본문 바로가기
HOME> 논문 > 논문 검색상세

논문 상세정보

Geosphere v.13 no.1, 2017년, pp.201 - 226   SCIE
본 등재정보는 저널의 등재정보를 참고하여 보여주는 베타서비스로 정확한 논문의 등재여부는 등재기관에 확인하시기 바랍니다.

Geochemical constraints on mantle-melt sources for Oligocene to Pleistocene mafic rocks in the Four Corners region, USA

Gonzales, David A. (Department of Geosciences, Fort Lewis College, 1000 Rim Drive, Durango, Colorado 81301, USA ) ; Lake, Ethan T. (Department of Geological Sciences, The University of Texas at San Antonio, 1 UTSA Circle, San Antonio, Texas 78249, USA ) ;
  • 초록  

    Small masses of intraplate mafic plutonic and volcanic rocks are exposed in the Navajo volcanic field (26–24 Ma), Dulce dike swarm (25–20 Ma), and western San Juan Mountains (7–0.6 Ma) along the eastern boundary of the Colorado Plateau. Geochemical and Sr-Nd isotopic data for these rocks were employed to assess the time-space variations in melt compositions and to investigate the contributions from different mantle and crustal sources during magma production. Geochemical data signify that post–26 Ma mantle melts produced in the Four Corners region were heterogeneous in composition, dominantly alkaline, and distinguished by trace-element patterns with elevated LILE and LREE. These magmas were generated by melting of metasomatized subcontinental lithospheric mantle (SCLM) with minor contributions from a mantle source that produced melts with geochemical affinities of oceanic island basalts. Nd and Sr isotopic data reveal that some melts could have experienced minor contamination (<1%) with upper crust, whereas the Dulce magmas formed by contamination of mantle melts with up to 40% lower crust or melting of SCLM with low time-integrated Sm/Nd. Relative to minettes in the Navajo volcanic field, mafic rocks in the western San Juan Mountains have similar Nd and Sr isotopic compositions but are lower in some chemical values (Mg#, K 2 O, Rb, Zr, La/Lu, La/Ta, and Th/Yb) and higher in others (Al 2 O 3 , Na 2 O, and CaO). We postulate that these different chemical traits are evidence of heterogeneity in the lithospheric mantle. Voluminous magma production involving mantle melts from 35 to 26 Ma could have modified the chemistry of the lithospheric mantle beneath the western San Juan Mountains. Alternatively, this region may be underlain by SCLM with distinct chemical attributes imparted by subduction processes during Proterozoic arc accretion. Our work provides a snapshot of broader regional trends wherein heterogeneity in mantle reservoirs was a major contributor to the variable compositions of mafic alkaline rocks produced over the Colorado Plateau and adjacent Southern Rocky Mountains after 26 Ma.


 활용도 분석

  • 상세보기

    amChart 영역
  • 원문보기

    amChart 영역

원문보기

무료다운로드
  • 원문이 없습니다.
유료다운로드

유료 다운로드의 경우 해당 사이트의 정책에 따라 신규 회원가입, 로그인, 유료 구매 등이 필요할 수 있습니다. 해당 사이트에서 발생하는 귀하의 모든 정보활동은 NDSL의 서비스 정책과 무관합니다.

원문복사신청을 하시면, 일부 해외 인쇄학술지의 경우 외국학술지지원센터(FRIC)에서
무료 원문복사 서비스를 제공합니다.

NDSL에서는 해당 원문을 복사서비스하고 있습니다. 위의 원문복사신청 또는 장바구니 담기를 통하여 원문복사서비스 이용이 가능합니다.

이 논문과 함께 출판된 논문 + 더보기