Amazonia E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 1470

Veröffentlichungsjahr: 2011

Beschreibung

The book focuses on geological history as the critical factor in determining the present biodiversity and landscapes of Amazonia. The different driving mechanisms for landscape evolution are explored by reviewing the history of the Amazonian Craton, the associated sedimentary basins, and the role of mountain uplift and climate change. This book provdes an insight into the Meso- and Cenozoic record of Amazonia that was characterized by fluvial and long-lived lake systems and a highly diverse flora and fauna. This fauna includes giants such as the ca. 12 m long caiman Purussaurus, but also a varied fish fauna and fragile molluscs, whilst fossil pollen and spores form relics of ancestral swamps and rainforests. Finally, a review the molecular datasets of the modern Amazonian rainforest and aquatic ecosystem, discussing the possible relations between the origin of Amazonian species diversity and the palaeogeographic, palaeoclimatic and palaeoenvironmental evolution of northern South America. The multidisciplinary approach in evaluating the history of Amazonia has resulted in a comprehensive volume that provides novel insights into the evolution of this region.

Leseprobe

Contents

Dedication to Thomas van der Hammen

List of contributors

Prologue

ONE Introduction: Amazonia, landscape and species evolution

Motivation

A journey through the geological history of Amazonia

Outlook

Acknowledgements

References

PART I Tectonic processes as driving mechanisms for palaeogeographical and palaeoenvironmental evolution in Amazonia

TWO Geological evolution of the Amazonian Craton

Introduction

Archean mobile belts

Trans-Amazonian orogenic belt

Granitoid terranes

Grenvillian mobile belts

Platform covers

Mafic dykes and sills

Origin of Paleozoic intracratonic basins

Relief development and sediment generation

Conclusions

Acknowledgements

References

THREE The Paleozoic Solimões and Amazonas basins and the Acre foreland basin of Brazil

Introduction to the region’s geological evolution

The Amazonas Basin

The Solimões Basin

The Paleozoic-Mesozoic foreland Acre Basin

Conclusions

Acknowledgements

References

FOUR Tectonic history of the Andes and sub-Andean zones: implications for the development of the Amazon drainage basin

Introduction

The history of the Amazon River in a regional geological context

The Andes and their relationship with the plate tectonic context

Cenozoic shortening history in the Central and Northern Andes

Surface uplift data in the Andes

Exhumation histories

Structural styles and timing of the structures in the sub-Andean zones

The Vaupés Swell and the Fitzcarrald Arch

Discussion

Conclusions

Acknowledgements

References

FIVE Cenozoic sedimentary evolution of the Amazonian foreland basin system

Introduction

Basic concepts

Geological setting and stratigraphy of Amazonian foreland basin deposits

Cenozoic sedimentary evolution of the Colombian foreland basin system

Cenozoic sedimentary evolution of the Ecuadorian foreland basin system

Cenozoic sedimentary evolution of the Peruvian and northern Bolivian foreland basin system

Neogene(?) to Present

Sedimentation rates

Discussion

Conclusions

Acknowledgments

References

SIX The Nazca Ridge and uplift of the Fitzcarrald Arch: implications for regional geology in northern South America

Introduction

The Nazca Ridge feature

Andean Nazca Ridge subduction imprints

Morphological records, drainage system and crustal structure of the Fitzcarrald area

Miocene to Pleistocene sedimentological record of the Fitzcarrald Arch area

Timing of the Fitzcarrald Arch uplift

Origin of the Fitzcarrald uplift

Consequences of the Fitzcarrald Arch uplift on Amazonian basin evolution and its biota

Acknowledgements

References

PART II Cenozoic depositional systems in Amazonia

SEVEN The Amazonian Craton and its influence on past fluvial systems (Mesozoic-Cenozoic, Amazonia)

Introduction

Evolution of the Amazonian Craton

Modern cratonic rivers of Amazonia: classification and composition of the sediment load

Climate and weathering in the cratonic source area

Cratonic rivers, past and present: evidence from the sedimentary record in Amazonia

The shift from cratonic- to Andean-dominated fluvial systems

Conclusions

Acknowledgements

References

EIGHT The development of the Amazonian mega-wetland (Miocene; Brazil, Colombia, Peru, Bolivia)

Introduction

Definition of a wetland and mega-wetland

Causes for wetland development during the Neogene in Amazonia

The Miocene Amazonian wetland: evidence from the sedimentary record

The Amazonian Miocene mega-wetland in its regional context

Conclusions

Acknowledgements

References

NINE Marine influence in Amazonia: evidence from the geological record

Introduction

Methods

Geological indications of marine influence in Miocene Amazonia

Discussion

Conclusions

Acknowledgements

References

TEN Megafan environments in northern South America and their impact on Amazon Neogene aquatic ecosystems

Introduction

Data and methodology

Megafan characteristics

Megafans and biodiversity

Landscape evolution and possible biodiversity implications

Discussion and conclusions

Acknowledgements

References

ELEVEN Long-term landscape development processes in Amazonia

Introduction

Andean tectonics and the development of the Amazon River system

Fluvial landscapes in the Andean foreland basin

Várzeas in the lower reach of the Amazon River

Fluvial landscapes in other parts of the Amazon Basin

Landscape evolution in terra firme

Biotic patterns and environmental processes

Summary and conclusions

Acknowledgements

References

PART III Amazonian climate, past and present

TWELVE Climate variation in Amazonia during the Neogene and the Quaternary

Introduction

Climate of Amazonia: seasonality

Climate of Amazonia: interannual variation

Quaternary climate evolution of Amazonia: glacial-interglacial variation

Amazonian climate in the Neogene

Conclusions

Acknowledgements

References

THIRTEEN Modelling the response of Amazonian climate to the uplift of the Andean mountain range

Introduction

Model and experiments

Results and discussion

Conclusions

Acknowledgements

References

FOURTEEN Modern Andean rainfall variation during ENSO cycles and its impact on the Amazon drainage basin

Introduction

Methods

Spatiotemporal rainfall variations in the Andes and the Amazon drainage basin

Results

Discussion

Conclusions

Acknowledgements

References

PART IV Cenozoic development of terrestrial and aquatic biota: insights from the fossil record

FIFTEEN A review of Tertiary mammal faunas and birds from western Amazonia

Introduction

The terrestrial mammalian and avian faunas of lowland Amazonia

Discussion

Conclusions

Acknowledgements

References

SIXTEEN Neogene crocodile and turtle fauna in northern South America

Introduction

Localities

Crocodyliforms

Turtles

Biogeographical relationships between Amazonia and southern South America during the Miocene

Neogene Amazonian palaeoenvironments

Conclusions

Acknowledgements

References

SEVENTEEN The Amazonian Neogene fish fauna

Introduction

Material and methods

The Neogene fish fauna from Amazonia and related basins

Palaeoenvironment

Community structure

Timeline of Amazonian fish diversification

Conclusions

Acknowledgements

References

EIGHTEEN Amazonian aquatic invertebrate faunas (Mollusca, Ostracoda) and their development over the past 30 million years

Introduction

Oligocene faunas (c. 34–24 Ma)

Early to early Late Miocene long-lived lake faunas (Pebas stage: c. 24–11 Ma)

Miocene fluvial, fluvio-lacustrine and marine invertebrate assemblages

Late Miocene (Acre stage: 11–7 Ma): extinctions and the onset of the modern Amazonian faunas

Pliocene faunas (5–2 Ma)

Modern Amazonian invertebrate faunas

Neogene biogeography

Conclusions

Acknowledgements

References

NINETEEN The origin of the modern Amazon rainforest: implications of the palynological and palaeobotanical record

Introduction

Palynology

Palaeobotany

Conclusions

Acknowledgements

References

TWENTY Biotic development of Quaternary Amazonia: a palynological perspective

Introduction

Origins of Amazonian diversity and climate change

Podocarpus in ice-age Amazonia

Post-glacial Amazonia

Conclusions

Acknowledgements

References

PART V Modern perspectives on the origin of Amazonian biota

TWENTY-ONE Contribution of current and historical processes to patterns of tree diversity and composition of the Amazon

Introduction

Separating the regional and local signal in tree diversity

What factors determine regional tree diversity?

Factors affecting the local signal in tree alpha-diversity

Forest composition

Conclusions

Acknowledgements

References

TWENTY-TWO Composition and diversity of northwestern Amazonian rainforests in a geoecological context

Introduction

Macroscale

Mesoscale

Microscale

Discussion

Conclusions

Acknowledgements

References

TWENTY-THREE Diversification of the Amazonian flora and its relation to key geological and environmental events: a molecular perspective

Introduction

Gondwana and boreotropical origins of the Amazonian flora

Andean orogeny

Pleistocene climate changes

Ecological speciation: lowland habitats within the Amazon drainage basin

Conclusions and outlook

Acknowledgements

References

TWENTY-FOUR Molecular studies and phylogeography of Amazonian tetrapods and their relation to geological and climatic models

Introduction

Patterns of phylogeographic diversification of tetrapods in the Amazon

Conclusions

Future approaches and systems

Acknowledgements

References

TWENTY-FIVE Molecular signatures of Neogene biogeographical events in the Amazon fish fauna

Introduction

Amazonia as the core of Neotropical fresh waters

Geological and palaeogeographic context

Molecular data and biogeography: considerations and opportunities

Progress to date: molecular signatures of Neogene palaeogeographic events

Conclusions and future challenges

Acknowledgements

References

PART VI Synthesis

TWENTY-SIX On the origin of Amazonian landscapes and biodiversity: a synthesis

Introduction

Landscape evolution and driving factors

Evolution of Amazonian biodiversity: the message from DNA

Amazonian biodiversity and the fossil record

Cenozoic Amazonian landscapes and the development of its biota: an outline

Acknowledgements

References

Colour plates

Index

Colour plate 1

Companion website

A companion website for this book is available at:

www.wiley.com/go/hoorn/amazonia

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Figures from the book for downloadingColor versions of selected figuresAdditional illustrations.

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Library of Congress Cataloguing-in-Publication Data

Amazonia—landscape and species evolution: a look into the past/edited by C. Hoorn, F.P. Wesselingh; editorial advisors, H.B. Vohnof, S.B. Kroonenberg, H. Hooghiemstra.

p. cm.

Includes bibliographical references and index.

ISBN 978-1-4051-8113-6 (hardback: alk. paper)

1. Natural history—Amazon River Region. 2. Historical geology—Amazon River Region. 3. Paleontology—Amazon River Region. 4. Geology, Stratigraphic—Cenozoic. I. Hoorn, C. (Carina) II. Wesselingh, F. P.

QH112.A435 2010

508.81´1—dc22

2009021979

Dedication to Thomas van der Hammen

We dedicate this book to the life and work of Professor Thomas van der Hammen who is one of the most prominent Dutch geoscientists, making many links between geology, biology and archaeology. The study of altitudinal vegetation distributions in the northern Andes is a red line through his work and it has served studies of the Neogene uplift history of the northern Andes as well as studies of pollen-based Pleistocene climate change. During more than two decades he lectured at the University of Amsterdam and inspired generations of Dutch students. Since his retirement in 1989 he has lived in Colombia where, with his never-ending enthusiasm, he continues to motivate large numbers of Colombian students.

Carina Hoorn, Frank P. Wesselingh (editors)

Henry Hooghiemstra, Hubert Vonhof, Salomon Kroonenberg (editorial advisors)

Biography

Thomas van der Hammen was born in The Netherlands in 1924 and had an innate interest and love for nature. After the Second World War he studied geology at Leiden University. He was trained as a palynologist by Professor F. Florschütz but also had regular contact with other founding fathers of this discipline such as J. Iversen and R. Potonié. His PhD dissertation was on ‘Lateglacial flora and periglacial phenomena in the Netherlands’, a subject that would remain of interest to him for the rest of his life. In 1951 he started working for the Geological Survey in Colombia and did pioneering research on Cretaceous and Cenozoic sediments. Through his trademark multidisciplinary approach he unravelled the stages of tectonic uplift of the Andes. Later, he and his co-workers were able to make a link with the evolution of the montane forest and páramo vegetation of the Northern Andes.

In 1959 Thomas returned to The Netherlands and worked at the Department of Geology of Leiden University. He developed a research line in palaeoecology and climate history in the eastern part of The Netherlands while continuing his research in tropical palynology, often in cooperation with the geologist Lex Wijmstra, and focusing on exploratory studies in Guyana, Suriname and the Amazon Basin. In 1966 Thomas moved to the University of Amsterdam where he was appointed as a Professor in Palynology. A suite of both Dutch and Colombian (PhD) students were trained in topics such as geology, archaeology, biostratigraphy, climate history and vegetation analysis, and conducted field work in areas located in Brazilian Amazonia, Colombian Amazonia, the Colombian Andes and Venezuela. During the late 1970s and early 1980s he designed the large ‘Ecoandes Project’ and the ‘Tropenbos Colombia Programme’ respectively. The Ecoandes Project focused on integrated palaeo/actuo-ecological research of transects across different sectors of the Colombian Andes. These unprecedented studies resulted in seven volumes in the series Studies ofTropical Andean Ecosystems, published at Cramer/Borntraeger in Germany. The Tropenbos Colombia Programme studies focused on a wide variety of subjects, ranging from fishery, plant systematics, floristic inventories, sociogeographical studies, anthropology, palaeoecology, geology and tropical vegetation ecology. These studies resulted in 20 volumes of the series Studies on Colombian Amazonia, published at Tropenbos-Colombia office in Bogotá. To promote distribution of scientific results among Colombian institutes and colleagues around the world in 1973 he started the series El Cuaternario de Colombia [The Quaternary of Colombia], which he edited up to volume 20 (1995).

Perhaps his most valuable contribution to science was to increase our understanding of the history of Pleistocene climate change. His training in the climate history of Western Europe enabled him to show us that the Neotropics also had a dynamic history of climate change. Thomas van der Hammen discovered the immense value of the pollen archives in the deep intra-Andean sedimentary basins. He studied the first deep boreholes in the Bogotá Basin and the Fúquene Basin, and created a basis for later studies on long continental pollen records from Colombia. During the decades that Thomas lectured in The Netherlands he played an active role in Dutch nature conservation and in developing international structures for nature assessment studies. His contributions to the advancement of science were rewarded by her Majesty Queen Beatrix with a knighthood.

After his retirement he implemented his valuable experience in Colombia and, in collaboration with national research institutes such as the Geographical Institute (IGAC), the Geological Institute (Ingeominas), the Archaeological Institute, and the Von Humboldt Biodiversity Institute, he helped to promote many collaborative studies. Thomas van der Hammen was the author of more than 100 international peer-reviewed publications and contributed much to our understanding of tropical ecology and tropical climate history. His contributions to the training of Colombian scientists, and to the development of nature conservation and awareness of infrastructural issues in Colombia are highly valued. For the latter Thomas received the Colombian Order of San Carlos, which he received out of the hands of the Colombian President. Thomas’s enthusiasm, charisma, vision and ability to make people work together made him a most inspiring person and a true leader.

Henry Hooghiemstra and Carina Hoorn

List of contributors

Aguilera, O.A. Universidad Nacional Experimental Francisco de Miranda, Centro de Investigaciones en Ciencias Básicas, Complejo Docente Los Perozos, Carretera Variante Sur, Coro, 4101, Falcón, Venezuela. e-mail: [email protected]

Albert, J.S. Department of Biology, University of Louisiana Lafayette, PO Box 42451, Lafayette, LA 70504–2451 USA. e-mail: [email protected]

Antoine, P-O. LMTG, University of Toulouse III-IRD-CNRS, France. e-mail: [email protected]

Antonelli, A. Institute of Systematic Botany, University of Zurich, Zollikerstrasse 107, CH 8008 Zurich, Switzerland. e-mail: [email protected]

Antonioli, L. Universidade Estadual do Rio de Janeiro (UERJ), Faculdade de Geologia - DEPA. Campus Francisco Negrão de Lima Pavilhão João Lyra Filho R. São Francisco Xavier, 524, 4° andar Bloco A - Sala 2030 Maracanã – Rio de Janeiro – RJ – Cep 20550–900, Brazil. e-mail: [email protected]

ATDN (Amazon Tree Diversity Network) http://www.bio uu.nl/~herba/Guyana/ATDN.

Baby, P. Laboratoire des Mécanismes et Transferts en Géologie, Université de Toulouse; UPS (SVT-OMP); CNRS/IRD; LMTG; 14 Av, Edouard Belin, F-31400 Toulouse, France. e-mail: patrice. [email protected]

Barbarand, J. Université Paris Sud, UMR CNRS 8148 IDES, Bâtiment 504, Orsay cedex, F-91405, France. e-mail: jocelyn. [email protected]

Bates, J.M. Department of Zoology, The Field Museum of Natural History, 1400 S. Lake Shore Dr., Chicago, IL 60605–2496, USA. e-mail: [email protected]

Behling, H. Department of Palynology and Climate Dynamics, Albrecht-von-Haller-Institute for Plant Sciences, University of Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany. e-mail: [email protected]

Bocquentin-Villanueva, J. Federal University of Acre, Rio Branco, AC, Brazil. e-mail: [email protected]

Bookhagen, B. Department of Geography, UC Santa Barbara, Santa Barbara, CA 93106, USA, e-mail: [email protected]

Brusset, S. Laboratoire des Mécanismes et Transferts en Géologie, Université de Toulouse; UPS (SVT-OMP); CNRS/IRD; LMTG; 14 Av, Edouard Belin, F-31400 Toulouse, France. e-mail: [email protected]

Bush, M. Department of Biological Sciences, Florida Institute of Technology, 150 W. University Boulevard, Melbourne, fl32901, USA. e-mail: [email protected]

Christophoul, F. Université de Toulouse; UPS (SVT-OMP); CNRS/IRD; LMTG; 14 Av, Edouard Belin, F-31400 Toulouse, France. e-mail: [email protected]

Crawford, A.J. Naos Molecular Labs, Smithsonian Tropical Research Institute, Apartado 0843–03092, Balboa, Ancón, Republic of Panama. e-mail: [email protected]

Cunha, P.R. Petrobras Exploration and Production - Espírito Santos Basin, Avenida República do Chile 65, Rio de Janeiro, Brazil. e-mail: [email protected]

Dahdul, W.M. Department of Biology, The University of South Dakota, 414 E. Clark St., Vermillion, SD 57069, USA. e-mail: [email protected]

Dick, C.W. Department of Ecology and Evolutionary Biology, University of Michigan, 2011 Kraus Natural Science Bldg., 830 N. University, Ann Arbor, MI 48109–1048, USA. e-mail: cwdick@ umich.edu

Dino, R. Petrobras, Rua Horácio Macedo, 950, Cidade

Universitária - Ilha do Fundão, 21941–915 - Rio de Janeiro, RJ, Brazil. e-mail: [email protected]

Duivenvoorden, J.F. Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands. e-mail: [email protected]

Duque, A.J. Universidad Nacional de Colombia, Departamento de Ciencias Forestales, Calle 59A No 63–20, A.A. 1027, Medellin, Colombia. e-mail: [email protected]

Eiras, J.F. PetroGeo – Serviços Geológicos S/S Ltd, Manaus, Amazonas, Brazil. e-mail: [email protected]

Espurt, N. Laboratoire des Mécanismes et Transferts en Géologie, Université de Toulouse; UPS (SVT-OMP); CNRS/IRD; LMTG; 14 Av, Edouard Belin, F-31400 Toulouse, France. Now: CEREGE UMR6635 Université Paul Cézanne CNRS BP80 13545 Aix en Provence, France. e-mail: [email protected]

Ferigolo, J. MCN, Fundação Zoobotânica do Rio Grande do Sul, Porto Alegre, RS, Brazil. e-mail: [email protected]

Fluteau, F. Institut de Physique du Globe de Paris, Place Jussieu, Paris, 75005 France. e-mail: [email protected]

Gingras, M. Department of Earth and Atmospheric Sciences, 1–26 Earth Science Building, University of Alberta, Edmonton, T6G2E3, Canada. e-mail: [email protected]

Grillo, O. Museu Nacional, Quinta da Boa Vista s/n, São Cristóvão, Rio de Janeiro, Brazil. e-mail: [email protected]

Guerrero, J. Departamento de Geociencias, Universidad Nacional, A.A. 14490, Bogotá, Colombia. e-mail: geochron2002@ yahoo.com

Hermoza, W. PeruPetro S.A., av. Luis Aldana 320, San Borja, Lima 41, Peru. Now: REPSOL-YPF, Paseo de la Castellana 280, 1ª Pl., 28046 Madrid, Spain. e-mail: [email protected]

Herrera, F. Smithsonian Tropical Research Institute, Box 084303092, Balboa, Republic of Panama. e-mail: [email protected]

Hooghiemstra, H. Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands. e-mail: [email protected]

Hoorn, C. Institute for Biodiversity and Ecosystem Analysis, University of Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands. e-mail: [email protected]

Hovikoski, J. Department of Geology, University of Turku, 20014 Turku, Finland. Now at: Department of Stratigraphy, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, 1350 Copenhagen K, Denmark. e-mail: [email protected]

Irion, G. Research Institute Senckenberg, Marine Science Department, 26382 Wilhelmshaven, Germany. e-mail: g.irion@ gmx.de

Jaramillo, C. Smithsonian Tropical Research Institute, Box 0843–03092, Balboa, Republic of Panama. e-mail: JaramilloC@ si.edu

Kaandorp, R. Vrije Universiteit Amsterdam, Faculty of Earth and Life Sciences, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands. e-mail: [email protected]

Kalliola, R. Department of Geography, University of Turku, FI-20014 Turku, Finland. e-mail: [email protected]

Kreslavsky, M.H. Earth and Planetary Sciences, University of California-Santa Cruz, 1156 High St., Santa Cruz CA 95064, USA. e-mail: [email protected]

Kroonenberg, S.B. Delft University of Technology, Department of Geotechnology, P.O. Box 5028, 2600 GA Delft, The Netherlands. e-mail: [email protected]

Leite, F. Smithsonian Tropical Research Institute, Box 084303092, Balboa, Republic of Panama. Now: Institute of Geosciences, University of Brasília, 70910–900, Brasília, Brazil. e-mail: fprleite@ gmail.com

Lovejoy, N.R. Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C 1A4 Canada. e-mail: [email protected]

Lundberg, J.G. Department of Ichthyology, The Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, PA 19103–1195, USA. e-mail: [email protected]

Mapes, R. Department of Geological Sciences, University of North Carolina, CB#3315, Mitchell Hall, Chapel Hill, NC 275993315; now at: Exxon Mobil Corporation, Houston, TX, USA

Marshall, L.G. Arizona Museum of Natural History, 53 North Macdonald St., Mesa AZ 85201, USA

Mora, A. ECOPETROL, Instituto Colombiano del Petroleo. Piedecuesta, Santander, Colombia. e-mail: [email protected]

Negri, F.R. Universidade Federal do Pará, Campus Universitario de Altamira, Rua Coronel Jose Porfirio, No 2515, Barrio São Sebastião, Altamira, PA Brasil, CEP 68372–040. e-mail: frnegri@ ufpa.br

Ochoa-Lozano, D. Center for Tropical Paleoecology and Archeology, Smithsonian Tropical Research Institution, Apartado Postal 0843–03092, Balboa, Ancon, Panama. e-mail: dochoa1709@ yahoo.com

Oliveira, G.R. Universidade Federal do Rio de Janeiro, Setor de Paleovertebrados, Departamento de Geologia e Paleontologia, Museu Nacional, Quinta da Boa Vista, 20940–040, Rio de Janeiro, RJ, Brazil. Fellow of Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). e-mail: gustavoliveira@ gmail.com

Parra, M. Institut für Geowissenschaften, Universität Potsdam, Potsdam, Germany; now at: The University of Texas at Austin, 1, University Station c1100 Austin, TX 78712–0254, USA. e-mail: [email protected]

Pennington, R.T. Royal Botanic Garden Edinburgh, 20a Inverleith Row, Edinburgh EH3 5LR, UK. e-mail: t.pennington@ rbge.org.uk

Quijada-Mascareñas, A. School of Natural Resources, 325 Biological Sciences East, The University of Arizona, Tucson, Arizona 85721, USA. e-mail: [email protected]

Quiroz, L. Smithsonian Tropical Research Institute, Box 0843–03092, Balboa, Republic of Panama; and Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada. e-mail: [email protected]

RAINFOR (Amazon Forest Inventory Network) http://wwwgeog.leeds.ac.uk/projects/rainfor./

Ramos, M-.I.F. Museu Paraense Emílio Goeldi, Campus de Pesquisa, CCTE, Av. Perimetral, 1901 Caixa Postal 399, Bairro Terra Firme, CEP. 66077–530, Belém, Pará, Brasil. e-mail: [email protected]

Räsänen, M. Department of Geology, University of Turku, 20014 Turku, Finland. e-mail: [email protected]

Riff, D. Instituto de Biologia, Universidade Federal de Uberlândia, Campos Umuarama, Bloco 2D-sala 28, Rua Ceará s/n, Bairro Umuarama, Uberlândia, Minas Gerais, Brazil. e-mail: [email protected]

Roddaz, M. Laboratoire des Mécanismes et Transferts en Géologie, Université de Toulouse; UPS (SVT-OMP); CNRS/IRD; LMTG; 14 Av, Edouard Belin, F-31400 Toulouse, France. e-mail: [email protected]

de Roever, E.W.F. NALCO EUROPE, P.O. Box 627, 2300 AP Leiden, The Netherlands. e-mail: [email protected]

Romano, P.S.R. Universidade Federal do Rio de Janeiro, Setor de Paleovertebrados, Departamento de Geologia e Paleontologia, Museu Nacional, Quinta da Boa Vista, 20940–040, Rio de Janeiro, RJ, Brazil. Fellow of Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). e-mail: [email protected]

Sabaj Pérez, M.H. Department of Ichthyology, The Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, PA 19103–1195, USA. e-mail: [email protected]

Sepulchre, P. Department of Earth Sciences, University of California, Santa Cruz, USA. e-mail: [email protected]

Silva, S.A.F. Smithsonian Tropical Research Institute, Box 0843–03092, Balboa, Republic of Panama. Now: Instituto Nacional de Pesquisas da Amazonia-INPA, Coordenação de pesquisas em Botânica, Laboratório de Palinologia, Av. André Araujo 2936. P.O Box-478, Manaus, AM, Brazil. e-mail: [email protected]

Sloan, L.C. Department of Earth Sciences, University of California, Santa Cruz, USA, email: [email protected]

ter Steege, H. Institute of Environmental Biology, Section Ecology and Biodiversity, Utrecht University, Padualaan 8, 3584 CA Utrecht, The Netherlands. e-mail: [email protected]

Strecker, M.R. Institut für Geowissenschaften, Universität Potsdam, Germany. e-mail: [email protected]

Uba, C. Institut für Geowissenschaften, Universität Potsdam, 14476 Potsdam, Germany, e-mail: [email protected]

Velazco, P.M. Department of Zoology, The Field Museum of Natural History, 1400 S. Lake Shore Dr., Chicago, IL 60605–2496, USA; Dept. of Biological Sciences, University of Illinois at Chicago, 845 W. Taylor St. Chicago IL 60607, USA. e-mail: pvelazco@ fieldmuseum.org

van der Ven, P.H. Petrobras Exploration and Production Equatorial Margin and Interior Basins, Avenida República do Chile 65, Rio de Janeiro, Brazil. e-mail: [email protected]

Vonhof, H.B. Vrije Universiteit Amsterdam, Faculty of Earth and Life Sciences, Dept of Sedimentology and Marine Geology, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands. e-mail: [email protected]

Wanderley-Filho, J.R. Petrobras Exploration and Production Amazônia Business Unit, Manaus, Amazonas, Brazil. e-mail: [email protected]

Wesselingh, F.P. Museum of Natural History, P.O. Box 9517, Darwinweg 2, 2300 RA Leiden, The Netherlands. e-mail: [email protected]

Wilkinson, M.J. Jacobs Engineering, NASA-Johnson Space Center, 2224 Bay Area Blvd., Houston TX 77058, USA. e-mail: [email protected]

Willis, S.C. School of Biological Resources, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588 USA. e-mail: [email protected]

Wüster, W. School of Biological Sciences, Bangor University, Bangor LL57 2UW, Wales, UK. e-mail: [email protected]

Prologue

It is now almost 60 years since I arrived in Colombia for the first time to start investigations for a geological survey. I had one great desire: to work in Amazonia. Very soon afterwards, early in 1952, this desire was fulfilled; for one month I was able to work in one of the most remote and undisturbed areas of Western Amazonia, the middle to lower Apaporis River, to study the flora and the geology. This was possible because of the help of the (ethno)botanist Dick Schultes, who had good relations with the rubber trade company in Soratama. The company had a base there and collected rubber from the local Indian tribe. Once a month this rubber was sent to Bogotá with the Catalina (a small airplane) but – on request – it occasionally also transported researchers.

An assistant, two local Indians and I set off in a tree-canoe equipped with two hammocks, a plant-press, sample bags and some food. We travelled several hundreds of kilometres along the Apaporis and Cananari Rivers to study the rainforest and the outcrops. We climbed the table mountains, measured the crossbedding in the old tepui sandstone formations and established that in early (Palaeozoic) times the rivers ran to the northwest, instead of to the modern southeasterly direction. We also encountered the younger Tertiary sediments, and concluded that the presence of iron oölite and manganite could only indicate one thing: that lacustrine and brackish-water conditions had once ruled in the heart of Amazonia.

After a month of fieldwork in the area I came back to Soratama to wait for the plane; Schultes also arrived from another expedition at the same time, and so we had some days together. We were out of food and lived on what was available in Soratama. One day Schultes said to me: ‘I have still a tin with plum-pudding, let’s go into the forest and eat it together!’ And so we did: Christmas pudding in March, in the jungle. I was 27 years old then and at the beginning of a life lived in pursuit of understanding the composition and evolution of the forests through time in the Andes and in Amazonia.

It was some 25 years after our first Amazonian survey that I again saw samples from this area. This time they came in the form of bagged clays that were collected during an extensive Colombian survey, the Proradam project (1974 to 1979). The question that came with the bags was whether the age and environment could be established through palynology. A Neogene age was soon evident, and the presence of abundant pollen of mangrove trees (Rhizophora) for the first time confirmed the presence of saline or brackish waters in ancestral Amazonia.

Around this time two other major geological and geographical surveys were carried out in Brazil: the RadamBrasil survey and the coal exploration project by the Companhia de Pesquisa de Recursos Minerais (CPRM). The latter project drilled close to 50 cores in the subsurface of Brazilian Amazonia, and so far constitutes the best register of Neogene Amazonian history. In addition, the Brazilian oil company Petrobras drilled numerous cores though the Lower to Middle Cretaceous, which permitted the reconstruction of the floral history of that period. There were of course also groups of dedicated researchers who spent most of their life in Amazonia. One of them was Harald Sioli, who recently died but is much remembered through both his research papers and his autobiography.

Another 10 years passed and in the 1980s Tropenbos International, an initiative of the Dutch government, established a large research project with the Amazonian ecosystem as its focal point. Within this project, Carina Hoorn carried out a much more extensive and profound geological, palynological and environmental study of the Miocene of western Amazonia. This coincided with a renewed interest in Amazonia by several other countries, which all greatly increased our knowledge of the Neogene history.

Meanwhile Quaternary geologists and palynologists contributed to the knowledge of the younger Pleistocene-Holocene history of the area, indicating that Amazonia passed through periods of drier climate. Moreover, the first reconstruction by the international CLIMAP project (in 1976) of the Last Glacial Maximum indicated lower temperatures for Amazonia. It was Jürgen Haffer who in 1969 published his theory of speciation of Amazonian forest birds and his theory of glacial forest refugia. For many years his ideas had an enormous influence and caused deep controversies and forthright discussions, which, as more data become available, gradually became less extreme. The time necessary for the formation of subspecies or species may have been much longer than originally was assumed, but still the place and functions of the centres of endemism and their history continue to be a key point in the scientific debate.

The first palynological data that showed the glacial time transition of rainforest to grass-savanna (in Rondondia, Brazil), were published in 1972. These were followed by data showing the more or less continuous presence of forest in other areas (Lake Pata, in the north of Brazilian Amazonia), the drying up of lakes during the Last Glacial Maximum and/or the replacement of forest by open vegetation (Carajas, Brazil). Other areas (Rio Branco) in the northern part of Brazil show a well-dated glacial time and early Holocene extension of dune fields. Vegetation maps of the possible – or probable – situation during the Last Glacial Maximum, based on the available data and the use of present rainfall patterns, have been published, and are open to corrections – if and when more data become available.

Not all problems and discussions on Amazonia’s past have been resolved, and the cause of its enormous biodiversity is one of the great mysteries that still need an explanation. Nevertheless, our knowledge has advanced considerably since 60 years ago, and the time seems to be right for a major effort to gather all our present knowledge on Amazonia’s history and evaluate the problems and existing controversies, whilst reflecting on the gaps that still exist in our knowledge. Altogether this book will form a solid base to direct future research.

One of the most promising avenues of future research that can resolve some of our current questions is the study of genetics and the use of the molecular clock as an indicator of the separation of subspecies and species. This could enable us not only to compare geological and climatic history with the present climatic pattern, but also to assess the differences within Amazonia and the earlier proposed centres of endemism, as suggested by Haffer, Prance and others. These centres of endemism are, at least in part, related to geographical and climatic patterns that existed since the Late Miocene, Pliocene and the Quaternary. In particular, during the glacial periods the differences may have become much more pronounced because of the resulting changes of vegetation.

It now seems more than probable that new species and subspecies were formed over millions of years; there are even strong indications that biodiversity was greater during the Miocene than at Present. This suggests that the speciationextinction balance may have become negative during the Pleistocene glaciations, when the lower temperatures and drier climate intervals led to higher extinction rates (but eventually to the appearance of certain new subspecies).

The importance of the Amazonian rainforest and its enormous biodiversity for the conservation of the environmental equilibrium of the earth can only be underestimated. Moreover, the expected negative effect of the disappearance of a major part of the forest on both Amazonia and Earth as a whole, would affect us all. Therefore a better understanding of this sensitive ecosystem and its dynamics over a range of timescales is important to the global scientific and political community. The conservation of Amazonia, and a better understanding of its plant, animal and human life, is doubtlessly related to the future well-being of our planet.

This book may therefore be considered as a very important contribution to the knowledge of Amazonia, but also to science in general. It concludes a period of intensive investigations but also might herald the beginning of a new era of investigations that will hopefully lead us to the answers of many of the questions that for long have remained unanswered, and to more definite guidelines that will ensure the future of our Earth and its living inhabitants.

Thomas van der Hammen

Chía (Colombia), July 2009

ONE

Introduction: Amazonia, landscape and species evolution

Carina Hoorn1 and Frank P. Wesselingh2

1 University of Amsterdam, The Netherlands

2 Naturalis, Leiden, The Netherlands

Motivation

The Amazon drainage basin covers over 8 million km2 and has the largest rainforest on earth (Sioli 1984). The Amazon River is 6400 km long, from its source in the Andes to its mouth in the Atlantic, and the drainage basin includes a variety of landscapes such as the enigmatic tepuis in the north, the forested slopes at the foot of the Andes in the west, and the wide tracts of rainforest in the central part of the basin.

The region is renowned for its great biodiversity, both aquatic and terrestrial. Exact figures to quantify this diversity do not yet exist, and estimates of species numbers are still increasing. This incomplete understanding of species numbers makes any firm estimate impossible; nevertheless, the region is thought to harbour no less than 7500 butterfly species (possibly about 40% of the world butterfly species), 1500 species of birds (about one- third of the world total) and an estimated 11,200 tree species (Hubbell et al. 2008).

The Amazon system plays a significant role in the world’s climate as it produces about 20% of the world’s oxygen supply. Nutrients delivered by the Amazon River to the Atlantic Ocean help to foster oceanic life that sequesters globally relevant amounts of carbon (Subramaniam 2008), and in the terrestrial realm the Amazon rainforest is responsible for 10% of the net primary productivity of the whole terrestrial biosphere (http://earthobservatory.nasa.gov). Therefore, Amazonia is of the greatest concern to us all.

In spite of Amazonia’s importance the number of studies on species composition and their distribution is still limited. Diversity hotspots seemingly coincide with biological field stations and specific large-scale biological expeditions (Nelson et al. 1990), and indicate just how much basic research still is required. Even the classification of habitats in Amazonia is far from straightforward (e.g. Kalliola et al. 1993) as major parts of the region are hardly accessible and remote sensing techniques cannot grasp the variety without substantial ‘ground-truthing’.

If our knowledge of Amazonia’s present is limited, this is even more so for its past. When did the Amazonian landscape and jungles arise? What climatic, chemical, geological and other non-biological processes were involved in the development of these ecosystems and sustain them now, and what part did they play in the previous episodic demise of these ecosystems? In order to assess ecosystem resilience it is imperative to understand the historical (i.e. geological) processes that have shaped Amazonian landscapes and their biota.

For decades scientists have speculated about the evolution of species and biodiversity. However, the scientific debate was mostly dominated by biologists and geomorphologists using species and geomorphology as a basis for their theories (Haffer 1969; Ab’Sabr 1982; Absy et al. 1991; Colinvaux et al. 2000, 2001; Haffer & Prance 2001; see also Chapter 26) and few geologists were involved in this discussion. Scientists are now increasingly aware that the geological substrate in Amazonia, and the relatively young age of the Andes and the Amazon River, were of paramount importance in species evolution and distribution of diversity hotspots (e.g. Salo et al. 1986; Hooghiemstra & Van der Hammen 1998; Lundberg et al. 1998; Lovejoy et al. 1998; Van der Hammen & Hooghiemstra 2000; Nores 2002; Wesselingh and Salo 2006; Tuomisto 2007; Antonelli 2008) yet an undisputed theory about the timing and context of Amazonian diversifications – in the light of geological evidence– still has to materialize.

Geology only recently started playing a role in the debate on the origin of biodiversity as it was hampered by the same obstacles as the biological and geomorphological sciences – the lack of firm evidence due to the difficult access to the terrain. However, in the past two decades geological studies in Amazonia quickly followed one another. The sedimentary environments in Amazonia and their age (e.g. Räsänen et al. 1987; Hoorn 1993; Wesselingh et al. 2002; Hovikoski 2006), the ancient nature of rainforests (e.g. Morley 2000; Jaramillo et al. 2006), the importance of soil heterogeneity and distribution in relation to floristic biodiversity (e.g. Kalliola & Flores-Paitan 1998; Ruokolainen et al. 2007), past climate dynamics (Sugden 2000; Bush & Flenley 2006; Bush et al. 2007) and the exact age of the establishment of the Amazon River (Dobson et al. 2001; Figuereido et al. 2009) are but a few of the thrilling insights that were obtained.

Simultaneously, a relatively young branch of science, DNA studies, increasingly suggested that the origin of extant bio-diversity dates back well before the Quaternary (Antonelli 2008; Rull 2008) and may have coincided with regional geological events (see Chapters 23–25). Consequently, at the turn of the millennium, geology and biology were drawn to each other in a concerted effort to explain the origin of Amazonian biodiversity and landscapes.

A journey through the geological history of Amazonia

The scientific advances of the past two decades, and the newly gained perception that biotic and abiotic evolution might be intimately related, demanded an interdisciplinary, multinational effort to summarize the state of the art in Amazonian geo- logical sciences. This book attempts to fulfil this role. It not only presents an outline of the geological history, but also assesses the implications of the geological past for landscape evolution and biotic diversity. The contributors show that the development of Amazonian diversity is intimately linked to landscape evolution, and that modern Amazonian ecosystems were formed during the geodynamic processes of the Cenozoic. The implication of this work is that before the Quaternary there were periods with even more diverse ecosystems.

The contributions to this book are grouped into five themes, corresponding to the book’s five parts. The first of these themes discusses the origin, architecture and stratigraphic and tectonic relationships of the major geological units of the eastern Andes and Amazonia. The second theme focuses on the Amazonian sedimentary record from the Mesozoic era to the Quaternary period. This record is subdivided into cratonic and Andean-driven depositional systems although Neogene and Quaternary systems are a combination of both Andean and cratonic fluvial systems. In addition, megafan depositional systems in western Amazonia are also reviewed. Climatic evolution and the implications for the Amazonian region during the Miocene are assessed in the third part. The Amazonian palaeontological record of the aquatic and terrestrial realms constitutes the fourth part of the book. Despite the uneven concentration of fossiliferous deposits in western Amazonia and the adjacent Andes, the palaeontological chapters provide an in-depth insight into the development of Amazonian floras and faunas. The final, fifth, part of the book is concerned with modern perspectives on the origin of Amazonian biodiversity. The book concludes with a chapter by Wesselingh et al., who summarize the highlights of each chapter and provide a synopsis of the Cenozoic history of Amazonia. The best localities for observing the out- crops and fossils are shown in Fig. 1.1.

Main geological processes shaping Amazonia through time

The geography of Amazonia was shaped during three principal geological phases. The first was a Proterozoic phase (3–1 Ga [gigayears]) of cratonic formation dominated by magmatism, continental accretion and tectonic processes (see Chapter 2 by Kroonenberg & de Roever). The craton forms most of eastern Amazonia and consists of ultrastable basement with landscapes that date back to the Cretaceous and Paleogene. In terms of bio- diversity these areas are relatively poor compared to the nutrientrich, Andean-dominated western part of Amazonia (see Chapters 21 & 22). At the end of the Proterozoic a series of east–west orientated intracratonic sedimentary basins were formed, which acted as fluvial conduits. Throughout geological history basement reactivation formed ‘arches’ that, at different times, created drainage divides. Seismic data and new stratigraphic charts from the Brazilian oil company Petrobras illustrate the development of these sedimentary basins in Brazilian Amazonia (see Chapter 3 by Wanderley Filho et al.).

The second major geological phase was characterized by rifting and break-up of the supercontinent Pangaea. This period also saw the opening of the Atlantic (Jurassic, c. 195 Ma) during which the Americas became fully separated from Europe and Africa. The separation was completed during the Cretaceous after which sedimentation of the intracratonic basins was resumed (c. 120 Ma). The third and final geological phase was determined by changes in plate configuration along the Pacific. This plate activity was an aftermath of the continental break-up and ultimately responsible for the uplift of the Andean Cordilleras that was initiated during the Cretaceous.

Pulses of uplift continued throughout the Cenozoic; however, Andean tectonism only reached a climax during the Late Miocene and Pliocene (c. 10–4 Ma). This resulted in intense denudation, increased subsidence in the sub-Andean zone and progression of the sedimentary wedge into Amazonia, and ultimately connected the inland drainage system with the Atlantic Ocean creating the Amazon River (see Chapters 4 & 5 by Mora et al. and Roddaz et al.; Figuereido et al. 2009).

Andean uplift remained high during the Pliocene while subduction of the Nazca Ridge caused tectonic uplift of the Fitzcarrald Arch (southeastern Peru and adjacent Brazil). As a consequence the western Amazonian lowlands, which during the Miocene formed continuous aquatic habitats, became fragmented and dissected (see Chapter 6 by Espurt et al.). A final marker event in the geological history of northern South America was the closure of the Panama isthmus around 3 Ma. Although tectonism is on-going, this concluded the Present geographical configuration of the South American continent, its landscape and modern drainage systems (see also Chapter 26).

Cratonic and Andean-driven depositional systems

River systems of cratonic descent or local lowland origin have dominated Amazonian landscapes throughout their history. In this book we review the Mesozoic and Cenozoic cratonic fluvial systems by comparing four different fluvial formations that range in age from Cretaceous to Late Neogene (see Chapter 7). From the Oligocene onwards Andean-driven depositional systems dominated the sub-Andean zone and western Amazonia. These systems extended to at least 1.5 million km2 during the Miocene and were characterized by very large lakes and wetlands and occasional marine influence. During the Early and Middle Miocene a lake- and wetland-dominated system occurs (Pebas phase) whereas in the Late Miocene the newly formed Amazon River introduces a fluvial element into this otherwise wetland-dominated system (Acre phase) (see Chapter 8). Andean drainages are crucial for the soil development and distribution of species-diverse vegetation on nutrient-rich Andean-derived substrate. Instead relatively species-poor vegetation develops on the craton-derived substrate.

The presence and extent of marine influence in the history of Amazonia has been a hotly debated topic. In Chapter 9, Hovikoski et al. argue that in the past 30 Ma well-documented episodes of marine influence in Amazonia are limited to the Miocene. However, there is no evidence for fully established marine corridors (‘seaways’) throughout the South American continent in the Cenozoic.

Fig. 1.1 This map represents the principal Amazonian rivers and outcrops of Cretaceous and Cenozoic origin in Amazonia that are referred to in the various chapters of this book. The locations are represented as numbers and either indicate the author or the common name of the locality. (1) Pebas/Solimões outcrops (Hovikoski et al., see Chapter 9). (2) Pebas/Solimões outcrops (Hoorn et al., see Chapter 8). (3) Fossil mammals (Negri et al., see Chapter 15). (4) Localities of both Negri et al. and Hovikoski et al. (the localities close to the city of Assis Brasil are situated on the margins of the Acre River, which is not represented here. (5) Cretaceous-Paleogene Alter do Chão (source Petrobras, in Hoorn et al., see Chapter 7). (6) Neogene fluvial deposits of cratonic origin (Hoorn et al., see Chapter 7). (7) Fitzcarrald mammal fauna (Negri et al., see Chapter 15). (8) Lower Miocene Castillo Formation – other important Venezuelan localities are placed close to/into the cities of Urumaco (Upper Miocene Urumaco Formation) or Barinas (Middle Miocene Parángula Formation) – see Riff et al., Chapter 16. (9) Middle Miocene Honda Group (La Venta Fauna), Magdalena Valley. (10) Atalaia Beach (Salinópolis city) and Ilha de Fortaleza (Sao João de Pirabas city), Lower Miocene Pirabas Formation (see Riff et al., Chapter 16). Map made by D. Riff and J. van Arkel.

The Cenozoic Andean uplift and increased denudation rates further resulted in megafan systems along the Andean foothills (see Chapter 10 by Wilkinson et al.). Megafans are low-gradient river systems choked by sediments, which force them to continuously change their courses. Understanding their dynamic behaviour sheds light on the development and distribution of aquatic biota. The extent of megafan depositional systems in the history of Amazonia is greatly underestimated.

Late Neogene and Quaternary fluvial systems are further explored in Chapter 11, by Irion & Kalliola. They outline the fluvial depositional environments and processes from the foreland basins in the west to the mouth of the Amazon in the east, and consider the resulting landforms, which dominate a major part of the surface of lowland Amazonia. Quaternary fluvial systems along the trunk Amazon River have been dominated by strong eustatic-driven base-level changes.

Amazonian climate

Although palaeoclimatic data are hard to obtain, isotope data from fossil molluscs and cyclicity in the sediment beds indicate that the modern Amazonian hydrological cycle, which ensures the year- round wet conditions that sustain the rainforests, was in place in the Miocene (see Chapter 12). Experimental climate modelling for a low-elevation Andes and the effect on Amazonian climate is explored by Sepulchre et al. in Chapter 13. Based on their model, the role of the Andes in maintaining permanent wet conditions in the lowlands is seemingly less prominent than one would expect. The wet character of the Amazonian climate is mostly the result of the Amazonian hydrological cycle. However, a lower Andes would create different precipitation patterns than at Present, and the removal of the Andes would increase seasonality.

Another climatic controlling mechanism that affects Amazonia is the El Niño Southern Oscillation (ENSO). In Chapter 14 Bookhagen & Strecker explore the influence of the negative ENSO climatic phenomenon (also known as La Niña) on sediment influx and aggradation in the fluvial systems. The extreme high water levels as a result of high precipitation during the negative ENSO years have a disproportionate effect on denudation and are thus extremely important to the Amazonian river dynamics.

The palaeontological record in Amazonia

Amazonia has hosted a highly diverse mammal fauna at least since the Paleogene. Recently discovered Eocene-Oligocene faunas and Middle Miocene faunas from the Peruvian-Brazilian border area provide us with detailed information on the faunal composition. However, most noticeable is the rich Late Miocene fauna from Acre (Brazil), which includes species with remarkably large forms (see Chapter 15 by Negri et al.). The demise of the giants coincided with the arrival of North American immigrants associated with the emergence of the Panama land bridge (Stehli & Webb 1995).

The Amazonian crocodile and turtle faunas indicate that during the Cenozoic diversification was slow, but culminated in the Miocene fauna with a diversity and disparity that remains unrivalled (see Chapter 16 by Riff et al.). This fauna contains the largest crocodile and turtle that ever lived, as well as a remarkable diversity of gharial species. The Pliocene and Quaternary faunas are clearly less diverse, a feature linked by the authors to global cooling and the disappearance of the large productive aquatic ecosystems of the Miocene.

The diverse Amazonian fish fauna, too, has a long history of gradual diversification, as is shown by Lundberg et al. in Chapter 17. Already in the Miocene an essentially modern fauna inhabited the Amazonian aquatic ecosystems. The fishes have provided some of the best indications of the changing outline of Amazonian water-sheds throughout their Cenozoic history. Especially well reflected in this fauna is the separation, during the Late Neogene, of northern coastal and Andean drainages from Amazonia.

The Miocene invertebrate fauna developed through a large evolutionary radiation of endemic mollusc and ostracod species in the long-lived lakes of the Pebas megawetland (see Chapter 18 by Wesselingh & Ramos). In addition, species associations characteristic for restricted marine conditions occur in some intervals. Nevertheless, since the Late Miocene the Amazonian rivers and lakes have been the domain of a low-diversity fluvial mollusc fauna and a stunningly diverse decapod fauna.

The palynological and palaeobotanical record of plants shows us that modern angiosperm-dominated rainforests existed in Amazonia throughout the Cenozoic (see Chapter 19 by Jaramillo et al.). Diversity culminated during the Eocene, and a major extinction occurred at the Eocene-Oligocene transition. Modern genera were already present during the Miocene, when the current rainforest biome developed and diversities were as high, or even higher, than at Present. In Chapter 20 Behling et al. further show that although the Quaternary glaciations affected the distribution of plant species in Amazonia, they did not seem to promote speciation in the Amazonian lowlands. During the Quaternary the fringes of the rainforest were affected at precessional timescales, but the core of lowland Amazonia remained covered by forest. Nevertheless, the composition of forests changed through different parts of the glacial cycle.

Modern perspectives on the origin of Amazonian biota

In Chapter 21 ter Steege et al. present the region-wide diversity patterns and explore their relationships with a range of factors, such as edaphic variation and climate. Although the documentation of biodiversity is notoriously incomplete, the addition of niche modelling has substantially improved our insights, and will do so in future. The importance of edaphic heterogeneity for plant diversity is further illustrated by Duivenvoorden & Duque in Chapter 22, which investigates the relationships between the abiotic environment (geology, geomorphology, soils) and biodiversity.

Recently, many important new insights into the origin of Amazonian biodiversity and biogeography have emerged from molecular studies. In Chapter 23 Pennington & Dick review evidence from plants, while Antonelli et al. in Chapter 24 review the development of tetrapods, and the fish are treated in Chapter 25 by Lovejoy et al. All contributors caution about hasty interpretation of age estimates from so-called molecular clock studies because of the underlying assumptions. Nevertheless, results clearly indicate that the origination of modern biota has been a steady process that mostly played in the Cenozoic.

Outlook

New insights and data about the origin of Amazonian landscapes, ecosystems and biodiversity are accumulating even as we compile this book. Further integration of the various biological, geographical and geological disciplines, as well as further technical and conceptual developments within the different fields, will continue to bring new insights about the Amazonian biological system and its resilience, as well as the importance of Amazonia on global processes on a variety of time scales.

As Amazonia is suffering badly from human activities, new and much more ambitious efforts to assess its biodiversity, mostly by time-consuming field-based taxonomic inventories combined with niche modelling, are paramount to get a better sense of the magnitude of species richness and to identify further priorities for conservation. Molecular studies have become an indispensable tool in identifying real species richness.

Further processing of subsurface data, both seismic as well as borehole data and samples, will add to our knowledge of the development of the region and its landscapes. Study of the reaction of biodiversity to previous natural perturbations will bring more insights about ecosystem resilience, at a time when such insights are so badly needed.

Raising awareness of the unique and amazing diversity of life in Amazonia is needed in order to achieve better protection for the region and its biota. With this book we hope to enhance appreciation of the vast timescales that were needed to create these great ecosystems, which we are challenging so profoundly at this moment in history.

Acknowledgements

This book is the result of an intense cooperative effort of more than a hundred people from different continents who all share a scientific, and often a personal, interest in Amazonia. As editors we were overwhelmed by the enthusiasm of all our colleagues who participated in this project. The novel and original insights presented through the chapter authors and reviewers encouraged us at all times. It has been a long journey during which many things happened in our personal lives; however, the book project always joined us together. The compilation of this book has been a long process (2.5 years to reach publishable form) but during that process we have learnt a great deal about Amazonian history from colleagues old and new. However, this book would not have reached its present shape without the help of all the reviewers (sometimes in a dual role of authors) who shared their time with us and helped us improve the manuscripts.

A big thanks to the following people (in alphabetical order): Frank Audemard, German Bayona, Bodo Bookhagen, Chris Brochu, Alberto Cione, Joost Duivenvoorden, Richard Field, Jorge Figueiredo, Paul Fine, Jose I. Guzman, Mathias Harzhauser, Ren Hirayama, Henry Hooghiemstra, Jussi Hovikoski, Teresa Jordan, Wolfgang Junk, Risto Kalliola, Salle Kroonenberg, John Lundberg, Bruce MacFadden, Richard Madden, Koen Martens, Jose Ignacio Martinez, Mark Maslin, Francis Mayle, Michael McClain, Bob Morley, Brice Noonan, Onno Oncken, Jim Patton, Toby Pennington, Sir Ghillean Prance, George Postma, Victor Ramos, Roberto Reiss, Colombo Tassinari, Eric Tohver, Graham Wallis, Wilfried Winkler, Martin Zuschin, and a number of colleagues who requested to remain anonymous.

Our editorial advisors, Hubert Vonhof, Salomon Kroonenberg and Henry Hooghiemstra, helped us with many tasks related to the book. But above all we owe them special thanks for standing beside us and giving us all their support and advice during crucial moments in this project. Overseas, at the Petrobras offices, we warmly thank Paulus van der Ven for his continual support; Petrobras management are also thanked for the valuable subsurface information that the company made available to this book.

None of this would have ever happened, though, if Ian Francis from Wiley-Blackwell Publishers had not believed in this project in the first place. We thank him for his trust and also thank Delia Sandford and Kelvin Matthews, also from the publishing house, and project manager, Nik Prowse, for their patience, help and advice in this project.

The success of this project is also based on the unconditional support of our beloved ones (Alastair Milne and Maaike Wickardt, respectively) who enabled us to complete the process of the making of this book. Our families have born most of the brunt of our work. We are so happy they still love us and are in good health with us to enjoy this milestone after considerable periods of mental absence.

Finally, we are immensely thankful that Thomas van der Hammen managed to complete the prologue of this book, this in spite of his deteriorating health. Thomas has been our mentor, who inspired us to take on the mighty Amazon. We dedicate this volume to him in admiration of his longstanding commitment to Amazonian research, and hope that this book will inspire young scientists to undertake further research, just as Thomas inspired us to engage in research in wonderful Amazonia. There is still so much to research out there in the virgin rainforest of South America...

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