The Paxton Group of Southeastern New England


Book Description

The Paxton Schist of Perry and Emerson (1903), referred to as the "Paxton Quartz Schist" by Emerson (1917), consists of medium-gray, thin- to medium-bedded, fine to coarse-grained schistose granulite, which weathers the same color or slightly darker with a brownish cast. It is pre- Ordovician and probably late Proterozoic in age. The Paxton is herein elevated to group status. The Paxton as revised excludes strata now assigned to the overlying Brimfield Group (Peper and others, 1975). The lower, fine-grained part of the Paxton is herein named the Dudley Formation, and the upper, interbedded, fine to coarse-grained part is referred to as the Southbridge Formation (Pease, 1972). An excellent reference section for the Paxton is present along the north- east side of the Quinebaug River southeast of Southbridge, Mass. The approximate thickness of exposed mapped width of the Paxton is 4,700 meters (m), of which the Dudley forms 1 ,000 m and the Southbridge 3,700 m. The Paxton conformably overlies the Oakdale Formation and underlies the Brimfield Group in its type area in central Massachusetts. It forms a northeast-trending belt extending from east-central Connecticut into southern Maine and probably into the central Maine coast. It is correlative with the Hebron Formation in eastern Connecticut, the upper part of the Berwick Formation in southern Maine, and the Rye Formation on the New Hampshire coast. A slight coarsening of the unit toward the northwest suggests a source in that direction.




U.S. Geological Survey Bulletin


Book Description

The Gospel-Hump Wilderness lies in central Idaho. A mineral survey of the 206,500 acre area in Idaho County was conducted by the U.S. Geological Survey and the U.S. Bureau of Mines during 1980 to 1983. The study consisted of new geologic mapping, geochemical sampling of the wilderness and vicinity, geophysical surveying, and investigation of claim blocks in or near the wilderness. Fractures in the roof zone of plutons of the Idaho batholith host gold and silver deposits in mining districts that are contiguous with and included in the Gospel- Hump Wilderness. Subeconomic gold and silver resources are indicated and inferred at the War Eagle and Blue Jay mines (southeastern part of the area). Parts of the eastern half of the wilderness area, which are included in mining districts and which are along the trends of known mineralized fractures, have a high potential for gold and silver resources and moderate potential for copper, lead, zinc, and molybdenum resources in quartz fissure-veins. Other parts of the wilderness that have the same geologic setting have a moderate potential for gold and silver resources in undiscovered quartz veins that lie along the trend of or are parallel to known veins. The western third of the wilderness has a moderate potential for tungsten, silver, lead, copper, nickel, and possibly gold resources in skarn or metasomatic replacement deposits along thrust faults adjacent to carbonate units.







Basement Tectonics 10


Book Description

The 10th International Basement Tectonics Conference was conducted on the campus of the University of Minnesota, Duluth, in Duluth, Minnesota, USA, from August I through August 11, 1992. A total of 78 individuals were in attendance, 47 of which represented the host country, with the remaining 31 traveling from 11 different foreign countries. The four days of presentations were divided into three technical sessions, namely "Shear Zones", "Basement Control On Younger Structures", and "Rifting Midcontinent Rift System". This tripartite conference theme was also employed in the field trip agenda with three excursions being offered, all ably organized by Field Trip Chairman John C. Green. The pre-conference trip set the stage through a two day review of the "Archean and Early Proterozoic Rocks of Northeastern Minnesota". Under beautiful summer skies, 16 sites were visited within the Vermilion district of Minnesota, considered to be the best example of an Archean greenstone belt in the United States. All registrants participated in the mid-conference trip conducted along the gabbroic and volcanic terrain of the "Midcontinent Rift, Northeastern Minnesota".




Recent Advances in North American Paleoseismology and Neotectonics East of the Rockies


Book Description

"This volume focuses on the continental intraplate region of the United States and provides an update and overview of documented Quaternary faulting and paleoseismic liquefaction east of the Rocky Mountains, and of the application of these results to seismic hazard and risk assessments. Contributions include papers that describe zones of newly recognized Quaternary deformation such as the East Tennessee Seismic Zone, as well as reinterpretations of well-known areas such as the New Madrid Seismic Zone. The chapters make important contributions to the recognition of earthquake sources active during the Quaternary and assess the seismic hazards posed by these sources. This volume should interest a wide range of readers from geology, seismology, hazard assessment, and emergency management"--Provided by publisher.