First Advisor

Michael L. Cummings

Term of Graduation

2011

Date of Publication

1-1-2011

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Geology

Department

Geology

Language

English

Subjects

Paleontology -- Pacific Northwest -- Miocene, Mammals -- Speciation -- Pacific Northwest, Mammals -- Evolution -- Pacific Northwest

DOI

10.15760/etd.726

Physical Description

1 online resource (x, 130 pages)

Abstract

The impact of large-scale volcanic eruptions on landscapes can affect many processes ranging from interrupting or redirecting regional soil forming processes and hydrological systems to generating temporary changes in global climate. Though more studies exist every year, less is known of the direct impact of large-scale volcanic eruptions on ecosystems and extinction, while even less is known of their impact on speciation. In deposits throughout the Pacific Northwest a special combination and association of volcanic magnitude with palaeoecological yield frequently presents unique prospects for inquiry. In this study, particular attention is given to large, late Miocene ash-flow tuffs of central and eastern Oregon, the Rattlesnake Tuff among them. Additionally, a scenario is tested whereby populations become isolated from one another across the expanse of ash-flow tuff and enclosed by nearby physical barriers. Exploration into this scenario and the effects of ecological recovery on speciation in mammals are made through a cellular automaton created here and speciation modeling by H.A. Orr. The cellular automaton is validated by a small data set from New Zealand with results of all models compared to studies in ecology, the fossil record, genetics, and island evolution. Results suggest ecosystem recovery is much faster than mammalian species origination rates. Though evolution in mammals is known to occur over relatively short intervals of time (101 - 103 yrs), based on model comparisons, primary productivity generally returns to its carrying capacity two orders of magnitude (102 - 103 vs. ≥ 104 yrs) faster than mammalian speciation.

Rights

In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

Persistent Identifier

http://archives.pdx.edu/ds/psu/6954

Download

Included in

Geology Commons

Share

COinS