Geochemistry Of Laramide Igneous Intrusions, Northern Black Hills, With Implications For Petrogenetic Relationships And Magma Sources
C.K. Shearer, 1990. "Geochemistry Of Laramide Igneous Intrusions, Northern Black Hills, With Implications For Petrogenetic Relationships And Magma Sources", Metallogeny of Gold in the Black Hills, South Dakota, Colin J. Paterson, Alvis L. Lisenbee, Tommy B. Thompson
Download citation file:
The Cenozoic igneous province of the northern Black Hills uplift appears to represent the easternmost exposure of rocks formed by Tertiary alkalic igneous activity that occurred in the north central and northwestern United States (i.e., Highwood Mountains and Northern Crazy Mountains, Central Montana; Leucite Hills, Wyoming). The Tertiary magmatism in the northern Black Hills is defined by a 105 km east- west linear trend of thirteen (13) major igneous centers (Lisenbee, 1985; Kamer, 1985) consisting of shallow intrusives and minor extrusives (flow-breccia, tuffs, lahars). Igneous centers in the western portion of this trend contain phonolites and rocks with carbonatitic affinities whereas, to the east the intrusive centers are silica-saturated (Lisenbee, 1985). In general, different types of mineralization appear to be spatially related to the igneous centers (Lisenbee, 1985) and may be associated with different episodes of magmatism (Lisenbee, 1985; Paterson et al., 1989). Understanding the processes relating rock types (extent of fractional crystallization, partial melting) and ultimate magma source(s) is critical to elucidating the intimate magmatism-mineralization "connection." This paper touches upon geochemical and mineralogical aspects of the Tertiary magmatism in the northern Black Hills.