KlondikeBasin-late Laramide depocenter insouthern New Mexico by TimothyF. Lawton and Busse// E. Clemons, Departmentof Earth Sciences, New Mexico State University, Las Cruces, NM 88003 Abstract It was deposited in alluvial-fan, fluvial, Basinis thusa memberof a groupof late and plava environments adiacent to the Laramidebasins developed in and ad- The Klondike Basindefined in this pa- Lund uftift. Conglomerates'inthe lower iacentto theforeland in Paleogenetime. per occurs mostly in the subsurfaceof part of the section were derived from southwestem New Mexico, north of the nearby sedimentary shata of the uplift; Introduction Cedar Mountain Range and southwest volcanic arenites in the middle and up- Mexico and of Deming. The basin is asymmetric, per part of the section were derived from In southwestern New thickening from a northern zero edge in older volcanic rocks, including the Hi- southeastern Arizona, the Laramide the vicinity of Interstate 10 to a maxi- dalgo Formation, lying to the west and orogeny created a broad belt of north- mum preservedthickness of2,750 ft (840 northwest, and possibly to the north as west-trending faults and folds during the m) of sedimentary strata about 3 mi (5 well. approximate time span of 75-55 Ma (Da- km) north of the sbuthembasin margin. The age of the Lobo Formation and vis, 1979;Drewes, 1988).In contrast with The southem basin margin is a reverse development of the Klondike Basin are Laramide deformation of the Rocky fault or fault complex that bounds the bracketedas early to middle Eocene.The Mountain region, extensivevolcanism ac- Laramide Luna uplift, alsodefined here. asdasts Hidalgo Formation, which occurs companied shortening in Arizona and New The uplift consists of Paleozoic strata in the Lobo, has an upper fission-track has been inter- overlain unconformably by mid-Tertiary ageof 54.9+2.7Ma (Marvinetal.,1978\. Mexico. This volcanism ash-flow tuffs and andesitic volcanics. The overlying Rubio Peak Formation in preted as subduction related (Coney and The principal sedimentary unit of the the Victorio Mountains is 41.7Ma (Thor- Reynolds, 1977;Keith, 1979).The defor- Klondike Basin is the Lobo Formation. man and Drewes, 1980).The Klondike mation itself has been attributed to un- derthrusting of the Farallon plate beneath North America (Seagerand Mack, 1985). Sedimentary basins formed in associa- tion with Laramide deformation. Laram- Alsoin thisissue Upcomingmeetings p.7 NMGSspring meeting p. 7 Albuquerque'swater tabl* Winter1988-89 p.8 Eocenemammal from the BobcalHill Conglomerate, PeloncilloMountains, VV Rhyolite southwestemNew Mexico p. I ., Tuff v Galleryof Geology p. 13 Geothermalresources in Cabullona Group NewMexico p. 14 Summaryof chargesfor naturalresources other than oil and gas on New Mexico state lands p. 16 NMGS1992 abstracts p.17 Service/News p.22 Topographicmaps p.23 Staffnotes p.24 ide sedimentary units include an and Love RanchBasins (Seager and Mack, FIGURE 3-Conelation of stratigraphy of the assemblageof strata that range in age from 1985).The late Laramide basins of the Pa- Victorio Mountains and subsurfaceunits en- Late Cretaceousto middle(?) Eocene(Fig. leogene developed on the North Ameri- countered in the Saltys, Cockrell, and Bisbee 1), although agesof the Paleogeneunits can craton, whereas the early Laramide Hills wells, shown as projected onto a section are as yet poorly constrained. Improved basins of the Cretaceousdeveloped within trending N20"8 through the Victorio Moun- Fig. 2 interpretation of the timing and style of the tains. See for well locations. Explanation: region of the older BisbeeBasin and Bliss Formation; Oe, El Paso Formation; Laramide deformation hinges Ob, on our un- Chihuahua trough, which formed by Om, Montoya Group; Sf, Fusselman Forma- derstandingof the agesand dishibution crustal extensionin Early Cretaceoustime tion; Dp, Percha Shale; Mk, Keating Forma- of these syntectonic units. The obiective (Dickinson, 1981;Bilodeaq 1982;Mack et tion; Mh, Hachita Formation; Mp, Paradise of this report is to describe the evidence al., 1986;Dckinson et al., 1989). Formation; Ph, Horquilla Formation; Pe, Earp for a newly discovered Laramide basin, Formation; Kl, undifferentiated Lower Creta- here named the Klondike Basin, in south- Methods ceous; Kh, Hell-to-Finish Formation; Ku, U- westem New Mexico and to discuss its Bar Formation; Kn, Mojado Formation; Tl, Lobo significance.The Klondike Basin takes its The Klondike Basin was defined largely Formation; Tr, Rubio PeakFormation; Tv, mid- name from a small range known as the through subsurfaceanalysis (Clemons and Tertiary tuffs. Klondike Hills immediately north of the Lawton, 1991).Cuttings from three wells (Fig. Cedar Mountain Range(Pearce, 1955). 2) wereprepared as thin sectionsand examined pehographically. Stratigraphic correlations of sedimen- Gamma-ray are overlain by conglomeratewith clasts and logs tary formations deposited as a result of sonic of the wells were corre- derived dominantly from Lower Creta- lated, l^aramidedeformation suggestthat at least and formation tops picked from ceous strata. The conglomerate and Pa- two generations of Laramide basins exist cuttings were depth adjusted to match leozoic strata are overlain by mid-Tertiary (Fig. 1). The older generation,ranging in lithologic changes indicated by the well ash-flow tuffs (Bromfield and Wrucke, logs. age from Campanian through late Maas- Surface sections of Paleozoic,Mes- 1961);no Lower Cretaceousrocks are ex- hichtian, encompassesthe Fort Critten- ozoic, and Tertiary strata were examined posed in the range. Southeastward,along in den Formation in Arizona, the Cabullona the Victorio Mountains, Cedar Moun- the general trend of the northem flank of tain Range, Group in Sonora, and the Ringbone and Klondike Hills, and West Lime the Cedar Mountain Range, the West Lime McRae Formations in New Mexico (Dick- Hills in order to compare lithologies seen Hills contain a seriesof northeast-vergent in inson et a1.,7989;Basabilvazo, l99l; G1l- cuttings with the variability of in- reverse faults, the southwesternmost of terbedded lette et al., 1986).Ages of the formations lithic types observed in out- which emplaces Permian carbonates are understood largely from interpreta- crops. The thicknessesof units depicted (Thompson, 1982) above conglomerate tions of the biostratigraphic significance in Fig. 3 were reconstructed using dips composed of Paleozoiccarbonate clasts. indicated of dinosaur fossils (Miller, 1964;Lucas et by dipmeter logs for the Saltys and Bisbee al., 19%);Lucas and Gonzalez-Leon, in Hills wells. Fig. 3 was con- press).The younger generationof basins structed by projecting the sections on to is probably late Paleoceneto Eoceneand a line of azimuth 20olocated midway be- is represented by the Love Ranch, Lobo, tween the Saltys and BisbeeHills wells. New AAexfic@ and Skunk RanchFormations (Seagerand Mack, 1986;Seager et al., L986;Wilson et Geologic setting GEOLOGV al., 7989; Wilson, 1991). Representative In the Cedar Mountain Range south of late-Laramide basins include the Potrillo the BisbeeHills well, lower Paleozoicstrata . Scienceand Serrice ISSiN 0196-944X Volume 14, No. 1, February 1992 Erlitor: Carol A. Hjellming Publishedquarterly by New Mexico Bureau of Mine and Mineral Resourcs a division of New Mexico lnstitute of Mining & Tehnology BOARD OF REGENTS Ex-Officio Bruce King, Gwor ol Nm Mulm Alan Morgan, Supeilfltendentol Public Instrution Appointed Lt. Cen. L@ Marquez, Prq., 1 9-7995,Albu4wque Charfes Zimmerly, Se.lTrus., 7997-19E7,S@to Diane D. Denish, 7992-19E7,Albuquaqw z J. Michaet Kelly, 7992-1997, Rogwll Steve Tores, 1967-1997,Albu4uerqw New Mexico Institute of Mining & Tehnology Columbus Pr6iddl. .... lnurenceH.tattman N New Mexico Bureau of Mines & Minenl Resoures Directu Md State Gnwist . Chades E. Chapin o ? Sub*riptirc: lssued qwterly, Februry, (E May, August, 0 20mi November; subffi iption prie 96.0(Velendar year. q\ Editorial rcttq: Articles submitted for oublication should be in the editor's hands a minimm of five 0 30 km (5) months before date of publication (Februry, Mat Augut, or November) and should be no longer than 20 typewritten, double-spacedpages. All scientific papers will be rwiewed by at least two peopl€ in the apprcpriate field of study. Address inquiriG to Carcl A. Hielmh& Editor of Nru Manlco Crolqy, New Mexi@ Bureau of Mines & Mineral Rercurces, Sqono. NM 87U74796. Published.as publicdoruin, thq4ore rcpldrcible without _t pmision. Sowe crcdit rcquested. Circul^tion:\,ffi FIGURE 2-Selected physiographic features of southwestem New Mexico and locations of wells P/ifltfl: University of New Mexico Printing Servies studied for this report. February 7992 New Metico Geology Northeast Sonthwest 4. SALTYS UNIT #1 (33-25s-15w) SURFACE 3. COCKRELL STATE #1 (14-2sS-16W) Fault zone in llmestone 2. BISBEEHILLS UNIT #1 (11-26S-11W) SUFFACE 1. VICTORIOMTNS. 'r"ll (FROMKOTTLOWSKI, La'l 1960) 't'4 SILICICASH-FLOW TUFFS OUATERNARY DEPOSITS Palgoiolc rock6 laull6d ov€r Lobo lormation Plnchout ol Lobo in RUBIOPEAK FORMATION viclnitY ol l-10 onto Laramido gurro uPlilt / of Seeger and Meck , (1986) 1 LOBO FORMATION Nar Meria Gmlogy February The conglomerate may be Hell-to-Finish Formation (Lower Cretaceous)or Lobo. The conglomerateis faulted againstmet- amorphosed and overtumed Ordovician through Mississippian strata, which are in turn thrust over the Hell-to-Finish For- mation. This system of faults trends northwestward toward the Cedar Moun- tain Range and illustrates the structural complexity created by