sgr ms thesis - University of Maine

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A 900 Temperature versus time curves Spherical clast in 75% matrix 850 R*1.1 T i = 900°C, τ = 0.1995 Temperature ( C) 800 750 R R*0 Solidus T i = 800°C, τ = 0.3 700 B Temperature (°C) 650 900 850 800 750 700 650 600 550 500 0 0.5 1 1.5 2 tK/r2 R*1.1 R R*0 Temperature versus time curves Spherical clast in 34% matrix Solidus Tc = 650°C, τ = 0.24 Tc = 450°C C 450 900 850 0 0.2 0.4 0.6 0.8 1 tK/r 2 Temperature versus time curves Spherical clast in 16% matrix 800 Temperature (°C) 750 700 650 600 550 R R*1.1 T i = 650°C T i = 400°C Solidus 500 450 R*0 400 0 0.1 0.2 0.3 0.4 0.5 tK/r 2 Figure 7.4. Temperature changes over time for points in a clast. R*0, R, and R*1.1 represent points in the center, edge, and 1/10th the clast radius into the magma, respectively. A) Magma is initially 75% of total volume, T i = 900°C and 800°C, T c = 650°C. B) Magma is initially 34% of total volume, T c = 650°C and 450°C, T i = 900°C. C) Magma is initially 16% of total volume, T c = 650°C and 400°C, T i = 900°C. Dimensionless time values for when the clast center reaches 720°C are given where applicable. 103
thermal model ignores advection of heat due to flow of the matrix magma relative to the clasts, there had to be an advective component at least during magma intrusion. Flow of magma around the partially melting clasts would have facilitated dissagregation, though “ghosting” of some clast margins suggests that diffusion, or local mixing of the two magmas, may have occurred without marked flow of the matrix magma. Flow is the physical component for complete disaggregation to occur. Without it, clast melting and local mixing would still occur, but flow is more effective at mixing the melted material into the magma, essentially removing that clast. Small clasts reach melt temperatures within seconds after emplacement, when there is a greater potential for magmatic flow. This could lead to small clast disaggregation well before the cores of large clasts reach solidus. There is no constraint on magma flow because there is no evidence for its existence except at the local scale. Regardless of this, Bar Harbor Formation clasts with the average bulk chemistry eventually achieve supersolidus temperatures and given any magmatic flow, they have the potential to disaggregate. The degree of melt in Bar Harbor Formation clasts is dependent on the melt temperature, the matrix to clast volume ratio, and the initial temperatures of clast and intruding magma. As mentioned in sections (2.3) and (6.1), The Bar Harbor Formation is heterogeneous with layers consisting of pelites, sandstone, volcanic tuff, detrital quartzite, calc-silicates, and volcanic tuff. It should not be expected that all Bar Harbor Formation clasts within the Shatter Zone should have the same solidus temperature, and it is possible that some units did not 104
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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
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thinned lithosphere allows for part
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A B C Figure 3.1. Formation of a la
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1997; Branney and Kokelaar, 1998; J
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Effusive-Type Eruption max 10 0 - 1
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magma quickly intrudes the develope
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Piston Downsag Piecemeal Funnel Tra
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fragmentation, and thermal energy h
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Chapter 4 THERMAL FRAMEWORK FOR CON
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contrast, conduction is heat transf
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A B Grt C Grt D Crd Crd E 1 mm F Cr
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! ! ! ! Biotite Zone Garnet Zone !
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4.3.1. Model Setup The model is use
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to make a “hockey puck” style g
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t = 0s t = 1E11 t = 1E12s t = 1E13s
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850 750 650 550 450 400m Into Chamb
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approximately 140m thinner. The Sha
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Chapter 5 ROCK MECHANICS AND THE FR
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A β δ σ 1 σ 3 σ t c a σ 1 σ
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friction along the closed crack sur
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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 and 78: eaction processes were involved in
Page 79 and 80: Chapter 6 ANALYSIS AND RESULTS The
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: Figure 7.4 displays model results f
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
Page 129 and 130: This thermal fracture model explain
Page 131 and 132: disaggregation of Bar Harbor clasts
Page 133 and 134: REFERENCES Acocella, V. (2007). Und
Page 135 and 136: Billen, M.I. and Gurnis, M. (2001).
Page 137 and 138: Clarke, D. B. (2007). Assimilation
Page 139 and 140: Fisher, R.V. (1960). Classification
Page 141 and 142: Hartmann, W.K. (1969). Terrestrial,
Page 143 and 144: Johnson, S.E.; Paterson, S.R.; Tate
Page 145 and 146: Mandelbrot, B.B. (1967). How long i
Page 147 and 148: Oliver, N.H.S.; Rubenach, M.J.; Fu,
Page 149 and 150: Schoutens, J.E. (1979). Empirical A
Page 151 and 152: Wiebe, R.; Holden, J.; Coombs, M.;
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