John F. Slack
John Slack is a Scientist Emeritus with the USGS Geology, Energy & Minerals (GEM) Science Center in Reston, VA.
Science and Products
Filter Total Items: 64
Bedded jaspers of the Ordovician Løkken ophiolite, Norway: seafloor deposition and diagenetic maturation of hydrothermal plume-derived silica-iron gels
Sedimentary beds of jasper (red hematitic chert) in the Ordovician Løkken ophiolite of Norway are closely associated with volcanogenic massive sulphide (VMS) deposits. The jaspers occur in the immediate hangingwall and laterally peripheral to the large Løkken (25–30 Mt) and small Høydal (0.1 Mt) VMS deposits, and are exposed discontinuously for several kilometres along strike. Massive or laminated
Authors
Tor Grenne, John F. Slack
Geochronology and geology of late Oligocene through Miocene volcanism and mineralization in the western San Juan Mountains, Colorado
This paper presents 25 new 40Ar/39Ar dates from the main calc-alkaline ash-flow sheets and related younger plutons of the western San Juan volcanic field, the ash-flow sheets of the Lake City caldera cycle, and veins and other altered rocks in the Lake City region. The goal of the study was to produce similar quality 40Ar/39Ar ages to those currently published for the eastern and central San Juan
Authors
Dana J. Bove, Ken Hon, Karin E. Budding, John F. Slack, Lawrence W. Snee, Ross A. Yeoman
Sm-Nd dating of the giant Sullivan Pb-Zn-Ag deposit, British Columbia
We report here Sm and Nd isotope data for hydrothermal tourmalinites and sulfide ores from the giant Sullivan Pb-Zn-Ag deposit, which occurs in the lower part of the Mesoproterozoic Purcell (Belt) Supergroup. Whole-rock samples of quartz-tourmaline tourmalinite from the footwall alteration pipe yield a Sm-Nd isochron age of 1470 ± 59 Ma, recording synsedimentary B metasomatism of clastic sediments
Authors
Shao-Yong Jiang, John F. Slack, Martin R. Palmer
USGS research on mineral resources, 1991; program and abstracts
No abstract available.
Authors
Elizabeth E. Good, John F. Slack, Rama K. Kotra
Summary results of the Glens Falls CUSMAP project, New York, Vermont, and New Hampshire
No abstract available.
Authors
John F. Slack
Mineral resources of the Citico Creek Wilderness Study Area, Monroe County, Tennessee
No abstract available.
Authors
John F. Slack, E. R. Force, P. T. Behum, B. B. Williams
Mineral resources of the Big Frog Wilderness Study Area and additions, Polk County, Tennessee and Fannin County, Georgia
No abstract available.
Authors
John F. Slack, Gertrude C. Gazdik, Maynard L. Dunn
The Yellow Dog peridotite and a possible buried igneous complex of lower Keweenawan age in the northern peninsula of Michigan
Partly serpentinized peridotite of early Keweenawan age crops out in two places along a 20-kilometer-long zone of positive aeromagnetic anomalies in northern Marquette County, Michigan. Most of the area is mantled by Pleistocene drift with few bedrock exposures.Petrographic and electron microprobe studies show that the peridotite was originally a plagioclase lherzolite containing 40 to 50 percent
Authors
John S. Klasner, David W. Snider, W. F. Cannon, John F. Slack
Mineral resources of the Citico Creek Wilderness Study Area, Monroe County, Tennessee
No abstract available.
Authors
John F. Slack, E. R. Force, P. T. Behum, B. B. Williams
Geochemical analyses of rock, soil, and stream sediment samples from the Big Frog Wilderness Study Area, Polk County, Tennessee and Fannin County, Georgia
Semiquantitative spectrographic analyses for 31 elements and atomic absorption analyses for gold and zinc on 43 stream sediments, 5 panned concentrates, 65 soils, and 81 rock samples from the Big Frog Wilderness Study Area and vicinity, Polk County, Tennessee, and Fannin County, Georgia, are reported here in detail. Locations for all 194 samples are given in Universal Transverse Mercator (UTM) coo
Authors
R. T. Hopkins, A.L. Meir, John F. Slack
K-Ar age of alunite alteration at Red Mountain, Lake City area, western San Juan Mountains, Colorado
The San Juan Mountains of southwestern Colorado are famous for rich vein deposits of base and precious metals and for patterns of conspicuous hydrothermal alteration. Areas of acid-sulfate alteration, characterized by extensive base leaching of volcanic rocks or hypabyssal plutons, are of current interest because of their local association with Au, Ag, and, in some cases, U mineralization (Lipman
Authors
Harald H. Mehnert, John F. Slack, Gerald T. Cebula
Mineral resources of the Big Frog Wilderness Study Area, Polk County, Tennessee and Fannin County, Georgia
The proposed Big Frog Wilderness is comprised of approximately 1820 hectares (18.2 km2) of mountainous terrain in the Cherokee and Chattahoochee National Forests south of the Ocoee River in Polk County, Tennessee, and Fannin County, Georgia. Rocks of the study area are greenschist-facies metasandstone, meta-arkose, metagraywacke, and dark slate of the Ocoee Supergroup of late Precambrian age. A ma
Authors
John F. Slack, Gertrude C. Gazdik, Maynard L. Dunn
Science and Products
Filter Total Items: 64
Bedded jaspers of the Ordovician Løkken ophiolite, Norway: seafloor deposition and diagenetic maturation of hydrothermal plume-derived silica-iron gels
Sedimentary beds of jasper (red hematitic chert) in the Ordovician Løkken ophiolite of Norway are closely associated with volcanogenic massive sulphide (VMS) deposits. The jaspers occur in the immediate hangingwall and laterally peripheral to the large Løkken (25–30 Mt) and small Høydal (0.1 Mt) VMS deposits, and are exposed discontinuously for several kilometres along strike. Massive or laminated
Authors
Tor Grenne, John F. Slack
Geochronology and geology of late Oligocene through Miocene volcanism and mineralization in the western San Juan Mountains, Colorado
This paper presents 25 new 40Ar/39Ar dates from the main calc-alkaline ash-flow sheets and related younger plutons of the western San Juan volcanic field, the ash-flow sheets of the Lake City caldera cycle, and veins and other altered rocks in the Lake City region. The goal of the study was to produce similar quality 40Ar/39Ar ages to those currently published for the eastern and central San Juan
Authors
Dana J. Bove, Ken Hon, Karin E. Budding, John F. Slack, Lawrence W. Snee, Ross A. Yeoman
Sm-Nd dating of the giant Sullivan Pb-Zn-Ag deposit, British Columbia
We report here Sm and Nd isotope data for hydrothermal tourmalinites and sulfide ores from the giant Sullivan Pb-Zn-Ag deposit, which occurs in the lower part of the Mesoproterozoic Purcell (Belt) Supergroup. Whole-rock samples of quartz-tourmaline tourmalinite from the footwall alteration pipe yield a Sm-Nd isochron age of 1470 ± 59 Ma, recording synsedimentary B metasomatism of clastic sediments
Authors
Shao-Yong Jiang, John F. Slack, Martin R. Palmer
USGS research on mineral resources, 1991; program and abstracts
No abstract available.
Authors
Elizabeth E. Good, John F. Slack, Rama K. Kotra
Summary results of the Glens Falls CUSMAP project, New York, Vermont, and New Hampshire
No abstract available.
Authors
John F. Slack
Mineral resources of the Citico Creek Wilderness Study Area, Monroe County, Tennessee
No abstract available.
Authors
John F. Slack, E. R. Force, P. T. Behum, B. B. Williams
Mineral resources of the Big Frog Wilderness Study Area and additions, Polk County, Tennessee and Fannin County, Georgia
No abstract available.
Authors
John F. Slack, Gertrude C. Gazdik, Maynard L. Dunn
The Yellow Dog peridotite and a possible buried igneous complex of lower Keweenawan age in the northern peninsula of Michigan
Partly serpentinized peridotite of early Keweenawan age crops out in two places along a 20-kilometer-long zone of positive aeromagnetic anomalies in northern Marquette County, Michigan. Most of the area is mantled by Pleistocene drift with few bedrock exposures.Petrographic and electron microprobe studies show that the peridotite was originally a plagioclase lherzolite containing 40 to 50 percent
Authors
John S. Klasner, David W. Snider, W. F. Cannon, John F. Slack
Mineral resources of the Citico Creek Wilderness Study Area, Monroe County, Tennessee
No abstract available.
Authors
John F. Slack, E. R. Force, P. T. Behum, B. B. Williams
Geochemical analyses of rock, soil, and stream sediment samples from the Big Frog Wilderness Study Area, Polk County, Tennessee and Fannin County, Georgia
Semiquantitative spectrographic analyses for 31 elements and atomic absorption analyses for gold and zinc on 43 stream sediments, 5 panned concentrates, 65 soils, and 81 rock samples from the Big Frog Wilderness Study Area and vicinity, Polk County, Tennessee, and Fannin County, Georgia, are reported here in detail. Locations for all 194 samples are given in Universal Transverse Mercator (UTM) coo
Authors
R. T. Hopkins, A.L. Meir, John F. Slack
K-Ar age of alunite alteration at Red Mountain, Lake City area, western San Juan Mountains, Colorado
The San Juan Mountains of southwestern Colorado are famous for rich vein deposits of base and precious metals and for patterns of conspicuous hydrothermal alteration. Areas of acid-sulfate alteration, characterized by extensive base leaching of volcanic rocks or hypabyssal plutons, are of current interest because of their local association with Au, Ag, and, in some cases, U mineralization (Lipman
Authors
Harald H. Mehnert, John F. Slack, Gerald T. Cebula
Mineral resources of the Big Frog Wilderness Study Area, Polk County, Tennessee and Fannin County, Georgia
The proposed Big Frog Wilderness is comprised of approximately 1820 hectares (18.2 km2) of mountainous terrain in the Cherokee and Chattahoochee National Forests south of the Ocoee River in Polk County, Tennessee, and Fannin County, Georgia. Rocks of the study area are greenschist-facies metasandstone, meta-arkose, metagraywacke, and dark slate of the Ocoee Supergroup of late Precambrian age. A ma
Authors
John F. Slack, Gertrude C. Gazdik, Maynard L. Dunn