New Mexico Bureauof Mines & Mineral Resources Open-File Report 105 MAPS SHOWING THEREGIONAL EXTENT OF SANDSTONE BODIESWI.THIN THE GALLUP SANDSTONE COMPILED.FOR.THE SAN JUAN BASIN HYDROGEOLOGIC STUDY Nancy H. Mizell, Geologist and William J. Stone, Hydrogeologist August, 1979 CONTENTS .................... ..................... Introduction 1 Purpose 1 Previous work ........ . . . . . . . . . . . . 1 ..................2 Acknowledgements . . . . . . . . . . . . . . . . . . 3 Map C o n s t r u c t i o n Methods . . . . . . . . . . . . . . 3 Molenaar (1973and 1 9 7 4 ) . . . . . . . . . . . . 4 Datasources 2 Mercer andCooper Stoneand Mizell F i n a lC o m p i l a t i o n .............4 (1978) . . . . . . . . . . . . -11 . . . . . . . . . . . . . . . -11 (1970) Errors Involved i n Compilation . . . . . . . . . . . . . . .1 2 . . . . . . . . . . . . . . . .1 7 R e s u l t s and Conclusions Selec'tedReferences . . . . . . . . . .11 ILLUSTRATIONS Figure 1 - - Sampleinduction-electriclogsshowing sandstone bodies in Gallup Sandstone 10 Table 1 - - 5 Table 2 - - 7 Plate 1 - - pbcket Plate 2 - - pocket Location of control points used for maps and cross sections Distribution, top elevation, and thickness of sandstone bodies"within_ Gallup Sandstone Cross sections showing stratigraphic relationship of sandstone bodies within Sandstone Gallup . Map showing regional extentof Torrivo sandstone body,Gallup Sandstone .~ .- Plate 3 . - - Map showing regional extent of sandstone bodies A, B, and.C, Gallup Sandstone',; pocket : Plate 4 - - Plate 5 -- Map showing regional extent of sandstone bodies D, Eland E', Gallup Sandstone Map showing thicknessoi!:.sagdstone .. within Gallup Sandstone bodies pocket pocket 1 INTRODUCTION Purpose This studywas designed t o i n t e r p r e t the r e g i o n a l extentofthesevensandstonefacies d e s c r i b e d byMolenaar(1973). f a c i e s ,d e s i g n a t e d A, B, C, of GallupSandstone H e i d e n t i f i e ds i xm a r i n e D , E , and F sandstones, and a s i n g l e nonmarine f a c i e s whichhe Sandstone P4ember. named t h e T o r r i v i o of t h e v e r t i c a l b ec a l l e ds a n d s t o n eb o d i e s .D e l i n e a t i o n and h o r i z o n t a l limits o f t h e s a n d s t o n e b o d i e s futurestudiessuch system in the will I nt h i sr e p o r tM o l e n a a r ' sf a c i e s w i l l aid as r e f i n i n g a model oftheground-water San Juan Basin. Previous Work Numerous p u b l i c a t i o n s i n t h e g e o l o g i c l i t e r a t u r e many more d e a l w i t h describe the Gallup Sandstone, and t h es t r a t i g r a p h y of t h e San JuanBasin. Only t h o s e investigationsthataresingularlysignificantarecited here. A b r o a d e rb i b l i o g r a p h y may beobtained by c l o s e study of the specific papers cited. Sears (1925) named theGallupSandstoneforoutcrops near the city of G a l l u p , e s t a b l i s h i n g t h e t y p e a r e a t h e r e . Beaumont (1957)describedtheGallupSandstonealongthe westernmarginoftheSanJuanBasin and Dane andoddiers: ( 1 9 5 7 )d e s c r i b e dt h ea g ea n ds t r a t i g r a p h yo ft h eG a l l u p Sandstonesouthand east of t h et y p ea r e a .U s i n g electric-logdataStoneand M i z e l l (1978) tracedtheGallup S a n d s t o n et h r o u g ht h es u b s u r f a c ei nt h e San JuanBasin. 2 a Other sources o f s u b s u r f a c e d a t a d r i l l i n gr e p o r t s .I n are ground-waterand t o theGallupSandstone Cooper ( 1 9 7 0 ) p r o v i d e d d a t a p e r t a i n i n g area. a q u i f e rs y s t e mi nt h eG a l l u p - T o h a t c h i ground-waterstudies Mercer and a ground-waterstudy, of t h e GallupSandstone, More recent by Mercer and L a p a l l a ( 1 9 7 2 ) and H i s s and M a r s h a l l( 1 9 7 5 )i n c l u d er e s u l t s of pumping t e s t s as well as c o r e and e l e c t r i c - l o g d a t a . Detailedstratigraphicstudies of theGallupSandstone since its definition have resulted in a better understanding for t h e u n i t . of t h e d e p o s i t i o n a l e n v i r o n m e n t s r e s p o n s i b l e Budd (1957)suggestedfour.faciestrendsdevelopedwithin theGallupSandstone.Campbell San Juan Basin, of the Gallup Sandstone in the northwestern suggestedtheGallup shoreline. a study ( 1 9 7 1 and1979),from as a d e p o s i t i o n a l model of a beach Campbell ( 1 9 7 2 ) a l s o discussedoffshoreage e q u i v a l e n t s of t h eG a l l u pi nn o r t h w e s t e r n otherstudies New Mexico. In of n o r t h w e s t e r n New MexiAo, Molenaar(1973, 1 9 7 4 ) d i s c u s s e dt h es a n d s t o n e facies i n t h e G a l l u p . Data. Sources The d a t a u s e d i n p r e p a r a t i o n of this study o u t c r o p d a t a , p u b l i s h e ds u b s u r f a c ed a t a , are p u b l i s h e d and p u b l i s h e d facies i n t e r p r e t a t i o n s .O u t c r o pd a t ac o n s i s to fm e a s u r e ds e c t i o n s , which are shown on P l a t e 1 i n c r o s s s e c t i o n fromMolenaar(1973, 1974). The p r i n c i p a l s o u r c e Molenaar(1973, form,modified of s u b s u r f a c e o r well d a t a i s 1 9 7 4 ) withsupplementarydatafrom Mercer 3 andCooper ( 1 9 7 0 ) and Stone and M i z e l l ( 1 9 7 8 ) . Cross w e l l d a t a fromMolenaar s e c t i o n s on P l a t e 1 p r e s e n t Sample l o g s , e l e c t r i c l o g s ,t o pe l e v a t i o n s (1973, 1 9 7 4 ) . were^ drkwn from .Me.rcer and and t h i c k n e s s e s . o f u n i t s Cooper ( 1 9 7 0 ) . Well d a t a from Stone and M i z e l l (1978) c o n s i s to fn i n e e l e c t r i c l o g s .F i q u r e 1 shows r e p r e s e n t a t i v e samplesofthelogcharacteristicsofeachofMolenaar's (1973)sandstonebodies. DatafromMolenaar's(1973, thebasisforthe 1974)cross s e c t i o n s a r e maps o ft h e A, B, C , D, E , s a n d s t o n eb o d i e so ft h eG a l l u pS a n d s t o n e . surfaceelevations,usedto t h i c k n e s s of eachbody, F, a n dT o r r i v i o The sourcesof compute t o p e l e v a t i o n s and are O'Sullivan and Beikman (1963), Hackman and Olson ( 1 9 7 7 ) , and Wyant andOlson (1978). ACKNOWLEDGEMENTS W e wish t o thank C.M. d r a f t s of P l a t e s 1 - 4 . Molenaar f o r r e v i e w i n g o r i g i n a . 3 H i s comments andsuggestionshavebeen h e l p f u l ' b u t any e r r o r s t h e r e o n a r e o u r s alone ...., MAP CONSTRUCTTON METHODS The approachused i n thisstudyincludesfoursteps: 1) a comprehensive review o f t h e l i t e r a t u r e p e r t a i n i n g t o t h eG a l l u pS a n d s t o n e ; paperstodetermine 2 ) e x t e n s i v es t u d yo fs i g n i f i c a n t methodsof 3 ) c o m p u t a t i o no ft o pe l e v a t i o n sandstone body;and extractinguseableinformation; and t h i c k n e s so f 4 ) f i n a lc o m p i l a t i o no fd a t a each from selected 4 papers needed t o produce m.aps s h o w i n g t h e r e g i o n a l e x t e n t of t h es a n d s t o n eb o d i e s . Uniqueproblemswitheachdata sourcenecessitateseparatediscussionofthemajorsources. Molenaar(1973and Threetypes 1974) of d a t a u t i l i z e d fromMolenaar(1973, i n c l u d e : 1) l o c a t i o n of well c o n t r o l p o i n t s ( T a b l e 2 ) l o c a t i o n of o u t c r o pc o n t r o lp o i n t s( T a b l e 3 )c r o s ss e c t i o n so f 1974) 1); 1); and the S a n ' J u a nB a s i n .E l e v a t i o n sf o r were determined from thetopoftheGallupSandstone g e o l o g i c maps ( O ' S u l l i v a n and Beikman, 1963; Hackman and Olson, 1 9 7 7 ; Wyant andOlson, l o c a t i o n s( T a b l e 1 9 7 8 ) and u s i n gc o n t r o l - p o i n t 1 ) . E l e v a t i o n sf o rt h et o p and t h i c k n e s s e s 0-f-eachsandstone body (Table 2 ) were determinedfromcross s e c t i o n s( P l a t e 1) a n dp r e v i o u s l yc a l c u l a t e dt o pe l e v a t i o n s fortheGallupSandstone. Mercer andCooper Selecteddata (1970) from Mercer andCooper ( 1 9 7 0 ) were chosen because: 1) t h e i r wells p e n e t r a t eG a l l u pS a n d s t o n ei nt h e area east and n o r t h o f t h e c i t y i s notalreadycovered of Gallup; 2 ) t h e i r l o c a t i o n by Molenaar's data, but enough t o o t h e r d a t a t o a l l o w c r o s s c h e c k i n g ; e l e c t r i c l o g sa r ea v a i l a b l e . is close 3 ) sample o r Four wells (Table 1) meet these c r i t e r i a and were u s e d i n c a l c u l a t i n g t o p e l e v a t i o n s . 5 TABLE 1 L o c a t i o n of c o n t r o l p o i n t s used f o r maps and cross sections; M = Molenaar ( 1 9 7 3 ,1 9 7 4 ) , MC = Mq:rcer and CoopeT. (197!3)., and SM = Stone and M i z e l l ( 1 9 7 8 ) . See p l a t e s 1, 2 , 3 and 4 . . Part I - , . . . . . I . . . . Surface c o n t r o l Control Location Reference Point 4 5 6 7 8 9 10 11 12 13 14 15 16 22 23 27 28 29 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 62 63 64 SWk 30-31N-19W 5-30N-19W 20-30N-19W 12-29N-20W 26-29N-20W 7-28N-19W 25-28N-19W 17-27N-19W 33-27N-19W 18-26N-19N 31-26N-19W 30-25N-19W 12-24N-20W 31-24N-19W 16-23N-19W 27-23N-19W 19-20N-19W 17-18N-20W 12-17N-21W 36-17N-21W 31-15N-20W 29-15N-19W 13-15N-18W 15-16N-17W 7-16N-16W ll-16N-16W 22-16N-15W 3-16N-15W 15-16N-14W 4-15N-13W 9-15N-12W 7-15N-llW 36-15N-llV? 4-14N-10W 1-14N-10W 22-14N-9W 6-13N-8W 28-12N-8W 2-10N-8W 19-llN-6W 4-llN-5W 30-13N-4W M M M M M M M M M M M M M M M M M M M M M M M M M M M M M M M M M M M M M M M M M M Cross Section A-A A-A ' A-A ' A-A ' A-A ' A-A ' A-A ' A-A ' A-A ' A-A A-A ' A-A ' A-A ' A-A' A-A ' A-A ' A-A ' A-A A-A A-A ' c-c ' c-c ' c-c ' c-c ' c-c ' c-c ' c-c ' c-c ' B-B', c-c c-c ' c-c ' c-c c-c c-c I c-c ' c-c c-c ' D-D ' D-D ' D-D ' D-D ' C-C' 6 65 66 67 68 69 SE$ SW%SW$ NEkSWk E% NW%NW% 4-13N-4W 7-14N-3W 27-15N-3W 10-15N-3W 36-16N-2W M M M M M D-D D-D D-D D-D D-D' ' P a r t 11-Subsurface C o n t r o l Control Point 1 01 :~102 1 03 104 105 106 1 07 108 109 110 ..117 ~ ~ 1 1 8 120 121 93 94 95 96 Well Location Well 20-15N-18W 28-15N-18W 8-18N-12W 26-20N-13W 18-21N-12W 23-23N-12W 29-24N-llW 17-25N-llW 9-26N-llW 10-27N-llW 33-15N-8W 9-15N-7W 25-16N-5W 29-17N-4W 8-15N-18W 3-15N-19W 17-16N-18W 27-19N-18W Doty Water Well Maddox Jones and P e a c h e e S i n c l a i r No.1 S i n c l a i r No 1 H u m b l e O i l No. Magnolia P e t . No. 1 S h e l l O i l No. 1 1 3 - 1 7 P a n American P e t . No. 1 S i n c l a i r No. 7 R.A. Crane, Jr. No.1 C r o w nC e n t . P e t . No. 6 Hughes and Hughes N o . 1 R e f i n e r s Pet: No. 1 Gallup 15 Miller-Gamerco 1 292 30 2 311 22-21N-llW 19-20N-llW 32-19N-12W 312 14-19N-llW 334 343 347 366 371 8-17N-7W 5-15N-6W 29-19N-17W 33-16N-8W 32-18N-16W Name H.P. V.F. MWoz 1-A B u r e a u Indian A f f a i r s 14T-514 T e s o r o Pet. 1 Boundary Davis O i l 1 Wild Card Hughes & Hughes 1 S t a t e T r a c t 18 S i n c l a i r 1 S a n t a Fe 7 4 N. Ranch Davis O i l 1 E l T i g r e S h a r - A l a n 2 Fernandez P u r e O i l 1 Coyote Canyon S h a r - A l a n 3 Fernandez S u p e r i o r O i l K-1 Navajo Ref. M M M M M M fif M M M M M M M MC MC MC MC SM SPI SM SM SM SM SM SM SM Cross Section c-c ' B-B ' B-B ' B-B B-B ' B-B B-B B-B B-B B-B ' ' TABLE 2 Distribution, top elevation, and thickness of sandstone bodies within the Gallup ft) See Plate. 1;. 2,'3 and 4 Sandstone (top elevation; $t/thicXnes$, . Control Member; Point Torrivio 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 27 28 29 38 39 40 41 42 43 44 45 D B A Missing 6750/59 6200/65 6200/39 6800/46 7000/20 6400/115 7000/:80 7718/66 ? /70 ? j44.,, 5755/27 ? /?.O ., 6378/100 6279/60 7140/75 Present 6900/40 ? /30 7234/49 7200/31 Missing 7385/24 Missina ? /55 Missing 6691/60 C E F 5000/lO 5000/20 5250/40 5600/40 5578/50 5571/54 5570/57 ? - I/5n " ? /46 ~ 6135/80 6128/57 6680/29 6911/30 Missing Missing 6282/49 6917/55 7586/21 Missing Missing 6881/10 6233/30 6862/37 7550/20 : ?_ J30' ?' /25 5662/36 . ?. /i 5.. 6219/58 6550/45 6994/84 Missing ~ Missing 7050/56 Present 6850/47, ? /40'. 7171/32 7140/42 8020/57 7320/62 Missing /88 ? /120 5581/105 ? /48 6122/15 6460/64 6867/19 Present I' ? ? ? ? ? 7180/30 7130/19 ? /46 6043/46 6340/54 6748/8 ? ? ? 6963/50 ? Missing TABLE 2, continued Control Member. Point 46 47 48 49 50 51 52 53 62 63 64 65 66 67 68 69 101 102 ~ 13 0 104 105 106 10 7 108 109 110 117 Torrivio A 6000/98 6000/60 7000/85 600/85 P E 7470/80 7280/61 7420/81 ? /150 7440/126 7260/101 7300/66 7129/32 7215/26 Present Present 7037j19 ?/73 7680/75 6080/75 6770/110 ? ? D C Missing ? /33 Missing ? . ?/ 54 ? ? Missing ?. ../8'3 Missing ? /110 Missing Missing ? /88 Missing ? /30 ? ? ? . ?.'/SO ?/ '60 .- ? /60 /45 /56 /lo5 Missing 6730/100 5500/90 118 120 121 93 94 B 6055/30 6025/100 Missing 5398/? 5740/? 5290/? Missing m 5190/? 5610/? 5100/? 5538/? 0 TABLE 2 ,c o n t i n u e d Control Point 95 96 292 302 311 312 334 343 34 7 4929/31 36 6 371 Torrivio Member A 5102/? 5300/? D C B E F Missing 4730/? 4872/? 4992/? 4960/? 5070/? 5275/? 3405/140 3972/130 4928/40 4743/130 4822/10 4972/33 4289/120 4812/43 5711/100 4533/45 4289/120 4761/24' 5556/30 5252/20 5545/15 5505/33 5460/35 5132/42 5395/30 W 10 Fig. 1 Sample induction.electric logs showing sandstone bodies (stippled) in Gallup Sandstone; a from well 312, b from well 106, c from well 371 (Tablel). Km = Mancos Shale. 11 M i z e l l (1978) Stoneand were selected. t o DatafromStoneandMizell(1978) f i l l i n gapsfrom other sources and especially the central a n de a s t e r ne d g eo ft h es t u d ya r e a . Top andbottomelevations I beady; are based on e l e c t r i , & l o g " p i c k s " f o r . e a c h s a n d s c o n e , examples are shown i n f i a u r e . 1 . ' '~ I The t h i c k n e s s . o f . s a n d s t o n e I" b o d i e s idetermined. s then - Final Compilation S t e p si n v o l v e di nf i n a lc o m p i l a t i o ni n c l u d e : p a r i s o no fa l le l e v a t i o nv a l u e s( T a b l e 1) com- 2 ) t o d e t e r m i n et h e i.e. correctverticalpositionofthesandstonebodies, t h e C sandstone i s p l o t t e d on t h e C sandstone boay. map and n o t t h e D o r E sandstones; 2 ) u s e o f c r o s s s e c t i o n s A-A', C-C', B-B', and D-D' on P l a t e 1 t o d e l i n e a t e h o r i z o n t a l boundariesofeachsandstonebody; 3) d a t a p r o j e c t i o n and i n t e r p r e t a t i o n f o r a r e a s ; . v & e r e , d a k a .are ,,scarce or. l a c k i n g . The f i n a l r e s u l t s are a map o f t h e T o r r i v i o S a n d s t o n e ( P l a t e 2 ) , a map o ft h e A, B and C s a n d s t o n eb o d i e s( P l a t e a map of t h e D , E and F s a n d s t o n eb o d i e s( P l a t e isopach maps ofeachsandstone EFrorsTnvolved body 4), and body ( P l a t e 5 ) . inCompilation The accuracy of t h e t o p e l e v a t i o n a n d t h i c k n e s s v a l u e s (Table 2 ) used t o make r e g i o n a l e x t e n t sandstone bodies within the Gallup Sandstone andisopach maps f o r is estimated 3), 12 t o bebetween +- 80 and 9 0 p e r c e n t f o r t h i c k n e s s . a n d . 150 f t f o r t o p e l e v a t i o n s . T h i s t o p e l e v a t i o n e r r o r f a c t o r combines e r r o r s from: 1) measured s e c t i o n s (P.lolenaar, 1973, p. 8 6 ) ; 2 ) c a l c u l a t i n gs u r f a c ee l e v a t i o n s ; 3)determining ( 1 9 7 3 , 1 9 7 4 ) c r o s ss e c t i o n s ; topsandbottomsfromMolenaar's and 4 ) choosingtopsandbottomsfrom e l e c t r i c andsample I logs. These e r r o r s s h o u l d n o t d e t r a c t ! o ft h e maps o f Fhe sandstonebodies. from. t h e u s e f u l n e s s i I RESULTS AND: CONCLUSIONS; , 1. The T o r r i v i oS a n d s t o n e body ( P l a t e 2 ) extends e a s t w a r df r o mm e a s u r e ds e c t i o n1 3( n o r t ho fS a n o s t e e )t o e ' w e l l 105 (west of Chaco Canyon),thensouth s e c t i o n 45 ( s o u t h e a s t of Crownpoint). I t o measured Inthisareathe Torrivio Sandstone i s thehighestsandstone Gallup. Cross sections A-4' and B-B' body i n t h e ( P l a t e 1) s u g g e s t t h e T o r r i v i o may merge w i t h the A and B sandstones (Molenaar, 1 9 7 9 , written' c o r n m i c a t i o n ) , a n d n e v e r o v e r l i e t h e A. T h e . T o r r i v i oS a n d s t o n er a n g e si nt h i c k n e s s( P l a t e 5) from 1 0 0 ff a t .measused s e c t i o n . .28 ( w e s . t . . o f ~ G a l l u p ) t o . 2 0 f t 'at measurea section 2. 1 7 ( s o u t h of^ S a n o s t e e ) . Croppingoutnorthwardfrommeasuredsection ( n o r t h of Sanostee) , t h e A s a n d s t o n e ( P l a t e f a r t h e s t toward t h e c e n t e r o f extends eastward in a the b a s i n . 12 3 ) .extends The A sandstone a narrow b e l t from northwest of B i s t i t o measured s e c t i o n 6 8 ( 2 4 miles west of San Ysidro) A t thesurface,the - A sandstone i s o n l y s e e n t o o v e r l i e t h e 13 B a t measured s e c t i o n 1 2 , however, i n t h e s u b s u r f a c e t h e o v e r l i e st h e B, and t h e C ( P l a t e 1. ) . Cross s e c t i o n B-B' ( P l a t e 1) shows t h e A sandstone t o b e h i g h e r t h a n t h e b u ti n D-D', A B, (1979, t h e A doesnotappearhigher.Molenaar written'.communication)suggestedtheabsenceofabrupt s t r a t i g r a p h i c rises.. in t h e s o u t h e a s t .&rt o f t h e b a s i n , , whe.re sandstone, bodies A,, B, and C.;'may. a l l 'I merge t o g e t h e r .P l a t e 5 shows t h e A s a n d s t o n e body t h i c k e n i n g From 55 f t a t measured. towardthecenterofthebasin. s e c t i o n 1 2 (northofSanostee) on t h e &est, and 98 f t measured s e c t i o n 6 7 (southwestof at San Ysidro) on t h e e a s t , s a n d s t o n e body A t h i c k e n s t o 1 4 0 fC a,t!well 2 9 2 (west of Chaco Canyon) 3. . The B sandstoneextendsnorthfrommeasuredsection 1 6 ( s o u t h of S a n o s t e e ) t o B i k l a b i t o ) , and eastward 1 0 4 and 2 9 2 (southwestof (1973)suggestedthe Chaco Canyon) t o well 343 (west of B-B'). A and C. Molenaar B and C s a n d s t o n e s are s e p a r a t e f a c i e s thickness changes in overlying nonmarine depositsbetweenmeasuredsections15and s e c t i o n A-A') wells i n a b e l t which t h i n s n e a r it merges w i t hs a n d s t o n e s Sail Ysidro)where based onsudden measured s e c t i o n 6 . ( s o u t h of 1 6 ( P l a t e 1, c r o s s and wells 1 0 4 and 1 0 6 ( P l a t e 1, c r o s s s e c t i o n Sandstone body B v a r i e sv e r ya b r u p t l yi nt h i c k n e s s i nt h ec e n t e ra n de a s t e r n t h ew e s t e r no u t c r o pt h e marginofthebasin B i n c r e a s e sf r o m In (Plate 5 ) . 29 f t a t measured s e c t i o n 30 (southwest of S a n o s t e e ) t o a maximum t h i c k n e s s of 80 f t .t~ measured sec.tion .14'( w e s t pf Sanostee) , and . 14 thendecreasesto 2 0 f t toward t h e n o r t h a t body i s t h e The most extensivemarinesandstone I t extends west from theoutcrop,measured C ( P l a t e3 ) . well 9 5 ( n o r t ho f s e c t i o n s 6 2 t h r u 6 4 ( n o r t ho fL a g u n a ) ,t o Gallup)andmeasuredsections Sanostee). 2 0 t h r u1 3( n o r t ho f The C sandstone body o v e r l i e st h e F (Plates 1, 2 , 3,and 4). D , E , and Sandstone body C a p p e a r st oh a v e no d e f i n i t et h i c k n e s sp a t t e r n( P l a t e T h i c k n e s so ft h e 5). 15 f t a t we.11-371.(urest~.o.f"Crownpoi,fit),eo- . C ranges from 150 f t a t measured s e c t i o n 49 (northwest of 5. I . section 4 (eastofBikalbito) 4. measured P;mbrosia Lake) Sandstone body D ( P l a t e 3)cropsoutinanoblong ( 1 8 miles northwest of area between measured sections 23 Gallup)and 1 7 (southofSanostee) on t h e e a s t , a n d betweenmeasured on t h e west, well 371 s e c t i o n s 2 7 ( 2 miles west 39 ( 1 8 miles n o r t h e a s to fG a l l u p ) ofGallup)and s o u t h ( P l a t e 1, c r o s s s e c t i o n s body p r i n c i p a l l y o v e r l i e s t h e a r e a si nt h es o u t h A-A' , C-C') . E but also the and e a s t ( P l a t e 4). sandstone body D t o r a n g e i n t h i c k n e s s on t h e The D sandstone F $n-gma,ll . . P l a t e 5 shows from 1 0 f t at^ measured s e c t i o n 1 7 ( s o u t h o f S a n o s t e e ) i n t h e n o r t h , t o 84 f t . a t m e a s u r e d - s e c t i p n ~ . 3 8 _ ( n o r t h w e s b b f G a l l u p ) i n t h e south. The D a p p e a r st ob e more e v e n l y d i s t r i b u t e d t h a t t h e other sandstone bodies. 6. . Sandstone body E i s developed i n two p o c k e t - l i k e .rn t h e west t h e E e x t e n d s west t o t h e a r e a s( P l a t e 4). outcropfrom well 371 t o measured s e c t i o n 2 0 (southwestof 15 well 371 t o measured s e c t i o n SheepSprings)andsouthfrom 38 ( 1 2 miles east of G a l l u p ) . southwestfrom The e a s t e r n area e x t e n d s well 366 ( s o u t h of S t a r Lake) t o t h e o u t c r o p a t measured s e c t i o n 4 4 ( s o u t h e a s t o f C r o w n p o i n t ) , t o theoutcrop a t measured s e c t i o n 62 ( n o r t h w e s t of Laguna). The E i s m i s s i n g toward t h e c e n t e r o f t h e b a s i n t o b ed i s c o n t i n u o u s a t t h es u r f a c e andappears ( P l a t e 1, c r o s s s e c t i o n The E s a n d s t o n e body o v e r l i e s t h e C-C'). and s o u t h e a s t F betweenmeasured I s e c t i o n s 2 7 (west of Gallup)and (east ofGallup), 29 ( i nG a l l u p ) , and 52 and 53 (south Thickness of sandstone Mateo). iofSan body E i n t h e w a s t e r n 38 and 39 area rangesfrom 1 1 2 0 f t . a t measured s e c t i o n 22: ( n o r t h e a s t of G a l l u p ) t o 1 5 ft ~ a t measured s e c t i o n 2 8 (west o fG i l l u p )( P l a t e5 ) .I n the eastern area t h e t h i c k n e s s i s n o t so g r e a t and r a n g e s t measured s e c t i o n 4 6 (southeast .of Crownpoint) from 66 f t a t o 15 f t a t measured s e c t i o n 4 9 . ( n o r t h e a s t o f ~ A m b r o s i a . . Lake) . 7. Sandstone body F i s developed i n small pockets a l o n gt h es o u t h e r nG a l l u pS a n d s t o n eo u t c r o pb e l t (Plate 4 ) . Tn t h e e a s t t h e F i s found i n measuredsections ( s o u t h of San Mateo), with s e c t i o n5 3 a thicknessof ( P l a t e 5 ) .I nt h e 54 f t a t measured west i n two areas, between measured s e c t i o n s 38 ( e a s t ofGallup)and Crownpoint)and 52 and53 well 3 7 1( n o r t ho fG a l l u p ) , 42 (west of andmeasured s e c t i o n s 27 (west ofGal1up)and 2 9 ( i n Gallup).Thickness of s a n d s t o n e body F rangesfrom 6 0 f t a t well 101 ( i n G a l l u p ) t o 8 f t a t measured s e c t i o n 39 ( e a s t o f G a l l u p ) . 16 SELECTED REFERFNCES Beaumont, E. C., 1957, The Gallup Sandstone as exposed in the western part of the San Juan Basin: Four Corners Geological p. 114-120 Society, Guidebook 2nd field conference, Budd, Harrell, 1957, Facies development of the Gallup Formation: Four Corners Geological Society, Guidebook 2nd field conference, p. 121-127. Campbell, C. V . , 1971, Depositional model--Upper Cretaceous Gallup beach shoreline, Shiprock area, northwestern New Mexico: Journal of Sedimentary Petrology,v. 41, no. 2, p. 393-409 Campbell, C. V., 1973, Offshore equivalents of upper Cretaceous Gallup beach sandstone, northwestern New Mexico: Four Corners Geological Society, Guidebook 18th field conference, p. 78-84 Campbell, C: V . , 1979, Model for beach shoreline.inGallup Sandstone (Upper Cretaceous) of northwestern New Mexico: New Mexico Bureau of Mines and Mineral Resources, Circ. 164, 32p. Dane, C. H., Bachman, G. O., and Reeside, Jr., J. B.., 1957, The Gallup Sandstone, it's age and stratigraphic relationships south and eastof the type locality: Pour Corners Geological Society, Guidebook 2nd field conference, p. 99-113 Hackman, 8. 3 . , and Olson, A., B., 1977, Geology, structure, and Mexico. and uranium depositsof the Gallup 2' shee~;New Arizona: U . S . Geological Survey, Misc. Geol. Xnv. Map 2-981 Hiss, W. L., and Marshall, J, G., 1975, Xnterpretatjon of geologic Gallup, and hydrologic data grom the Ray-1 well, of city McKinley County, New Mexico: U.S. Geological Survey, OpenFile Repk. 75-573, 58p. Kirk, A. R.., and Sulliyan, M. W.., 1976, PrelLrninary.geolpgic map of the DaltonPqss quadrangle, McKinley County, New Mexico: U.S. Geological Survey., Open-Pile Rept, 76-184, nap Kirk, A. R,, and Zech, R. S . , 1976, Prelininary,geolpgic andstructwe contour maps of the oak Spring quandrqngle, McKinley County, New Mexjco: U,S. Geolpgical Survey, Open-Pile Repti 76-347, map Mercer, 3. W., and Cooper,J.. B., 1970, &vailabilj;ty of groundwi+tex in the Gallup-.Tohatchi area, NcKinley County, New Mexico: U.S. Geological Survey, Open-Pile Rept. MK-31, 194p. Mercer, 9. W., and Lappala, E. G,, 1972, ETwip-1 pmduction well, U,S.' Gedl09iCal ckty QZ Gallup, McKinley County, New Mexico; Survey, Open-File 'Rept., 53p. 17 Molenaar, C. M. , 1973, Sedimentary facies and correlations of the Gallup Sandstone and associated formations, northwestern New Mexico: Four Corners Geological Society, Guidebook 18th field conference,p. 85-110 Molenaar, C. M., 1974, Correlation of the Gallup Sandstone and associated formations, Upper Cretaceous, eastern San Juan and Acoma basins, New Mexico: New Mexico Geological Society, Guidebook 25th field conference, p. 251-258 O'Sullivan, R. B., and Beikman, H. M., 1963, Geology, structure, and uranium deposits of the Shiprock 2"-:&eet,:New Mexico: U.S. Geological Survey,Misc. Tnv. Map T-345 Robertson, 3. F., 1976, Preliminary geologic map o f the Casamero U.S. Geological Lake quadrangle, McKinley County, New Mexico: Survey, Open-File Rept. 76-681, map Robertson, J. F., and Jackson, T. J., 1975;Geologic and structure . . . . contous maps .of hosta :the Butte. quadrangle;. McKinley :County, New Mexico: U.S. Geological Survey, Open-File Rept. 75-302, map Sabins, F. F., 1963, Anatomy of stratigraphic trap, Bisti field, New Mexico: ?mer. Association Petroledl Geologists,v. 47, no. 2, p. 193-228 Stone, W. J., and Mhell, N. H., Basic subsurface data compiled for hydrogeologic study of San the 3uan~Basin,northwest New Mexico: New Mexico Bureauof Minesiand Mineral Resources, Open-File Rept. 89, 41p. II I Wyant, D. J., and Olson, Annabelle, 1978, Geologic map of the . . Albuquerque 2".sheet,. northwestern New.:I$exic_o:U.:g.. Geological Survey, Open-File Rept. 78-476, map O P E N - F I L E REPORT 105 PLATE 2