Graduate Thesis Or Dissertation
 

Stratigraphy and structure of the Rock Creek area, Beaverhead County, Montana

公开 Deposited
default representative image
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/05741w137

Descriptions

Attribute NameValues
Creator
Abstract
  • The Rock Creek area consists of 53 square miles located in the eastern foothills of the Pioneer Mountains, Beaverhead County, Montana. Approximately 8, 500 feet of late Paleozoic and early Mesozoic contact-metamorphosed sedimentary rocks and late Mesozoic sedimentary rocks are exposed in the area of study. Most of the late Paleozoic and Mesozoic rocks were deposited along the eastern edge of the Cordilleran miogeosyncline. The oldest exposed rocks in the map area belong to the Amsden Formation of Late Mississippian to Early Pennsylvanian age. Other late Paleozoic rock units include the Quadrant Formation of Pennsylvanian age and the Phosphoria Formation of Permian age. Mesozoic formations include the Dinwoody Formation of Triassic age and the Kootenai Formation and Colorado Group of Cretaceous age. The Tertiary is represented by basin deposits and basaltic andesite extrusives. Unconsolidated Quaternary glacial and fluvial deposits complete the stratigraphic succession. Granodiorite intrusive rocks occupy the southwestern corner of the area mapped and compose part of the eastern margin of the Mount Torrey Batholith, which is probably genetically related to the Boulder Batholith. Along the margin of the intrusive, contact metamorphism has destroyed the original sedimentary characteristics of the late Paleozoic and early Mesozoic Formations. During the Late Cretaceous Laramide orogeny the sedimentary rocks were tilted and faulted. The structures in the area are related to the main episode of Laramide deformation, emplacement of the Mount Torrey Batholith, and later phases of structural adjustment. The main structures are the Lost Creek tear fault and a northwest-trending high-angle reverse fault. Minor folds are present in the eastern half of the mapped area.
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
权利声明
Publisher
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 24-bit Color) using Capture Perfect 3.0 on a Canon DR-9050C in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR. Plate: Master map file scanned at 600 dpi, 24-bit color on a Paradigm ImagePRO GxT 42 HD (OEM version of ColortracSmartLF Bx 42). Image manipulated by SmartLF1.3.05.
Replaces

关联

Parents:

This work has no parents.

属于 Collection:

单件

缩略图 标题 上传日期 公开度 行动
file details PetersJamesF1971.pdf 08/17/2017 公开
file details Peters1.jpg 08/17/2017 公开