Dg Sl Dss Geologic map of the west-central part of the Grant Range, Nye County Nevada Qf2a Qp S 87 Qf1 6 25 17 Opl Dss Phyllis Camilleri Qp Opk Qp 60 Department of Geosciences, Austin Peay State University, Clarksville TN 70 70 70 30 Ops POGONIP GROUP CONTINUED Low-angle normal fault slice 45 Qal of Opl along fault #2 Qal—Unconsolidated gravel, sand, and mud in modern alluvial fan and stream deposits Opp 35 Qal Parker Spring Formation. The minimum tectonic thickness of the Parker Spring Formation is 355 m. This unit consists of thin- to medium-bedded, light grayish-green, 45 Sl Qp—Pluvial shoreline deposits. Predominantly unconsolidated gravel, with minor sand and mud. This unit consists of a series of shoreline deposits superimposed on fine-grained limestone and argillaceous limestone intercalated with thin (1 mm to 1 cm thick) sericite phyllite. Limestone contains irregular-shaped chert that tends to transect o Dg bedding. Chert ranges in morphology from lenticular to crescent shaped. Phyllite is a minor constituent, but this as well as intraformational conglomerate are distinctive of this unit. 38 34’ 00’’ Qp older alluvial fan surfaces. Dashed blue line indicates position of highstand shoreline at ~ 4870’ elevation. Sl Oes Quaternary Qf3 Qf3—Alluvial surface(s) incised into Qf2; contains some Qal COpg Dg Goodwin Limestone. The Goodwin Limestone is bounded above by low-angle normal fault # 4, and in places, low-angle normal fault # 5 forms the base of the formation. Oes Qf2a Qf2a and Qf2b—Alluvial surface incised into Qf1; contains some Qal Dg Its minimum tectonic thickness is 396 m. This unit has been variably altered to dolostone, particularly in proximity of low-angle normal fault # 5. The Goodwin Limestone can be Qp Ops Sl grossly divided into three sections. The upper section consists of thin-bedded, light gray limestone with bedding-parallel chert lenses and nodules. The middle section consists of Qf1 Qf1—Older alluvium--unconsolidated to moderately consolidated gravel, sand, and mud in inactive alluvial fans; contains some Qal very thick-bedded, light gray, massive limestone with minor chert. Gastropod fossils are present near the bottom of the middle section. The lower section has a variable thickness Dg Dg (0 to 30 m) and is cut out in places because it lies above a low-angle normal fault associated with fault # 5. The bulk of the lower section consists of thin-bedded, light gray-blue Granitic dike Andesitic dike Dg Tertiary Tg Ta limestone (mostly hydrothermally altered to dolostone) and bedding-parallel chert lenses. However, near the base of the lower section, the limestone is black to dark gray and laminated, and chert appears to preferentially occur as partial to complete replacement of orange-weathering laminated dolomitic layers. Ops Chainman Shale and Joana Limestone, undivided. Sandstone, siltstone, shale, and limestone (Chainman Shale), and tan to gray crinoidal limestone with tan to pink chert (Joana Mississippian Mcj The lower section of the Goodwin Formation is different than the middle and upper sections in that it constitutes a distinctive zone of stratal disruption (ZSD), which is not found 65 35 Limestone) (Hyde and Huttrer, 1970; Lund et al., 1987). Dss in stratigraphically higher rocks. The ZSD comprises breccia, disharmonic folds, and small faults. Some of the folds transition into small faults, and in places strata merge into 75 Opk 70 17 10 Ordovician breccia. In outcrop, in the breccias and folds, carbonate rocks commonly appear ductiley deformed and quartz and graphitic carbonate rocks are brittlely deformed. Nowhere can Dg Guilmette Formation. Thick-bedded limestone with sparse silty limestone and dolostone (Hyde and Huttrer, 1970; Lund et al., 1987). Qf1 35 the folds be traced for more than 5 m and orientations of strata are both vertically and laterally chaotic: the ZSD lacks a uniform fabric. Although the rocks appear brittlely and Devonian ductiley deformed at the outcrop, evidence of brittle or ductile microstructure in minerals is generally lacking in this zone at the microscopic scale. Much of the deformation in the Sevy Dolomite and Simonson Dolomite, undivided. Gray to brown dolostone with pink to gray chert near the base (part of Sevy Dolomite) and quartzose dolostone at the base of the 85 Dss ZSD is probably syn-sedimentary in origin, although the proximity of fault # 5 necessarily raises the question of (1) whether or not the ZSD, or at least some of the deformation, is 25 Simonson dolostone (Hyde and Huttrer, 1970; Lund et al., 1987). 25 Oe A’ a consequence of movement on fault # 5 and (2) whether or not some of the deformation formed in response to earlier tectonic folding and thrust faulting. However, tectonic 17 25 fabrics (e. g. foliation and lineation) such as those produced in east- or west-vergent folding are lacking. Moreover, folds in the ZSD lack a uniform orientation, a situation that 35 Silurian Laketown Dolomite. Fossiliferous black to light-gray to light brown dolostone (Hyde and Huttrer, 1970). Dg Sl might be expected as a result of syn-sedimentary slumping rather than tectonic processes. Structures in the ZSD are morphologically similar to carbonate slump and flow deposits Mcj A Opp described by Nelson and Lindsley-Griffin (1987), and those described by Cook and Taylor (1977) in coeval (?) rocks 70 km to west in the Hot Creek Range. Hence, the ZSD in Ops Qp Oe Oes Ely Springs Dolomite. Fossiliferous black to light-gray to light brown dolostone (Hyde and Huttrer, 1970). Railroad Valley Eureka Quartzite excised from the Grant Range is probably mostly primary sedimentary structure rather than tectonic. The lower section is correlative with rocks mapped as the Windfall Formation in the south- U M the footwall of, and brittley “smeared” out ern Grant Range by Cebull (1967) and in the southern White Pine Range by Moores et al. (1968). However, in the Mt. Hamilton area in the southern White Pine Range, Hum- along, fault #3 (includes klippe 17 Eureka Quartzite. The Eureka Quartzite is approximately 60 m thick and is composed of thin- to very thick-bedded, white to black to reddish-brown quartzite. Sedimentary structure within beds 55 of Eureka Quartzite to the south). 12 Oe phrey (1960) mapped this same lithofacies as "member one" of the Goodwin Formation. I have also included it in the Goodwin Formation but have not considered it a mappable M 45 is generally not discernable, however, in one place tabular crossbeds were observed. Argillite (up to 3 dm thick) and sericite phyllite layers (less than 3 cm thick) are interbedded with quartzite 17 unit because of its minor and irregular extent. in the bottom 3 m of this unit. The top of the Eureka Quartzite is marked by a 3 dm-thick bed of brownish red quartzite and the contact with the overlying Ely Springs Dolomite is sharp. 20 Dg Ops 15 POGONIP GROUP The Pogonip Group exposed in the map area was heretofore undivided. Five mappable units with the Pogonip Group are recognized. In descending stratigraphic order they are the Ordovician Clm 24 Little Meadows formation. The Little Meadows formation in the map area is everywhere dismembered by extensional faults so that no complete section exists. Cebull 5 Opp Lehman Formation, Kanosh Shale, Shingle Limestone, Parker Spring Formation, and the Ordovician-Cambrian Goodwin Limestone. The stratigraphically four highest units are correlated with similar
13
Qal M 24 Oe Oe (1967) informally named the Little Meadows formation and designated a type section in the southern Grant Range. The type section is 154 m thick (Cebull, 1967), well exposed Z units established by Kellogg (1963) in the southern Egan Range to the east of the Grant Range, but the lowest unit is more similar to, and hence correlated with, the adjacent Goodwin Formation and M 12 and very much like the section in the northern Grant Range. The tectonic thickness of the Little Meadows formation in the map area generally does not exceed 40 m and in most 65 part of the Windfall Formation mapped by Cebull (1967) in the southern Grant Range (see adjacent correlation diagram). In the southern Grant Range, Cebull (1967) divided the Pogonip Group into 70 places is less than 30 m. The dominant rock types are massive, light blue-gray limestone or marble and white limestone or marble with a pinkish tinge. In the eastern part of the 14 Oe three formations and used names for similar strata recognized by Nolan et al. (1956) in the Eureka area; the Antelope Valley Limestone, Ninemile Formation, and Goodwin Limestone. Although the 60 map area, much of the Little Meadows formation has been hydrothermally altered to dolostone. No fossils were found in the northern Grant Range but Cebull (1967) indicates that 17 Qf1 Ordovician uppermost four units of the Pogonip Group are more similar to units in the Egan Range, they are broadly correlative with what Cebull (1967) mapped as the Antelope Valley Limestone and Ninemile Ta Opl fossils in the Little Meadows formation in the southern Grant Range are Late Cambrian. Qp Qal 24 Formation. Opp Qf1 Opk The units in the Pogonip Group are metamorphosed. In the Kanosh Shale, Shingle Limestone and Parker Spring Formation, pelitic layers greater than 3 cm thick are argillite, whereas thinner S Sidehill Spring formation. Cebull (1967) informally named the Sidehill Spring formation for strata between the Little Meadows Formation and Pole Canyon Limestone. I have Opp Qal 9 bedded pelite was converted to sericite phyllite. The degree of development of metamorphic white mica appears to be enhanced in deformed regions. White mica and rare chlorite appear to be the only Qp Dg retained Cebull's (1967) nomenclature for correlative strata but have recognized three mappable units that I informally name, from stratigraphically highest to lowest, the Blue Dg C 25 metamorphic minerals in the carbonate rocks. Beaty Canyon 30 Oes Southern Egan Range Northwestern Grant Range Southern Grant Range Eagle member, Grant Canyon member, and Willow Springs member. The stratigraphic thicknesses of these units are not known because the rocks are faulted and folded.
Mcj fault scarp 13 S (Kellogg, 1963) (this study) (Cebull, 1967) Opp 60 Ops 10 Oe Eureka Quartzite o modified 41 S Opl Csb Blue Eagle member. The Blue Eagle member consists of thin-bedded, fine-grained, light blue-gray limestone intercalated with resistant, orange weathering, 38 30’ 00’’ by pluvial S 22 Oes B’ Lehman Formation The Lehman Formation is approximately 137 m thick and is composed of very Eureka Quartzite B 5 S 3 18 Lehman erosion? fine-grained, light bluish-gray limestone wherein bedding is defined by wavy argillaceous/carbonaceous medium gray limestone. Resistant layers are graphitic (?) and contain quartz. The Blue Eagle member contains rare intrafromational conglomerate. The best place to observe the Opk Oe Lehman Formation Qp Dg S Blue Eagle member is in Blair Canyon. The minimum thickness of this unit is 20 m. Metamorphic minerals in the Blue Eagle member are white mica and tourmaline porphyrob- partings. The uppermost 6 m of the Lehman Formation contains 2 dm- to 2 m-thick beds of tan dolostone. Formation fault 16 Antelope Kanosh Valley lasts.
Fossils include ostracodes and pelmatozoan fragments. Cambrian Mcj Shale Dg Mcj Limestone Dg Dss Opk Csg Kanosh Shale. The Kanosh Shale is approximately 46 m thick and is composed of 1 cm- to 3 dm-thick Grant Canyon member. The upper part of Grant Canyon member consists of dark gray-blue limestone with orange weathering dolomitic mottling (burrows?) Mcj Qf1 beds of laminated argillite that are interbedded with medium- to thick-bedded, fine- to coarse-grained, greenish- interbedded with thin-bedded greenish-gray limestone, phyllite (up to at least 5 cm thick) and minor intraformational limestone conglomerate. The lower part of the Grant Canyon Ninemile Qp gray limestone and argillaceous limestone. Argillite volumetrically composes approximately 20% of the Kanosh Shingle member consists of phyllite and alternating thin-bedded, blue-gray limestone and argillaceous limestone. This unit contains a few disharmonic folds that lack tectono-metamorphic Limestone ? Formation fabric and may be syn-sedimentary in origin. The Grant Canyon member is fossiliferous. Fossils include trilobites, linguloid brachiopods, and sponge spicules. The minimum Qf1 Dss Shale. Fossils in this unit include orthocone cephalopods, oncolites, sponges, and abundant Receptaculites sp. Mcj thickness of the Grant Canyon member is 50 m. Phyllite contains white mica, chlorite and in some places ilmenite (?; altered to leucoxene). The limestone was not observed in
Opp (outlined in red) COpg thin section and thus its metamorphic mineral assemblage(s) are unknown. Qal 28 Ops Shingle Limestone. The Shingle Limestone is approximately 305 m thick. This unit can be qualitatively
Dg divided into upper, middle, and lower sections. The lower section consists of alternating sets of interbedded Parker Spring 28 U Dss Csw Opp Formation Willow Springs member. The Willow Springs member consists of light grayish-green to light bluish-green to orangish-brown, thin- to thick-, but dominantly
43 fine-grained, thin-bedded, dark grayish-green argillaceous limestone and limestone that alternate with thick- Units assigned to the Pogonip Group Mcj Qf1 Blair Canyon45
U 25 bedded, dark grayish-green, fine-grained limestone that contains minor chert and rare intraformational conglom- thin-bedded fine-grained calcite marble. Bedding is defined by poikiloblastic amphibole (after phlogopite) and or phlogopite-rich layers. This unit also contains minor zircon (in 25 fault phlogopite) and metamorphic chlorite and white mica. Near low-angle normal faults, phlogopite is variably altered to chlorite. The minimum thickness of this unit is 100 m. Certain Csw erate. The middle section is similar to the lower section except that the rocks are dominantly medium bluish- House Goodwin Cpc gray, vary from fine- to medium-grained, contain minor argillite in beds up to 1 dm thick and contain sparse Limestone parts of the Willow Springs member contain a strong, thick (~3 mm) phlogopite-bearing cleavage (S1) and it is in these rocks that two distinct planar elements, both bedding and 24 C’ Limestone Opp cleavage, are evident. The differentiation between the two usually can be discerned because large micas are generally concentrated in cleavages whereas micas in bedding tend Qp 46 36 35 small-scale, fossil-debris-filled channels. The upper section is thick- to very thick-bedded, coarse- to medium- Qp Sl to be small and sparsely distributed. Mcj 440 Csw grained, medium to light grayish-blue limestone. Rocks in the upper section tend to contain abundant fossil hash Dss 200 meters Goodwin
Whipple undivided Mcj such as abundant tiny (~2 mm in diameter) pelmatozoan fragments. Cave Dg Limestone and Cpc Pole Canyon Limestone. The Pole Canyon Limestone (Drewes and Palmer, 1957) consists of thin- to thick-bedded, light blue-gray and dark blue-gray, fine-grained Qal Clm Opp Formation Formation Windfall 24 Windfall marble with subordinant tabular, resistant, reddish-brown weathering, quartzose-micaceous layers up to 2 dm thick and thin-bedded schist or phyllite. Fossils in this unit include 24 Intraformational limestone conglomerate Formation Qal 446 Chert Little Meadows trace fossils, and in Grant Canyon 3 km south of the map area, oncolites. Marble contains phlogopite, white mica, and chlorite. Phyllite or schist contains white mica, biotite, and
Mcj Qf1 Csw 15 Mcj U Cpc 34 formation chlorite, and the quartzose-micaceous layers contain biotite, white mica, and chlorite. D COpg Opp Mcj Csb Fault #1
AA’ Fault #2 Dss 7000’ Sl Dg Mcj COpg Fault #3 Dss Dg Dss Low-angle normal faults Opp Dg Fault #4 Qp 6000’ (dashed where approximately located, COpg Clm Sl dotted where concealed) Dg Dg Dg Fault #5* Oes Sl *fault #5 may include up to three parallel fault strands Mcj Mcj D’ 5000’ Opl Qf3 Qf1 Dg Ops Oe Fault #6 Qf1 Opk Qal 29 Opp 39 18 Dg 4000’ 30 High-angle normal fault (ball and bar on downthrown side; dashed Mcj 12 All thrust faults shown where approximately located, dotted where concealed) Qal 39 Sl ? in the cross sections postdate Cpc the east-vegent folds e.g. Thrust fault (teeth on hanging wall)
Qf3 Dss BB’ Qp ? Mcj Dss 7000’ Stratigraphic contact (dashed where approximately located, Mcj 17 Dg Dss 10
Dg dotted where concealed) Opk 5 35 Location of highstand pluvial shoreline (~ 4870’ elevation) 15 Sl 6000’ Opl 55 Mcj Qf1 Sl Dg ? 17 Ops Oes Qal ? Dg 17 Strike and dip of bedding Dg Dg Mcj Csw Opp Oe ? 40
Mcj Mcj 10 Qf1 Csg Z COpg Dg COpg 39 5000’ Strike and dip of overturned bedding Mcj 34 20 Sl 85 Dg Mcj 48 Qf2a 40 Qf2a 25 Strike and dip of S1 foliation (associated with F1 folds) 24 Dg fault # 1 15 4000’
5
fault # 3 S Strike and dip of S2 foliation (associated with F2y folds) Mcj U 35 13 Mcj Sl CC’ Ta Clm 7000’ Dss
9 7
26 20 U
Dg Dg Sl S Z Minor F1 fold showing trend and plunge of hinge and asymmetry (S or Z fold)
S 5 S Clm S 13 viewed in the down-hinge direction 26 15 65 Qf1 Dss ? Qf1 1 folds* 18 20 20 25 Opp Qal COpg 29 F Qf1 Dg 24 6000’ Dg Csb U 1 U Cpc Minor F fold showing trend and plunge of hinge Ta 39 Mcj
Qf1 Ta Cpc 30 ?
Qf1 Ops 15 Heath Canyon S S 14 Z Minor F2x fold showing trend and plunge of hinge and asymmetry (S or Z fold) Qf1 Dg 45 5000’ Qf1 D D’ 26 viewed in the down-hinge direction Qf2b ? Ops ? E’ 8000’
? Qal 28
Dss 2x folds*
F Dg U Mcj Minor F2x fold showing trend and plunge of hinge Dg 27
Mcj Ta Sl U Dss Qal 28 COpg Qf1 55 Cpc Clm 7000’ M Qf2a Mcj Tg Tg 10 40 Csb 25 Opp Minor F2y upright fold showing trend and plunge of hinge Csg Opk Oes 14 Csw Sl 2y fold*
zone of fault slices of Clm, Csb and Cpc? at the F 34 U Tg Clm base of fault #5 (units are not differentiated) Mcj 5 Mcj 55 6000’ Csw Dg Dg 25 Opk Qf1 Landslide deposit of Paleozoic strata ? Tg Mcj Qf2a Cpc Dg Dg Tg Tg *The attitudes of fold hinges, where not measured in the field, were determined 42 Cpc Mcj 24 geometrically on a stereonet utilizing the attitudes of the fold limbs. Mcj Csb 24 38 Opk 5000’ ? Csb Tg Ops 30 26 Csb Clm Qf2a Opp Opk E E’
Qf1 5 Clm 28 7000’ Csg Z Sl Dss 26 45 Tg 28 Oes Sl Sl Dss Csb Sl 38 Oes Sl 38 6000’ Csb Oes Csg Csb Clm COpg Sl ? Clm Opk Opl Cross section note: Landslide Csg Csb E COpg Clm Csb Qf1 Qal Qal Trace of bedding is shown as a fine o deposit Opp Ops COpg Clm dotted line. 38 26’ 00’’ Csg ? 5000’ 22 Tg Cpc Csb ? Oes 20 Csw COpg 31 Sl N Scale 1:18,000 zone of fault slices of Clm and Csb Dry Basin fault #5 merges into a single strand at the base of fault #5 01 32 approximately to the west (left) of this point Dss 4000’ mile 35 USGS 0 1 2 6 Quadrangles Map construction. Mapping of Paleozoic bedrock was primarily conducted at a scale of 1:12,000 by Camilleri (1988) on the following U.S.G.S. quadrangles Nevada that were enlarged to the 1:12,000 scale: 1:62,5000 15’ Currant quadrangle with a 80 foot contour interval (area #1); 1:62,500 15’ Blue Eagle Mountain 2 1 kilometers quadrangle with a contour interval of 40 feet (area #2); 1:62,500 15’ Troy Canyon quadrangle with a 40 foot contour interval (area #3); a preliminary copy of the 1:24,000 7 1/2’ Forest Home quadrangle with a 40 foot contour interval (area #4). This map and cross sections were produced by scanning Camilleri’s o o 34 original 1988 map and transfering contacts on scanned images of the aforementioned quadrangles. Then, additional 1:50,000 scale mapping of upper Contour interval 40 and 80 feet 115 30’ 00’’ 115 26’ 00’’ Paleozoic strata from Lund et al. (1987,1988) and 1: 24,000 scale mapping of Quaternary units (Camileri, unpublished) was compiled and added to this map. Oes See text and Figure 2 for additional details about sources of geologic mapping and mapping of Quaternary units.
DIGITAL MAP AND CHART SERIES DMCH014 Published by Camilleri, P., compiler, 2013, Geologic map and structure of DOI: 10.1130/2013.DMCH014 The Geological Society of America, Inc. the west-central part of the Grant Range, Nye County, Nevada: 3300 Penrose Place • P.O. Box 9140 Geological Society of America Digital Map and Chart Series 14, Boulder, Colorado 80301-9140 doi:10.1130/2013.DMCH014. For permission to copy, contact [email protected]. ©2013 The Geological Society of America. All rights reserved.