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San Andrés, Old Providence and Santa Catalina (Caribbean Sea, Colombia)

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San Andrés, Old Providence and Santa Catalina (Caribbean Sea, Colombia) REEF ENVIRONMENTS AND GEOLOGY OF AN OCEANIC ARCHIPELAGO: SAN ANDRÉS, OLD PROVIDENCE AND SANTA CATALINA (CARIBBEAN SEA, COLOMBIA) with Field Guide JÓRN GEISTER Y JUAN MANUEL DÍAZ República de Colombia MINISTERIO DE MINAS Y ENERGÍA INSTITUTO COLOMBIANO DE GEOLOGÍA Y MINERÍA INGEOMINAS REEF ENVIRONMENTS AND GEOLOGY OF AN OCEANIC ARCHIPELAGO: SAN ANDRÉS, OLD PROVIDENCE AND SANTA. CATALINA (CARIBBEAN SEA, COLOMBIA with FIELD GUIDE) INGEOMINAS 2007 DIAGONAL 53 N°34-53 www.ingeominas.gov.co DIRECTOR GENERAL MARIO BALLESTEROS MEJÍA SECRETARIO GENERAL EDWIN GONZÁLEZ MORENO DIRECTOR SERVICIO GEOLÓGICO CÉSAR DAVID LÓPEZ ARENAS DIRECTOR SERVICIO MINERO (e) EDWARD ADAN FRANCO GAMBOA SUBDIRECTOR DE GEOLOGÍA BÁSICA ORLANDO NAVAS CAMACHO COORDINADORA GRUPO PARTICIPACIÓN CIUDADANA, ATENCIÓN AL CLIENTE Y COMUNICACIONES SANDRA ORTIZ ÁNGEL AUTORES: 315RN GEISTER Y JUAN MANUEL DÍAZ REVISIÓN EDITORIAL HUMBERTO GONZÁLEZ CARMEN ROSA CASTIBLANCO DISEÑO Y DIAGRAMACIÓN GUSTAVO VEJARANO MATIZ J SILVIA GUTIÉRREZ PORTADA: Foto: Estación en el mar Cl. San Andrés: Pared vertical de Bocatora Hole a -30 m. El coral Montastraea sp. adoptó una forma plana. Agosto de 1998. IMPRESIÓN IMPRENTA NACIONAL DE COLOMBIA CONTENT PREFACE 7 1. GENERAL BACKGROUND 8 2. STRUCTURAL SETTING AND REGIONAL GEOLOGY OF THE ARCHIPÉLAGO 9 2.1 Caribbean Piafe 9 2.2 Upper and Lower Nicaraguan Rises 9 2.3 Hess Escarpment and Colombia Basin 11 2.4 Islands and atolls of the Archipelago 12 3. CLIMATE AND OCEANOGRAPHY 14 4. GENERAL CHARACTERS OF WESTERN CARIBBEAN OCEANIC REEF COMPLEXE (fig. 7) 15 4.1 Gross geomorphology of reef complexes 15 4.2 Recent erosional and depositional processes 16 4.3 Collapse of carbonate platforms 18 4.3.1 Platform margin failures in the Archipélago 18 4.3.2 Shedding of megabreccias 19 4.3.3 Causes of collapse 20 4.3.4 Recurrence time of collapsing margins 20 4.4 General reef and lagoon ecology 20 4.4.1 Shallow reef facies 21 4.4.2 Deep reef facies 22 4.4.3 Hardground facies 22 4.4.4 Shallow sand facies 22 4.4.5 Shallow to deep sand facies 23 4.4.6 Deep sand facies 23 4.4.7 The fauna of stony corals and mollusks of the archipelago 23 5. STATUS OF REEF ENVIRONMENTS TAC171' 24 5.1 Natural versus anthropogenic degradation 24 5.2 Mortality rates of corals 24 5.3 Increases in macroalgae 25 5.4 Effects of overfishing 25 5.5 Recovery 25 5.6 Natural reserves and protection 25 6. ISLAND GEOLOGY AND REEFS OF THE LOWER NIC 26 6.1 Island geology and reefs of San Andrés (fig. 15, for island topography see fig. 25) 26 6.1.1 Early island origins 27 6.1.2 Miocene lagoon and reef environments 27 6.1.3 Pleistocene terraces and marine environments 29 6.1.4 Relative and absolute dating of Pleistocene marine terraces, sea cliffs and coral reefs 34 6.1.5 Pleistocene tectonics: absolute tilting rates and fracturing 35 6.1.6 Geologic history of the modern reef complex since the Middle Pleistocene transgression 36 6.1.7 Main characteristics of the Recent reef complex 38 Island geology and reefs of Old Providence and Sta. Catalina (maps on fig. 31, table 2) 40 6.2.1 Early island origins 42 6.2.2 Extrusion of rhyolite dome and formation of breccia aprons ("older volcanic series") 42 6.2.3 Formation of a composite volcanic cone ("younger volcanic series") 43 6.2.4 Notes on the petrography and geochemistry of the volcanic rocks by Claudio Scarcia (Bern). 45 6.2.5 Miocene carbonate environments 46 6.2.6 Pleistocene carbonate environments, delta deposits and sea-level stands 46 6.2.7 Holocene terrestrial deposits 47 6.2.8 The Recent reef complex (fig. 33-36) 47 6.3 Geology and reefs of the atolls and coral banks 50 6.3.1 Courtown Cays atoll (figs. 37 and 38) 50 6.3.2 Albuquerque Cays atoll (figs. 39 and 40) 52 6.3.3 Roncador Bank atoll (figs. 41 and 42) 54 6.3.4 Serrana Bank atoll (figs. 43 and 44) 55 6.3.5 Quitasueño Bank half-atoll (figs. 46 and 47) 58 6.3.6 Serranilla Bank half-atoll (fig. 48) 59 6.3.7 Alice Shoal drowned atoll (fig. 49) 60 6.3.8 Bajo Nuevo coral bank (fig.50) 61 7. GEOLOGICAL RISKS IN THE ARCHIPELAGO 62 7.1 Volcanism 62 7.2 Earthquakes 62 7.2 The geological record of earthquakes in the Archipelago 62 7.2 Earthquake hazards in the Archipélago 63 7.3 Tsunamis 64 7.3.1 Tsunamis in the Caribbean Sea 64 7.3,7 Tsunami threat in the Archipelago? 65 7.4 Tilting and sea-level fluctuations at San Andrés 65 7.4. , Effects of tilting 65 7.4.2 Holocene sea-level history and short-term prospecta 66 7.4,3 Possible effects in the Archipélago 66 7.5 Hurricanes and tropical storms 66 7.5.1 Geological effects of hurricanes 66 7.5.2 Hurricane threats to the Archipélago 67 7.6 Erosion and accretion of coastline: past and present 67 8. FIELD TRIPS TO THE ISLANDS AND REEFS 68 8.1 Visit to San Andrés Island: Holocene, Pleistocene and Miocene reefs and lagoonal environments (Trips A to E) 68 8.2 Visit to Old Providence Island: Quaternary reefs and island geology (Trips F to L) 82 8.3 Visit to Holocene atoll environments of Courtown Cays 93 9. OVERFIGHT OF THE ARCHIPELAGO BY CHARTERED PLANE 95 9.1 San Andrés Island and barrier reef complex from the air 95 9.2 Courtown Cays atoll from the air (see plan fig. 120, figs. 130 to 133) 97 9.3 Albuquerque Cays atoll from the air (see plan fig. 134) 98 9,4 Quitasueño Bank half-atoll from the air (see maps on figs. 46 and 47) 99 9.5 Serrana Bank atoll from the air (see plan fig. 146) 100 9.6 Roncador Bank atoll from the air (see plan fig. 150) 101 9,7 Old Providence Island and barrier reef complex from the air 102 Adresses of authors: PD Dr. rer. nat. Jórn Geister Naturhistorisches Museum Bern, Abteilung Erdwissenschaften, Bernastrasse 15, CH - 3005, Bern (Switzerland) [email protected] and GeoBio-Center at the Ludwig-Maximilians-Universitát München Richard-Wagner-Str. 10 D-80333 München (Germany) Dr. rer. nat. Juan Manuel Díaz Instituto de Investigaciones Marinas y Costeras "José Benito Vives de Andreis" - INVEMAR. Santa Marta. Current Adress: Instituto de Investigación de Recursos Biológi- cos "Alexander von Humboldt".- Bogotá. [email protected] Credit Photographs JÓRN GEISTER and JUAN MANUEL DÍAZ FIGURES: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145,146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156. PREFACE his book compiles the results of studies carried out active participation of Alvaro Nivia and financed by the in the Archipélago since 1968 (J.G.) together with Geological Survey of Colombia. The authors are especially the results of more recent unpublished work. Early grateful to INVEMAR and COLCIENCIAS (Bogotá) and to Tre-surveys of the reefs and reconnaissance studies in the direction of INGEOMINAS and CORALINA for the the volcanic rocks of Old Providence were carried out in support offered to them over many years of field studies. 1979 in the company of Marion Frantz. Subsequent studies which focused on the degradation of San Andrés reefs and Claudio Scarcia (Bern) contributed mapping results from the on the exploration of the four surrounding atolls (JMD) were southern part of Old Providence and geochemical data of supported by INVEMAR and COLCIENCIAS (Bogotá). The volcanic rocks. Geochemical analyses of volcanic rock sam- present book is based on a field-guide prepared and published ples were carried out by the Institut de Minéralogie et de Pé- for the "8th International Coral Reef Symposiurn" held at trographie of the University of Fribourg and the Institut de Panama City in 1996 (Geister & Díaz 1997). That guide and Minéralogie et de Géochimie of the University of Lausanne the present book were only possible after a joint re-survey (both Switzerland). We are grateful to Nan Mercolli (Bern) of the reefs carried out by both authors in October 1994 at for lis advice on volcanic rock samples and comments on San Andrés and Old Providence; this survey was financed by the text concerning Old Providence. Photographic work was COLCIENCIAS (Bogotá) and supported by INVEMAR, the financed by the Institut für Geologie of the University of Corporación CORALINA and the Swiss Ministry of Foreign Bern . Affairs (EDA/DEH). Subsequent (1998) studies in the Quitasueño Bank were financed by COLCIENCIAS (grant Graphic support and drafting was done by GEOTEC Ltda. to J. M. D.) and supported by the Swiss Ministry of Foreign (Bogotá). Much encouragement came from Fabio Cediel Affairs (EDA/DEH) (grant to J.G.).
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