Physical Sciences and Mathematics Commons^™

Kinematic Vorticity And Porphyroclast Rotation In Mylonites Of The Norumbega Fault System: Implications For Paleoviscometry, Hendrik Lenferink

Honors College

Crystallographic and shape preferred orientation (SPO) fabrics that develop in mylonitic shear zones can preserve the mean kinematic vorticity number (Wm) of bulk flow. Microstructural methods exploiting dynamically recrystallized quartz and porphyroclast SPO fabrics typically yield conflicting values of Wm. The Sandhill Corner Mylonite Zone of the Norumbega Fault System, Maine, USA, serves as a case study for investigating this discrepancy; Wm estimates range from 0.90 to 1.00 employing the former method (Method 1) and from 0.3 to 0.6 employing the latter method (Method 2). Using a numerical model, I show how a low-viscosity layer (LVL) surrounding clasts affects their …

Stratigraphic Architecture Of Pozuelo Mounds As Revealed By Earth Resistivity Tomography, Caeli Connolly

Honors College

This study is a geoarchaeological analysis using earth resistance tomography (ERT) surveys of two of four mounds at Pozuelo (Formative Period, cal yr 3000 BP) in the Chincha Valley of coastal, southern Peru. Layers identified in the subsurface were to determine the presence or absence of regional continuity between the mounds. This effort is part of a larger investigation examining the paleoenvironmental setting of the site, and its influence on site location and use. Ten earth resistance tomography profiles were collected using an ABEM Terrameter LS2 and 81 pin array. These profiles were then topographically corrected using topographic survey data …

A Practical Solution: The Anthropocene Is A Geological Event, Not A Formal Epoch, Philip L. Gibbard, Andrew M. Bauer, Matthew Edgeworth, William F. Ruddiman, Jacquelyn L. Gill, Dorothy J. Merritts, Stanley C. Finney, Lucy E. Edwards, Michael J. C. Walker, Mark Maslin, Erle C. Ellis

Biology and Ecology Faculty Scholarship

The Anthropocene has yet to be defined in a way that is functional both to the international geological community and to the broader fields of environmental and social sciences. Formally defining the Anthropocene as a chronostratigraphical series and geochronological epoch with a precise global start date would drastically reduce the Anthropocene’s utility across disciplines. Instead, we propose the Anthropocene be defined as a geological event, thereby facilitating a robust geological definition linked with a scholarly framework more useful to and congruent with the many disciplines engaging with human-environment interactions. Unlike formal epochal definitions, geological events can recognize the spatial and …

Distribution Of First Row Transition Elements In Eclogites, Natalie Harmon

Honors College

Surficial materials are recycled back into the deep Earth at subduction zones. The oxidation state of subducted materials affects the oxidation state of major geochemical reservoirs in the Earth, such as the mantle and the crust. First row transition elements (FRTEs), such as V and Sc, are highly redox sensitive and thus have the potential to track important redox processes in subduction zones. In this project, concentrations of FRTEs in garnet, omphacite, and rutile were determined for a global suite of oceanic eclogites, which represent exhumed subducted materials. Data were collected by LA-ICP-MS using an ESI NWR193UC laser ablation system …

Application Of Boron Isotopes To Constrain The Depositional Environment Of The Precursors To Proterozoic Granulite-Facies Borosilicate Paragneisses, Larsemann Hills, Antarctica, Edward Grew

University of Maine Office of Research Administration: Grant Reports

Intellectual Merit. Major challenges in understanding high P-T granulite facies terranes are identifying the original protolith rocks and the tectonic environment in which they were originally deposited. This project focuses on granulitic gneisses exposed in the Larsemann Hills, Prydz Bay (East Antarctica). These rocks are considered to be metasediments (paragneisses), but, despite more than 20 years of intense study, the tectonic framework of deposition of the original rocks is still debated. However the origin of these rocks has important implications for determining the assembly of the ancient Gondwana continent. The unique B-rich character of the rocks offers potential insight into …

Heterogeneous Deformation Of Gabbroic Rocks, Calvin Mako

Honors College

The Grenville province is the exhumed remains of a more than 1 billion year old orogen. Mid to lower crustal rocks of this orogen are now exposed at the surface, affording the opportunity to examine deeper crustal processes during orogeny. I have studied an outcrop of anorthositic gabbro from the Central Metasedimentary Belt boundary thrust zone (CMBbtz) in the Grenville province of southern Ontario. The CMBbtz is a region that separates two major lithotectonic domains of this part of the Grenville province and is thought to have accommodated large scale thrusting in the mesoproterozoic era. The CMBbtz comprises large crystalline …

Coupled Deformation And Metamorphism, Fabric Development, Rheological Evolution And Strain Localization, Scott E. Johnson

University of Maine Office of Research Administration: Grant Reports

When Earth's tectonic plates interact with one another the rocks that comprise them are deformed, commonly forming great mountain chains. During this deformation, the minerals that make up the rocks can become spatially or crystallographically aligned to form a fabric. The development of rock fabric is a primary factor affecting the strength, or rheological evolution of deforming rocks. Fabric development commonly involves coupling of both physical and chemical processes. For example, crenulation cleavage is the most common type of fabric in multiply deformed rocks, and its formation leads to extreme mineral segregation and rheological anisotropy. It is also commonly associated …

Three-Dimensional Modeling Of Continental Subduction And The Evolution Of Ultra High Pressure Metamorphism, Peter O. Koons

University of Maine Office of Research Administration: Grant Reports

This project investigates driving forces and material behavior associated with continental subduction and ultra high-pressure metamorphism through an integration of numerical modeling of continental subduction and structural/petrological evolution of the material caught in the collision. The natural ultra high-pressure and high-pressure assemblages of the Western Gneiss of Norway provide rheological, geometric and geochronological information for the modeling, while the active obliquely convergent plate boundary of central New Zealand serves as a modern analog of a collision-subduction transition. Continental subduction zones represent regions where the crust-mantle interaction changes from nearly horizontal to dominantly vertical, accentuating the competing influences of body and …

Beryllium In Antarctic Ultrahigh-Temperature Granulite-Facies Rocks And Its Role In Partial Melting Of The Lower Continental Crust, Edward S. Grew

University of Maine Office of Research Administration: Grant Reports

This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a project to investigate the role of beryllium in lower crustal partial melting events. The formation of granitic liquids by partial melting deep in the Earth's crust is one of the major topics of research in igneous and metamorphic petrology today. One aspect of this sphere of research is the beginning of the process, specifically, the geochemical interaction between melts and source rocks before the melt has left the source area. One example of anatexis in metamorphic rocks affected by conditions found deep …

Collaborative Research: Locating The Mantle Component In Granite, Daniel R. Lux, John P. Hogan, David Gibson

University of Maine Office of Research Administration: Grant Reports

Granitic plutons of the Coastal Maine Magmatic Province (CMMP) commonly display dramatic field relations that record interaction between magmas of markedly different composition (chemical and isotopic) and physical properties. Silicic magma chambers, derived from the crust, received influxes of denser mafic magma that spread out along the floor of these chambers to produce a compositional stratification know as Mafic and Silicic Layered Intrusions (MASLI). The spectacular field relations and large compositional variation in the vicinity of the interface between contrasting magma types are well document by recent studies. In contrast, the extent of physical and chemical coupling between the base …

Magmatic To Solid-State Fabric Transition In A Post-Tectonic Tonalite Pluton, Scott E. Johnson

University of Maine Office of Research Administration: Grant Reports

Magma chambers are an essential component in the construction of oceanic and continental lithosphere, and profoundly influence the thermal and mechanical behavior of the crust and mantle. The mechanical properties of a magma chamber change during cooling and crystallization, as accommodation of deformation changes from magmatic flow to solid-state processes. Thus, to understand the thermo-mechanical evolution of magma chambers, it is crucial to understand the relative importance of magmatic and solid-state flow, and the nature of the transition between them. This project is investigating such a transition preserved in the San Jose pluton, Baja California, Mexico. The pluton postdates the …

Mri: Acquisition Of A Modern Electron Microprobe At The University Of Maine, Charles V. Guidotti

University of Maine Office of Research Administration: Grant Reports

This award, made through the Major Research Instrumentation (MRI) Program, provides support for the acquisition of a state-of-the-art electron microprobe (EMP) for the microchemical characterization of geological materials. A new EMP will replace an aging (vintage 1981) ARL SEMQ in the Department of Geological Sciences at the University of Maine. The instrument will facilitate research on a range of topics in metamorphic petrology including, the speciation of Fe and distribution of OH- in metapelites, and light element (i.e. Li, B, Be) partitioning in granulite facies rocks. Research in paleoclimatology will also be enhanced by this instrument. The probe will be …

Beryllium In Granulite-Facies Pegmatites In Archean Napier Complex, Antarctica, Edward S. Grew

University of Maine Office of Research Administration: Grant Reports

This award, provided by the Office of Polar Programs of the National Science Foundation, supports participation of a researcher from the University of Maine in an expedition of the Japanese Antarctic Research Expedition (JARE) to study beryllium enriched minerals in Enderby Land. Beryllium is a rare element in crustal rocks and enrichments are especially unusual in granulite-facies (high temperature and pressure, and relatively dry conditions) metamorphic rocks. This project focuses on unique beryllium-enriched pegmatites in the Archean ultra-high temperature (up to 1000 degrees C) granulite-facies Napier Complex in eastern Casey Bay, Enderby Land, East Antarctica. The primary objective is to …

Acquisition Of An Automated Powder X-Ray Diffraction System, Charles V. Guidotti, Edward S. Grew, Martin Yates

University of Maine Office of Research Administration: Grant Reports

This grant provides $70,295 as one-half support of the costs of acquiring a state-of-the-art powder X-ray diffractometer (XRD) that will be housed in a newly constructed Global Sciences building on the Orono campus of the University of Maine. This acquisition will allow these PI's to continue their internationally recognized research programs in petrologic mineralogy including studies of the phase equilibria of solid solutions in metamorphic rocks and borosilicates. The characterization of both structural properties and mineralogic identification of unknowns is fundamental to these researchers and the establishment of a modern XRD facility at the University of Maine will benefit a …

Explorations, Vol. 1, No. 2, Jim I. Mead, Emilee M. Mead, Carol J. Bombard, Ronald B. Davis, Marcella H. Sorg

Explorations — A Journal of Research

The cover print is a multi-plate colored etching entitled Skull and Sun Dial, by Susan Groce, Associate Professor of Art at the University of Maine at Orono, where she teaches Printmaking and Drawing.

Articles include:

"The Quaternary"

"Ice Age Plants and Animals: Secrets of the Colorado Plateau," by Jim I. Mead and Emilee M. Mead

"Finding the Facts: Pieces of the Puzzle"

"On Location: In Search of the First Americans"

"A Temporal Vegetational Continuum: From Tundra to Forest," by Carole J. Bombard for Ronald B. Davis

"Anatomy of an Excavation," by Robson Bonnichsen

"What the Bones Tell Us," by …

Interpretation Of The Chemical And Physical Time-Series Retrieved From Sentik Glacier, Ladakh Himalaya, India, Paul Andrew Mayewski, N. Ahmad, Gordon Smith, M. Pourchet

Earth Science Faculty Scholarship

Spectral analysis of time series of a c. 17 ± 0.3 year core, calibrated for total β activity recovered from Sentik Glacier (4908 m) Ladakh, Himalaya, yields several recognizable periodicities including sub-annual, annual, and multi-annual. The time-series, include both chemical data (chloride, sodium, reactive iron, reactive silicate, reactive phosphate, ammonium, δD, δ(¹⁸O) and pH) and physical data (density, debris and ice-band locations, and microparticles in size grades 0.50 to 12.70 μm). Source areas for chemical species investigated and general air-mass circulation defined from chemical and physical time-series are discussed to demonstrate the potential of such studies in the …

An Active Rock Glacier, Wavbal Pass, Jammu And Kashmir Himalaya, India, Paul Andrew Mayewski, P. Andrew Jeschke, N. Ahmad

Earth Science Faculty Scholarship

A currently active rock glacier with a snout elevation of 4,055 m was observed in the Jammu and Kashmir Himalaya. Its formation is ascribed to stagnation of the terminal area of a true glacier.

Characteristics And Significance Of Rock Glaciers In Southern Victoria Land, Antarctica, Paul Andrew Mayewski, Jon Hassinger

Earth Science Faculty Scholarship

[From the introduction] Rock glaciers, large-scale masses of frozen debris...form a group of features that, because of their dependence on temperature and precipitation, can be used as monitors of climatic change.

Dickey-Lincoln School Lakes Project Environmental Impact Statement: Appendix A: Geology And Seismology (Supplement), Walter A. Anderson, New England Division, United States Army Engineer Division

Dickey-Lincoln School Lakes Project

The plan was prepared for a close working relationship between the evaluation teams and the immediate availability of geochemical and geophysical data to the geologic mapping team. Those samples determined in the field to be anomalously high in heavy metals by cold extractable procedures were sent to North American Laboratories where metal content determinations were made through: atomic absorption and spectrophotometry after hot acid digestion techniques.

Lichenometric Distribution Of Rhizocarpon Geographicum On Mt. Washington: A Relative Dating Tool., Paul Andrew Mayewski, Peter A. Jeschke

Earth Science Faculty Scholarship

Excerpt from summary, p. 83: In addition to marking the distribution of snowpatches and the relative age of patterned ground features, local departures from the regional lichenometric trend may also be used to define and relatively date: changes in the distribution of soils and vegetation, avalanche deposits, and abrasion of hiking trails. Lichenometric studies will be undertaken in the following year to date more precisely features and events on Mount Washington.

Geotechnical Impact Study. Map Volume, United States Department Of Energy

Dickey-Lincoln School Lakes Project

Surficial Deposits Legend Maps of Dickey/Lincoln School lakes Transmission - E.I.S.Project, Environmental Assessment of Alternative Routs, Geotechnical Study, United States Department of the Interior.

Transmission Reconnaissance Study : Dickey-Lincoln School Lakes Project, United States Department Of Interior

Dickey-Lincoln School Lakes Project

Two dams are proposed on the St. John River in northern Maine: Dickey, a high earth filled dam immediately above the confluence of the Allagash with the St. John, will have an installed generating capacity of 760 MW; and Lincoln School Dam, 11 miles downstream, a capacity of 70 MW. These dams are scheduled for completion during the mid 1980's. The U.S. Corps of Engineers, New England Division, has been allocated funds to design the project and prepare their own environmental impact statement. This report (Transmission Reconnaissance Studies) discusses alternative transmission facilities needed to connect the project with the New …

Use Of Remote Sensing To Quantify Construction Material And To Define Geologic Lineations : Dickey-Lincoln School Lakes Project, Maine, H. L. Mckim, C. J. Merry

Dickey-Lincoln School Lakes Project

This report contains Appendixes A and B of Special Report 242, use of remote sensing to quantify construction material and to define geologic lineations.