OEOI,OOY OF T H E S Te F R A N C I S D A M A R E A9 L O S A N G F; L E S C O U Ir T Y, C A L I F OR 11T I A., Thesis by .resus Ru:liz Eli.zondo In Partial Fulfillment or the Requirements tor the Degree of Masi.er of Soienoe in Ooologv California Institute of Technology Pasadena, California 1953 ;i ,, Topogi•e,pl1:io ai.'1d Geologic map ~ • ., ., o., .. ey", "'¢ ~ ~" • ,. •• ., .. o"." .. " ( foldco.; Colum1'l<'!'lr section Iii part b) t'>f l<;ocene ( ".i') -:uocene ( ? ) t•o,1'! k~; - o a 4-<11 st.ruct.u:i.~,~.l. 5,a,ot:t011s A-D""-0 a:n,d D-E "'.," ~" • ,,, ".,.,., • o • ., • ., • ",; "<11, J.>'). ;., StrueturtiL sections PLATE a 1 c Abova; Genera.l v'ie1.,1 along San Framd:.::iqui to Canyon 9 illmrt,rating windlng pat te:i.~n ot the s't1•e!:!f1lc Beluvu View looktng north i"rom. the paved :road San Franolsqu:Lt.o Canyon, AP.'1'1"!'!11~a1 m:lles sou.th of the ~i.reai:t illustrating wlde span of alluvium separated by hills of m,Jderato relief'.,"".,"""" 0., "" i:, II."""~.,~" .. " <!I". e. "" ~ ~ ~"" ~,," 5 lia Above a,, Contact r.'elations betWfHc':n J?clo:na schist.a and overlying thin red bed0 and li.ght. yell.aw conglomerates of th,~ ~1:int Onnyon formatipn" Viaw Ill taken from paved road II fa -~o the west., BelO',H A zood exposure of Pelona Schistf.lJ view look• ing west from pav0d road., ••••• , • .,, ••• ., •••••••••• c••~"•••• III, View from paved. road, looking to the wem wall ·or &u.1 Franc:i.squito C:e.nyon. 11 illustrating; Abovei Scarp faces ocr!ur•r:iti.et on Eooene ( f )~iocenis ( 't) rookeri Belowi .Mea:r southern end o:f f'oldi.¥1g Modelo formation.,,.,o••••••••••••tott1e1t,••t IV" Abovei View f.'.r'om paved roe.d 11 north of stt n·Eu:10:h; Dam 11 looking \I.rest to low hills of Eocene (J)-Miocene ( ?) red oode" · Belowi VieY looking south, .taken from Charlie Canyone,omc,o,t•~~,,,.,." ••••.•• ,.".o"'''"~•Q""""t••~••«• 4:7 V, Above; View looking to the southve st_ £roui C1:i.a:i"lie Oe.nyon lllustra.tine cavernous weathering. Bel~,rt View :.,orth, from Charlie. Canyon.,,, Ca.vernous weathering on south highest cliff in the e.rae. ., o o • , . 111 " " ~ o ~ t • o • "" • ., , ., • -. .. "" , • ~ " • • ., • ~ • ,i, • , ~ " ., " ., I! ., ., "' 11 o o " " A,9 Vl. AbovYl!l I iliet,1 takcm f;rom tx,uck trail between s:tte of' st. F:rane:i.a I\'9,,,1' 1mcl El:tza.beth La~, and. loold.iig north"" eaatei It illm11tratei 1;ion11lonlerate1 tracod on the :w1p arn:::I indico.tf.!ct es 'J:' 1•:('1)-1·1( ?):,.., r-eloiA: 011 Charlie Cali1J.ronl'> A:pp:r<lX, ove mile southwest ft"om aama road Ulustrat:tng detailed cloaa.,,,packing 01" 4::neuus i"rug:11:ient,1, occu:rrlne: in .ranglomera,t<::i de postts ot the Eocene (? )-Mfocene ( ?) u u., u., u u u u u e u 51 VII.. View ti itl ;~!an 11':1:•tm(daqui!.o Canyon, l.ookin.g wos-t. ir1to Mooolc• hills, t.aken ut, x Abov~ i non.·;; sotrl:.h end of m•eu., Below: hills n short diat9.nce north tram .santa Clar(t '.Ri ve:r"" .. ., ,. i1' ,. " • c • ., ., c '',;, ., ,, ,, "'" ., • ., ,, ,. ,. " ,. " "., e • .,, ,. " • .,"" 5'.3 INTRODUCTION 3 :Popt1l.t~t,ion o ., 0 ~ '° Q im: ~ ti ~ ~ o \') a ~ a i) o c 1• " ~ o I'!!' o =., ,~ o v ® ~ ~ ,;ll o Q ., ~ c Ill o ~ o .) i;lJ ~ • o Q 7 Scc.pe of• this wo:rl;: o o o • ., ~" • ., • ., •• ., " ~" o ... " • ., .... " • ,. • ., •• o."., ".,., S PravlouB worka " • ., ••• " • ., •• , • o • " •• o • ., ., " " ... ., ., o .. • o • " Aokn,O\,rledgment,s O O" 0 "0 0 •• "".". 0. "a O." • "0"." 0., a O ••• " 0".". 0" "9 10 11 Eooent:~ x·ooks b f) C C O ~ C C: 0 0 @ l!!I Ii) 0 $ ~ ~ G !tr 1t ~ -Ill (I ~ & ~ 0 1' 0 I!! t1 4' $ ·• t) ~ l'tt! fJI 4 !t; 0 0 ~ 0 0 It') l!J Eocene ( ?)•Miocene ( ?) rocka ., • .,, ., c.,". o • ., •• ., o,,., • ., "'o.,.,"., o o o., o o., o 16 (b) Coarse cone:loi:nn1"'a.tee ., • .,,. ......... e•""""""'""o•o•o•""""o 20 About ;ooo teet of Terti8ry sediment~ e)rposed :b1 vicinity of the old st. Francis Dar1i Reservo:i.rfll San Franeis...~uito C,imyon, toe Angeles County, Cal:ifon.1ia., art1.H1 the~ri oco11t' is 1,,1,~ted i.n the e~iste:rnmost ·t.he Ventura Bai:1:b.11! At lea.st ;oo feet of \.Tell bedded :rred siltertoncrci, 2700 feet ot piedmont depo@it~ o.1;m l;x,; assigned to theae deposits, but to tbe m:»i"'th they are un""' conf'o:mably undt11t>lain mar1.. nitll ,1&t.11"~rt.a of' FncGr:-.e ags!"l,. in"ia• th:hik bedded to tno.6aive arkOSIOSo To the vest, aoutb and southwest 1,iiedinortt depoaite are unconforniabl_y overlain by non~mrine I.k':l.ssive sa11dstones of the Upper Miocene Mlnt Oe.nyon f'o~1.tlon., Thr:i evidence p:revails that the sediments in the aree stud5.ec1 ff.it"ess1vely younger to the south and to the westl:l !:u1 happens ev,~,ry-whe:re el,se in the ei:i.stt,rnmoat part of the Ventura Baeino Foasiliferoua of. the uppermost P1iocene Modelo formation unconfo1"ll'lably overlie Mlnt, CtUJYon bads· t.o t.he south ~nd to the Pre....Crotaceous rocks composed of gray, qu£-irtz-rnuscov:l:te t c:rop out in the :northeaeto:n:1most part or the a:i.~()a, Metaquartzitas and quGflt.!i ve:bu; are :m1nor part,ei of "th5.s torr,arie.. Thi~ group of :t"ocke ie kna1-m as Pelona Soh:ll:'!tao m- and poi;t-Mint Canyon diP""'slip reverse faulting aoe'ifil:;i form thi,:i dominant structurul fea.ture o.f' t.he a:roao A poS!:lsibUi.t.y of r:u:arrna.1 !'ault,;tirl/J; ox::h,·t:.s in the northw~stl:clI'n p3rt, the 1:u:"ea, bGtween Eocene ( ?)-M1.ooe,lii::i ( ?) :rooks e.nd the .Hint Canyo-.r, tormati.o:n, ani:'.l ts .f'ully The e,131Ji.r,1:2ntary forma.tione a.re f'olded&l &"ld the .!L"'t(:)lS follarr1 11 northwest-eouth.'3ast direction in the northern p!U1:, of f,.he ar;:,a, 1a.nd a1N3 p1"'ohably related to a first stage d.ef'or.rc1.e:t:ion in pra.,,.r,iint, Oa:r(YOD. ·t.:i.meaB to the south, tha fold axes tre:nd north.,,,eouth 9 and seam to related. t,o ·a second stage of deforraat:lon that probably took plaee in pi~st-late M:looeue tim0,, 'fn,9 area :ls in its late youth to early mature state of' topoeraphic dev~lopmant. T'na r:rt.re ..?-.m along S,1;;,11 Franci!13quito Ca.:r..yon cute a.c:roea the at.1"uci~t'l.r.e o.t· ·the ~lone ichists iriibcriminately for least one mile 9 r~f'leoting 1n:001r1i~ar1ce drain~ge system estl.!l.bU.sl1ed t.mder rlif'ferent 0011.diM.one. CaVfJ~oue weiatherji.niR b lairgc,ly cu::n1f inir~d to hard 11 illaiss~Lvel! conglome:rati0 srmdstone of J;,~ig~ene( J...ir•1;1(;:c,~ioo(?) age, in the north central of e,roc,. INTR.ODUCTION Location am Ph711aal Feature,. TlJe area discussed in this report is located in the ee.ste:rnm151t part of' the Ventura Basin, :in Loe Angeles CoM.ty, Calif'omia, and covers al;>out 14 square miles,, The southernmost part of the area , miles airline distance north of' saugus t which in turn is 45 miles northwest of Los Angeles. The.entire area is crossed 'b1' a narrow, paved road, which extends &10111 much of San ~anc:lsqu:t.to Canyon and connects the town of' SaUgus with Hughes Lake, 29 miles to the nor-th. Excellent rock exposures are present on both walls of' the canyon, and can be reached easily tromthis road. A tractor road extends i,reetward from 'bbc eite of th-s Still Francie Reservoir, and gives access to the' western and northwestern parts of the area, :tn the viclnity ot Charlie Canyon. To the southeast, well maintained dirt and gravel roade serve the area north of' Dry- can;ron Reservoir. (See Index Map, Fig. ~ Both Charlie and ~ Caeyons can be traversed along gooo trails tor reasonable distances up stream from the southern end of' the areao In addi:t:lon, several firebreaks and traile, ma:l.ntained by the U,S, Forest Service, cut irregularly across hill7 country throt~hout the whole area, The lO'!izeat point in the area is 1n San Jli'anoisquito .Caeyonl!I vest ot the DI':,' C~on Resenou-, and ii l.317 .t"eet above sea level; it is situated in a wide .span of alluvium which separates hilla 300 to 400 f'eet high. The highest point in the map area is on the west side -4- INDEX MAP I\J SCA LE /'i!3Zooo1 ,C ,. J " ' 1 Ml LE 5 =- MAP A REA FIG -5- 1"_,"; Plate I. Above: General view a.long Oan Francisquito Canyon illustrating winding pattern of the stream. Below: View looking north from the paved road of Sa,n Fra:ncisqui to Canyon 7 several miles south of the area~ ~ of Charlie Oaeyon and is the summit of an isolated, cone-shapedi:, steep sided ridge; its crest 23% feet above sea level.