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Table of Contents - Special Paper 491

Geology and Geomorphology of Barbados:
A Companion Text to Maps with Accompanying Cross Sections, Scale 1:10,000

By Robert C. Speed; edited by Christine Speed and Richard Sedlock

CD-ROM CONTENTS vii
NOTE FROM THE EDITORS ix
Parishes of Barbados x
Index to 1:10,000 Geologic Maps xi
Generalized Locations of Cross Sections A, B, C, and D xii

ABSTRACT
1
1. SCOPE AND OBJECTIVES 2
2. EXPLANATION OF MAPS AND CROSS SECTIONS 2
2.1 Maps 2
2.2 Cross Sections 2
3. PREVIOUS AND CURRENT RESEARCH 2
4. SYNOPSIS OF GEOLOGICAL EVOLUTION OF BARBADOS 3
4.1 Barbados Ridge 3
4.2 Island Emergence 4
5. GEOMORPHIC ZONATION OF BARBADOS 5
5.1 Zone I: Central Highlands 6
5.2 Zone II: Terraced Flank 6
5.3 Zone III: Windward Slope 7
5.4 Zone IV: Scotland District 7
6. GEOCHRONOLOGY 7
7. STRATIGRAPHY 7
7.1 Elementary Rock Stratigraphy 7
7.2 Time Stratigraphy 10
7.3 Tectonic Stratigraphy 12
8. ROCK AND SEDIMENT UNITS 12
8.1 Holocene Deposits 12
8.1.1 Beach 12
8.1.2 Dune 14
8.1.3 Estuary 14
8.1.4 Lagoon 14
8.1.5 Stream 14
8.1.6 Manmade 14
8.1.7 Diverse Shore Zone Sediments 14
8.2 Holocene or Pleistocene Deposits 14
8.2.1 Colluvium 14
8.2.2 Older Stream Deposits 14
8.2.3 Older Dunes 15
8.2.4 Landslides 15
8.3 Holocene Deposits and Pleistocene Limestone, Undivided 16
8.4 Pleistocene Limestone 16
8.4.1 Unit Pyu 17
8.4.2 Unit P5a 18
8.4.3 Unit P5c 18
8.4.4 Unit P5e 18
8.4.5 Unit P5o 18
8.4.6 Unit P7 18
8.4.7 Unit P7o 18
8.4.8 Unit Po 18
8.4.9 Unit Poc 19
8.4.10 Unit Pc 19
8.5 Pre-Quaternary Deposits 19
8.5.1 Bissex Hill Formation 19
8.5.2 Conset Formation 19
8.5.3 Unit of Kingsley Club 19
8.6 Paleogene Strata in Tectonic Complexes 20
8.6.1 Oceanic Allochthon 20
8.6.1.1 Oceanic Nappes 20
8.6.1.2 Bissex Hill Nappe 20
8.6.1.3 Springfield Nappe 20
8.6.1.4 Undifferentiated Oceanic Allochthon 20
8.6.2 Basal Complex 20
8.6.2.1 Terrigenous Strata 20
8.6.2.2 Radstone Strata 21
8.6.2.3 Diamictite 21
9. STRUCTURES 21
9.1 Map Representation of Structural Data 21
9.2 Faults 22
9.3 Active Faults 22
9.4 Inactive Faults 23
9.5 Active Folds 23
9.6 Active/Southwest Tilting 26
9.7 Inactive Folds and Continuum Deformation 26
1. 9.8Structural Evolution 27
10. GEOMORPHOLOGY: BACKGROUND 27
10.1 Geomorphic System of Barbados 27
10.2 Sea-Level Changes and Geomorphic Development 29
10.3 Island Area and Sea-Level Change 30
10.4 Shoreline Erosion 30
10.5 Shore Zone Sediments 32
10.6 Effects of Changing Sea Level 32
10.7 Windward versus Leeward Differences 33
11. GEOMORPHOLOGY OF THE MODERN SHORE ZONE 33
11.1 Beaches 33
11.2 Dunes 34
11.3 Cliffs and Abrasion Terraces 36
11.4 Estuaries and Lagoons 36
11.5 Specific Coastal Segments 37
11.5.1 Eastern St. Lucy 37
11.5.2 Northern St. Lucy 37
11.5.3 Boscobelle Coast 37
11.5.4 Scotland District 38
11.5.5 Newcastle Coast 39
11.5.6 Northern St. Philip 40
11.5.7 Southern St. Philip 41
11.5.8 Oistins Coast 41
11.5.9 West Coast 41
12. ACTIVE MARINE CLIFF EVOLUTION 41
12.1 Cliffs in Limestone 41
12.2 Cliffs in Foundation Rock 43
12.3 Cliffs in Landslides 44
13. RAISED (ANCIENT) MARINE TERRACES 44
13.1 Background 44
13.2 Architecture and Processes 44
13.3 Sequence, Dating, and Correlation of Terraces 45
13.4 Terrace Descriptions 46
13.4.1 Worthing and Winterhaven Terraces 46
13.4.2 Ventnor Terrace 46
13.4.3 Rendezvous Hill and Related Terraces 46
13.4.4 Kendal and College Savannah Terraces 47
13.4.5 Older Terraces of St. Lucy 47
13.4.6 Older Terraces of St. Philip 47
13.4.7 Older Terraces of Western and Southern Barbados 47
14. RIVERINE (STREAM) FEATURES AND PROCESSES 47
14.1 Background 47
14.2 Riverine Geomorphology of Zone I 48
1. 14.3Riverine Geomorphology of Zone II 49
14.4 Riverine Geomorphology of Zone III 49
14.5 Riverine Geomorphology of Zone IV 49
14.5.1 Major Drainages 50
14.5.2 Coastal Drainages 50
14.5.3 Floodplains 50
14.5.4 Stream Terraces 50
15. MASS WASTING AND LANDSLIDING 51
15.1 Introduction 51
15.2 Landsliding Processes 51
15.3 Landslide Terraces 51
15.4 Landslides at Active Marine Cliffs 51
15.5 Landslides in Zone III 52
15.6 Landslides in Zone IV 55
15.7 Ground Instability Classification 55
16. KARST 55
17. UPLIFT RATES 56
18. HYDROLOGY 59

ACKNOWLEDGMENTS
60
REFERENCES 60
1. General Onland Geology, Pre-Pleistocene 60
2. Pleistocene Limestone and Sea-Level History of Barbados 61
3. Structure and Tectonics of Barbados and Barbados Ridge 62
4. Geomorphology, Soils, and Hydrology 63
5. Marine Geology and Biogeology 63