Copyright by Nysha Chaderton 2009 - The University of Texas at ...

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They are common in accretionary prism settings (Fossen et al., 2007). Deformation bands were observed in 2 of the 10 samples point counted. There is a reduction in porosity and permeability along deformation bands. However there is thought to be an initial dilation that may aid in fluid flow and lead to preferential cementation along these linear features (Ngwenya et al., 2000; Olgivie and Glover, 2001; Fossen et al., 2007). Fractured quartz grains provide clean sites for nucleation of quartz cements that are so abundant in sand (Walderhaug, 1996, Fossen and Bale, 2007). Although it is often thought that deformation band zones are baffles to fluid flow, Fossen and Bale (2007) showed that the impact of deformation bands on reservoir performance may be small or negligible. Within the Scotland Formation samples, no quartz cementation was observed within the deformation bands. This observation further supports the idea that the Scotland Formation did not experience temperatures greater than 60˚C. In addition the observations that cataclastic deformation bands develop at depths of 2.5 km or less and even in sediments buried as shallowly as 50 m also support the concept that the Scotland Formation was never buried very deeply. Based on the calculations of the IGV of the samples which ranged from a minimum of 27.5% to a maximum of 42 % the rocks of the Scotland Formation appear to have been buried less than 2500 m and possibly only about 1500 m. 43
CONCLUSIONS 1. No quartz cementation occurs during diagenesis of the Scotland Formation. Quartz cementation as overgrowths is fractured and interpreted to be of recycled origin. 2. Scotland Formation sediments have never been exposed to temperatures greater than ~ 60 C. 3. Scotland Formation sediments have probably been buried less than 2500 m and possibly have never been buried much more deeply than 1500 m. 4. Sandstones within channels, lobes and levee facies have all preserved significant amounts of primary porosity and all of them have an IGV of 27.5% or higher. 5. Cementation is minor and although some samples have kaolinite, chlorite and hematite cements that obstruct pore throats, they are probably not present in large enough quantities to present a major hindrance to fluid flow. 6. The sample from the levee facies sands appears to have been more compacted and this combined with these sands being the thinnest (on the scale of cms) and the least laterally continuous of all the facies, indicate that these sands make the least favorable reservoirs. 44
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Copyright by Nysha Chaderton 2009
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Sedimentation within the Tobago For
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Acknowledgements I would like to th
Page 7 and 8: Table of Contents List of Tables ..
Page 9 and 10: List of Tables Table 2.1: Latitudes
Page 11 and 12: Figure 2.14: Planar parallel lamina
Page 13 and 14: Figure 2.42: Coarse, cobble and peb
Page 15 and 16: Figure A.3a: Chalky Mount Ridge mea
Page 17 and 18: 1. Development history of the south
Page 19 and 20: Formation. This interpretation requ
Page 21 and 22: DATA AND METHODOLOGY Extensive work
Page 23 and 24: DESCRIPTIVE METHODOLOGY Each sectio
Page 25 and 26: Two or more channel complexes stack
Page 27 and 28: These poorly sorted sands are later
Page 29 and 30: East Coast Road Although the East C
Page 31 and 32: succession of interlaminated siltst
Page 33 and 34: Mount All The beds of the Mount All
Page 35 and 36: Lobes are non-channelized bodies, 3
Page 37 and 38: Sandy units are the most resistant
Page 39 and 40: SUMMARY DEPOSITIONAL SETTING OF THE
Page 41 and 42: Chapter Three: Petrographic Analysi
Page 43 and 44: had not been buried deeply or long
Page 45 and 46: Feldspars Calcium Plagioclase Felds
Page 47 and 48: Authigenic Minerals Authigenic mine
Page 49 and 50: amounts of chlorite and kaolinite c
Page 51 and 52: Sample: WRA 16 This sample was take
Page 53 and 54: cementation is observed. A number o
Page 55 and 56: COMPARISON WITH PREVIOUS WORK Punch
Page 57: K feldspar preservation to slightly
Page 61 and 62: The highest point of the island, is
Page 63 and 64: STRATIGRAPHIC FRAMEWORK ONSHORE TO
Page 65 and 66: STRUCTURAL FRAMEWORK OF THE BARBADO
Page 67 and 68: Sandy material is primarily quartz
Page 69 and 70: esult of extension caused by flexur
Page 71 and 72: 1994). The origin of the Oceanic Fo
Page 73 and 74: Oligocene-age sediments are deposit
Page 75 and 76: The observation of channel geometri
Page 77 and 78: Pudsey, (1982) interpreted smectite
Page 79 and 80: The interpretation of the Scotland
Page 81 and 82: Figure 1.2: Convergent margins arou
Page 83 and 84: NSF Study Lines Grenada St. Kitts S
Page 85 and 86: Figure 2.2: Generalized vertical se
Page 87 and 88: Figure 2.4: Detailed Geological map
Page 89 and 90: Figure 2.6: Photographs and illustr
Page 91 and 92: Figure 2.8: Bedsets on the channel
Page 93 and 94: S 50 m Figure 2.10: Photo-panorama
Page 95 and 96: Figure 2.13: Laminated silt and mud
Page 97 and 98: Figure 2.16a: Measured section at C
Page 99 and 100: Figure 2.16c: Measured section at C
Page 101 and 102: Figure 2.18: Correlation of section
Page 103 and 104: Figure 2.21: Parallel laminated sil
Page 105 and 106: Wach, Vincent and Chaderton March 2
Page 107 and 108: Wach, Vincent and Chaderton March 2
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Wach, Vincent and Chaderton March 2
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Figure 2.24: Channel element identi
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WRB S N Fresh rock face exposed by
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Figure 2.28: Photograph of Diplocra
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Figure 2.31: Conglomerate with eros
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Figure 2.33: Thalassinoides trace f
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Figure 2.35: Mount All measured str
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Figure 2.37: Medium grained sand be
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Figure 2.38b: Inner Turner’s Hall
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Figure 2.38d: Inner Turner’s Hall
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Figure 2.39: Spa Hill measured stra
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Juniper Ridge, California Scotland
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Figure 3.1: Fractured quartz grain
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SGRF 1C SGRF 9C Figure 3.5: Measure
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Figure 3.8: Photo of sample SGRF 11
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Figure 3.10: Photo of sample SGRF 1
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Figure 3.12: Photo of sample WRA 16
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Figure 3.14: Photo of sample WRB 8
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Figure 3.16: Photo of sample ITR 9
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Figure 3.19: Photo of sample CMRA s
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Figure 3. 23: Composition of Scotla
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Figure 4.1: Base map showing seismi
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Figure 4.3: Channels within Unit Fi
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Figure 4.5: Seismic reflection prof
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Figure 4.7 Isochron maps of the old
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Figure 4.9: Illustration of the Spe
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Figure 4.11: Illustration of Hypoth
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necessary to clear a path. Keep to
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2006 Figure A.2a: Lidar Ridge measu
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Figure A.3b: Chalky Mount Ridge mea
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2006 Figure A.4a: Chalky Mount Ridg
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2006 Figure A.4c: Chalky Mount Ridg
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2006 Figure A.6: Chalky Mount Ridge
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Figure A.7b: Measured Section of Ch
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2006 Figure A.8a: Sleeping Giant Ri
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2006 Figure A.9: Sleeping Giant Rid
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2006 Figure A.11: Sleeping Giant Ri
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Figure A.13a: Sleeping Giant Ridge
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2006 Figure A.14a: Coast Road Below
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2006 Figure A.14c: Coast Road Below
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2006 Figure A.14e: Coast Road Below
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2006 Figure A.14g: Coast Road Below
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2006 Figure A.15: Ermy Bourne Ridge
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2006 Figure A.17: Spa Hill Fold Mea
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2006 Figure A.19: Ermy Bourne Ridge
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Figure A.20b: Walkers Ridge Measure
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Figure A.21: Walkers Ridge Measured
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Figure A.22b: Walkers Ridge Measure
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2007 Figure A.23b: Inner Turner’s
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2007 Figure A.23d: Inner Turner’s
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Framework grains Quartz Feldspar Ro
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CRIMES, T.P., 1977, Trace fossils o
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MONTGOMERY, S.L., BARKER, C.E., SEA
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RICHARDS, M., BOWMAN, M., and READI
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WEBER, J.C., DIXON, T.H., DEMETS, C
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