sgr ms thesis - University of Maine

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A 650 Orthogonal Distance from Chamber Contact (m) 0 100 200 300 400 500 600 700 800 900 1000 630 610 Peak Temperature (°C) 590 570 550 530 510 B 490 470 450 5710 25710 45710 65710 85710 105710 125710 145710 165710 185710 Time (years) a er intrusion 650 630 610 Orthogonal Distance from Chamber Contact (m) 0 100 200 300 400 500 600 700 800 900 1000 observed Tmax vs. distance trend 45 degree contact dip correc on Peak Temperature (°C) 590 570 550 530 510 490 470 450 5710 25710 45710 65710 85710 105710 125710 145710 165710 185710 Time (years) a er intrusion Figure 4.6. Maximum metamorphic temperature with orthogonal distance from the contact. A) Isograd positions are located from colored points. Cordierite, garnet, and biotite could form at the observed maximum temperatures, but the conductive model cannot explain the formation of metamorphic pyroxene. B) A comparison between the apparent thickness of metamorphic zones (solid line) and the thickness of zones if the intrusive contact is dipping at 45 degrees (dashed lines). If the observed contact is oblique, the metamorphic aureole would be skinnier. 41
approximately 140m thinner. The Shatter Zone thickness is 300m thinner. Unfortunately, there is not enough data on the depth geometry of the Shatter Zone, and there is no proof for a tilted section on the eastern side of the Cadillac Mountain intrusive complex. 4.4. Evidence for an Actively Mixing Chamber The maximum temperature achieved by this model does not explain the existence of a pyroxene zone. The assumptions used for this model are therefore unrealistic for the Cadillac Mountain intrusive complex, proving that magma reservoir convection and replenishment were active components of heat transfer. Additionally, wall-rock groundwater convection from 2-5km depth likely played a part in contact metamorphism. The Cadillac Mountain intrusive complex was part of a volcanically active region, which experienced several eruptive sequences (Chapman, 1962; Berry and Osberg, 1989; Seaman et al., 1995; Seaman et al., 1999). Widespread presence of enclaves (Wiebe et al., 1997b), evidence of magma mixing (Chapman, 1962), and the presence of interlayered gabbro and diorite sheets at the chamber base prove that the Cadillac Mountain Granite was host to magma replenishment and actively mixing before eruption. Bimodal chamber systems can often undergo several sequences of reactivation from mafic dike “entrapment” (e.g. Wiebe, 1994, Wiebe et al., 2004), and chamber replenishment can lead to overpressurization and potential eruption (e.g. Folch and Marti, 1998). The thermal input after wall rock brecciation, discussed in Chapter 7, would have been substantial. The Cadillac Mountain Granite likely 42
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FRACTAL ANALYSIS AND THERMAL-ELASTI
Page 3 and 4:
LIBRARY RIGHTS STATEMENT In present
Page 5 and 6: emplacement of mafic magma, resulti
Page 7 and 8: © 2011 Samuel Geoffrey Roy All Rig
Page 9 and 10: TABLE OF CONTENTS ACKNOWLEDGEMENTS
Page 11 and 12: 5.3.5. Clast Circularity Analysis .
Page 13 and 14: LIST OF FIGURES Figure 2.1. Figure
Page 15 and 16: LIST OF TABLES Table 6.1. Table 7.1
Page 17 and 18: subvolcanic magmatic systems, the l
Page 19 and 20: Chapter 2 GEOLOGIC SETTING 2.1. Reg
Page 21 and 22: Somesville granite suite to the wes
Page 23 and 24: Biotite is metamorphic in origin, a
Page 25 and 26: 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: 850 750 650 550 450 400m Into Chamb
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 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
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mesh to better evaluate large therm
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consistent with Type 3 breccias. Th
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A temperature versus time plot was
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Dimensionless time 0 0.05 0.1 0.15
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Figure 7.4 displays model results f
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thermal model ignores advection of
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Zone experienced a relatively weake
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7.4. Thermal-Induced Fracture Field
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Metapelite/hornfels Diorite dike E
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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
Page 147 and 148:
Oliver, N.H.S.; Rubenach, M.J.; Fu,
Page 149 and 150:
Schoutens, J.E. (1979). Empirical A
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Wiebe, R.; Holden, J.; Coombs, M.;
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