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Full-Text Articles in Physical Sciences and Mathematics
Geology And Mineralization Of The Great Excelsior Mine, Whatcom County, Washington, Russell J. Franklin
Geology And Mineralization Of The Great Excelsior Mine, Whatcom County, Washington, Russell J. Franklin
WWU Graduate School Collection
The Great Excelsior Mine is located in the North Cascades of northwest Washington, approximately 6 miles (10 km) east of the town of Glacier. The deposit consists of Ag with subordinate Au and is hosted within felsic volcanic breccias, tuffaceous siltstones and graywackes, and felsic tuffs belonging to the Middle Jurassic Wells Creek Volcanics. The deposit is located approximately 1000 feet (305 m) below the contact between the Wells Creek Volcanics and the overlying Nooksack Group metasediments. Both units comprise the lowermost structural-metamorphic unit of the western North Cascades System.
The Wells Creek Volcanics have been informally subdivided into four …
The Geology And Structure Of The Canyon Creek-Church Mountain Area, North Cascades, Washington, Jeffrey T. (Jeffrey Thomas) Jones
The Geology And Structure Of The Canyon Creek-Church Mountain Area, North Cascades, Washington, Jeffrey T. (Jeffrey Thomas) Jones
WWU Graduate School Collection
Four major rock assemblages ranging from Precambrian to Lower Cretaceous occur in the Canyon Creek/Church Mountain area of northwestern Washington. Lithologic, structural, and fossil evidence were used to discriminate among the assemblages and to correlate them with the Chilliwack Group, the Nooksack Group, the Yellow Aster Complex, and a unit previously included in the Chilliwack Group, referred to here as the "chert/basalt unit." These assemblages were juxtaposed during middle Cretaceous tectonism along low angle and high angle faults. There is some evidence for additional structural deformation after the middle Cretaceous.
The Chilliwack Group, consisting of volcanic rocks, volcaniclastic rocks, and …
Stratigraphy And Petrology Of The Nooksack Group In The Glacier Creek-Skyline Divide Area, North Cascades, Washington, Jon Niels Sondergaard
Stratigraphy And Petrology Of The Nooksack Group In The Glacier Creek-Skyline Divide Area, North Cascades, Washington, Jon Niels Sondergaard
WWU Graduate School Collection
The 6-7 kilometer thick Upper Jurassic-Lower Cretaceous Nooksack Group is divided informally into four units on the basis of lithology. The basal unit consists of tuffaceous sandstone and keratophyric tuff with minor intercalations of argillite and intermediate crystalline volcanic rocks. The lower unit is composed of interbedded black argillite and volcaniclastic sandstone. The middle unit consists of thick-bedded volcaniclastic sandstone and coarse, sedimentary breccia with minor argillite. The upper unit is comprised of interbedded black argillite and volcaniclastic sandstone.
Lithologies and sedimentary structures within these units suggest: (1) the lower and upper units represent depositional lobe deposits of a middle …