sgr ms thesis - University of Maine

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(5.10) Substituting this into equation (3) for circularity (C): (5.11) This successfully produces a ratio between the area of a clast and the area of an imaginary circle with perimeter equal to that of the clast. The ratio can range from 0 to 1, with very elongate shapes trending to 0 and very compact shapes trending to 1. 63
Chapter 6 ANALYSIS AND RESULTS The Shatter Zone represents the brittle response to magma reservoir pressure fluctuations during evacuation. Reservoir overpressure occurs when the rate of pressure loading cannot be accommodated by visco-elastic deformation of wall rock. The differential stresses produced by overpressurization and subsequent evacuations are substantial enough to overcome the elastic limit and fracture wall rock, after which a volatile rich component of magma quickly intrudes the fractures. Luckily, these intrusive features chill relatively quickly, providing evidence for volcanic activity. The impetus of this thesis is to better understand the mechanics of rigid rock in a subvolcanic setting. The Shatter Zone formed from a subvolcanic reaction to volcanic eruption and I explore the possible brecciation mechanisms that may have been active in the development of the Shatter Zone. Field observations within the Shatter Zone describe the gradational breccia characteristics. I discuss the methods used to collect CSD, CBS, and CCA data, then provide the results of the analysis and move on to confirm explosive brecciation as the likeliest developmental mechanism for the Shatter Zone. 64
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FRACTAL ANALYSIS AND THERMAL-ELASTI
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LIBRARY RIGHTS STATEMENT In present
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emplacement of mafic magma, resulti
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© 2011 Samuel Geoffrey Roy All Rig
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TABLE OF CONTENTS ACKNOWLEDGEMENTS
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5.3.5. Clast Circularity Analysis .
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LIST OF FIGURES Figure 2.1. Figure
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LIST OF TABLES Table 6.1. Table 7.1
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subvolcanic magmatic systems, the l
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Chapter 2 GEOLOGIC SETTING 2.1. Reg
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Somesville granite suite to the wes
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Biotite is metamorphic in origin, a
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Chapter 3 PHYSICAL DESCRIPTION OF S
Page 27 and 28: thinned lithosphere allows for part
Page 29 and 30: A B C Figure 3.1. Formation of a la
Page 31 and 32: 1997; Branney and Kokelaar, 1998; J
Page 33 and 34: Effusive-Type Eruption max 10 0 - 1
Page 35 and 36: magma quickly intrudes the develope
Page 37 and 38: Piston Downsag Piecemeal Funnel Tra
Page 39 and 40: fragmentation, and thermal energy h
Page 41 and 42: Chapter 4 THERMAL FRAMEWORK FOR CON
Page 43 and 44: contrast, conduction is heat transf
Page 45 and 46: A B Grt C Grt D Crd Crd E 1 mm F Cr
Page 47 and 48: ! ! ! ! Biotite Zone Garnet Zone !
Page 49 and 50: 4.3.1. Model Setup The model is use
Page 51 and 52: to make a “hockey puck” style g
Page 53 and 54: t = 0s t = 1E11 t = 1E12s t = 1E13s
Page 55 and 56: 850 750 650 550 450 400m Into Chamb
Page 57 and 58: approximately 140m thinner. The Sha
Page 59 and 60: Chapter 5 ROCK MECHANICS AND THE FR
Page 61 and 62: A β δ σ 1 σ 3 σ t c a σ 1 σ
Page 63 and 64: friction along the closed crack sur
Page 65 and 66: h h/2 h/4 Figure 5.2. A cube displa
Page 67 and 68: where N (≥r) is the count of clas
Page 69 and 70: to place a minimum size limit when
Page 71 and 72: moment of sudden fracture tip failu
Page 73 and 74: produced results in a self-similar
Page 75 and 76: 13 ln(area) (pixels) 12 11 10 9 ln(
Page 77: eaction processes were involved in
Page 81 and 82: Type 1 Type 2 500 m N Type 1 Type 2
Page 83 and 84: A B Figure 6.3. Type 2 Shatter Zone
Page 85 and 86: A B Figure 6.5. Centimeter-scale bo
Page 87 and 88: A B Figure 6.6. Brecciation texture
Page 89 and 90: The final breccia classified in thi
Page 91 and 92: esolution images of each box were s
Page 93 and 94: Clast circularity data were produce
Page 95 and 96: A 1000 Clast Size Distribu on: Type
Page 97 and 98: diorite dike with D s = 2.62 and R
Page 99 and 100: 6.3.3. Clast Circularity Analysis (
Page 101 and 102: with decreasing clast size in all T
Page 103 and 104: possibilities as postulated previou
Page 105 and 106: Chapter 7 MECHANISMS FOR SECONDARY
Page 107 and 108: magma. To prove the viability of th
Page 109 and 110: mesh to better evaluate large therm
Page 111 and 112: consistent with Type 3 breccias. Th
Page 113 and 114: A temperature versus time plot was
Page 115 and 116: Dimensionless time 0 0.05 0.1 0.15
Page 117 and 118: Figure 7.4 displays model results f
Page 119 and 120: thermal model ignores advection of
Page 121 and 122: Zone experienced a relatively weake
Page 123 and 124: 7.4. Thermal-Induced Fracture Field
Page 125 and 126: Metapelite/hornfels Diorite dike E
Page 127 and 128: 7.4.2. Results and Discussion COMSO
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This thermal fracture model explain
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disaggregation of Bar Harbor clasts
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REFERENCES Acocella, V. (2007). Und
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Billen, M.I. and Gurnis, M. (2001).
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Clarke, D. B. (2007). Assimilation
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Fisher, R.V. (1960). Classification
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Hartmann, W.K. (1969). Terrestrial,
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Johnson, S.E.; Paterson, S.R.; Tate
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Mandelbrot, B.B. (1967). How long i
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Oliver, N.H.S.; Rubenach, M.J.; Fu,
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Schoutens, J.E. (1979). Empirical A
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Wiebe, R.; Holden, J.; Coombs, M.;
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sgr ms thesis - University of Maine

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