1962 Number I
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PACIFIC PtTftO!.tUM CaOIOGIS t }IEWS LETIER OT IFIE PACIFIq SECIION A'NERICANI ASSOCIA'IIONI OF PEIROTEUM GEOTOGISIS Volume | 6 Jonuory,1962 Number I ASSOCIA'nON ACrIV I rl E s IOS ANGETJE^S LI,'NCHEON MMIING (4) The g.]|.anitic nassif 1n southem Sinai 1s sinilar in petrolory and elevation to a granltlc trTectonics of the Deatl Sea Faulttr uas the sub- massif bordering the northeast shore of the Dead sea. Ject of an enlightening and beautifully illustrated The sinal oasslf is about 14o kiloreters south of the talk given by l4r. Anthony E. t. l'Iorris, tbnager of proJectlon of the Arablan granitlc outcncp. EJeloration, Pau1ey Petroleum, I'nc., at Rodger Young Audj-toriun, December 7th. (5) The stralght northeast shoreline of the Retl sea is offset betneen Sinal and the Arabian blocl( Abstract: on the order of 14O kiloneters. The Dead Sea Fault 1s a north-south trenalinEi (6) The thickest section of Upper Cretaceous- flau in the earthrs cnrst traceable for over 1000 Eocene rocks east of the rift is Just east of the Deaal kilometers from the Real sea to eastern Turkey. rt Sea. Across the fault a comparable section is founal traverses the country of Jordan i{herein the greater midrday betwben the Dead sea and the Gulf of Agaba. part of the study was nEde. The loci of llaKirnrn thictgless have an approxjnrete horizontal oflset of 120 kilometers. Jordan has three alistinct geographic aJral geo- morphic provinces: (1) the TransJordan btoclc, a (7) I4aestrlchtian bltuminous chalk I00 tll--ters larqely desert area conprising the eastem three- thick is founal in only one locality in northern quarters (2) the Dead sea Depression, Jordan east of the Dead Sea falrlt. West of the rift of the country, (10O a long linear trough reflecting the proninent Dead the greatest alevelopnent of bltunlnous chalk Sea fault, and (3) the Judea Hi11s, a hiuy antl- rcteis i) of identlcal age is sone 1f2 kiloneters clinorlun probably resultant upon basement bLock south of the flrst occturence. faulting. (8) A 70 meter section of canbrian linestone Jordan has been on a hinge line between the Ara- an(t shale is present at the southeast corner of the bian Shield ard the Tethys Geosyncllne throughout Dead Sea. Weit of the fault a section identical in known About 850 neters of thicl(Iless anal Utholory, anal of cor.relative age' its Fologic history. pi-nch terestrial sealiments accrumlatetl on the land$aral is present Just north of A€aba.. Both-sectlons siale, 2000 rneters of mixeal shalLow marine, littoral out'southuaitl in identical fashlon. The strand llnes ard continental strata at the pj-vot llne anal nore have 130 l(lloneters of offset. than 5000 npters of narine beals in the basin side of the hinge. The sedioents range fron Cambrlan to (9) A larep, basic porphyry dilce occurs 45 Recent. kllorDeters south of the Dead Sea on the east side of the fault. It is boundeal by faults anal ls uithln The present structural pattern of the country has the Deatl Sea fault zone. A sinilar dlke is found devetopett since the Mittatle }bsozoic anal comenced I3O klloneters south of this locality on the Hest with relatively ninor basenent block fau1tlng. There side of the fault zone. The tro rocks have slmilar is no true geoslmcllnal folding in the area. gross petrolos/ antl are the only occurrences of rocl(s of thls type in the area. l'lovenent, of two tJDes, be€pn on the Dead.Sea cretaceous fault in oligocene tfule anat is stiU active. Therc (I0) The Tr1ass1c, Ilpper anal Louer is substantial evialence to suggest left-Iateral all pinch out, east of the faul.t at or north of the 11nes, strike-sI1p movenlent up to 1410 kilometers. Relatively latitutte of the Deatt Sea. The sane stranal ninor contemporaneous vertical novernent occurr€d and baseal on uell data, are in southern Israel about has given the present topographic confj-Brration. I30 kilorcters farther south. Ten points of evidence in ascendlng oraler of inportance are listed to substantlate thls proposltion: IOS ANGS,ES GEOIOGICAI FORUM (1) Ihe orientation of folds on both slales of tlE On the evenlng of December ISth' at Mobil Deaal Sea fault is consj.stent uith interpr€tation as Anditoriun, a large ptherlng of A.A.P.G. nembers drag folds along a naJor shear. vere treated to a subJect about vhich nearly all clair to have at least some first-hard laloule'lge-- (2) Recent fault scar?s, shoulng left-lateral the san Anatrcas Fbutt. Dr. John c. crovell, pro- stream offset are vislble ix the Deaat Sea Depression. Geolog/ U.c.L.A., began rlith a nost inter- i.""oi of trThe esting anal well-illustrateal talk on san Andreas (3) A large qraternary basalt flo$ in eastern Fbult 1n Southem californiarr. Jordan entl southern Syria termjnates abruptLy at the Dead Sea fault. Identical basalt is founat 35 klIo- Abftract: neters farther south on the vest side of the fault. There are no vents on the rest siate. Three segrents of a forrner east-uest trentling belt of terrane in southern California are inter- preted as dlsplaceal horizontally about I50 n1les on itre vertlcal San.Artdreas fault and 30 niles on its PoEe 2 They stressed that movenent of a few miles was not CllMMIIIEE. PACIFIC SECTI|)I{ in question, but they challengeal the ialea of nove- AMTRICAI{ ASS(ICIATIIII{ llF PTTRIITEUM ment of scores or hunalreals of miles. They also stresseai that they uere nohr offering only questions, lrving I. Srhwode Prasidcnl not ansuers--chal1enges, not solutions. Their un- lndrew J. flhtllillon Vite - Prcsidcnl resolved probelens were : Roborl 0. Poltersor Se(reloty Rithord l. Hcsfer fleorurar 1-A burieal granite-Franciscan contact, over 30O Ironk A. [xun ldltor niles 1ong, Lies untler the Great vauey of california Ihorno; A. loldwir Po:f- Prc;ident j.s Spenrer line Coosl Reprerenluliya As this contact, 1f it a fault, has not suffereat l. S. (honberr Son Jocquir RcDresertotiyG novenent since pre-Eocene tine, nust a siniliar' Soclonenlo live contact along the san Andreas fault be explained by Tertiary strike-slip novelpnt ? rblished monthly by the Pocilic Seoion. Amer z-The Pelona-type schist is dj.stributetl over ssociotion of Petroleum Geologists. Add a uiale area along both si.ales of the San Andreas antl ommunicolions to the Pocific Petroleum Geologist, Does .O. Box 17486, Garlock faults anat in the MoJave Desert. its Foy Storion, Los Angeles lZ, wide distribution permit employing it as a field criterion for large strike-sIlp novement? Arrislont Idifo]s: Perronol ltemr 5-Nine years ago the uniqueness of the San Seletled Bibliogrophy lury Blrdscll Gabriel Mountains anorthosite occurrence rrras cited, (orlooni:ls Illort l(line j.n offerlng j-t as the only possible source for Horold Sullwold (orrelpondenlr: certain conglomerates. since then, anorthosite-com- plex have been founat in,three adalitional (oo3l A1len Hanson rocks local- Alo:lo Roberl l(enyon ities. Does this rclative ubj.quity perhaps invali- lo: lngrlcr lohn Yon Altriagc date the earlier conclusions dram concerning the l{or f h wc:f ll, l. Grcene anorthosite? More recently, occurTences of anortho- So(roncnlo Georgc Srown site on elther siale of the San Anclreas have been Son Jronrisro Dovld Pleiffer employeal as crlteria for movement on that fault. Son Jooquln Gordon J. Welsh iJut tlo we knon about anorthosi.te llcnbcrship Sctrctory Gcne toore all occurrences? Anal how does one reconcile the fact that one occur- rence Lies five niles south of the fault, anal another eight niles north? ilunfaulting'r the san Andreas to l{crl Deodlinc the extent of 130 niles woulat sti.Il leave these ele- January 31, 1962 ments I3 miles apart. 4-Basement rock tJ@es have been recoraled in the San Bernartlino Mountains, apparently sleilar to those in the Solealaal and orocopi.a regions. Ilave the base- ment rocks of the San Bernardinos been fu]ly consial- branch, the San Gabriel faul.t, since tne earlj.est ered, relative to the sus.qested offset of the soledad and orocopia areas? Miocene. The terranes displaced by the San Antlreas are characterj.zeal by distinctive rocks yhich range 5-The in age from Precanbrian (:) to l,ouer Mlocene. Base- line drawn at the easternnost extent of ment types include augen gneiss and blue-quartz Ulrper Cretaceous rocks in California approaches the San Andreas gTleiss of the amphibolite facies uhich have been fault from either side, sith an area of no i.nformtion only about I0 mj_Ies IonE. This is, intrualed by a complex of gabbro, aliorite, anortho- trfine'r site, anal syenite. These rocks were intrudeal later furtherrcre, a true in the area near the fault on either side, a&in by ffanitlc types. Assocj-ateal distinctive 1.e., the eastern Cretaceous rocks on both sides of the fault i-nclude basic alikes limit is rrErkeal by an overlap of Eocene sealiments anal mafic bodies rich in ilnenite and apatite, blue- onto basement. Can this be reconcileat uith an earf- 1er suggestlon of a Cretaceous offset, shich was quartz granite, quartz-bearing syenite, tranophyre, ieastrt anal pegrnatite. Greenschist, narlne Eocene strata, baseal in part on an erosionaf Cretaceous bounalary anal ou-gocene nonmarine beds and volcanics are aLso lyinEi west of the san Andreas fault? displaced. The San Gabriel fault separates simitar rocks except for the anorthosite-syenite conplex. 6-The Mount Pinos-Frazier rvountain area appears to be, basically, a giant uplj.ft stEddlj.nq the San Andreas This conbineal displacenent of 160 niles appears fau1t. 0n either siale a sequence of Eocene compatible uith other stualies along the san Andreas narine, oligocene nonmrine, I*liocene volcanics dips anay fron the upllfr.