Physical Sciences and Mathematics Commons^™

Teco: Carbon Monoxide Consumption By Forest And Agroecosystem Soils, Gary M. King

University of Maine Office of Research Administration: Grant Reports

Carbon monoxide is a more dynamic component of the atmosphere than methane, occurring at a lower concentration but substantially higher flux. CO and hydroxyl radical interact rapidly, affecting a number of atmospheric parameters: the oxidative state of the troposphere; the fate and residence times of methane, non-methane organics and inorganics; tropospheric ozone; and the extent of thermal forcing. Soils consume atmospheric CO, accounting for 10-25% of the global carbon budget, depending on the source estimate. Some of the controls of soil CO uptake and production have been described generally, but much remains unknown. Details of CO uptake in agroecosystems are …

Methanesulfonate In The Firn Of King George Island, Antarctica, Jiankang Han, Zichu Xie, Xinping Zhang, Dongsheng Dai, Paul Andrew Mayewski, M. S. Twickler

Earth Science Faculty Scholarship

Methanesulfonate was investigated as a potential contributor to the sulfur budget, based on analysis of a firn core from Collins Ice Cap, King George Island, Antarctica (62°10' S, 58°50' W). The anion was found to be present at a mean concentration of 0.17 μeq L^-1, with a maximum of 0.73 μeq L^-1. Dating based on the δ¹⁸O profile suggests that the principal peaks of methanesulfonate are associated with snow deposited in summer and autumn. A careful examination of MSA, SO₄^2-and nssSO₄^2- profiles indicates that two of the three peaks …

High-Precision Dating Of Volcanic Events (A.D. 1301–1995) Using Ice Cores From Law Dome, Antarctica, Anne S. Palmer, Tas D. Van Ommen, Mark A. J. Curran, Vin Morgan, Joe M. Souney, Paul Andrew Mayewski

Earth Science Faculty Scholarship

A record of volcanic activity over the period A.D. 1301–1995 has been extracted from three Law Dome ice cores (East Antarctica). The record dating is unambiguous at the annual level from A.D. 1807 to 1995 and has an uncertainty of ±1 year at A.D. 1301. Signals from 20 eruptions are preserved in the record, including those of two unknown eruptions with acid deposition beginning in A.D. 1810.8 and A.D. 1685.8. The beginning of the ice core signal from the A.D. 1815 Tambora eruption is observed in the austral summer of A.D. 1816/1817. The mean observed stratospheric transport and deposition time …

Collaborative Research: Chemical Equilibria Involving Iron And Hydrogen In Metapelites From Western Maine, Charles V. Guidotti

University of Maine Office of Research Administration: Grant Reports

The primary goal of this research is to evaluate the chemical equilibria involving ferrous and ferric iron and hydrogen in metapelitic rocks from western Maine and related rocks at Black Mountain, New Hampshire. We will study samples from graphite, magnetite, and hematite-bearing rocks at three different metamorphic grades: garnet, lower sillimanite, and staurolite zone. This will permit the determination of:

(1) in situ partition coefficients for Fe3+ and Fe2+ among all the Fe-bearing phases and for H among hydrous phases;
(2) the temperature and fO2 dependence of Fe3+/Fetotal and effects of Fe3+ substitution on other cation substitutions plus their implications …

The Origin Of A Polar Ice Sheet In East Antarctica, George H. Denton

University of Maine Office of Research Administration: Grant Reports

This award supports a study to determine the sequence and chronology of events that led to the development of the Antarctic ice sheet. A continental-scale ice sheet probably first developed in East Antarctica close to the Eocene-Oligocene boundary under temperate climatic conditions. The purpose of this project is to determine, from landscape analysis (with a numerical chronology), when (and why) these early temperate conditions gave way to a polar environment in Antarctica. From previous field work and recent photographic analysis, an extensive relict landscape (older than 17 million years) with landforms and erosional features characteristic of temperate glaciation has been …

New Data On Welshite, E.G. Ca2mg3.8mn0.62+Fe0.12+Sb1.55+O2 [Si2.8be1.7fe0.653+Al0.7as0.17o18], An Aenigmatite-Group Mineral, Edward S. Grew, U. Hålenius, M. Kritikos, C. K. Shearer

Earth Science Faculty Scholarship

Electron and ion microprobe data on two samples of welshite from the type locality of Langban, Sweden, gave analytical totals of 99.38-99.57 wt.% and BeO contents of 4.82-5.11 wt.%, corresponding to 1.692-1.773 Be/20 O. Mossbauer and optical spectra of one of these samples gave Fe-[iv](3+)/Sigma Fe = 0.91, Fe-[iv](2+)/Sigma Fe = 0.09, and no evidence of Mn3+. The resulting formula for this sample is Ca2Mg3.8Mn0.62+Fe0.12+Sb1.55+O2[Si2.8Be1.7Fe0.653+Al0.7As0.17O18], and that for the second sample, Ca2Mg3.8Mn0.12+Fe0.12+F0.83+Sb1.25+O2[Si2.8Be1.8F0.653+Al0.25As0.25O18], is related by the substitution involving tetrahedral and octahedral sites: 0.59([vi,iv])(Fe,Al)(3+) approximate to 0.42([vi])(Mg,Mn,Fe)(2+) + 0.21(Sb-[vi],As-[iv])(5+), i.e. 3([vi,iv]) M3+ = 2([vi])M(2+) + M-[vi,iv](5+). WelShite is distinctive among aenigmatite-group …

Comment On "On Sharp Spectral Lines In The Climate Record And The Millennial Peak" By Carl Wunsch, L. D. Meeker, Paul Andrew Mayewski, Pieter M. Grootes, Richard B. Alley, Gerard C. Bond

Earth Science Faculty Scholarship

No abstract provided.

Acquisition Of Ion Chromatographs And Related Glaciochemistry Equipment, Paul Andrew Mayewski

University of Maine Office of Research Administration: Grant Reports

The goal of this project has been to upgrade the ice core processing and analytical equipment. This has been accomplished in three major areas: the design and construction of an ice core lathe, develpoment of a continuous melting system, and new ion chromatographs. The lathe is a unique ice core processing tool that operates similiar to a wood lathe. The lathe will reduce or eliminate the need for the cores to be hand scraped, the first cleaning step of core preparation.

Our continuous melting system is a modification of existing designs. Unlike other systems, we will collect discrete samples for …

Collaborative Research: Paleoclimate And Glaciological Recontructions In Central Asia, Karl J. Kreutz

University of Maine Office of Research Administration: Grant Reports

This project resulted in the collection of two intermediate-length (165 m) ice cores from the Inilchek Glacier, Central Tien Shan Mountains, Kyrgyzstan, during July/August 2000 with colleagues from UCSB, UNH, and the USGS. In addition, precipitation, fresh snow, surface snow, and aerosol samples were collected on the glacier and in the Inilchek Valley to assess atmospheric chemistry and deposition processes. The overall goal of the project (including a pending NSF/DOE proposal) is to develop high-resolution paleoclimatic records covering the last 1000-2000 years, which will be calibrated with meteorological data from the robust station network in the former Soviet Central Asian …

A Theory Of Global Climate Change On Millennial Time Scales, Kirk A. Maasch

University of Maine Office of Research Administration: Grant Reports

A Theory of Global Climate Change on Millennial Time Scales In the northern hemisphere, large and rapid shifts in environmental conditions have occurred repeatedly over the last glacial- interglacial cycle. Indications are that climate change occurs on two characteristic time scales, roughly 1 - 3,000 years and 5 - 10,000 years. Evidence for millennial-scale climate variability has been found in ice cores drilled through the Greenland ice sheet, sediment cores from the North Atlantic Ocean, pollen records from both North America and Europe, and glacial deposits in North America. Paleoclimate records from the southern hemisphere also show climatic variability on …

Glacial Lake Wright, A High-Level Antarctic Lake During The Lgm And Early Holocene, Brenda L. Hall, George H. Denton, B. Overturf

Earth Science Faculty Scholarship

We report evidence of a large proglacial lake (Glacial Lake Wright) that existed in Wright Valley in the McMurdo Dry Valleys region of Antarctica at the last glacial maximum (LGM) and in the early Holocene. At its highstands, Glacial Lake Wright would have stretched 50 km and covered c. 210 km(2). Chronology for lake-level changes comes from 30 AMS radiocarbon dates of lacustrine algae preserved in deltas, shorelines, and glaciolacustrine deposits that extend up to 480 m above present-day lakes. Emerging evidence suggests that Glacial Lake Wright was only one of a series of large lakes to occupy the McMurdo …

Long-Term And Seasonal Variations In Co2: Linkages To Catchment Alkalinity Generation, Stephen A. Norton, B. J. Cosby, I. J. Fernandez, J. S. Kahl, M. Robbins Church

Earth Science Faculty Scholarship

As atmospheric emissions of S have declined in the Northern Hemisphere, there has been an expectation of increased pH and alkalinity in streams believed to have been acidified by excess S and N. Many streams and lakes have not recovered. Evidence from East Bear Brook in Maine, USA and modelling with the groundwater acid-base model MAGIC (Cosby et al. 1985a,b) indicate that seasonal and yearly variations in soil PCO2 are adequate to enhance or even reverse acid-base (alkalinity) changes anticipated from modest decreases of SO4 in surface waters. Alkalinity is generated in the soil by exchange of H+ from dissociation …

A High-Altitude Snow Chemistry Record From Amundsenisen, Dronning Maud Land, Antarctica, E. Isaksson, W. Karlen, Paul Andrew Mayewski, M. Twickler, S. Whitlow

Earth Science Faculty Scholarship

In this paper a detailed record of major ions from a 20 in deep firn core from Amundsenisen, western Dronning Maud Land, Antarctica, is presented. The core was drilled at 75degreesS, 2degrees E (2900 m.a.s.l.) during austral summer 1991/92. The following ions were measured at 3 cm resolution: Na+, Mg2+, Ca2+, Cl-, NO3-, SO42- and CH3SO3H (MSA). The core was dated back to 1865 using a combination of chemical records and volcanic reference horizons. The volcanic eruptions identified in this core are Mount Ngauruhoe, New Zealand (1974-75), Mount Agung, Indonesia (1963), Azul, Argentina (1932). and a broad peak that corresponds …

Oxygen Isotopic And Soluble Ionic Composition Of A Shallow Firn Core, Inilchek Glacier, Central Tien Shan, Karl J. Kreutz, Vladimir B. Aizen, L. Dewayne Cecil, Cameron P. Wake

Earth Science Faculty Scholarship

Oxygen isotopic and soluble ionic measurements made on snow-pit (2 in depth) and firn-core (12.4 m depth samples recovered from the accumulation zone 5100 m) of Inilchek glacier 43degrees N, 79degrees E) provide information on recent (1992-98) climatic and environmental conditions in the central Tien Shan region of central Asia. The combined 14.4 m snow-pit/firn-core profile lies within the firn zone, arid contains only one observed melt feature (10 m temperature = - 12 degreesC), Although some post-depositional attenuation of the sub-seasonal delta(18)O record is possible, annual cycles are apparent throughout the isotope profile. We therefore use the preserved delta(18)O …

Evidence Of The Kuwaiti Oil Fires In The Dasuopu Glacier Ice Core, Central Himalaya, Shichang Kang, Qin Dahe, Paul Andrew Mayewski, Xie Shucheng, Duan Keqin

Earth Science Faculty Scholarship

No abstract provided.

Recent 180 Year Oxalate (C2o42-) Records Recovered From The Mount Everest Ice Core: Some Environmental Implications, Shichang Kang, Qin Dahe, Paul Andrew Mayewski, Cameron P. Wake

Earth Science Faculty Scholarship

No abstract provided.