... considering that each was allowed only about 3 months in which to construct a reconnaissance topographic map, study and plot the geology, and determine the mineral resources of his District. The work done since 1955 by the U.S. Geological Survey has required much more time to map a 7 1/2 minute quadrangle...

... serve as adequate source and reservoir rocks for petroleum and natural gas. Further study is recommended for several anticlines in northern Puerto Rico and along the faults between Ponce and Guayanilla in southern Puerto Rico that might serve as traps for oil and gas. Reconnaissance gravity surveys...

... Puerto Rico we can not find in Monroe’s paper any stratigraphic information that was not given in our 1970 paper. The only basic difference, perhaps, is Monroe’s insistence on including the entire stratigraphic sequence below our restricted Ponce Limestone in the Juana Diaz Formation. In addition, some...

... p. Gilluly , J. , and Masursky, H., 1965 , Geology of the Cortez quadrangle, Nevada, with a section on gravity and aeromagnetic surveys by D.R. Mabey: U.S. Geological Survey Bulletin 1175. 117 p. Glen , J.M.G. , and Ponce, D.A., 2002 , Large-scale fractures related...

...D.A. Ponce; J.M.G. Glen Abstract We consider the origin and character of a prominent large-scale geophysical feature in north-central Nevada that is coincident with the western margin of the northern Nevada rift—a mid-Miocene rift that includes mafic dike swarms and associated volcanic rocks...

... (<2) and Poisson’s ratios (<0.3) are low, suggesting crystalline rocks. Furthermore, a near-vertical zone of low Vp / Vs ratios and Poisson’s ratios is between near-surface traces of the Hayward and East Chabot faults, likely corresponding to the San Leandro Gabbro of Ponce et al. (2003) . (5...

... of geophysical surveys were conducted in this area to establish a geologic framework model (GFM) that reflects fundamental geological chronology of different rock units. These studies include gravity surveys ( Snyder and Carr, 1982 ; Healey et al. , 1987 ; Ponce et al. , 1988 ; McCafferty and Grauch, 1997...

... of the southeast quarter of the Priest Valley quadrangle, Fresno and Monterey counties, California : U.S. Geological Survey Mineral Investigations Field Studies Map MF-303, 1 sheet, scale 1:31,680 . Roberts C.W. Jachens R.C. Ponce D.A. Langenheim V.E. , 2004 , Isostatic residual gravity map...

...R.C. Jachens; C.M. Wentworth; R.W. Graymer; R.A. Williams; D.A. Ponce; E.A. Mankinen; W.J. Stephenson; V.E. Langenheim Abstract The Evergreen basin is a 40-km-long, 8-km-wide Cenozoic sedimentary basin that lies mostly concealed beneath the northeastern margin of the Santa Clara Valley near...

... encompassing 15 USGS topographic quadrangles was influenced by Hugo ( Figure 1 ). The island of Culebra was not mapped. Owing to the land area covered by some of the quadrangles and the orientation of the shoreline, 12 separate hazard maps were compiled ( Table 1 ). Plates 1–12 are the hazard maps (see also...

... methods on potentially disparate sample media, and results for individual elements are commonly not comparable from quadrangle to quadrangle. As an example, Figure 3 shows a map of arsenic distribution in the study area, based on the original NURE HSSR analyses. Although some of the features of our newer...

...R.W. Graymer; D.A. Ponce; R.C. Jachens; R.W. Simpson; G.A. Phelps; C.M. Wentworth Abstract In order to better understand mechanisms of active faults, we studied relationships between fault behavior and rock units along the Hayward fault using a three-dimensional geologic map. The three-dimensional...

... Investigations Series Map I-2668 , scale 1 : 24,000 . John , D.A. , and Wrucke , C.T. , 2003 , Geologic map of the Mule Canyon quadrangle, Lander County, Nevada : Nevada Bureau of Mines and Geology Map 144 , scale 1 : 24,000 . John , D.A. , Wallace , A.R. , Ponce , D.A...

...) interpreted the boundary as a normal fault. Geologic mapping conducted at the southeastern end of the Lajas Valley for the preliminary geological map of the Guánica Quadrangle ( Addarich‐Martinez, 2009 ) revealed evidence of a fault. Steeply inclined Miocene Ponce Limestone within the Punta Montalva area...

... . Buland R. (1986) . Uniform reduction error analysis , Bull. Seism. Soc. Am. 76 , 217 - 230 . Burchfiel B. C. (1965) . Structural geology of the Specter Range quadrangle, Nevada, and its...

... from less than 500 m thick on the west to greater than 1 km thick on the east ( Watt and Ponce, 2007 ). Quaternary scarps are not well developed, appearing as local gentle swales that affect the alluvial surfaces. Because these faults are well outboard of the topographic range front...

...., 2000 ), digital elevation model (DEM) topography ( USGS DEM, 2009 ), and tectonic and sediment fill compilations ( Blakely and Ponce, 2002 ). Figure 3 is a tectonostratigraphic chart showing a compilation of Neogene geologic events in the Death Valley region. The area covered ranges from Kingston...

... . Hewett , D.F. , 1956 , Geology and mineral resources of the Ivanpah quadrangle, California and Nevada : U.S. Geological Survey Professional Paper 275, 2 sheets, scale 1:125,000, https://doi.org/10.3133/pp275 . Kucks , R.P. , Hill , P.L. , and Ponce , D.A. , 2006 , Nevada...

... Limestone is estimated to be thicker than 200 m between Ponce and Tallaboa cities (Penuelas and Punta Cuchara quadrangles) ( Monroe 1980 ). Recent studies using strontium isotopes have refined and further constrained some of the biostratigraphic ages for the Ponce Limestone ( Ramirez et al. 2006 ; Ruidiaz...

... Oregon. The majority of mapping was performed at the 1:24,000 scale in northern McDermitt volcanic field, field-checking and remapping contacts previously mapped in published 7.5′ quadrangles ( Rytuba et al., 1982a – 1982g ; Rytuba and Curtis, 1983 ; Rytuba et al., 1983a , 1983b ; Peterson...