UID:
kobvindex_GFZBV035680109
Format:
X, 112 Seiten
,
Illustrationen
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1 Beilage
Series Statement:
CRREL Report 79-9
Content:
Sedimentation at the terminus of the Matanuska Glacier has been found to be primarily subaerial in a 100- to 300-m wide, ice-cored zone paralleling the edge of the active ice. Certain physical and chemical characteristics of the ice and debris of the superglacial, englacial and basal zones of the glacier indicate the debris of the basal zone, the primary source of sediment, is entrained during freeze-on of meltwater, probably surficially derived, to the glacier sole. Till formation results from the melting of buried ice of the basal zone. Melt-out till inherits the texture and particle orientations of basal ice debris; other properties are not as well preserved. Most deposits result from resedimentation of till and debris by sediment gravity flows, meltwater sheet and rill flow, slump, spall, and ice ablation. Depositional processes are interrelated in the process of backwasting of ice-cored slopes. Sediment flows are the primary process of resedimentation. Their physical characteristics, multiple mechanisms of flow and deposition, and characteristics of their deposits vary with the water content of the flow mass. Deposits of each process are distinguished from one another by detailed analysis of their internal organization, geometry and dimensions, and the presence of other internal and related external features. Genetic facies are defined by these characteristics. The interrelationship of processes develops a composite depositional sequence defined in terms of genetic facies associations; an upper, resedimented facies association, a middile, till facies association, and a lower, subglacial-resedimental facies association. The lateral and vertical distribution of genetic facies within the associations is mainly nonrepetitive.
Note:
CONTENTS
Abstract
Preface
Summary
Chapter 1. Introduction
Field site
Historical background
Chapter 2. Characteristics of the debris and ice
Characteristics of the facies and subfacies
Basal zone
Characteristics of the debris
Discussion
Chapter 3. Oxygen isotope analysis
Sampling and analysis
Results
Discussion
Chapter 4. Depositional processes—till formation
Methods of analysis
Environmental setting
Till formation
Chapter 5. Depositional processes—resedimentation
Sediment flows
Other resedimentation processes
Resedimentation process relationships
Chapter 6. Process distribution, sediment dispersal and depositional patterns
Physical characteristics
Sediment dispersal
Sedimentary facies
Patterns of terminus sedimentation
Chapter 7. Conclusions
Literature cited
In:
CRREL Report, 79-9
Language:
English
Keywords:
Forschungsbericht
URL:
https://apps.dtic.mil/docs/citations/ADA072000
URL:
https://hdl.handle.net/11681/9016
