Basaltic Volcanism Associated with Basin and Range Extension, Central Nevada - Geochemical Variation in Space and Time

通过初步研究，已在内华达州中北部(靠近Winnemucca、法伦以东、凯恩斯普林斯和月球火山口火山场之间)确定了岩浆过渡的地点(例如，从高Ba/Nb钢状熔岩到低Ba/Nb碱性玄武岩)。然而，这些岩浆的成分也可能受到基底(包括岩石圈地幔)年龄和成分的横向变化的影响。该项目将对内华达州中北部大致南北和东西方向的镁铁质熔岩进行详细的地球化学研究，以评估其来源特征。将对选定的样品进行年龄测定，以建立岩浆源转变的年代学。这些数据将为Cordilleran地区新生代区域伸展期间的地幔参与提供重要的制约因素。

Through preliminary studies, loci of magmatic transitions (e.g., from high Ba/Nb Steens-like lavas to low Ba/Nb alkalic basalts) have been identified in north central Nevada (near Winnemucca, East of Fallon, and between Kane Springs Wash and the Lunar Crater volcanic field). However, compositions of these magmas could also be influenced by lateral variations in basement (including lithospheric mantle) age and composition. This project will carry out a detailed geochemical study of mafic lavas from roughly north-south and east-west transects across north-central Nevada to evaluate source characteristics. Age determinations will be made for selected samples to establish the chronology of magma source transitions. These data will provide important constraints on mantle involvement during the Cenozoic regional extension of the Cordilleran region.