DOCSLIB.ORG

Late Pleistocene Deglaciation History at Point Partridge, Central Whidbey Island, Washington Cynthia A

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Late Pleistocene Deglaciation History at Point Partridge, Central Whidbey Island, Washington Cynthia A Western Washington University Western CEDAR WWU Graduate School Collection WWU Graduate and Undergraduate Scholarship Spring 1992 Late Pleistocene Deglaciation History at Point Partridge, Central Whidbey Island, Washington Cynthia A. Carlstad Western Washington University Follow this and additional works at: https://cedar.wwu.edu/wwuet Part of the Geology Commons Recommended Citation Carlstad, Cynthia A., "Late Pleistocene Deglaciation History at Point Partridge, Central Whidbey Island, Washington" (1992). WWU Graduate School Collection. 789. https://cedar.wwu.edu/wwuet/789 This Masters Thesis is brought to you for free and open access by the WWU Graduate and Undergraduate Scholarship at Western CEDAR. It has been accepted for inclusion in WWU Graduate School Collection by an authorized administrator of Western CEDAR. For more information, please contact [email protected]. LATE PLEISTOCENE DEGLACIATION HISTORY AT POINT PARTRDIGE, CENTRAL WHIDBEY ISLAND, WASHINGTON by Cynthia A. Carlstad Accepted in Partial Com'{!>letion of the Requirements for the Degree Master of Science Dean of Graduate Scho< Advisory Committee MASTER’S THESIS In presenting this thesis in partial fulfillment of therequirements for a master’s degree at Western Washington University, I agree that the Library shall make Its copies freely available for inspection. I further agree that extensive copying of this thesis is allowable only for scholarly purposes. It is understood, however, that anv copying or public ation of this thesis for commercial purposes, or for financial gain, shall not be allowed without mv written permission-. MASTER'S THESIS In presenting this thesis in partial fulfiliment of the requirements for a master's degree at Western Washington University, 1 grant to Western Washington University the non-exclusive royalty-free right to archive, reproduce, distribute, and display the thesis in any and all forms, including electronic format, via any digital library mechanisms maintained by WWU. I represent and warrant this is my original work and does not infringe or violate any rights of others. I warrant that I have obtained written permissions from the owner of any third party copyrighted materiai included in these files. I acknowledge that I retain ownership rights to the copyright of this work, including but not limited to the right to use all or part of this work in future works, such as articles or books. Library users are granted permission for individual, research and non-commercial reproduction of this work for educationai purposes only. Any further digital posting of this document requires specific permission from the author. Any copying or publication of this thesis for commercial purposes, or for financial gain, is not allowed without my written permission. Name: Signature: CxI lA-VUC C(X\T 1 Date: LATE PLEISTOCENE DEGLACIATION HISTORY AT POINT PARTRIDGE, CENTRAL WHIDBEY ISLAND, WASHINGTON A Thesis Presented to the Faculty of Western Washington University In Partial Fulfillment of the Requirements for the Degree Master of Science by Cynthia A. Caristad June 1992 ABSTRACT The study area contains a record of deglaciation events that has not been recognized elsewhere in the Puget Lowland. This record includes both subaerial outwash and glaciomarine deposition. The geologic history of the study area during recession of the Vashon ice sheet is marked by the following events: (1) deposition of a kame delta complex from grounded ice probably located in Penn Cove and west of Point Partridge. This delta complex was built into marine water with a sea-level at approximately 55 meters. Eventually, ice drained by the outwash streams stagnated in the Point Partridge kettle region. (2) Isostatic rebound of the depressed land surface caused relative sea-level to drop as the ice continued to become thinner. (3) Deposition of sand and gravel from outwash streams ceased as the ice continued to thin and eventually floated, depositing glaciomarine drift below approximately 37 meters. Narrow marine terraces were carved into Vashon till and Partridge outwash around the perimeter of Penn Cove. In addition to these events, the relationship between the Partridge outwash and Everson glaciomarine drift is described. Partridge outwash is an Everson Interstade unit, deposited by meltwater streams in a marine environment. ACKNOWLEDGMENTS First and foremost, I want to thank Don Easterbrook, chair of my advisory committee. Through the years that I have known Don, his friendship, wisdom and encouragement have greatly impacted the choices I have made in my life. Chris Suczek and Derek Booth, my other advisors, also desenre special thanks for their valuable guidance and suggestions regarding this project. Chris’s encouragement and general positive attitude have helped keep me moving. Derek agreed to join my advisory committee after the project was underway, and his enthusiasm and perspective shaped this thesis in many ways. One of the greatest side-benefits for me in writing this thesis was becoming better acquainted with all of you. Ma ny Geology folks have helped me with this project through technical assistance and friendship. George Mustoe, Chris Sutton, Vicki Critchlow, and Patty Combs deserve special mention. This thesis was partially funded through a Geology Department grant and through a Washington Department of Natural Resources contract. Thanks to Hank Schasse of WDNR for help with the WDNR contract. My employer, ENSR Consulting and Engineering, has been supportive of me in this academic endeavor. Many thanks also to my colleagues at ENSR who have individually offered encouragement and worked around my school schedule during the last several months. ii Because I have taken seven years to complete this degree, many people along theway have reminded me of the importance of completing it. In particular I want to thank my family for all their love and moral support. Last but not least, my gratitude goes out to my husband Bret, who, over the course of this project, has truly demonstrated the power of a life-partner. Ill CONTENTS 1.0 INTRODUCTION ........................................................................................................ 1-1 1.1 Pleistocene History of the Puget Lowland ........................................................ 1-1 1.2 Statement of Problem......................................................................................... 1-8 2.0 METHODOLOGY AND APPROACH.......................................................................... 2-1 2.1 Methods............................................................................................................... 2-1 2.1.1 Map and Air-Photo Interpretation.......................................................... 2-1 2.1.2 Geologic Mapping ................................................................................ 2-1 2.1.2.1 Well Logs ............................................................................... 2-2 2.2 Approach ............................................................................................................. 2-3 2.2.1 Dating and Correlation ......................................................................... 2-3 2.2.2 Reconnaissance Mapping in Related Regions .................................... 2-4 2.2.3 Comparison of Study Results to Existing Knowledge about Final Deglaciation in the Puget Lowland ........................................................ 2-5 3.0 GENERAL SETTING .................................................................................................. 3-1 3.1 Physical and Climatological Setting................................................................... 3-1 3.2 General Geologic Framework ............................................................................ 3-2 4.0 PREVIOUS WORK...................................................................................................... 4-1 5. 0 STRATIGRAPHY, SEDIMENTOLOGY, AND MORPHOLOGY.................................. 5-1 5.1 Double Bluff Drift ................................................................................................ 5-1 5.1.1 Description............................................................................................. 5-1 5.1.2 Distribution and Stratigraphic Relationships.................... 5-3 5.1.3 Age........................................................................................................ 5-5 5. 2 Whidbey Formation ........................................................................................... 5-5 5.2.1 Description............................................................................................. 5-5 5.2 .2 Distribution and Stratigraphic Relationships........................................ 5-6 5.2 .3 Age and Correlation.............................................................................. 5-9 5.3 Vashon Drift.......................................................................................................... 5-9 5.3.1 Esperance sand .................................................................................. 5-12 5.3.1.1 Description ........................................................................... 5-12 5.3 .1.2 Distribution and Stratigraphic Relationships...................... 5-12 5.3 .1.3 Age and Correlation............................................................. 5-13 5.3.2 Vashon Till and Associated Drift ........................................................ 5-15 iv CONTENTS (Cont’d) 5.3.2.1 Description and Origin .......................................................
Load more

Recommended publications
  • Isotopes, Inc. Radiocarbon Measurements V Milton A
    [RADIOCARBON, VOL. 8, 1966, P. 161-203] ISOTOPES, INC. RADIOCARBON MEASUREMENTS V MILTON A. TRAUTMAN and ERIC H. WILLIS Isotopes, Inc., Westwood, New Jersey INTRODUCTION This list presents dates on samples measured at Isotopes, Inc., dur- ing the years 1963 to 1965 and measurements made previously for which sample data has been recently received. The many results which do not appear are withheld pending additional information or at the request of our clients. Procedures employed in sample pretreatment, preparation of CO2, and method of counting are generally unchanged, as are our methods of age calculation. Suitable bone samples are now pretreated by the method of Berger, Harney and Libby (1964). In May, 1965, the three counters and associated electronics previ- ously described (Isotopes I, II, III) were retired after producing well over 2000 radiocarbon dates, geophysical measurements, and ultralow- level C14 measurements. A completely new laboratory was activated em- ploying four new counters. Shielding consists of 31 cm of selected low- background steel, 10 cm paraffin and 2.5 cm "aged" lead. Each counter has its own multianode annular anticoincidence geiger counter. Elec- tronics were designed and fabricated at Isotopes, Inc. The counters have an active volume of 1 L and when operated at a normal pressure of 3 atm, yield background counts of slightly over 2 counts j min, Aox x 0.95 is ca. 18.7 at 24° C. C13/C12 ratios are measured periodically by our mass spectrometry section, but not routinely on samples unless requested by clients. ACKNOWLEDGMENTS It is recognized that data obtained at Isotopes, Inc.
    [Show full text]
  • Sea Level and Global Ice Volumes from the Last Glacial Maximum to the Holocene
    Sea level and global ice volumes from the Last Glacial Maximum to the Holocene Kurt Lambecka,b,1, Hélène Roubya,b, Anthony Purcella, Yiying Sunc, and Malcolm Sambridgea aResearch School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia; bLaboratoire de Géologie de l’École Normale Supérieure, UMR 8538 du CNRS, 75231 Paris, France; and cDepartment of Earth Sciences, University of Hong Kong, Hong Kong, China This contribution is part of the special series of Inaugural Articles by members of the National Academy of Sciences elected in 2009. Contributed by Kurt Lambeck, September 12, 2014 (sent for review July 1, 2014; reviewed by Edouard Bard, Jerry X. Mitrovica, and Peter U. Clark) The major cause of sea-level change during ice ages is the exchange for the Holocene for which the direct measures of past sea level are of water between ice and ocean and the planet’s dynamic response relatively abundant, for example, exhibit differences both in phase to the changing surface load. Inversion of ∼1,000 observations for and in noise characteristics between the two data [compare, for the past 35,000 y from localities far from former ice margins has example, the Holocene parts of oxygen isotope records from the provided new constraints on the fluctuation of ice volume in this Pacific (9) and from two Red Sea cores (10)]. interval. Key results are: (i) a rapid final fall in global sea level of Past sea level is measured with respect to its present position ∼40 m in <2,000 y at the onset of the glacial maximum ∼30,000 y and contains information on both land movement and changes in before present (30 ka BP); (ii) a slow fall to −134 m from 29 to 21 ka ocean volume.
    [Show full text]
  • Pre-Vashon Interglacial Deposit Investigation
    Investigation of a Pre-Vashon Interglacial Fine-Grained Organic-Rich Sedimentary Deposit, South Lake Union, Seattle, Washington Cody Gibson A report prepared in partial fulfillment of the requirements for the degree of Master of Science Earth and Space Sciences: Applied Geosciences University of Washington March 2017 Project Mentors: Kathy Troost, University of Washington Matt Smith, GeoEngineers Inc. Internship Coordinator: Kathy Troost Reading Committee: Kathy Troost Juliet Crider MESSAGe Technical Report Number: 56 ©Copyright Cody Gibson i Executive Summary This study evaluates a fine-grained interglacial deposit found in the subsurface of the South Lake Union (SLU) area, Seattle, Washington. The nearly one-square-km SLU study area is defined as north of Denny Way, south of Aloha Street, east of Aurora Avenue, and west of Interstate 5. The evaluation required an in-depth study of over 600 existing geotechnical and environmental boring logs found for the study area. My evaluation consisted of mapping the distribution, determining the depositional environment, and characterizing the organic-rich pre-Vashon deposits. The fine-grained organic-rich deposits correlate to the Olympia formation, which occurred prior to the last glaciation of the Puget Sound Lowland known as the Vashon. To characterize the subsurface conditions in SLU, I assigned the materials described on the boring logs to one of 3 basic layers: pre-Vashon, Olympia Formation (Qob), and Vashon. In the SLU, the Qob consists of grey silt with interbeds of sand and gravel, and has an abundance of organic debris including woody debris such as well-preserved logs and branches, fresh-water diatoms, and fresh-water aquatic deposits such as peat.
    [Show full text]
  • Deglacial Permafrost Carbon Dynamics in MPI-ESM
    Clim. Past Discuss., https://doi.org/10.5194/cp-2018-54 Manuscript under review for journal Clim. Past Discussion started: 6 June 2018 c Author(s) 2018. CC BY 4.0 License. Deglacial permafrost carbon dynamics in MPI-ESM Thomas Schneider von Deimling1,2, Thomas Kleinen1, Gustaf Hugelius3, Christian Knoblauch4, Christian Beer5, Victor Brovkin1 1Max Planck Institute for Meteorology, Bundesstr. 53, 20146 Hamburg, Germany 2 5 now at Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany 3Department of Physical Geography and Bolin Climate Research Centre, Stockholm University, SE10693, Stockholm, Sweden 4Institute of Soil Science, Universität Hamburg, Allende-Platz 2, 20146 Hamburg, Germany 5Department of Environmetal Science and Analytical Chemistry and Bolin Centre for Climate Research, Stockholm 10 University, 10691 Stockholm, Sweden Correspondence to: Thomas Schneider von Deimling ([email protected]) Abstract We have developed a new module to calculate soil organic carbon (SOC) accumulation in perennially frozen ground in the 15 land surface model JSBACH. Running this offline version of MPI-ESM we have modelled permafrost carbon accumulation and release from the Last Glacial Maximum (LGM) to the Pre-industrial (PI). Our simulated near-surface PI permafrost extent of 16.9 Mio km2 is close to observational evidence. Glacial boundary conditions, especially ice sheet coverage, result in profoundly different spatial patterns of glacial permafrost extent. Deglacial warming leads to large-scale changes in soil temperatures, manifested in permafrost disappearance in southerly regions, and permafrost aggregation in formerly glaciated 20 grid cells. In contrast to the large spatial shift in simulated permafrost occurrence, we infer an only moderate increase of total LGM permafrost area (18.3 Mio km2) – together with pronounced changes in the depth of seasonal thaw.
    [Show full text]
  • Geology of Blaine-Birch Bay Area Whatcom County, WA Wings Over
    Geology of Blaine-Birch Bay Area Blaine Middle Whatcom County, WA School / PAC l, ul G ant, G rmor Wings Over Water 2020 C o n Nest s ero Birch Bay Field Trip Eagles! H March 21, 2020 Eagle "Trees" Beach Erosion Dakota Creek Eagle Nest , ics l at w G rr rfo la cial E te Ab a u ant W Eagle Nest n d California Heron Rookery Creek Wave Cut Terraces Kingfisher G Nests Roger's Slough, Log Jam Birch Bay Eagle Nest G Beach Erosion Sea Links Ponds Periglacial G Field Trip Stops G Features Birch Bay Route Birch Bay Berm Ice Thickness, 2,200 M G Surficial Geology Alluvium Beach deposits Owl Nest Glacial outwash, Fraser-age in Barn k Glaciomarine drift, Fraser-age e e Marine glacial outwash, Fraser-age r Heron Center ll C re Peat deposits G Ter Artificial fill Terrell Marsh Water T G err Trailhead ell M a r k sh Terrell Cr ee 0 0.25 0.5 1 1.5 2 ± Miles 2200 M Blaine Middle Glacial outwash, School / PAC Geology of Blaine-Birch Bay Area marine, Everson ll, G Gu Glaciomarine Interstade Whatcom County, WA morant, C or t s drift, Everson ron Nes Wings Over Water 2020 Semiahmoo He Interstade Resort G Blaine Semiahmoo Field Trip March 21, 2020 Eagle "Trees" Semiahmoo Park G Glaciomarine drift, Everson Beach Erosion Interstade Dakota Creek Eagle Nest Glac ial Abun E da rra s, Blaine nt ti c l W ow Eagle Nest a terf California Creek Heron Glacial outwash, Rookery Glaciomarine drift, G Field Trip Stops marine, Everson Everson Interstade Semiahmoo Route Interstade Ice Thickness, 2,200 M Kingfisher Surficial GNeeoslotsgy Wave Cut Alluvium Glacial Terraces Beach deposits outwash, Roger's Glacial outwash, Fraser-age Slough, SuGmlaacsio mSataridnee drift, Fraser-age Log Jam Marine glacial outwash, Fraser-age Peat deposits Beach Eagle Nest Artificial fill deposits Water Beach Erosion 0 0.25 0.5 1 1.5 2 Miles ± Chronology of Puget Sound Glacial Events Sources: Vashon Glaciation Animation; Ralph Haugerud; Milepost Thirty-One, Washington State Dept.
    [Show full text]
  • The Antarctic Contribution to Holocene Global Sea Level Rise
    The Antarctic contribution to Holocene global sea level rise Olafur Ing6lfsson & Christian Hjort The Holocene glacial and climatic development in Antarctica differed considerably from that in the Northern Hemisphere. Initial deglaciation of inner shelf and adjacent land areas in Antarctica dates back to between 10-8 Kya, when most Northern Hemisphere ice sheets had already disappeared or diminished considerably. The continued deglaciation of currently ice-free land in Antarctica occurred gradually between ca. 8-5 Kya. A large southern portion of the marine-based Ross Ice Sheet disintegrated during this late deglaciation phase. Some currently ice-free areas were deglaciated as late as 3 Kya. Between 8-5 Kya, global glacio-eustatically driven sea level rose by 10-17 m, with 4-8 m of this increase occurring after 7 Kya. Since the Northern Hemisphere ice sheets had practically disappeared by 8-7 Kya, we suggest that Antarctic deglaciation caused a considerable part of the global sea level rise between 8-7 Kya, and most of it between 7-5 Kya. The global mid-Holocene sea level high stand, broadly dated to between 84Kya, and the Littorina-Tapes transgressions in Scandinavia and simultaneous transgressions recorded from sites e.g. in Svalbard and Greenland, dated to 7-5 Kya, probably reflect input of meltwater from the Antarctic deglaciation. 0. Ingcilfsson, Gotlienburg Universiw, Earth Sciences Centre. Box 460, SE-405 30 Goteborg, Sweden; C. Hjort, Dept. of Quaternary Geology, Lund University, Sdvegatan 13, SE-223 62 Lund, Sweden. Introduction dated to 20-17 Kya (thousands of years before present) in the western Ross Sea area (Stuiver et al.
    [Show full text]
  • Geologic Map of the Coupeville and Part of the Port Townsend North 7.5
    WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES GEOLOGIC MAP GM-58 Geologic Map of the Coupeville and Part of the Port Townsend North R1W R1E 42¢30² 122°45¢ 40¢ 122°37¢30² 48°15¢ 48°15¢ Qgtv Qco Qb Qgoge Qco Qgdp 7.5-minute Quadrangles, Island County, Washington Qml 1 Qco schematic section Qgog Qgd 5 e Qcw from top to Qgav; Qgav Qgdme elev. 197 ft schematic section elev. 160 ft measured section Qgdp Qml Qgav Qgoge elev. 150 ft Qs <10 ft sand by Michael Polenz, Stephen L. Slaughter, and Gerald W. Thorsen ~10 ft below Qgav Qd active dune sand Qp Qs 110,124,182 6 to 12 ft 5 ft Qs sand Qgdm 18 ft sand and gravel Qgdm Qco silt and clay e Qgav 7 ft Qgdm diamict e Qb liquefaction features e Qgdme Qml Qc 15 ft silt 9 ft Qgd diamict Qcw o and small shears in Qd Qgoge Qgd 9 ft Qgt till 188 p 10 ft silt and clay silt and sand at ~100 ft June 2005 v Qgtv <75 ft Qgoge 11 ft Qgav sandy gravel Qcw Qp Qmw 177,178 gravel with ~30 ft mixed deposits—sand, Qmw silt boulders silt, and minor gravel Qgd Qp Qgomee? Qm Qgdmels? ~20 ft lahar runout (Table 2, samples 188 and 182*) GEOLOGIC SETTING AND DEVELOPMENT We suggest that this sediment source is partly documented by a high-energy outwash Deposits of the Fraser Glaciation (Pleistocene) alluvial facies reflect ancestral Skagit River provenance. Sparse, local Glacier REFERENCES CITED channel deposits— Qgomee Qcw Qgd 79 ft p clean sand with Qls Qb Qcw ~15 ft channel deposits—sand and minor gravel gravel unit (unit Qgoge), which locally grades up into Partridge Gravel, and which we Peak dacite and pumice pebbles, such as those found to the east of Long Point very sparse gravel Like most of the Puget Lowland, the map area is dominated by glacial sediment and lacks Armstrong, J.
    [Show full text]
  • Deglaciation of Central Long Island
    159 FIELD TRIP I: DEGLACIATION OF CENTRAL LON(; ISLAND· Les Sirkin Earth Science Adelphi University Garden City, NY 11530 This trip covers the geology of a south to north transect through the sequence oflate Wisconsinan glacial deposits--the· Terminal Moraine, Recessional Moraines, Outwash Plains, Proglacial Lakes and a Prominent Meltwater Channel-- in central Long Island. The Connetquot Rivers which drains southcentral Long Island from north to south, and the Nissequogue River, which flows through northcentral Long Island from south to north, have nearly coalescing drainage basins in central Long Island (Figure 1. The route crosses, from south to north, the USGS 7.5' Quadrangle Maps: Bay Shore East, Central Islip and Saint James). These two underfit rivers together appear to cinch the waist of Long Island and reveal an intriguing stream valley system that originated as a late­ glacial meltwater channel draining a series of proglaciallakes north of the terminal moraine, flowing through a gap in the moraine and across the outwash plain and continental shelf. The trip straddles the arbitrary geographic boundary between eastern and western Long Island. Geologically, it is situated east of the late Wisconsinan Interlobate Zone between the Hudson and Connecticut glacial lobes in the vicinity of Huntington. The Interlobate Zone resulted in the complex ofinterlobate morainal deposits, meltwater channel gravels and proglaciallake beds that make up the north-south range of hills: Manetto Hills, Half Hollow Hills and Dix Hills. The route of the field trip lines up roughly with the axis of the last interlobate angle between the receding glacial lobes and trends northward toward the interlobate angle formed at the inferred junction of the Sands Point Moraine of the Hudson Lobe and the Roanoke Point Moraine of the Connecticut Lobe projected beneath Smithtown Bay.
    [Show full text]
  • Reconstruction of Early Holocene Jokulhlaups Along the Hvita River and Gullfoss Waterfall, Iceland
    EGU2020-1065 https://doi.org/10.5194/egusphere-egu2020-1065 EGU General Assembly 2020 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Reconstruction of Early Holocene jokulhlaups along the Hvita River and Gullfoss waterfall, Iceland Greta Wells1,2, Þorsteinn Sæmundsson2, Sheryl Luzzadder-Beach1, Timothy Beach1, and Andrew Dugmore3 1Department of Geography and the Environment, University of Texas at Austin, USA ([email protected]) 2Institute of Earth Sciences, University of Iceland, Reykjavík, Iceland 3School of Geosciences, University of Edinburgh, Scotland, UK Glacial lake outburst floods (GLOFs) have occurred across the planet throughout the Quaternary and are a significant geohazard in Arctic and alpine regions today. Iceland experiences more frequent GLOFs—known in Icelandic as jökulhlaups—than nearly anywhere on Earth, yet most research focuses on floods triggered by subglacial volcanic and geothermal activity. However, floods from proglacial lakes may be a better analogue to most global GLOFs. As the Icelandic Ice Sheet retreated across Iceland in the Late Pleistocene-Early Holocene, meltwater pooled at ice margins and periodically drained in jökulhlaups. Some of the most catastrophic floods drained from ice-dammed Glacial Lake Kjölur, surging across southwestern Iceland from the interior highlands to the Atlantic Ocean. These floods left extensive geomorphologic evidence along the modern-day course of the Hvítá River, including canyons, scoured bedrock, boulder deposits, and Gullfoss—Iceland’s most famous waterfall. The largest events reached an estimated maximum peak discharge of 300,000 m3s -1, ranking them among the largest known floods in Iceland and on Earth. Yet, all our evidence for the Kjölur jökulhlaups comes from only one publication to date (Tómasson, 1993).
    [Show full text]
  • Earth, Atmospheric, and Planetary Physics
    GEOPHYSICAL RESEAIO,CH LETTEI•,S. VOl,. 28, NO. 2, PAGES 2813-286,.IANUARY 15,2001 CO2 levelsrequired for deglaciationof a "Near-Snowball" Earth Thomas J. Crowley, William T. Hyde Dept. of Oceanography,Texas A&M University,College Station,Texas W. Richard Peltier Dept. of Physics,University of Toronto,Toronto, Canada Abstract. Geologic evidence suggeststhat in the Late Hoffman et al. [1988] invoked estimatesby Caldiera and Neoproterozoic,(-600 Ma) almost all land masses were Kasting[1992] that massivelevels of atmosphericCO 2 (--0.i glaciated, with sea-levelglaciation existing even at the bar) were requiredto escapefrom this state,and suchvalues equator. A recentmodeling study has shownthat it is possi- are comparableto thosecalculated by Hydeet al. [2000]. ble to simulate an ice-coveredEarth glaciation with a cou- A furtherresult of the Hyde et al. [2000] study is that pledclimate/ice-sheet model. However,separate general cir- stand-alonegeneral circulation model (GCM) experiments culation model experimentssuggest that a secondsolution with fixed ice sheetsin some casesyielded open water may exist with a substantialarea of ice free ocean in the conditionsin equatorialregions removed from the ice sheet tropics.Although 0.1 to 0.3 of an atmosphereof CO2 (-•300 [cf. Baumand Crowley,2000]. The existenceof openwater to 1000 X) is requiredfor deglaciationof a "SnowballEarth," solutionsreflects standardlength-scale arguments discussed the "exit"CO 2 levelsfor an openwater solution could be in the climate literature[North, 1984; Manabe and Broccoli, significantly less. In this paper we utilize a coupled 1985], in which the thermalinfluence of an ice sheet(or other climate/ice sheet model to demonstratefour points: (1) the perturbation)diminishes by a scale which is determinedfrom openwater solution can be simulatedin the coupledmodel if characteristicradiative damping and heat transportvalues for the sea ice parameter is adjusted slightly; (2) a major the Earth.
    [Show full text]
  • The Last Deglaciation Simulated with a Coupled Atmosphere/Ocean/Ice Sheet/Solid Earth Model
    EGU21-2278 https://doi.org/10.5194/egusphere-egu21-2278 EGU General Assembly 2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. The last deglaciation simulated with a coupled atmosphere/ocean/ice sheet/solid earth model Uwe Mikolajewicz1, Olga Erokhina1, Marie-Luise Kapsch1, Clemens Schannwell1, and Florian Ziemen2 1Max-Planck-Institut f. Meteorologie, Hamburg, Germany ([email protected]) 2Deutsches Klimarechenzentrum, Hamburg, Germany It is challenging to model the last deglaciation, as it is characterized by abrupt millennial scale climate events, such as ice-sheet surges, that are superimposed on long-term climate changes, such as a global warming and the decay of a substantial part of the glacial ice sheets. Within PMIP, several groups have simulated the last deglaciation with CMIP-type models prescribing ice sheets from reconstructions. Whereas this type of simulations accounts for the effects of ice-sheet changes including meltwater release on climate, the prescribed ice sheet evolution is typically not consistent with the simulated climate evolution. Here we present a set of deglacial simulations that include fully interactive ice sheets that respond to changes in the climate. The setup also allows for feedbacks between ice sheets and climate and , hence, allows for a more realistic representation of the mechanisms of the last deglaciation, as the simulated climate and ice sheet changes are fully consistent.. The model consists of the coarse resolution set-up of MPI-ESM coupled to the ice sheet model mPISM (Northern Hemisphere and Antarctica) and the solid earth model VILMA. The model includes interactive icebergs and an automated calculation of the land-sea mask and river routing directions.
    [Show full text]
  • A Geomorphic Classification System
    A Geomorphic Classification System U.S.D.A. Forest Service Geomorphology Working Group Haskins, Donald M.1, Correll, Cynthia S.2, Foster, Richard A.3, Chatoian, John M.4, Fincher, James M.5, Strenger, Steven 6, Keys, James E. Jr.7, Maxwell, James R.8 and King, Thomas 9 February 1998 Version 1.4 1 Forest Geologist, Shasta-Trinity National Forests, Pacific Southwest Region, Redding, CA; 2 Soil Scientist, Range Staff, Washington Office, Prineville, OR; 3 Area Soil Scientist, Chatham Area, Tongass National Forest, Alaska Region, Sitka, AK; 4 Regional Geologist, Pacific Southwest Region, San Francisco, CA; 5 Integrated Resource Inventory Program Manager, Alaska Region, Juneau, AK; 6 Supervisory Soil Scientist, Southwest Region, Albuquerque, NM; 7 Interagency Liaison for Washington Office ECOMAP Group, Southern Region, Atlanta, GA; 8 Water Program Leader, Rocky Mountain Region, Golden, CO; and 9 Geology Program Manager, Washington Office, Washington, DC. A Geomorphic Classification System 1 Table of Contents Abstract .......................................................................................................................................... 5 I. INTRODUCTION................................................................................................................. 6 History of Classification Efforts in the Forest Service ............................................................... 6 History of Development .............................................................................................................. 7 Goals
    [Show full text]