Petroleum Potential of Wilderness Lands in New Mexico By Robert T. Ryder
PETROLEUM POTENTIAL OF WILDERNESS LANDS IN THE WESTERN UNITED STATES
GEOLOGICAL SURVEY CIRCULAR 902-1
This chapter on the petroleum geology and resource potential of Wilderness Lands in New Mexico is also provided as an accompany ing pamphlet for Miscellaneous Investigations Series Map 1-1543
CONTENTS
Page Abstract II Delaware basin, Northwest Shelf, and Central bas;n Introduction 1 platform 118 Geologic framework 2 Pedregosa basin 18 Physiographic provinces- 2 Raton and Las Vegas basins 18 Wilderness Lands 2 Basins in the Rio Grande Rift 19 Tectonic provinces and tectonic history 2 Source rocks, hydrocarbons shows, and thermal Colorado Plateau and Great Plains physiographic maturity 20 provinces 2 Pennsylvanian and Permian black limestone and Southern Rocky Mountain physiographic province 7 shale - 20 Basin and Range physiographic province 9 Upper Cretaceous shale and coal 20 Transitional zone______14 Devonian black shale- 21 Petroleum geology - 16 Middle Jurassic limestone- 21 USGS petroleum province boundaries- 16 Reservoirs and traps 21 Oil and gas fields- 16 Summary statement- 22 Thickness and origin of sedimentary rocks 17 Petroleum potential of Wilderness Lands- 23 San Juan basin 17 Summary 28 References cited 29
ILLUSTRATIONS
Page FIGURE 1. Maps of New Mexico showing distribution of Wilderness Lands, counties, and selected towns and cities. A, P' ys- iographic and tectonic provinces; B, Major outcrops of igneous and metamorphic rocks and lines of cross sec tions; C, Oil and gas field data 13 2. Upper Cretaceous time-stratigraphic section A-A' from the Zuni basin through the San Juan (top) and geologic cross section B-B' (bottom) through the San Juan basin 6 3. Geologic cross section C-C' through the Acoma basin and Lucero uplift 7 4. Geologic cross section D-D' through the Sangre de Cristo uplift and the Raton basin 8 5. Geologic cross section E-E' through the Tucumcari basin and Sierra Grande uplift 8 6. Restored stratigraphic cross section F-F' of the Pennsylvanian System and Lower Permian Series through the Northwest shelf and the Delaware basin 10 7. Restored stratigraphic cross section G-G' of the Leonardian (part), Guadalupian, and the Ochoan Series of the Permian System through the Northwest shelf and the Delaware basin 12 8. Geologic cross section H-H' through the Guadalupe Mountains uplift 13 9. Geologic cross sections /-/' and J-J' through parts of the Pedregosa basin and the superimposed Early Cretaceous rift basins - 13 10. Geologic cross sections through the Espanola basin (K-K\ Albuquerque basin (L-L1), and Tularosa basin and Sacramento Mountains uplift (M-M1) 14 11. Geologic cross section N-N' through the Sacramento Mountains and part of the Guadalupe Mountains uplift 15 12. Map showing the qualitative estimate of petroleum potential for Wilderness Lands in New Mexico 24
III
PETROLEUM POTENTIAL OF WILDERNESS LANDS IN THE WESTERN UNITED STATES
Petroleum Potential of Wilderness Lands in New Mexico
By Robert T. Ryder
ABSTRACT coveries in the sedimentary basins of New Mexico On the basis of in-depth geologic framework and petroleum will likely depend on imaginative, but geologically geology studies, the oil and gas potential of Wilderness Lands sound, interpretations of the complex structural, in New Mexico is rated qualitatively on a scale from high to depositional, and magmatic history of the State zero. A high rating is assigned to Wilderness Lands that are and on the testing of these interpretation * with located near or along the projected trend of hydrocarbon pro duction and that have all the geologic attributes of the produc reflection seismic profiles and deep drillir#. To ing area. A medium rating is assigned to Wilderness Lands date, drilling outside the regions of known f»xxiuc- that have all the attributes, including shows, of an oil and gas tion has been disappointing. The purpose of this producing area but presently lack commercial production. In investigations is to provide qualitative estiirites contrast, low, low to zero, and zero ratings are assigned to complete with written documentation of the fu Wilderness Lands that have few or no attributes of an oil and gas producing area. Usually a zero rating is reserved for re ture oil and gas potential of the 2,676,856 a "res of gions having autochthonous igneous and metamorphic rocks Wilderness Lands in New Mexico. Thes^ esti at or near the surface. mates are based largely on data derived from cur The Wilderness Lands in New Mexico are grouped into 18 rent published literature. Future estimates may clusters, each containing one or more tracts that have the same vary as new data and concepts become available. or similar geologic characteristics and the same hydrocarbon potential. Of the 2,676,856 acres of Wilderness Lands in New This report is divided into three parts. TH first Mexico the potential acreage can be summarized as follows: part, the geologic framework section, is intended high potential, 96.6 thousand acres; medium potential, 115.3 to acquaint the reader with the physiograpHc and thousand acres; low potential, 1,237.3 thousand acres; low to geologic provinces of New Mexico and th-? com zero potential, 158 thousand acres; and zero potential, 1,069.6 plex tectonic and magmatic history that shaped thousand acres. the provinces and ultimately helped control the distribution of oil and gas. The second pa~t, the INTRODUCTION petroleum geology section, consists of a funeral New Mexico is among the leading producers of treatment of several key elements related to the oil and gas in the United States and has the poten generation and entrapment of oil and gas n New tial for yielding significant undiscovered oil and Mexico. The third and final part, the pet-oleum gas resources (Dolton and others, 1981). Much of potential of Wilderness Lands, contains the qual New Mexico is still a frontier area in terms of oil itative estimates of the oil and gas potential of the and gas exploration. Future oil and gas dis Wilderness Lands in New Mexico.
II GEOLOGIC FRAMEWORK EXPLANATION (For figures 1A, B, and C) PHYSIOGRAPHIC PROVINCES Metamorphic and igneous rocks Precambrian New Mexico is divided into four major physiog raphic provinces: the Colorado Plateau, the Basin and Range, the Southern Rocky Mountain, and Intrusive igneous rocks Mesozoic and Tertiary the Great Plains (fig. LA)(Fenneman, 1931). The Great Plains and Colorado Plateau provinces oc Volcanic rocks Quaternary, Tertiary, and Mesozoic cupy the eastern half and northwest quarter of the State, respectively, and are separated by the Wilderness Lands northward-tapering, wedge-shaped Basin and Range province (fig. LA). A transitional zone be Oil, natural gas, and carbon dioxide fields tween the Colorado Plateau and Basin and Range provinces is situated in southwest New Mexico. Drill hole The Southern Rocky Mountain province is re Shell Oil Company, Santa Fe Pacific No. 1 drill hole stricted to two lobes which flank the northern ex tremity of the Basin and Range province. KCM No. 1 Forest Federal drill hole Humble No. 1 State BM drill hole WILDERNESS LANDS Grimm et al. No.l Mobil-32 drill hole
The 2,676,856 acres of Wilderness Lands in Line of geologic cross section New Mexico are distributed over the four phys Boundary between physiography provinces iographic provinces (fig. LA). Two-thirds of the Wilderness Lands is located in the Basin and - Boundary between USGS petroleum provinces Range province (31 percent) and the transitional zone (34 percent); the remainder of the Wilderness Boundary between tectonic provinces Lands is distributed mainly between the Col Approximate leading edge of Cordilleran fold orado Plateau (18 percent) and the Southern and thrust belt (Corbitt and Woodward, 1973) Rocky Mountain provinces (15 percent). Only 2 percent of the Wilderness Lands is in the Great the surface as either structural terraces capped by Plains province. gently dipping strata or mountain ranges with a core of granitic basement rocks. F^st-order struc TECTONIC PROVINCES AND tural features in the Colorado Plateau province TECTONIC HISTORY are the San Juan Basin, Defiance uplift, Zuni up The physiographic provinces, and to a large ex lift, Four Corners platform, Chama basin, Zuni tent the hydrocarbon accumulations within them, basin, Acoma basin, and Lucero rnlift of probable are controlled by the tectonic framework of the Laramide age (Woodward, 1974; Davis, 1978), the underlying rocks. The major tectonic features Paradox basin of Pennsylvanirn age, and a which shaped New Mexico's physiographic pro Pennsylvanian precursor to the Defiance and Zuni vinces are identified and discussed in the following uplifts (Peterson and Ohlen, li^; KottlowsM, sections. 1971) (figs. LA, 2, 3). The San Juan Basin has a combined thickness of 9,000 to 10,000 feet of COLORADO PLATEAU AND GREAT PLAINS Cretaceous and Tertiary rocks and 3,000 feet of PHYSIOGRAPHIC PROVINCES Pennsylvanian rocks (Peterson and others, 1965; The Colorado Plateau and Great Plains pro Molenaar, 1977) (fig. 2). Many of the first-order vinces represent a part of the North American structural features have been controlled by an un craton which has been relatively stable since the derlying basement block mosaic which probably late Precambrian. Structural features in the Col developed in Precambrian time and was reacti orado Plateau province are characterized by broad vated by later episodes of structural instability basins flanked by monoclines. Depending on the (Kelley, 1955; Davis, 1978). In the vicinity of the magnitude of the uplift involved, the structurally Four Corners platform and the Paradox basin, high blocks of the monoclines are manifested at several episodes of early Paleozo;« block faulting
12 SOUTHERN ROCKY MOUNTAIN PROVINCE 106° 104° DALHART BASIN oT| EARLY PERMIAN AND PENNSYL- VANIAN AGE PARADOX BASIN Of PENNSYLVANIAN AGE
FOUR CORNER PLATFORM
COLORADO " M I j DEFIANCE PLATEAU A S\ PROVINCE
UPLIFT TUCUMCARI BASI / o OF EARLYr"PERMIAN AND PENNSYLVANIAN
ROOSEVELT UPLIFT OF JLBENNSYLVANIAN AGE
DATIL-MOGOLLON LCANIC FIELD
DELAWARE PERMIA
SILLA, OROGRANDE BASIN OF BROKEOFF HILLS BASIN ( EARLY PERMIAN AND UPLIFT PEDREGOSA BASIN j PENNSYLVANIAN AGE F EARLY PER RIO GRANDE RIFT ANDHENl SYLVANIAN AI 0 50 100 MILES I I 0 50 100 150 KILOMETERS
FIGURE LA. Physiographic and tectonic provinces. Outline and tectonic features of the Rio Grande Rift are from Wood ward and others (1975).
13 108°
36'
34'
I 100 150 KILOMETERS FIGURE IB. Major outcrops of igneous and metamorphic rocks and lines of cross sections. Distributk n of igneous and metamorphic rocks are based on the geologic map of New Mexico (Dane and Bachman, 1965)
14 108
BATON BASIN-SIERRA GRANDE UPLIFT
SAN JUAN BASIN
PALO DURO 1 BASIN, I
SOUTH CENTRAL NEW MEXICO
100 150 KILOMETERS
FIGURE 1C. Oil and gas field data and petroleum provinces (Dolton and others, 1981). Oil and gas fields are from Bieberman and Weber (1969) and David (1977).
15 A' SAN JUAN BASIN BISTI FIELD | BLANCO GAS FIELD
EXPLANATION j I Marine shale 773 Marine and coastal barrier sandstone 3 Nonmarine deposits "V] Limestone or very calcareous shale \
Section removed by pre-mid-Tertiary erosion
Tertiary-Holocene erosion \ 0 20 40 MILES
t- -r -i- -r Greenhorn Limeston
4000-
EXPLANATION SEA LEVEL- r°«'»l Tertiary sedimentary rocks;
I I Cretaceous sedimentary rocks
fc=\ Jurassic sedimentary rocks
4000 |1 11 Triassic sedimentary rocks
fcvkl Permian sedimentary rocks
OH Pennsylvanian sedimentary rocks 10 20 MILES V//A Pre-Pennsylvanian sedimentary rocks 8000- |fivi| Precambrian basement rocks FIGURE 2. Upper Cretaceous time-stratigraphic section A-A' from the Zuni basin through the f ui Juan Basin (top) and geologic cross section B-B' (bottom) through the San Juan Basin. Lines of section are shown on figure IB. Cross section A-A is from Molenaar (1977) and section B-B' is from Peterson and others (1965).
16 C'
ACOMA BASIN ,,, I ALBUQUERQUE LUCERC? BAS|N
Permian sedimentary rocks Quaternary basalt FEET -3000 Pennsylvanian sedimentary rocks Tertiary sedimentary rocks -2000 Pre-Pennsylvanian sedimentary frr] Cretaceous sedimentary rocks -1000 rocks 12 8 Precambrian basement rocks Triassic sedimentary rocks MILES FIGURE 3. Geologic cross section C-C' through the Acoma basin and Lucero uplift. Line of section is shown in figure IB. Cross section is from Wengerd (1959).
are well documented (Stevenson and Baars, 1977). (Meyer, 1966) (fig. 6); the total Permian-Pennsyl- First-order structural features in the Great vanian section in the Delaware basin totals 18,000 Plains province are the Raton and Las Vegas ba feet (Silver and Todd, 196^; Hartrr 17 SANGRE DE CRISTO UPLIFT RATON BASIN 3000 10 20 MILES EXPLANATION '.:; -~'-? 0 » « o »% ;§£ Drill hole T ertiary Tertiary Cretaceous Jurassic and Permian Pennsylvanian Precambrian sed mentary intrusive sedimentary Triassic sedimentary sedimentary basement rocks rocks rocks sedimentary rocks rocks rocks rocks FIGURE 4. Geologic cross section D-D through the Sangre de Cristo Uplift and the Raton basin. Line of section is shown in figure IB. Cross section is from Baltz and others (1959). LAS VEGAS BASIN SIERRA GRANOE UPLIFT FEET 5000 SEA LEVEL 5000 J Conti- Nearshore Open Basinal Drill Tertiary Pre- Precambrian nental marine shelf no|e sedimentary Pennsylvanian basement rocks sedimentary rocks rocks TUCUMCARI BASIN £' o o FEET r5000 SEA f-LEVEL 5000 10 20 30 MILES FIGURE 5. Geologic cross section E-E' through the Tucumcari basin and Sierra Grande uplift. Line of section is shown in figure IB. Cross section is from Roberts and others (1976). 18 ing a thick sequence of late Cenozoic volcanic thick (Hayes, 1970; Kottlowski, 1971; Greenwood rocks (Bailey and others, 1969), is included with and others, 1977). the Southern Rocky Mountain province. Corbitt and Woodward (1973), Woodward BASIN AND RANG! PHYSIOGRAPHIC PROVINCE (1974), and Drewes (1978) believe that many of the thrust faults and folds in southwes* New The Basin and Range province, with its complex Mexico represent a structural link between the history of crustal extension, plutonism, and vol- Cordilleran fold and thrust belt of scnthern canism, represents a far more mobile sector of the Nevada and southeast California and the North American craton than the Colorado Plateau Chihuahua fold and thrust belt of northern and the Great Plains provinces. Major crustal in Mexico. Hamilton (1978), Davis ^1979), Dickinson stability appeared in the Basin and Range pro (1981), and Matthews (1982) disagree with such a vince in Early Permian and Pennsylvanian time linkage on the grounds that neither the ftratig- and resulted in the development of the Pedregosa raphic facies nor the structural features are pre basin in southwesternmost New Mexico, the sent. The leading edge of the Cordilleran fold and Orogrande basin centered over the Tularosa and thrust belt as defined by Corbitt and Woodward Jornada del Muerto basins of late Tertiary age, (1973) is shown in figure IA. and the Uncompahgre-San Luis and Nacimiento According to Hamilton (1978), the Laramide uplifts centered, respectively, over the Brazos and basement uplifts in New Mexico occurred along Nacimiento uplifts of Laramide age (Tweto, 1975; the eastern border of the northward-moving, Chapin and Seager, 1975; Greenwood and others, clockwise-rotating Colorado Plateau crustal plate. 1977) (fig. lA).The Pedregosa basin trends north Laramide crustal extension originated aloig the westward from its depocenter in north-central southern trailing edge of the Colorado Plateau Chihuahua, Mexico, through southwesternmost crustal plate (Hamilton, 1978). New Mexico, into southeasternmost Arizona Rifting began in what is today the Bapn and (Greenwood and others, 1977). Pennsylvanian and Range province of New Mexico with the evening Lower Permian marine carbonate rocks have a of the Rio Grande rift (fig. IA) about 2^ to 30 combined thickness of 5,000 feet in the New m.y. ago (late Oligocene) (Chapin and T^ager, Mexico part of the Pedregosa basin (Ross, 1973) 1975; Eaton, 1979). A second major episode of rift and 3,000 to 4,000 feet in the Orogrande basin ing began in the late Miocene! and (or) early (Greenwood and others, 1977). Pliocene (3-8 m.y. ago) and lasted into the late In Mesozoic time, the crust in the Basin and Pliocene and Holocene (2 m.y. ago to present) Range physiographic province of southwestern (Chapin and Seager, 1975; Seager and Horgan New Mexico was deformed by a Late Cretaceous 1979). The eruption of basaltic andesites al nut 20 (through early Tertiary) magmatic arc (Thorman to 26 m.y. ago and basalts about 5 m.y. age in the and Drewes, 1978; Dickinson, 1981), Early Cre Rio Grande rift seems to have been a direct conse taceous rifting (Bilodeau, 1982), Laramide com quence of the major rifting episodes, but lagged pression (Drewes, 1978; Corbitt and Woodward, behind the rifting by 3 to 5 m.y. (Chapin aM Sea 1973), and Laramide extension (Hamilton, 1978). ger, 1975). Many of the geologic complexities that resulted The Rio Grande rift cuts across major certers of from these tectonic and magmatic events are illus Oligocene calc-alkaline volcanism (30 to 88 m.y trated in figure 9. ago; Elston, 1976), such as in the Datil-Mogollon Early Cretaceous rift basins were superimposed volcanic province (figs. IA, B), subparallel to on the Pedregosa basin by an aulacogen which ex north-trending zones of crustal weakness inherited tended into southwest New Mexico and southeast from late Paleozoic and Laramide uplifts (Chapin Arizona from the Chihuahua trough in Mexico and Seager, 1975; Eaton, 1979; Kelley, 1979). (Bilodeau, 1982) (fig. 1A). Lower Cretaceous Structural basins in the rift are grabens and half rocks in these basins are collectively known grabens, which, from north to south, include the as the Bisbee Group (Hayes, 1970) or locally in San Luis basin, Espanola basin, Albuquerque New Mexico by names such as the Mojado (top), basin, Estancia basin, Jornada del Muerto basin, U-Bar, and Hell-to-Finish (base) Formations (Zel- Tularosa Basin, and the Mesilla basin (fig's, IA- ler, 1965). The nonmarine and marine deposits of IB, 10). Through a system of retyy faults, ramps, the rift basins are between 10,000 and 15,000 feet and benches, the Albuquerque, Espanola, and San 19 F o NORTHWEST SHELF LEONARDIAN^ xw ^ SERIES ^ ~ -(PART)- WOLFCAMPIAN SERIES MISSOURIAN SERIES*, MISSISSIPPIAN RC°.KS EXPLANATION PRECAMBRIAN ROCKS Brown anhydritic dolomite .-;?.: ;.'' Quartzose sandstone Light-colored fossil iferotic limestone and variegated shale 0 6 12 Dark brown and black limestone MILES Dark gray, brown and black shale and siltstone o Drill hole FIGURE 6. Restored stratigraphic cross section F-F of the Pennsylvanian System and Lower Permian Series through the North west shelf and the Delaware basin. Line of section is shown in figure IB. Restored section is from Meyer (1968). 110 F' o YESO FORMATION DELAWARE BASIN 111 G' O O O O O O OO E L A W A R NORTHWEST SHELF BASIN / SEVEN RIVERS FORMATION / / / /.i L I EXPLANATION 10TO V/\ Shelf evaporite i i Shelf-margin Shelf detrital * ' A and carbonate ' ' carbonate O Drill hole L fcv^ Basin detrital Basin 0 1 2 carbonate MILES 'Goat Seep Dolomite 'Getaway Limestone Member of Cherry Canyon Formation FIGURE 7. Restored stratigraphic cross section G-G' of the Leonardian (part), Guadalupian, and Ochoa" Series of the Per mian System through the Northwest shelf and the Delaware basin. Line of section is showirin figure IB. Restored sec tion is from Silver and Todd (1969). Luis basins have been set in a right en-echelon Hills uplift, and the Salt basin of southeast New pattern (Kelley, 1979) (fig. LA-IB). The 10,000 Mexico (figs. LA, 8,11). feet-thick Santa Fe Group in the Espanola basin is The Basin and Range province in southwest the most complete outcrop section of the rift-form New Mexico and adjacent southeas* Arizona had a ing deposits (Galusha and Blick, 1971; Kelley, different history than the Rio Grande rift. First, 1979). In the Albuquerque basin, only about a crustal extension began in southwest New Mexico fourth of the 12,000 to 13,000 feet of rift-filling about 30 to 29 m.y. ago, but rather than being nonmarine strata are exposed (Kelley, 1979). expressed as rifting the extension was confined Major horsts and tilted fault blocks adjacent to to plastic stretching of the lower crust of the kind and within the Rio Grande rift include the San which produced the metamorphic core complexes Andres Mountains uplift, Sacramento Mountains in southern Arizona. (Coney, 1978 Eaton, 1979). uplift, and Caballo Mountains uplift (figs. 1A, Secondly, rifting in southwest Nev Mexico began 10, 11). Basins and uplifts outside the Rio Grande later (20 m.y. ago; Elston and others, 1973; Deal rift proper, but tectonically akin to the rift, in and others, 1978) and ended earHe*1 (10 m.y. ago; clude the Guadalupe Mountains uplift, Brokeoff Eaton, 1979) than rifting in the IS Grande rift. 112 H BROKEOFF HILLS FEET UPLIFT GUADALUPE MOUNTAINS UPLIFT NORTHWEST SHELF 5000- SEA j LEVEL: 5000: 5 MILES EXPLANATION Permian Pennsylvanian Pre-Pennsylvanian Precambrian sedimentary sedimentary sedimentary basement rocks rocks rocks rocks FIGURE 8. Geologic cross section H-ff through the Guadalupe Mountains uplift. Line of section is shown in figure IB. Cross section is from Hayes (1964). Quaternary Tertiary Cretaceous Permian and Mississippian Cambrian and Precambrian alluvium intrusive sedimentary Pennsylvanian and Devonian Ordovician basement rocks rocks sedimentary sedimentary sedimentary rocks rocks rocks rocks J' BIG HATCHET MOUNTAINS HELL-TO-GET-TO BUGLE RIDGE FAULT SEA LEVEL 2 MILES FIGURE 9. Geologic cross sections /-/' and J-J' through parts of the Pedregosa basm and the superimposed Early Cr^aceous rift basins. Lines of sections are shown in figure IB. Cross section I-F is from Drewes and Thorman (1980) and cror< section J-J" is from Zeller (1975). Place names used in this figure do not appear on figures LA, IB, and 1C. 113 ESPANOLA BASIN 10,000' FEET ALBUQUERQUE BASIN 10.000 T SEA LEVEL' 10.000- 20.000- 10 MILES EXPLANATION Quaternary and Tertiary sedimentary rocks 10,000 Quaternary alluvium Pre-Pennsylvanian and Tertiary sedimentary sedimentary rocks rocks FIGURE 10. Geologic cross sections through the Espanola basin (K-K), Albuquerque basin ( L-L'), and TV'arosa basin and Sac ramento Mountains uplift (Af-Af). Lines of section are shown in figure IB. Cross sections K-K and L-L' are from Kelley (1979) and cross section Af-AT is from Oetking and others (1967). In adjacent southeast Arizona, major rifting may Plateau and the Basin and Ran TRANSITIONAL ZONE The transitional zone between the Colorado 114 N SACRAMENTO FEET MOUNTAINS 10.000n UPLIFT LEVEL EXPLANATION Drill hole Quaternary and Permian Pennsylvanian Pre-Pennsylvanian Precambrian Tertiary sedimentary sedimentary sedimentary sedimentary basement rock? rocks rocks rocks rocks GUADALUPE FEET MOUNTAINS r 10,000 PEDERNAL UPLIFT UPLIFT 10.000 FEET FIGURE 11. Geologic cross section N-N through the Sacramento Mountains and part of the Guadalupe Mountains uplift. Line of section is shown in figure IB. Cross section is from Black (1975). PETROLEUM GEOLOGY sic Entrada Sandstone (Vincelette and Chittum, 1981), Upper Cretaceous Dakota Sandstone (Black, USGS PETROLEUM PROVINCE BOUNDARIES 1978; Luce, 1978), and Upper Cretaceous Mancos The State of New Mexico is subdivided into Shale (Mallory, 1977). seven petroleum provinces by the U.S. Geological Most of the gas in the San Juan Basin is produc Survey for which oil and gas resource estimates ed from the giant, hydrodynamnally controlled have been prepared (Dolton and others, 1981). Blanco Basin gas field located along and adjacent The petroleum province boundaries do not per to the axis of the basin (Pochard, 1972; fectly match the physiographic and tectonic pro Molenaar, 1977) (figs. 1C, 2). Major producing vince boundaries because the USGS petroleum horizons in the Blanco Basin field are the Upper provinces often follow county lines to simplify the Cretaceous Dakota Sandstone (Deischl, 1973; tabulation of oil and gas data (figs. LA, C). Hoppe, 1978), Point Lookout Sar-istone (Pritch ard, 1973, 1978), Cliff House Sar 116 Committee, 1960; Nottingham, 1960; Broadhead, the Cretaceous Dakota sandstone and the Upper 1982, 1983) (figs. 1C, 7). Guadalupian shelf-margin Jurassic Morrison Formation along the cref t of a reefs are poor reservoirs and produce very little southeast-trending anticline (Arnold and others, oil (fig. 7). In contrast, the dolomitized shelf-mar 1978). Carbon dioxide is produced from the Tubb gin reefs of the Abo trend (Leonardian) are re sandstone (Leonardian), an economic unit, in the sponsible for large oil accumulations such as the northeast part of the State adjacent to the Sierra Empire field (Le May, 1960; Wilson, 1960). Grande uplift (Broadhead, 1982) (fig. 1C). S weral Oil fields in the Ellenburger Group, Simpson now-abandoned carbon dioxide gas fields on the Group, Montoya Dolomite, and Fusselman Dolo west flank of the Estancia basih produced from mite are confined to structural traps on the Cen Permian and (or) Pennsylvanian rocks (Beaumont, tral Basin platform whereas oil fields in the Devo 1961) (fig. 1C). nian dolomites are located in structural traps on THICKNESS AND ORIGIN OF the Central Basin platform and the Northwest SEDIMENTARY ROCKS shelf (Stipp and others, 1956). Missourian and Vir- gilian limestones yield oil from stratigraphic and The combined thickness of Paleozoic, Me^ozoic, structural traps on the Northwest shelf (Stipp and and Tertiary sedimentary rocks is 10,000 feet or others, 1956; Meyer, 1966) (fig. 6). greater in (1) the San Juan Basin, (2) the Dela At the end of 1979, over three-fourths of the ul ware basin and adjacent Northwest shelf anl Cen timate recoverable gas in southeast New Mexico tral Basin platform, (3) Pedregosa basin and was estimated to come from gas associated with superimposed Lower Cretaceous rift basics, (4) the oil fields (American Petroleum Institute and Raton and Las Vegas basins, arid (5) at le^st six National Gas Association, 1980). However, new Tertiary basins in the Rio Grande rift (Foster and discoveries have added significantly to the nonas- Grant, 1974). sociated gas reserves, probably to the point where the ultimate recoverable gas is divided about SAN JUAN BASIN equally between associated and nonassociated gas. Paleozoic sedimentary rocks in the Sar Juan For example, sandstone interbedded with gray to Basin range in thickness from about 2,500 to 5,000 black shale of Morrowan and Atokan age contains feet (Momper, 1957; Peterson and others, 1965). abundant nonassociated gas in southeast New Strata of the Cambrian, Devonian, and Mir-fissip- Mexico (Meyer, 1966; David, 1977; Anderson, pian System are relatively thin or absent and, 1977) (fig. 6). This gas comes from stratigraphic where present, generally have a combined thick and structural traps in the Delaware basin and ness of less than 500 feet (Loleit, 1963; Parker and Northwest shelf. Wheatley (1981a) reports that Roberts, 1963). Pennsylvanian rocks in tH San the Morrowan sandstone trend alone may contain Juan Basin composed of marine carbonate rocks, reserves of 10 trillion cubic feet of gas. The Abo black shale, and evaporite in the center and on the Formation (Wolfcampian) (Meyer, 1966) with in southwest flank of the Paradox basin and equiva terbedded sandstone and red shale units is a rela lent nonmarine arkose and red shale on the north tively new producer of nonassociated gas in the east flank of the Paradox basin attain a Northwest shelf and it has been estimated to have maximum thickness of about 3,000 feet (Peterson reserves of 3 trillion cubic feet of gas (Wheatley, and others, 1965). Permian rocks in the San Juan 1981b). Other stratigraphic horizons with signifi Basin are largely nonmarine in origin and have a cant quantities of nonassociated gas in southeast maximum thickness of about 2,lOO feet (Peterson New Mexico are the Ellenburger Group, Fussel and others, 1965). man Dolomite, unnamed dolomites in the Devo Mesozoic and Tertiary rocks in the San Juan nian System, and Desmoinesian, Missourian, and Basin have a maximum combined thickness be Virgilian Series of the Pennsylvanian System tween 11,000 and 12,000 feet. The Triassic and (Galley, 1971; Hill, 1971; Hartman and Woodard, Jurassic rocks are largely nonmarine in ori|pn and 1971; David, 1977). have a combined thickness ranging from slightly The only commercial oil and gas production less than 2,000 feet to 3,000 feet (Peterson and from other than northwest and southeast New others, 1965). As much as 6,500 feet of Cret" 117 nearshore marine sandstone, paludal shale, Pedregosa basin and as much as 15,000 feet of sandstone, and coal, and alluvial plain sandstone Lower Cretaceous rocks in the superimposed rift and shale at or near a northeastward prograding basins (Greenwood and others, 1977). More than shoreline (Molenaar, 1977, 1983). Tertiary rocks in 5,000 feet of Pennsylvanian and Lower Permian the basin are nonmarine and attain a maximum (Wolfcampian) shelf carbonate rocks, shelf-margin thickness of about 3,500 feet (Peterson and others, carbonate rocks, and basinal black shale and car 1965; Fassett and Hinds, 1971). bonate rocks were deposited in the Pedregosa basin (Ross, 1973). The remaininfr 2,500 feet of DELAWARE BASIN, NORTHWEST SHELF, AND CENTRAL BASIN PLATFORM Permian rocks is represented largely by shelf car bonates of the Leonardian Stage (Greenwood and In southeast New Mexico, Paleozoic sedimen others, 1970). Deposits of the Early Cretaceous tary rocks attain a combined thickness of between rift basins began with conglomerate of alluvial fan 9,000 and 23,000 feet (Meyer, 1966; Oriel and origin, but eventually evolved into shallow marine others, 1967; Hill, 1971; Hartman and Woodard, limestone, shale, and sandstone (Hayes, 1970). 1971; Bachman, 1975). The Paleozoic rocks gener Cambrian through Mississippian rocks with a ally thicken from the Northwest shelf and Central maximum combined thickness of as much as 4,000 Basin platform into the Delaware basin. A rela feet (Kottlowski, 1971; Greenwood and others, tively thin section of Triassic and Tertiary rocks, 1977) and Tertiary sedimentary an<* volcanic rocks with a combined thickness of 2,000 feet or less, locally as much as 6,000 feet thick (Thompson and overlies the Paleozoic section throughout most of others, 1978) further contribute to the already southeast New Mexico (Stratigraphic Research thick sedimentary section in southwest New Committee, 1956). Mexico. Because of the complex history of uplift, The Cambrian through Mississippian strata in erosion, and plutonism, the above-mentioned rock southeast New Mexico have a combined thickness units are not uniformly distributed throughout the between 1,000 and 5,000 feet and primarily consist area (fig. 9). Nonetheless, the overall thickness of of shelf carbonates with minor amounts of this depocenter is impressive. sandstone and black shale (Hill, 1971; Wright, 1979). These strata were removed from the north RATON AND LAS VEGAS BAf'NS ern extremity of the Northwest shelf by pre- Sedimentary rocks reach a maximum combined Pennsylvanian and pre-Permian erosion (Stratig thickness of between 14,000 and 2C,000 feet in the raphic Studies Committee, 1953; Stratigraphic Re Raton basin (Baltz, 1965; Roberts and others, search Committee, 1956). Pennsylvanian rocks 1976) and 12,700 feet in the Las Vegas basin thicken from about 1,000 feet on the Northwest (Baltz, 1965). The sedimentary section in these ba shelf to a maximum of about 3,000 feet in the Del sins is largely comprised of Pennsylvanian (about aware basin (Meyer, 1966; Bachman, 1975). The 5,500 feet maximum, Baltz, 196£; Roberts and Pennsylvanian rocks consist of shelf carbonate others, 1976), Permian (abou* 2,000 feet rocks and minor intercalated red shale on the maximum, Dixon, 1967; Robert^ and others, Northwest shelf and basinal sandstone and gray to 1976), Cretaceous (4,100 feet maximum, Molenaar, black shale and limestone in the Delaware basin 1983), and Tertiary (5,000 feet maximum, Speer, (Meyer, 1966; 1968) (fig. 6). Permian strata thic 1976) rocks. The Pennsylvanian and Lower Per ken from about 7,000 feet on the Northwest shelf mian rocks in the Rowe-Mora basin consist of dark to a maximum of about 14,000 feet in the Dela basinal shale in the lower part of the Pennsylva ware basin (Oriel and others, 1967; Hartman and nian System (Morrowan, Atokar, lower Des- Woodard, 1971). Shelf, shelf-margin, and basinal moinesian) which are flanked on tl ? west by non- carbonate fades are well defined in the Penman marine arkosic sandstones and on the east by shelf rocks, particularly in the rocks of the Guadalupian carbonate rocks (Roberts and others 1976; Casey, Series (Stratigraphic Studies Committee, 1953; 1980) whereas the upper part of the Pennsylva Meyer, 1966; Silver and Todd, 1969) (figs. 6, 7). nian System and the lower part of the Permian System (Wolfcampian) are represented by near- PEDREGOSA BASIN shore carbonate rocks flanked on the north, west, Southwest New Mexico has as much as 7,500 and east by arkosic sandstone and conglomerate feet of Pennsylvanian and Permian rocks in the (Roberts and others, 1976). Most of the arkosic 118 rocks were derived from the adjacent Sierra compahgre-San Luis uplift, except possibly along Grande and Uncompahgre-San Luis uplifts the east side of the basin where several thousand (Roberts and others, 1976). Nearshore marine feet of proximal Pennsylvanian rocks may have sandstone and shelf carbonate rocks dominate the been preserved (Baltz, 1965; Rascoe and Baars, upper part of the Permian System (Leonardian 1972; Mallory, 1972). Triassic, Jurassic, and prob and Guadalupian) (Roberts and others, 1976). able Cretaceous rocks also thuji from so'ith to A nearly complete section of Cretaceous and north across the San Luis basin (Baltz, 1965). Lip- Tertiary rocks is preserved in the Raton basin, man and Mehnert (1979) suggest in a diagramma but in the Las Vegas basin only the lower part of tic cross section through the San Luis basin that the Cretaceous section is present. The majority of at least 9,000 feet of Tertiary rift deposits fill the the Cretaceous rocks in both basins are shale and deepest part of the basin. , sandstone deposited in offshore marine, nearshore The Jornada del Muerto (about 6,700 feet marine, paludal, and alluvial plain environments, maximum), Mesilla (about 10,10Q feet maximum), along or near an easterly prograding shoreline and Tularosa (about 8,800 feet maximum) basins (Speer, 1976). have a slightly greater thickness^ of pre-rifl rocks than the northern rift basins (Greenwood and BASINS IN THE RIO GRANDE RIFT others, 1977). Moreover, the pre-rift rocks of the Sedimentary rocks attain a thickness of 10,000 Jornada del Muerto, Mesilla, and Tularosa basins feet or more in the Albuquerque, Espanola, Jor- are nearly all Paleozoic in age. Cambrian tl rough nado del Muerto, Mesilla, Tularosa, and San Luis Mississippian rocks in the southern rift basms are basins (fig. LA). largely shelf carbonate rocks with secondary Approximately 7,300 feet of Pennsylvanian sandstone and black shale (Kottlowski, 1971; through Cretaceous strata underlie the 10,000 to Greenwood and others, 1977). The thickr^ss of 12,000-foot-thick rift-filling Tertiary deposits of these rocks ranges between zero and 2,800 feet in the Albuquerque basin (Black and Hiss, 1974). the Jornado del Muerto and Tularosa basins and The pre-rift rocks encountered in the Shell Santa between 2,500 and 3,600 feet in the Mesillr basin Fe No. 1 (fig. 1C) are as follows: 600 feet of (Greenwood and others, 1977). Most of the Pennsylvanian sandstone, fossiliferous limestone, Paleozoic rocks are absent in the northern part of and black, gray, and reddish brown shale of the Jornada del Muerto and Tularosa basins largely marine origin; 1,400 feet of Permian red (Greenwood and others, 1977). dish brown sandstone and mudstone of nonmarine The Tularosa Basin is situated over the center origin and nearshore marine limestone; 2,000 feet of the Pennsylvanian-Permian Orogrande basin, of Triassic and Jurassic nonmarine sandtone, var whereas the Jornada del Muerto and Mesilla ba iegated mudstone, and local gypsum and dark sms are located on the flanks 0f the Ororrrande gray limestone; and 3,300 feet of Cretaceous basin (Meyer, 1966; Greenwood aWl others, 1977). sandstone and gray shale of offshore marine, near- Pennsylvanian rocks attain a maximum thickness shore marine, and paludal origin (Black and Hiss, of about 3,500 feet in the center of the Tnlarosa 1974). The Pennsylvanian section in the Albuquer Basin and thin to about 2,000 feet or less in the que basin probably thickens southward and west Jornada del Muerto and Mesilla basins (Green ward against the adjacent Lucero uplift wood and others, 1977). Shelf carbonate rocks, (Wengerd, 1959) (fig. 3). sandstone, and variegated shale of marir^ and Pre-rift rocks beneath the 10,000-foot-thick rift- nonmarine origin are the dominant rock types in filling Tertiary deposits of the Espanola basin the Orogrande basin (Meyer, li)66); however at probably have about the same thickness and times, particularly in the Virgilian, basinal shelf lithologic characteristics as the pre-rift rocks in margin, and shelf facies developed in the Orog the Albuquerque basin (Black, 1979a; Ingersoll rande basin. Locally, dark gray basinal shrle and and Kelley, 1979). However, Permian and shelf-margin bioherms are present (Pray, 1961; Pennsylvanian rocks may be thinner in the Es Kottlowski, 1971). panola basin than in the Albuquerque basin and Permian rocks in the Orogran4e basin ar^ simi contain a greater proportion of nonmarine rocks. lar to the Pennsylvanian rocks except that the In the San Luis basin the Pennsylvanian and Permian section contains more sandstone, red Permian section thins to a zero edge over the Un shale, and evaporite. Shelf-niargin carbonate 119 rocks and basinal dark shale and carbonate rocks ducing, basins such as the Albuquerque basin, are present in the Wolfcampian (Meyer, 1966; Jornada del Muerto basin, Las Vegas basin, Kottlowski, 1971). The maximum thickness of the Mesilla basin, Pedregosa basin, Rrton basin, and Permian rocks is about 2,000 feet in the Jornada Tularosa Basin. Oil and gas shovrs in Paleozoic del Muerto basin and about 3,000 feet in the rocks of these basins probably originated from Mesilla and Tularosa basins (Greenwood and Pennsylvanian and (or) Permian bhck shales (Pe others, 1977). troleum Information Well History Control System Approximately 1,000 feet of Lower Cretaceous (WHCS) files);(Northrop and otherr 1946; McCas- rocks are present in the southern basins of the Rio lin, 1974; Foster and Grant, 1974; Thompson and Grande rift and about 700 feet of marine Jurassic Bieberman, 1975; Thompson and others, 1978). A rocks are present in the Mesilla basin (Thompson positive correlation between oil and gas shows in and Bieberman, 1975; Greenwood and others, Paleozoic rocks and the presence of Pennsylvanian 1977). The combined thickness of the pre-rift and and (or) Permian black shale is rlso evident in rift-filling Tertiary rocks is about 3,000 feet in the marginally mature basins and uplifts such as the Jornada del Muerto basin (Sanford, 1968), about Estancia basin, Tucumcari basin, rnd Lucero up 6,000 feet in the Tularosa Basin (McLean, 1970), lift (Beaumont, 1961; Kottlowski, 1971; Reese, and 12,000 feet in the Mesilla basin (Thompson 1975; McCaslin, 1982, 1983). and Bieberman, 1975). Detailed geochemical studies of samples from the KCM No. 1 Forest Federal driT hole (fig. 1C), SOURCE ROCKS, HYDROCARBON SHOWS, Humble No. 1 State BA (fig. 1C) drill hole, and AND THERMAL MATURITY nearby outcrops suggest that the Pennsylvanian Organic-rich rocks, which have generated or are and (or) Permian black shales anc1 limestones in capable of generating significant quantities of oil the Pedregosa basin have a maximum weight per and gas in New Mexico, are Pennsylvanian and cent organic carbon value of slightly less than 1 Permian black marine limestone and shale, Upper and have kerogen types which are fas prone (Cer- Cretaceous offshore marine shale, Upper Cretace nock, 1977; Cernock and Bayliss, ir77; Thompson, ous paludal carbonaceous shale and coal, Upper 1980). A Conodont Alteration Index (CAI) of 5 in Devonian marine black shale, and Middle Jurassic the KCM No. 1 Forest Federal driT hole indicates lacustrine(?) black limestone. Depending upon bu that the Paleozoic rocks in this well have been rial history, regional geothermal gradient, and heated above the limit of dry fas generation proximity to magmatic activity, these rocks have (Behnken, 1977; Harris and otherr 1978). How attained a variety of maturation levels with re ever, this CAI value is strongly influenced by a spect to hydrocarbon generation ranging from quartz monzonite pluton encountered in the drill immature to overmature. hole at a depth of 4,116 feet (Thompson, 1977) and thus may not be indicative of the regional PENNSYLVANIAN AND PERMIAN paleotemperature. B. R. Wardlow and A. G. Har BLACK LIMESTONE AND SHALE ris (unpub. data) have shown, in the Pedregosa Pennsylvanian and Permian black shale and basin of Arizona, that once the ercessively high limestone are unquestionably the source for the CAI values near plutons have bee^ removed the numerous oil and gas accumulations in Pennsylva CAI values range between 3 and 4. If the nian and Permian reservoirs of the Northwest Pennsylvanian and Permian rockr in the New shelf, Central Basin platform, and Delaware basin Mexico part of the Pedregosa basin have similar (Jones and Smith, 1965; Meyer, 1966). Moreover, CAI values, the implied burial history would be oil and gas fields in Pennsylvanian rocks of the favorable for the generation of gas. Four Corners platform were probably supplied by UPPER CRETACEOUS SHALE ANT COAL Pennsylvanian black shale beds. The weight per cent organic carbon of the Pennsylvanian black The Upper Cretaceous Manco,** Shale, with shales in that area ranges from less than 1 to weight percent organic carbon values up to 2, is about 1.5 (Ross, 1980). the probable source for most of tve oil fields in Black shale and limestone units of Pennsylva Cretaceous rocks in the San Juar Basin (Ross, nian and (or) Permian age are present in many 1980). In contrast, most of the gas in the San Juan deep and thermally mature, but presently nonpro- Basin was probably generated fx>m thick se- 120 .ences of carbonaceous shale and coal of paludal Thompson and Bieberman (1975) sugges* that origin (Buckner, 1976; Rice and Threlkeld, 1983). an organic-rich, marine Jurassic unit (limestone?) Gas in the Wagon Mound field was probably gen in the Mesilla basin has the potential for bmg a erated from carbonaceous shale units in the petroleum source rock. However, the area! extent Dakota, but in light of the thin Cretaceous and of this unit in New Mexico seems to be rather lim Tertiary overburden in the Las Vegas basin, the ited (Greenwood and others, 1977). gas may be biogenic rather than thermal in origin. Thick, thermally mature sequences of Upper Cre RESERVOIRS AND TRAPS taceous gray marine shale, carbonaceous shale, Major reservoir characteristics and tr*»Dping and coal are present in the Albuquerque basin and conditions have already been discussed for the hy undoubtedly these rocks have been the source of drocarbon fields of the San Juan Basin, Northwest oil and gas shows reported in the Cretaceous sec shelf, Central Basin platform, and De^ware tion (Black, 1979a). Oil and gas shows in Cretace basin. The following discussion will ir^ntion ous rocks of the Espanola (Black, 1979b) and briefly those stratigraphic units where hydrocar Raton (Speer, 1976) basins were probably gener bons would most likely reside in presently unpro ated from gray offshore marine shale and paludal ductive basins of New Mexico and what the mode carbonaceous shale beds. of entrapment might be. DEVONIAN BLACK SHALE The Epitaph Dolomite (Permian), Concha Limestone (Permian), and the shelf-margin dolo An Upper Devonian marine black shale, be mite units of the Horquilla Limestone (Pennsylva- tween 100 and 400 feet thick, extends across most nian-Permian) seem to be the most prospective re of southern New Mexico (Greenwood and others, servoir units in the Pedregosa basin (Greenwood 1977; Wright, 1979). In southeast New Mexico and others, 1977; Thompson, 1980). Reservoirs of this black shale unit is known by some geologists secondary importance in the vicinity of tin Ped as the Woodford Shale and is commonly thought regosa basin include local rudistid reefs in the U- to have been the source of much of the pre- Bar Formation (Lower Cretaceous), shallow Pennsylvanian oil and gas on the Northwest shelf marine sandstone in the Mojado Formation and Central Basin platform (Greenwood and (Lower Cretaceous), and shelf carbonates and others, 1977; Wright, 1979). In south-central and dolomites in the El Paso Limestone (Ordo^ician), southwest New Mexico this black shale unit is Montoya Dolomite (Ordovician), and Fus^elman called the Percha Shale, but the source-rock char Dolomite (Silurian) (Thompson and others, 1978). acteristics remain the same. The Percha Shale A wide variety of structures, some in combmation may have been the source for the oil and gas with stratigraphic variations suitable for hydro shows in the pre-Pennsylvanian rocks of the Ped- carbon traps, are present in the Pedregosa basin. regosa (Thompson and others, 1978) and Mesilla Pennsylvanian and Lower Permian shelf carbo (Thompson and Bieberman, 1975) basins. nate rocks with local sandstone and shelf-margin MIDDLE JURASSIC LIMESTONE carbonate rocks (Magdalena Group) and dolomite in the Permian San Andres Limestone seen to be The black limestone member of the Middle the most important potential reservoir unitf in the Jurassic Todilto Formation is the probable source Jornada del Muerto and Tularosa basins (Green of the oil fields in the Jurassic Entrada Sandstone wood and others, 1977; Thompson and others, of the San Juan Basin (Ross, 1980; Vincelette and 1978). Both structural and stratigraphic tr*aps are Chittum, 1981). In the San Juan Basin this lime available. The El Paso Limestone, Montoya Dolo stone unit is thermally mature, yields up to 24 gal mite, and Fusselman Dolomite may also b-? impor lons of oil per ton, and has a maximum weight tant reservoirs in the Jornada del MueHo and percent organic carbon value of about 1 (Ross, Tularosa basins, particularly in areas where trun 1980; Vincelette and Chittum, 1981). Tanner (1974) cation traps are available (Kottlowski, 1971; Fos suggests that the Todilto Formation may be lacus ter and Grant, 1974). The favorable reservoirs in trine in origin. The organic-rich limestone unit in the Jornada del Muerto and Tularosa basins also the Todilto Formation extends as far east as the are present in the Mesilla basin; in addition, Albuquerque basin where it is the probable source Lower Cretaceous sandstone units are possible re of oil shows in the Entrada Sandstone (Black, servoirs in the latter (Foster and Grant, 1974). 1979a). 121 Potential traps in the Mesilla basin are largely of to the atmosphere. Another probhm is that many the structural variety (Foster and Grant, 1974). hydrocarbons or hydrocarbon so'irce rocks may The primary stratigraphic units with reservoir have been destroyed by high thermal regimes as potential in the Albuquerque basin, and probably sociated with plutonism and volcarism. the Espanola basin, are Upper Cretaceous shallow The Pedregosa basin with good source rocks, marine sandstones such as the Dakota, Gallup, and good reservoirs, and local hydrocarbon shows Point Lookout Sandstones, the Middle Jurassic seems to be one of the more premising frontier Entrada Sandstone, and shelf carbonates in the areas in New Mexico for oil and gas exploration. Pennsylvanian Madera Limestone. Faults and Unfortunately, most of the oil and gas in the area drape folds associated with individual fault blocks probably was generated during o^ shortly after a provide a trapping mechanism, in addition to the thick section of sedimentary rocks was deposited southward pinch out (truncation) of the Entrada in the superimposed Early Cretaceous rift basins; Sandstone across the southern part of the Al thus oil and gas accumulations were subject to re buquerque basin and fades variations and pinch distribution or destruction by Laramide, middle outs in the Cretaceous sandstones (Black, 1979a; Tertiary, and late Tertiary tectonic and magmatic Kelley, 1979). episodes that followed. Shallow marine sandstone units in the Upper The question of whether or not the Cordilleran Cretaceous Trinidad Sandstone and the Lower fold and thrust belt extends across southwest and Upper Cretaceous Dakota Sandstones have New Mexico and adjacent Arizona is still unresol the best potential as petroleum reservoirs in the ved. However, the results of the Phillips Arizona Raton and Las Vegas basins (Baltz, 1965; Speer, State No. A-l drill hole (Reif and Robinson, 1981) 1976). Shelf carbonates of the Pennsylvanian Mad- strongly suggest that if the thrust belt does ex era Limestone and nearshore marine conglomera tend through southwest New Merico, it is not ex tic sandstones of the Sandia Formation may also pressed as a major allochthon of crystalline rocks be good reservoir units in the Las Vegas basin that overlies a thick, previously unknown and un (Baltz, 1965; Foster and Grant, 1974). Both anti explored section of Paleozoic and Mesozoic clinal and stratigraphic traps are present in the sedimentary rocks (Hansen anc1 others, 1980). Raton and Las Vegas basins. Other traps may be Therefore, this unanswered question concerning formed by the updip truncation of the Madera the presence or absence of the tlmst belt proba Limestone and Sandia Formation hi the northern bly does not significantly affect the overall assess part of the Las Vegas basin beneath the Permian- ment of the oil and gas potential of southwest Pennsylvanian Sangre de Cristo Formation (Baltz, New Mexico. 1965; Foster and Grant, 1974). Rift basins in the southern part of the Rio Grande rift, such as the Jornada del Muerto, SUMMARY STATEMENT Mesilla, and Tularosa basins, also are promising areas for oil and gas exploration because of good Aside from the San Juan Basin, Delaware basin, source rocks, good reservoir rocl s, and local hy Northwest shelf, and Central Basin platform, drocarbon shows. However, tHse basins are much of New Mexico is a frontier area in terms of plagued by the same problems that exist in the oil and gas exploration. However, given the com Pedregosa basin and superimposed Early Cretace plex tectonic and magmatic history and the sus ous rift basins, namely, repeated1 episodes of ex- ceptibility of many of the potential reservoir rocks tensional tectonism, magmatism, and volcanism. to flushing by freshwater, the hydrocarbon poten The better opportunities for firming oil and gas tial in these frontier areas is considered by the au in the Pedregosa basin and tin basins in the thor to be low to moderate. One of the major southern Rio Grande rift probably exist in the problems that may have precluded large hydrocar deep parts of the basins where initially trapped bon accumulations from forming in the present hydrocarbons were least affected by repeated ex- frontier areas of the State is that the oil and gas tensionaJ tectonism and flushing by freshwater. may have been redistributed from primary traps Known centers of plutonism and volcanism should to secondary and tertiary traps as various genera be avoided for petroleum exploration. Tertiary tions of faults evolved in a given rift system. Com strata near the flanks of the basics may also have monly, these redistributed hydrocarbons escaped trapped hydrocarbons which were redistributed 122 from preexisting oil and (or) gas accumulations the hydrocarbon potential of the Wilderness in pre-rift rocks. Lands in New Mexico is rated qualitative^ on a Commercial oil and gas accumulations may also scale from high to zero. A high rating is assigned be found in the Albuquerque basin, but deep dril to Wilderness Lands that are located ling here has proven disappointing to date. Only near or along the projected trend of hydrocarbon one major gas show has been reported production and have all the geologic attributes of (Broadhead, 1983). A major difficulty could be the the producing area. A medium rating is aligned recognition of a trap that is well sealed and pre to Wilderness Lands that have all the attributes, dates the migration of hydrocarbons. Despite including shows, of a future petroleum producing these economic failures, the recent deep drilling area, but lack commercial production. In contrast, by the oil industry in the Albuquerque basin low and zero ratings are assigned, respectively, to exemplifies the type of action that must be taken Wilderness Lands that have few or no attributes if commercial hydrocarbons are to be found in the of a future petroleum producing area. Usually a Rio Grande rift. zero rating is reserved for regions characterized The Espanola and San Luis basins are not as at by autochthonous igneous and metamorphic rocks. tractive for hydrocarbon exploration as the Al For ease of discussion, the Wilderness Lands in buquerque basin but, nonetheless, may have some New Mexico are grouped into 18 clusters (f 7. 12), potential. The best exploration objectives are Cre each containing one or more tracts that hrve the taceous rocks in the Espanola and San Luis ba same or similar geologic characteristics and the sins, supplemented by Pennsylvanian rocks in the same hydrocarbon potential. Espanola basin. Major drawbacks to exploration Cluster 1 in these basins, in addition to multiple phases of Cluster 1 is comprised of a single tract of Wil extensional tectonics and the recognition of a suit derness Land along the west flank of the Mesilla able trap, may be the proximity of the Jemez vol basin in south-central New Mexico near the canic province to the Espanola basin and the prob Mexico and Texas border (figs. LA, 12). Quater able lack of Pennsylvanian reservoir and source nary basalt is exposed throughout the tract (Dane rocks in the San Luis basin. and Bachman, 1965). Judging from the sedimen Other basins and uplifts along the Rio Grande tary rocks in the nearby Grimm et al No. 1 Mobil- rift that may yield commercial hydrocarbons in 32 drill hole, the author believes a thick section of clude the Salt basin and the Guadalupe Mountains Paleozoic rocks probably exists beneath the uplift (fig. LA). Basins and uplifts such as the basalts (Thompson and Bieberman, 1975) (fig. 1C). Estancia basin, Caballo Mountains uplift, Sac Oil and (or) gas shows were reported in the ramento Mountains uplift, and San Andres Moun Grimm No. 1 drill hole from Tertiary rocks, tains uplift are less desirable because many of the Lower Cretaceous rocks, Pennsylvanian rocks, reservoir objectives are exposed and are suscepti and the Ordovician Montoya Dolomite (Thompson ble to flushing by freshwater. and Bieberman, 1975). Because of the hydrocar Of the basins outside the Rio Grande rift and bon shows and the thick section of sedur^ntary the southwestern part of the Basin and Range rocks in the Grimm No. 1, the hydrocarbon poten province, the Las Vegas basin, Raton basin, and tial of the tract in cluster 1 is rated medium. Units possibly the Tucumcari basin have the best poten having the best reservoir potential are Lower tial for yielding commercial hydrocarbons. Basins Cretaceous rocks, Pennsylvanian and Permian and uplifts such as the Acoma basin, Chama basin, rocks, the Fusselman Dolomite, the Montoya Lucero uplift, Sierra Grande uplift, and Zuni basin Dolomite, and the El Paso Limestone. Units hav are not as favorable for oil and gas accumulations ing the best source rock characteristics in the clus because of their thin sedimentary cover and their ter are the Devonian Percha Shale, Permian black susceptibility to flushing by freshwater. shale, and Jurassic marine rocks (Thompson and Bieberman, 1975). Anticlines, faulted anticlines, PETROLEUM POTENTIAL OF and tilted fault blocks are the most probable WILDERNESS LANDS traps. Negative aspects of cluster 1 in tenr<* of oil and gas exploration are adjacent centers of vol- On the basis of the geologic framework and pe canism and complex faulting associated with the troleum geology outlined in the previous sections, development of the Rio Grande rift. 123 EXPLANATION High Medium Low : : ##:} Low to zero Zero FIGURE 12. Map showing the qualitative estimate of petroleum potential for Wilderness Lands in New Mexico. The heavy lines and associated numbers define clusters of Wilderness Lands that have the same or similar geologic characteristics and the same hydrocarbon potential. 124 Cluster 2 depression, a large cauldron filled with up to 2,000 Cluster 2 contains 12 tracts of Wilderness feet of ash-flow tuff and lava flows (fig. LA, F). Two Lands in southwesternmost New Mexico that are nearby drill holes indicate that about 3,500 feet of distributed across the Pedregosa basin, Early Paleozoic rocks are present beneath the cover of Cretaceous rift basins, and the southern part of volcanic rocks (Thompson and Bieberman, 1975; the Rio Grande rift (figs. LA, 12). The hydrocar Thompson and others, 1980). One of the drT holes bon potential of these tracts is rated low. is about 5 miles southeast of the northernmost The tracts in the Pedregosa basin and superim tract in the depression. This drill hole yielded no posed Early Cretaceous basins have a thick sec oil and gas shows and the reservoirs have proba tion of Paleozoic and Lower Cretaceous rocks. bly been flushed by freshwater (Thompson and Some of these rocks are allochthonous (fig. 9, sec Bieberman, 1975). The second drill hole is in the tion J-J'). Source rocks, reservoir rocks, struc southwest corner of the large tract south of the tural traps, and thermal history are at least locally Goodsight-Cedar Hills depression. Gas shows favorable for the generation and entrapment of were reported in this well from the El Paso hydrocarbons. By analogy to the thermal history Limestone (Thompson and others, 1980). T^ hy of the Pedregosa basin in Arizona (B. R. Wardlaw drocarbon potential of the large tract south of the and A. G. Harris, unpub. data), the thermal his Goodsightr-Cedar Hills depression is rated1 lower tory of the Pedregosa basin in New Mexico proba than the adjacent tract in the Mesilla basin (clus bly favors the generation of gas over oil. Kerogen ter 1) because the sedimentary section in.tire tract types in the Pennsylvania black shale and lime near the Goodsightr-Cedar Hills depression is thin stone also favor the generation of gas over oil ner and is cut by more dikes, sills, and volcanic (Thompson, 1980). Both oil and gas shows have pipes than the tracts in the Mesilla basin. been reported from drill holes near the tracts Clusters 3 and 8 (Thompson and others, 1978). However, hydrocar bons generated in these tracts are very prone to Clusters 3 and 8 consist of three small tracts of leakage and destruction owing to the presence of Wilderness Lands that are in or adjacent to the several generations of faults and plutons, many of transitional zone between the Basin and Range which postdate the major phase of oil and gas gen and Colorado Plateau physiographic provinces eration and migration. Elston (1976) estimates (figs. LA, 12). The hydrocarbon potential of these that as much as a third of southeast New Mexico clusters is rated low to zero. The eastern tract in may be underlain by plutons such as the one en these clusters has Paleozoic and Cretaceour strata countered in the KCM No. 1 Forest Federal drill at the surface intruded by a Cretaceous and (or) hole (Thompson, 1977). The location of the tracts Tertiary pluton. The western tracts probably con along structurally high fault blocks, which permit tain no Paleozoic rocks and only a thin section of the entry of freshwater, further reduce their hy Cretaceous rocks (Dane and Bachman, 1965); Pre- drocarbon potential. cambrian rocks crop out a few miles northwest of The easternmost tract in the cluster is located both groups of tracts. on an intrarift horst block between the Goodsightr- Cluster 4 Cedar Hills depression and the Jornada del Muerto basin (fig. LA). Pennsylvanian and Per Cluster 4 is comprised of a single tract of Wil mian sedimentary rocks intruded by thick rhyolite derness Land in the northern part of the Jornada sills crop out at the surface and are very suscepti del Muerto basin (figs. LA, 12). Quaternary basalt ble to flushing by freshwater. No shows were re is exposed throughout the tract (Dare and ported in a nearby drill hole that reached Pre- Bachman, 1965) (fig. IB). The hydrocarbon poten cambrian basement rocks (Thompson and Bieber- tial of this tract is rated medium because of the lo man, 1975). A small piece of this tract is grouped cation of the tract near the axis of the basin and with cluster 6 for the quantitative petroleum as because 5,000 to 6,000 feet of Pennsylvanian, Per sessment because it falls across the south-central mian, and Upper Cretaceous rocks are present be petroleum province boundary, but for this discus neath the cover of volcanic rocks. Some pre- sion it will be included in cluster 2. Pennsylvanian sedimentary rocks may also be pre The tracts in the easternmost part of cluster 2 sent. Also, oil and gas shows have been reported are in or adjacent to the Goodsight^Cedar Hills from several drill holes in the deep part of the Jor- 125 nada del Muerto basin about 25 miles south of Tertiary basalts, Upper Cretaceous marine and cluster 4. Strata in cluster 4 are probably ther nonmarine rocks, and Triassic mnmarine rocks mally immature because of their thin overburden, are the most commonly exposed rocks in these so for hydrocarbons to be present they had to tracts and the total sedimentary section is less migrate there from the south. Pennsylvania!! than 5,000 feet thick. It is doubtful if the strata of rocks and the Ordovician El Paso Limestone are source rock quality in these trr"ts have been the most likely exploration objectives. Tilted fault buried deeply enough to generate oil and gas. blocks and (or) associated anticlines are the most Only one of a half dozen or more drill holes in or probable traps, although traps involving the near the tracts has yielded hydrocarbon shows. northward truncation of the El Paso Limestone Rocks of the Datil-Mogollon vc^anic field are are possible. Perhaps the most negative aspect of exposed throughout the tracts of the transition the tract, in terms of oil and gas exploration, is zone. The interior parts of the vohanic field, such that freshwater could easily enter the basin as clusters 7 (part) and 18, are mc^t likely under through outcrops of Paleozoic rocks along the west lain by a large pluton or compTex of plutons flank of the basin reducing the potential for petro (Elston and others, 1976). However, around the leum. fringes of the volcanic field, where tracts in clus Cluster 5 ters 6 and 14 are located, Paleozoic rocks and pos sibly Cretaceous rocks with adequate source and Cluster 5 is represented by a single tract of Wil reservoir characteristics may underlie the cover of derness Land in the Brokeoff Hills uplift of south volcanic rocks. east New Mexico, a highly faulted subblock of the All but one of the remaining tracts in clusters 6 Guadalupe Mountains uplift (figs. 1A, 12). The wil and 14 are astride intrarift horst bTocks in the Rio derness tract is about 20 miles west of the nearest Grande rift between the San Augustin and Jor- gas field on the Northwest shelf (fig. 1C). Permian nada del Muerto basins. The exception is a tract rocks of the Guadalupian Stage are exposed on the northwest flank of the Sierra Blanca basin, throughout the tract (Dane and Bachman, 1965). a northern extension of the Tularosa Basin (figs. The numerous northwest trending faults that 1A, 12). Many of the intrarift horst blocks are transect the wilderness tract were probably comprised of 3,000- to 4,000-foot-thick sections of formed during the late Tertiary phase of rifting in Pennsylvanian, Permian, and Up^er Cretaceous the Basin and Range province and, thus, post rocks. Commonly, these tracts are capped by vol dated the major late Paleozoic phase of oil and gas canic rocks of the Datil-Mogollon volcanic field and generation and migration in the Delaware basin by Tertiary rift-filling deposits. Y «. rocks in the and Northwest shelf. Most likely, any hydrocar horst blocks are probably thenrsdly immature, bons trapped in the Brokeoff Hills area as a result and even if hydrocarbons had been generated they of the late Paleozoic phase of generation and mig would have been very susceptible to flushing by ration would have been severely dislocated by the freshwater. The most probable sites for hydrocar extensional faulting and escaped to the atmos bon accumulations in these tracts are in the Ter phere. Drill holes near the wilderness tract have tiary rift basins that adjoin several of the intrarift not yielded oil and gas shows. The hydrocarbon horst blocks. Of the half dozen or so drill holes ad- potential of cluster 5 is rated low. iacent to these tracts, only one (about 18 miles south of Socorro) has a hydrocarbon (gas) show. Clusters 6 and 14 The single tract on the northwest flank of the Clusters 6 and 14 consist of numerous tracts of Sierra Blanca basin is comprised o* about 1,800 to Wilderness Lands spread across the southern part 2,000 feet of Pennsylvanian rocks (Meyer, 1966), of the Colorado Plateau province, the eastern part about 5,000 to 6,000 feet of Permian rocks (Meyer, of the transitional zone, and the southern part of 1966; Petroleum Information WHCS file), and a the Rio Grande rift (figs. 1A, 12). The hydrocar cover of Quaternary basalt. The sedimentary sec bon potential in these tracts is rated low. tion is thicker by about 500 to 1,000 feet if the The tracts in the Colorado Plateau province oc Mesozoic rocks along the eastern margin of the cupy parts of the Zuni basin, Zuni uplift, Acoma tract are included. A large northeast trending basin, Lucero uplift, and the northern flank of the anticline, which has been tested without shows to San Augustin basin (figs. 1A, 12). Quaternary and as deep as the Precambrian basement, extends 126 through the northern part of the tract (Woodward southwest flank of the San Juan Basin (fi^rs. LA, and others, 1975). Oil and gas shows have been re 12). The hydrocarbon potential of this cluster is ported from Permian rocks in several drill holes rated high because the cluster is located along less than two miles northeast of the tract. The hy several major producing trends in the basin. Sev drocarbon potential of this tract is not rated eral producing oil wells, probably drilled rs step- higher because part of the section has been in out wells to the Bisti field, are present in the truded by Cretaceous and (or) Tertiary plutons northernmost tract, and numerous subsurface oil (Dane and Bachman, 1965) and many of the units and gas shows have been reported from Upper having reservoir potential are susceptible to flush Cretaceous rocks in and around the other two ing by freshwater. tracts in the cluster. Oil fields in the Juraf sic En- trada Sandstone are located within 5 or 6 miles of Cluster 7 the southernmost tract. The most probable explo Cluster 7 contains tracts in the western part of ration objectives in cluster 9 are stratignnhically the transitional zone, along the flanks of the Jor- trapped oil and gas accumulations in Upp^r Cre nada del Muerto and Tularosa basins, and near the taceous nearshore-marine sandstones and in the center of the Sierra Blanca basin (figs. LA, 12). Jurassic Entrada Sandstone. The hydrocarbon potential of these tracts is rated low to zero. Cluster 10 The three westernmost tracts in cluster 7 have A single tract of Wilderness Land along the volcanic rocks of the Datil-Mogollon volcanic field southern flank of the San Juan Basin comprises at the surface. These tracts are rated low to zero cluster 10 (figs. LA, 12). Several Upper Cretace because Paleozoic rocks are probably absent ous sandstone and shale units and local Tertiary (Greenwood and others, 1977) and those sedimen basalts crop out in the tract (Dane and Bf *hman, tary rocks that are present have probably been in 1965). On the basis of the presence of Jurassic and truded by major plutons (Elston and others, Upper Cretaceous oil fields about 10 milef to the 1976). north, oil shows in nearby drill holes, and favora The tract on the east flank of the Jornada del ble reservoir and stratigraphic traps in Upper Muerto basin, south of the San Andres Mountains Cretaceous nearshore marine sandstones and the uplift, is dominated by a large Cretaceous and (or) Jurassic Entrada Sandstone, the hydrocarbon po Tertiary pluton which has pervasively intruded tential of cluster 10 is rated medium. The hydro adjacent Paleozoic rocks. Hydrocarbons, if present carbon potential is not rated high because numer at all in the area, would be located beneath the ous small Cretaceous and (or) Tertiary plutons are Tertiary rift deposits adjoining the westernmost scattered about the tract and freshwater r acces part of the tract. sible to the rocks beneath the tract from c'ltcrops The tract in the Sierra Blanca basin has also flanking the Nacimiento and Zuni upliftr Also, been intruded by a large Cretaceous and (or) Ter one unsuccessful test has been drilled to the Pre- tiary pluton. Sedimentary rocks beneath the plu cambrian basement in this tract. ton (in cluster 18) have probably been severely al tered. In contrast, sedimentary rocks along the Clusters 11 and 13 northwest fringe of the pluton (in cluster 7) may Clusters 11 and 13 are comprised of 6 tracts of have escaped destruction and might be adequate Wilderness Lands which extend from the southern reservoir units. One good gas show was reported part of the Chama basin, across the western mar from Pennsylvanian rocks about 10 miles south gin of the Nacimiento uplift, to the southeast west of the tract (McCaslin, 1974). corner of the San Juan Basin (figs. LA, 12). De The tract on the Sacramento Mountains uplift spite the nearby oil fields and oil and gas shows, has Pennsylvanian and Permian rocks at the sur the hydrocarbon potential of these tracts is rated face which seem to be free of igneous intrusions. low. However, the tract is given a low to zero rating A low rating is assigned to the tractf in the because freshwater would have easy access to all southern Chama basin because the Upp^r Cre the possible reservoir units. taceous reservoir units have been removed by ero Cluster 9 sion and the Pennsylvanian reservoir units are Cluster 9 consists of three tracts along the very susceptible to flushing by freshwater 127 Upper Cretaceous, Jurassic, and Pennsylvanian Gas in Morrowan sandstones and pre-Pennsyl- rocks are possible exploration objectives beneath vanian carbonates, in either stratigraphic or struc the western margin of the allochthonous Precamb- tural traps, is the most likely exploration objec rian basement rocks of the Nacimiento uplift. tive in the southern tracts. Some oil may be pre However, the units with reservoir potential are sent in the dark basinal carbonate rocks of the steeply dipping and would require very efficient Permian System (Broadhead, 1983). traps to retain hydrocarbons. In the northern tract, the main exploration ob The two tracts in the southeastern San Juan jective is gas in shelf carbonates and intercalated Basin are rated low because the westernmost sandstones of the Wolfcampian anrl Leonardian. tract is intruded by a small Cretaceous and (or) Stratigraphically trapped hydrocarbons would be Tertiary pluton and the easternmost tract has the most likely type of accumulation. been tested without success to the Precambrian basement. The strata with reservoir potential in Cluster 17 these tracts are closer to the Nacimiento uplift Cluster 17 has a single tract of Wilderness Land than the strata in cluster 10 and thus are more on the Sierra Grande uplift of Permian and susceptible to flushing by freshwater. Pennsylvanian age (figs. 1A, 12). Jurassic and Triassic rocks that crop out throughout the tract Cluster 12 cover a sequence of Permian and Pennsylvanian Cluster 12 consists of a single tract of Wilder rocks less than 3,500 feet thick (Dane and ness Land along the west flank of the San Luis Bachman, 1965; Roberts and others, 1976). The basin (figs. 1A, 12). Basalts of Tertiary and (or) hydrocarbon potential of the tract is rated low be Quaternary age crop out throughout the tract cause suitable reservoirs in the Pennsylvanian and (Dane and Bachman, 1965). The hydrocarbon po Permian rocks are generally absert and because tential of the tract is rated low because the no hydrocarbon shows have been recorded from sedimentary section here is probably limited to a nearby drill holes. thin section of Upper Cretaceous and Tertiary rocks. Cluster 18 Cluster 18 consists of numerous tracts in north- Cluster 15 central and central New Mexico having auto Cluster 15 is represented by a single tract of chthonous Precambrian crystalline Hsement rocks Wilderness Land on the eastern fringe of the or Cretaceous and (or) Tertiary intrusive rocks at, Jemez volcanic province (figs. LA, 12). A thick sec or near, the surface (figs. 1A,B, 12),The hydrocar tion of volcanic rocks is present at the surface, bon potential of these tracts is rated zero. Any and it is very likely that intrusive rocks associated sedimentary rocks in the tracts thH rest on Pre with these volcanic rocks have disrupted the un cambrian rocks are very thin and hf ve been highly derlying sedimentary rocks of Late Cretaceous, dissected by modern drainage. Those sedimentary Jurassic, and Pennsylvanian age and any hydro rocks that may exist beneath laccolith-type plu- carbons trapped within. The hydrocarbon poten tons of Cretaceous and (or) Tertian7 age are prob tial of cluster 15 is rated low to zero. ably very thin and pervasively intrided by satel lite intrusions. The large tract in southwest New Cluster 16 Mexico has volcanic rocks of the Datil-Mogollon Cluster 16 consists of several tracts of Wilder province at the surface and a large pluton or com ness Lands along the rim of the Delaware basin plex of plutons at depth (Elston and others, 1976). and one tract of Wilderness Land on the North west shelf (figs. 1A, 12). Shelf-margin carbonates SUMMARY of the Guadalupian crop out across the southern Of the 2,676,856 acres of Wilderness Lands in tracts whereas shelf carbonates of the Guadalu New Mexico the potential acreage can be sum pian crop out across the northern tract (Dane and marized as follows: high potential, 96.6 thousand Bachman, 1965). Oil and gas fields extend to the acres; medium potential, 115.3 thousand acres; borders of both groups of tracts, and for this low potential, 1,237.3 thousand acres; low to zero reason the hydrocarbon potential of these tracts is potential, 158 thousand acres; and zero potential, rated high. 1,069.6 thousand acres. The petroleum potential 128 by acreage of all Wilderness Land categories in Bender, M. J., 1956, Denton (Devonian), in Stipp, T. F., Hel the Western United States is shown in this circu mig, P. D., Alcorn, Rex, and Murphy, R. E., eds , The oil lar by B. M. Miller in table 1, chapter P. and gas fields of southeastern New Mexico, a synnosium: Roswell Geological Society, Roswell, New Mexico, p. ISO- 131. REFERENCES CITED Bieberman, R. A., and Weber, R. 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