Nelson, Daniel B
(2005)
Holocene Paleoenvironmental History from Stable Isotopes in Lake Sediment, North-Central Washington State.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Population growth in the Pacific Northwest has led to increased demand for water resources. Current understanding of the natural cycle of moisture availability is limited, however, by the short duration for which instrumental climate data are available. Here, a detailed paleoenvironmental study from Castor Lake in north-central Washington State is presented to examine the frequency, duration, and magnitude of droughts, lake system dynamics, and other climate events during the past ~16,000 years. The combined use of stable isotope measurements of endogenic carbonate and organic sediment with trace element analysis and standard sedimentological methodologies provides a more coherent basis for understanding environmental change through this period than would be possible through the application of a single technique. Results show that the region was significantly affected by the Younger Dryas cold reversal between approximately 12,500 cal yr BP and 11,500 cal yr BP. The period from approximately 8,200 cal yr BP to 5,900 cal yr BP contains evidence for prolonged aridity, as lake-levels declined and water column stratification broke down. The period spanning the last ~6,000 years is characterized by relative climate stability, but the highly resolved sediment proxy data for this interval reveal several drought events larger than anything experienced in the historic record, with some episodes persisting well over a century. Furthermore, the past fifty-years appear to be anomalously wet in the context of the long-term record obtained from Castor Lake. Preparation for large drought events may therefore be inadequate because water resource allocation laws were written during this interval. Future large-scale drought events are inevitable, however, given the frequency with which they are observed to occur in the past, and the increasing influence of anthropogenic warming.
Share
| Citation/Export: |
|
| Social Networking: |
|
Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
| Creators | Email | Pitt Username | ORCID  |
|---|
| Nelson, Daniel B | dbn1@pitt.edu | DBN1 | |
|
| ETD Committee: |
|
| Date: |
2 February 2005 |
| Date Type: |
Completion |
| Defense Date: |
16 November 2004 |
| Approval Date: |
2 February 2005 |
| Submission Date: |
10 December 2004 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Geology and Planetary Science |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
carbonate; climate; drought; geology; Holocene; isotope; lake; Pacific Northwest; paleoclimate; PDO; PDSI; sediment; trace element; Washington |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-12102004-063021/, etd-12102004-063021 |
| Date Deposited: |
10 Nov 2011 20:10 |
| Last Modified: |
15 Nov 2016 13:54 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/10268 |
Metrics
Monthly Views for the past 3 years
Plum Analytics
Actions (login required)
 |
View Item |
![[feed]](/images/feed-icon-32x32.png){kind=icon}