,riabr. rr rh, rrufrl,_ca.r.r.n ",,a o?-L.l*. elf,"r,(D) ar rh. KiLi.o u:l sc,.nrl., ..,,1( 6tleen

^:r..-- -r,,,i:". "-,'j" ,,ong rheshore of rlrc Ia\. trc,,r Buri,.ri.ai,n.t(r) rn the f.icinirv of the ]irhrrku oil scepage in the Rivcr. Semliki \rallcv, south_

-.rrrst.,ol thn la\c arrd:t rh, nurtl, rr, nd

"i,i. nr,,, "r",i'n"r,"".''' '"

I he o,l uc, urrrn"c ar Kil ir,, i.. nt ,rsl,hrlric r1o". ,, hn..+. r't,,: uii_:ino,.,.qn",.a ,"naat Kibuku currr.lirrs a mulc p.r,rfErrir r.rr,, r,.... Onll ,r

,l(ibrlo uar,rh, irrllrlg 1,. .";a'i" f.r," h

hydrocarbons miLy havesands, and particularlyhorizons.

BRowN, J. x{. .. 1951BIBLIOGRAPHY

.. Rcpot on a \risit to tle Belg;an Co.go and !'l'ra1,eBe oler ihe Albert IUft- Li pub- Reot.

.. Ruwenzori Expedilion, Grarity Nleasurcmcnts.Cr l- \ Ug44da-

.. Gravimctic SuNey of Plrt of BuDyoro D;strict.Geal. Su-.. Uganda.

been, horvo,er, strictly limited b)" the lcnticularityl of theby the prevalence of silt and clay frrctions in thc sand

ACKNOWLEDGMENTS .. . .This account of the prospectirig for oil in Uganda is complied from reports madc

l)y various omcers of the Geological Survey of llganda. Thcsc reports, mostlyunpuLli'hrd. [,ut availablc for reierrn.n ar Ih, h^adqu'rIe-. ^f thc GcologicalSu.r-et ol Uganda in Ertel-,bc, protiJ. addirional Jqtril.,,n r numbcr oI poinrs.Gratiiul ackn'ou'ledgmert is madc to the Board of Dircctors of the African andEuiopean Investment Company Limitcd of Johannesburg for permission to makeuse of reports originally submitted to the Governmcnt of Uganda. Acknorvledgmentis also made to the Directors oI British Petrolcum Company I-imitcd and of theShell Group for permission to publish t$'o rnalyses.

1952

1955a

195sb

1955c

1935

1936

t93719+S

1951

1955

1945

1954

1949a

1949h

19+9c

19+9d

U pub.R.Pt.

Re?l.

Pa i.

Rcft.

cmviiv \'leas,,rements in the Murc|ison Falls NationalUt.;,b. R. t'. u. 11. .cut!. t {.n \a.

.. Gravity Mc.sureme.ts in North-\Vest Ankole. UnPuL.t,ol .\u,r- t gr\,h-

BULLAR,], D. C,

lurr-anp, E. C.BL,sx, H. G.bo,,n', r. e.or nri^-^u-, l.DntrY, I. . -Ducl-^ux, F. s, al.

HAnnn, N.... "

Grayity lleasLlrements in East Africa. Bull. No.2, Geol. San-Llsan.fa- pp- 28)9-

Graviry XleasDrements in East ,\lrice. PL;]. Ttd s. RoJ. Soc.L

" /or.l':,:57. pp..1,15 5JL

X{onthly Nores. R,l,-,4rr/- Sd.. Geoph. Suppl.4 No. 1.On drc Noi,nal Fault;,g ol Ritt Vallcy Structures. G.o/. Mal'.

32. 1. pp- 3744-.. The Us,nda Section ot rhe \\rcstcrn llift. Geal- Mag. 33.6.

pp. 377 385.Le loss6 Tcctoni!uc soDS le Parallale d'Ishango. /rs/. d.s

fat,' hal dh ( ll l-rpl"r.. u P.\.4.. l, lILOn thc Faultins of ]tift Valley Structucs. Gcol. Mrg. 82. 3.

pP. t16 t.r 7.Etablissement d'ur Riseau g6naral dc Strtions gralinatriques

cn Afrique. O.R.S.T-O.M. Paris.Report on Borehole LibukD No. 1. Unfub. Repl. Geol. Suro.Repirt on Borehole Kibuku No. 2. urlttr. Rept. Ceat. Swa.Report o! Borclrole Kibulu No. 3. U,Qtb. Re?t. Gcol. Sw .1,61 on Bo,.loh K Iuku \o. 4. t lut,. RcPt. C?ot. Sutr.

iI,

l

HaRRrs, N. ..

FfoPwooD, A. T. andLtrPERsoNNn, J. ..

Johnson, D.

'JoHNsoN R. J.McCoNN:ELr-, R.

LEPrnsoNNE, J.

l{cCoN^TLL, R. B.

P,\xc!TER, R. C.

PENNY, F. W.

PurN,rM, c. R.SHAND, S. J.SwArN, F. M.

PRoKoPovrcE, N.

Wrlus, BatLEy

W^YLA^'D, E. J.

1950

1950

1953

1930

1951

1949

1951

1950

1953

1956

19+91950193940

19281936

1954

t936

1951a

19s1b1951c1951d

1952^

1952b

19201925

1930

1931

B. .. Nore. on rhe CFoioCI ot rhp Nolhern pa.r ot.\e Rurren,ori.

Ivrounta,ns.'C,ol. Mog.88. +. pp. ,4a 2su.re.ronrque ta. A]ben Semtjkr_La. tdouard. ,4,n.;rc. G,:ol- de BetE. 72. DD. t{ L2.

.. Rift aqd Shieid Srru.ru-;:n Easr {frica. (.R. Xy lth Int.G?al. Cahp-X[\,t, Da. 199 207.

.. Rcport on Borehotus i(,bulu Nos 6 7 tR"pt. Gpor- skft . { pando. ' Nvrl'ab:m i '/'t

.. Nu_trs on rhe Nort-hcrq f.rmincrion ot itp \tpsre,n R;fr.Rec. G,ol. S"fr. t.)sa Ja. pF. +g-52.

.. NorG on rhF C^".I"g: "rli. Lorr Muz;zi valhy, foro.Unpub. Jtept. Geal. Sutx. Usanda.

A.m. fppt. C^pat.. S- D. ! pl,d; Ja 1e47, pp. s_e.. . Ata. Rt?t. Gaol. Sulr. t Baddo tu /048. pi. J4 Jo... I(ppofls ol rhc {fricar anJ Lurope,n invpqm(nr Co Lrd.{r gdnda Oil Con, esron.r on r+ 6tes of rhr C.ol. Surv.

Usanda.

Report on Borehole Kibuku No. 5. Unrub. Re?t. Geot. Sun).Usa a.A h. Rept. Geot. Swa. Usdlda lo 194s. pp. 4 6.Pr;in,e de lorm2riols Jage,nioccr. ini.leur dans le foss{trcrolqup du Lac Ab(fl Fr de tr Br.sc Semliti,Conqn^

Belgc).. ,{,,, sot. ciot. de B"ts. 77. pp. B s, iji. -- ""uponorprorogr AsFt,. o Ritr \'atte\.. t. R. Xyth lnt.Geot. Cone_ II. pp. J5+ 37j.

Prot. Nat. Acad. S.. 1+. 5. o. 4tlRift Vallcy Ihprp"sion.. C;at. Mag. j3.4. pp. r07 Jj2.Sr.rtisrrphic Disrr:bJrjol o. L poid SubsrrnLUs ;n Ceda- Cre.k

-Bog. MinnAou. Butt. C.ot. !or.4,r. 05. pp. jj81 11,,8.

''Ea:l,i{liSan P'rreaur and Ritr vartc)-.. Crrnesie Jnsrirureol \! a6,h I ngton.

.. Gcology of the K;buku lvasa Arca. UO1L Rept. ceot. S1ro.Usa da.qolocy of,.h" t

rs EE A5 EE::oE

Appendix IILIST OF OIL AND GAS INDICATIONS (AFTER WAYLAND)

t,

1..2..3...1

..

5

9..10 ._1t ..12..1l ..15 ..

f i ..18 ..

19 ..

20 .,21 ._22 ..23..24 ,.

t

25._26 ..21 ..28..29 .,30 ..31 ..

32 .,33,.34 ..35 ..

-\aru.coI sordc.nd pos;ion i Fi.ld.

,. i.,,-.. , ro.ot,to...di.iD..r.pn,,r,ro amnr ,d,.- -"r.ho',1.1Le',\o.\l'...'1...,1. ^..t.1'oro trir.,..,. ro . rL'f\o mlles doNnn.rxn ol No. 1'1\ro ,nilcs upstream .l No. 1 . .Sddr dav risht bank ol rr"r L,cr*- ttt*.r,"". r]1r.

",ol Victoria ^-ilePn F.l near \\,0(i Rivcr ar 21' I

l'Lr l:.\ ne . \\.k tu\rr.,rr, lSrndlrr,,.I rr tr.,r nErr \\'xt k,\.r.Lr r2 IPn F.t near \\,0(i Rivcr a|23'Pn 1, c.ntre of \\,.[i llill it 30'\Vrtcrcourse E. of $al{i Hltl

Sh.,ll 61,. uf o'1 I namfin br\.rvcry aann oil rlnlj.

No o,l ar2+';oil rin,rs.t:10,.Slleht hut dhrnrdrace of6il.vcrr dccidcd oil rinls ard nhs.Lars. qux,,rir\.r rnspGstcd oit,

Good dc.id.d oil rinss.No oil. "Sak .l lic[ consists of

magnesiuD sulDhatc aDd chloridc \'nh tr:ccs ol sodium

Small ,cuov oil i.ss.Verr decided oil rinrsDisiinci!.ll.N

"il fri-.

Small bro$n nlD oa oil.

I-ignnc and somc bro$n oil.

Pir l, $esr s'de !l \\ rl, ttitl Jr l1llt 4, !r{ sid( of \lJl, llrll .tr.12I-,,lresh, rr .Jn.l .irurrrcJ Nrh p. r,, fl,nr re.,t,

-Top olsrlin. tavcr undcr boulJcr beds. riibir.Grcr-drab san(ly clrr' !ndc.lr ins nain fo$;lncrous ho, tzon (6onc b;jcrlt s,ndr !lr\ h.h\:(n r,5ro.u,d Nluirk.-L lht bull \ind\ .lrr h,. \ nn-, dh .-i r^, ,cray bchr rcd-c.rth and bouldcr tre.l in bed ot

sircxm S. of l4uirnkom. r]rout rtncc-.ruartcs oI a milo trom f..rL I ' bu' . rd

.. L.. .. r,4-, ..'h .a. bol ;.

E \n' (approx.) scarF S. orti.iso To.iaffals

Sr.d' clays con$itur;rs l.cal b.sr oasedimcnt.rics in sullcr S. ototd\digo track (noN x. cicphrnt D.th) . 1e$ Lur.tred \a.ds trom b,ceol i'nBJr' ...'. ,'d\....,, L-,. ot,.{,J r,*,, ,.",,,, r, .rr .,innot trrlrom lj $ (arrprox.)sc.rD

s.,d\,...,,ajr.\,;;.,.... 1rt..,,,r ro".k,,,' ..Loon \rnd\.h\ GrlinLr n.,e'ifi,.lJr \.xh .' c.'o , r,,tJt,\ t2 bjov .Jrta,-, I rj.;, r_l] oi) Jl 'rrr

. l:. - ( da,p, \1-.,, \roro\o 'r...'v^-v{'r

'.r-- 'o L,LF . h , l.'! p.ledrj,hta,.,,

",-,t.,,._ ,,*,,r-1'1. l -',L- i! '

\\:.. r, i, orlrl. r t,\ rco. nl..mPn.ile', L. dJ\.j\'

s-' l\ .,.. hfr. ..- Jo.1 \]i, rol' n .-. r."- '".

i.".,...,;P. xl-CofEo Lfu!k cro!ie. iior' r d. "n;n., roo',i,.,nh.',.t..o.\r,b,;a"R,\,. ..

\lo'.',,-r.-\ ;. , ,or". sr-ro\'r ',

t\ -pnj,h,\ ot i.,."Er R, IC,mn, undc.lvlnr fo$ilitr.o!! brdlurl ..nd o . I'o r ' i .-p .in-d .1er:t, \.o:(i ..rri.rC.",;c,-..b'o{rEfl' tla,'t { .,,,,..romt(i ,p Fe,C.,np ..u'o.\".r..LIJ,L rne.j'd'r!, .....1\,,p-rjr r,'h,re,J,,.

"n.lcLtrlld {.bdf4, I 'of ,{...rrrcr ( 1.RPrPJh bLrr

"ad pJr'. .onEt, a.tu., - i".,. .^",;,,o,,, Ki.el. l{o{ c.,. l] ..rrc'd '..-\.quJir/ t,r ",J i 1., I.rJ' F , of

^'seE' BedTLf

.-"d..o.^.t,o\,. K,t ,., ,, ,.,..c, ,!o,,,,kc, r I'r. ,otr -d ."'J,,o,., i, i\il ur , , .nn -n,

", oj.

.t

Sftall .jnss brown oil,

Kibuh hd 6cNccn Xihuku a.d sneor34

32

I

41 ..42 ..

43..

45..

1(rn,n. Otr SmrA.n:"Pdroleum (m rsolublc in acdonO,q"p;;i,i;; i;;";. ."r.,1r" ;" .1,r"'"i!".jAsh.od non-bitumjnoris orgxni. nritter..Calo.inc v.luc 10'322 snr.ll calorlcs or 18 s98

This oil, \fic. dricd, sas lound to harc , sp.ci6c srdliry oIl.tion yielded rhe rollorvine results:

Softlightcolourcdsandnonener.footol\carpD,\'Kibuku ..Vcrr soit srndnonc, appxr.nrly carbon2ccous, rvin a sliehd-L

rl. .'-u. .n. ll. . lor , rr{,, .. r. ,'r. Iii r.C,1t,.,r'1.,.d,a,. lr,J'..\,(.,Li.-Solt srer'-srcen pebLlc bcd, *i.ny ro louch, in trcd ol srrc.m r

beh nd l;lbrku''Naturalpu(y" aperolcum-sotrIcdlx.li.,lcnti.rlartcdabo!cl,''NaturarPutty apet,orcum-sotrrrcd kx.I.,rcnh.Cox$e yclnN to bun. saD dsron. (sort),ho!s.10 ..Pebble bed r6o!d 41

A.gill..eous sDdstonc.bo\e 42ci,i i"riiiiii r--

"..iiri.:;,i iJ i,, ,.r,r.1,:q -op".". . . . .\\-,',1

'-mp,,''.oue5"Lri, .1.1. ,. p.YcltovxDdred 6roNr precipitrtes in pool liom \rhich 44 Nns colle.icdL\p r' -L,ii.'r

'd r.n. ', h.llo\ p'' ^\cc- \r,1.L..' .ndS'rn!]n un' ,"fla[.lr\. ^.".x r.Loml 6rse (isegi llcds r6.ur x nri lt $. ol K rs.si C.mD .. ..l(-.en\'(Confono""13' -.' Jlr.'1n."D''Sand,v arsill3ccous deposit j,nrcti..ing \nL r.d-c.rth rbove, in brnt\.^rqr.k'

-.'4 .. ql.,''.\^ F-.' lo " ra,lSlabbr cal..reous volcani. tulTr, Iiigorongo Can! N. of l