Alaska Science Center


Petrogenesis and Mineralization of the Darby and Kachauik Plutons, Seward Peninsula, Alaska

The Darby and Kachauik plutons have unusually high-potassium alkaline compositions and unevaluated high concentrations of rare earth and high field strength elements (REE and HFSE). The objective of this project is to investigate the petrogenesis, sources and mechanisms of mineralization, and tectonic setting of these unusual plutons.

Abstract


High-K alkaline intrusive and extrusive rocks of the Hogatza igneous belt, which extends for 450 km from the eastern Seward Peninsula to the southern Brooks Range in northwestern Alaska, contain unevaluated concentrations of rare earth elements (REE). Two of the largest and best exposed plutons in this belt are the Darby and Kachauik plutons on the southeastern Seward Peninsula. The tectonic setting and petrogenesis of these plutons that have unusual compositions and mineral concentrations is uncertain. Resolution of the parameters that controlled the magmatic sources, evolution, and emplacement of the Darby and Kachauik plutons will contribute significantly to understanding the Hogatza igneous belt, and the regional tectonics of northwestern Alaska during the middle Cretaceous, a time of ubiquitous magmatic activity and mineralization throughout the state of Alaska.
Products
Title Type
Uranium-Lead Ages, Hafnium Isotope Ratios, and Trace Element Concentrations by Laser-Ablation Split Stream (LASS) Analysis of Igneous Zircons from the Darby Mountains Area, Seward Peninsula, AlaskaData

Contacts

Karl, Susan , 907.786.7428

Status: completed
Start Year: 2016
End Year: 2019

Project Sites

Location
Darby Mountains

USGS Mission Area and Program
Energy and MineralsMineral Resources