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At least 775 records · Page 43Linked to original sources
USGS2011

Geologic map of the Montoso Peak quadrangle, Santa Fe and Sandoval Counties, New Mexico

The Montoso Peak quadrangle is underlain by volcanic rocks and associated sediments of the Cerros del Rio volcanic field in the southern part of the Española Basin that record volcanic, faulting, alluvial, colluvial, and eolian processes over the past three million years. The geology was mapped from 1997 to 1999 and modified in 2004 to 2008. The geologic mapping was carried out in support of the U.S. Geological Survey (USGS) Rio Grande Basin Project, funded by the USGS National Cooperative Geologic mapping Program. The mapped distribution of units is based primarily on interpretation of 1:16,000-scale, color aerial photographs taken in 1992, and 1:40,000-scale, black-and-white, aerial photographs taken in 1996. Most of the contacts on the map were transferred from the aerial photographs using a photogrammetric stereoplotter and subsequently field checked for accuracy and revised based on field determination of allostratigraphic and lithostratigraphic units. Determination of lithostratigraphic units in volcanic deposits was aided by geochemical data, 40 Ar/ 39 Ar geochronology, aeromagnetic and paleomagnetic data. Supplemental revision of mapped contacts was based on interpretation of USGS 1-meter orthoimagery. This version of the Montoso Peak quadrangle geologic map uses a traditional USGS topographic base overlain on a shaded relief base generated from 10-m digital elevation model (DEM) data from the USGS National Elevation Dataset (NED). Faults are identified with varying confidence levels in the map area. Recognizing and mapping faults developed near the surface in young, brittle volcanic rocks is difficult because (1) they tend to form fractured zones tens of meters wide rather than discrete fault planes, (2) the youth of the deposits has allowed only modest displacements to accumulate for most faults, and (3) many may have significant strike-slip components that do not result in large vertical offsets that are readily apparent in offset of sub-horizontal contacts. Those faults characterized as "certain" either have distinct offset of map units or had slip planes that were directly observed in the field. Faults classed as "inferred" were traced based on linear alignments of geologic, topographic and aerial photo features such as vents, lava flow edges, and drainages inferred to preferentially develop on fractured rock. Lineaments defined from magnetic anomalies form an additional constraint on potential fault locations.

New Mexico↗
USGS2020

Geologic map of the Butte City 7.5' Quadrangle, Butte County, Idaho

The geologic map of the Butte City 7.5’ quadrangle is based on mapping summarized in the 1:100,000 scale map of the Idaho National Laboratory, U.S. Geological Survey Miscellaneous Investigations Map I-2330, by Kuntz and others, 1994. New surficial geologic mapping was completed by National Association of Geoscience Teachers (NAGT) interns, Evan Martin (2015) and Samuel Helmuth (2017). Previously published maps and associated data, by various authors, including Kuntz, M.A., Betty Skipp, M.A. Lanphere, W.E. Scott, K.L. Pierce, G.B. Dalrymple, L.A. Morgan, D.E. Champion, G.F. Embree, W.R. Page, R.P. Smith, W.R. Hackett, and D.W. Rodgers from 1994 to 2017, were incorporated into this project. The U. S. Geological Survey (USGS) Idaho National Laboratory Project Office, a field office of the Idaho Water Science Center, conducts subsurface investigations to study the Snake River aquifer at the Idaho National Laboratory. Many subsurface basalts erupted from vents exposed at the surface. Tracing the flows from the surface to the subsurface provides data for numerical models of groundwater flow and contaminant transport.

Idaho↗
USGS2015

Bedrock geologic map of the Worcester South quadrangle, Worcester County, Massachusetts

The bedrock geology of the 7.5-minute Worcester South quadrangle, Massachusetts, consists of deformed Neoproterozoic to Paleozoic crystalline metamorphic and intrusive igneous rocks in three fault-bounded terranes (zones), including the Avalon, Nashoba, and Merrimack zones (Zen and others, 1983). This quadrangle spans the easternmost occurrence of Ganderian margin arc-related rocks (Nashoba zone) in the southern New England part of the northern Appalachians, and coincides with the trailing edge of Ganderia (Merrimack and Nashoba zones) where it structurally overlies Avalonia (Hibbard and others, 2006; Pollock and others, 2012; van Staal and others, 2009, 2012). Neoproterozoic intrusive rocks and minor metasedimentary rocks crop out in the Avalon zone and structurally underlie the rocks of the Nashoba zone along the Bluddy Bluff fault. Due to poor exposure, the position of the Bloody Bluff fault is not well-constrained and its location is partly extrapolated from mapping in adjacent areas (Barosh, 2005; Walsh and others, 2011a). Cambrian intrusive rocks and Cambrian to Silurian metasedimentary and metavolcanic rocks crop out in the Nashoba zone, and are overlain by largely Silurian metasedimentary rocks of the Merrimack zone along the Clinton-Newbury fault. Ordovician to Permian(?) plutonic rocks intrude the Merrimack and Nashoba zone rocks. Paleozoic metamorphism in the Merrimack and Nashoba zones peaked during Salinic, Acadian, and Neoacadian orogenesis from the Silurian to Mississippian (Wintsch and others, 2007; Stroud and others, 2009; Walsh and others, 2011a; Hepburn and others, 2014). Metamorphism in the Avalon zone peaked during Alleghanian orogenesis in the Mississippian to Permian (Wintsch and others, 1992, 1993, 2001; Attenoukon, 2008). Evidence for garnet-grade extensional Alleghanian mylonitization showing normal motion along the Clinton-Newbury fault occurred after presumed original terrane juxtaposition by left-lateral Acadian thrusting (Goldstein, 1994). Subsequent post-peak metamorphic deformation produced outcrop-scale open folds and weak cleavage, local faults, veins, shear bands, and pegmatite dikes. Locally, along re-activated ductile faults such as the Bloody Bluff fault and along the Wekepeke fault, late Paleozoic to Mesozoic mainly brittle normal fault motion led to the current configuration of fault-bounded lithotectonic terranes (Goldstein, 1982, 1994, 1998; Goldstein and Hepburn, 1999; Goldsmith, 1991; Attenoukon, 2008; Wintsch and others, 2012). The youngest deformation includes kink bands, brittle faults, and joints. The bedrock geology was mapped to study the tectonic history of the area and to provide a framework for ongoing hydrogeologic characterization of the fractured bedrock of Massachusetts. This report presents mapping by Gregory J. Walsh and Arthur J. Merschat from 2008 to 2010. The report consists of a map and GIS database, both of which are available for download at http://dx.doi.org/ 10.3133/sim3345. The database includes contacts of bedrock geologic units, faults, outcrop locations, structural information, and photographs.

Massachusetts↗
USGS1976

Geologic map of the Oxia Palus Quadrangle of Mars

The Oxia Palus quadrangle contains three distinct geologic provinces: (1) an elevated cratered plateau that occupies three-fourths of the quadrangle and is similar to much of the southern hemisphere of Mars; (2) the low, relatively featureless Chryse Planitia in the northwest corner; and (3) a complex province of chaotic terrain and immense channels or valleys that divides the plateau and terminates in Chryse Planitia. Generally, the oldest geologic units occur in the plateau province and the youngest in Chryse Planitia. Discovery by Mariner 9 of the channels, the four largest of which are given names meaning “Mars” in Akkadian, Sumerian, Angelo-Saxon, and Greek (west to east), renews the possibility of water and therefore life on Mars. This possibility may be tested in July 196 by a landing of the unmanned Viking spacecraft in Chryse Planitia at the mouths of the channels (lat 19 1/2˚ N., long 34˚).

IMAP↗