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

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ANALOGS FOR THE SCOTLAND FORMATION The Scotland Formation of Barbados shows similarities to the Juniper Ridge Conglomerate (JRC) and the associated Upper and Lower Waltham Shales which are part of the Great Valley Group (GVG) of California. These GVG sediments were deposited in a Cretaceous age forearc basin (Lowe, 2004). The JRC and associated Upper and Lower Waltham Shales are made up of five lithofacies. Including: (1) Coarse, cobble and pebble conglomerate channel fill, (2) Thick bedded sandstone fill, (3) interbedded sandstone and mudstone levee-deposits flanking the channels, (4) thick-bedded channel mouth and proximal lobe deposits and (5) Intervening thick mudstone formations made up of thin fine grained muddy turbidites, recording periods of low coarse clastic-sediment influx. (Lowe, 2004) Facies 1, 2, 3 and 5 of the Scotland Formation correspond to the JRC channel- levee complex system. Facies 4 corresponds to the JRC channel mouth and proximal lobe sandstone. Facies 6 is the equivalent of the closely associated setting of the Upper and Lower Waltham Shales (Figures 2.6, 2.7, 2.41 and 2.42). 25
Chapter Three: Petrographic Analysis of the Scotland Formation Sandstones Eocene-Oligocene sandstones found interbedded with sand and shale in the succession known as the Scotland Formation, onshore Barbados, are the equivalents of the reservoirs that are being produced from in the Woodbourne oilfield in the southern part of the island. Outcrops of this formation are exposed in the northeastern portion of Barbados where the Pleistocene limestone cap has been eroded to expose the underlying Tertiary sediments. The Scotland Formation sediments have been interpreted as abyssal plain or trench deposits that were tectonically incorporated into the accretionary prism (Speed 1982; Larue and Speed, 1983; Torrini et al., 1985; Gortner and Larue, 1986). Their location onshore Barbados Island means that, if these sediments were originally deposited in a trench setting, they would had to have been tectonized during subduction deformation, transported westward and subsequently uplifted after becoming part of the prism. If this is the case, these deposits were potentially translated > 100 km westward from the trench to the present location through shortening of the prism. Although none of the previous workers have disputed a trench origin for the Scotland Formation, the results of previous petrographic analyses suggest that the Scotland Formation did not experience such a tectonic history (Larue and Kasper, 1985; and Larue, et al., 1987; Punch, 2004). 26
Page 1 and 2: Copyright by Nysha Chaderton 2009
Page 3 and 4: Sedimentation within the Tobago For
Page 5 and 6: 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: SUMMARY DEPOSITIONAL SETTING OF THE
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 and 58: K feldspar preservation to slightly
Page 59 and 60: CONCLUSIONS 1. No quartz cementatio
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
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Figure 2.16c: Measured section at C
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Figure 2.18: Correlation of section
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Figure 2.21: Parallel laminated sil
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Wach, Vincent and Chaderton March 2
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Figure 2.24: Channel element identi
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WRB S N Fresh rock face exposed by
Page 115 and 116:
Figure 2.28: Photograph of Diplocra
Page 117 and 118:
Figure 2.31: Conglomerate with eros
Page 119 and 120:
Figure 2.33: Thalassinoides trace f
Page 121 and 122:
Figure 2.35: Mount All measured str
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Figure 2.37: Medium grained sand be
Page 125 and 126:
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
Page 137 and 138:
Figure 3.8: Photo of sample SGRF 11
Page 139 and 140:
Figure 3.10: Photo of sample SGRF 1
Page 141 and 142:
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
Page 217 and 218:
WEBER, J.C., DIXON, T.H., DEMETS, C
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