Geobiology (eBook)

Nora Noffke is Associate Professor for Geobiology at Old Dominion University; Ocean, Earth & Atmospheric Sciences; For her research she has received the SEPM James Lee Wilson Award 2007, the GSA Fellowship 2007, and is nominated for the AAAS Fellowship 2008; Nora Noffke is Vice Chair of the GSA Division for Geobiology and Geomicrobiology, Member of the Council of GSW in Washington, and served for the NASA Astrobiology science definition team, Mars Exploration Rover.

Foreword 5
Preface 6
Contents 8
Introduction 12
I.1 Microbial Mats, Stromatolites and MISS – an Overview 12
I.2 The Geobiological Concept 16
I.3 Microbially Induced Sedimentary Structures 20
I.3.1 The Scholarly Definition 20
I.3.2 Taxonomic Relation of MISS to Stromatolites 20
I.3.3 Etymology of the Term 21
I.3.4 History of MISS Research 21
I.3.5 Distribution of MISS in Space and through Time 22
I.3.5.1 Temporal Distribution 22
I.3.5.2 Spatial Distribution 23
I.4 Significance of MISS – Status and Perspectives 24
I.4.1 Sedimentology 24
I.4.1.1 Biotic-Physical Sediment Dynamics Versus Physical Sediment Dynamics 24
I.4.1.2 A New Group of Primary Sedimentary Structures 24
I.4.1.3 Indicators for Sequence Stratigraphy and Basin Analysis 24
I.4.2 Paleontology and Microbiology 25
I.4.2.1 First Cyanobacteria 25
I.4.2.2 First Photoautotrophic Microbiota 25
I.4.3 Astrobiology 25
I.4.3.1 Earthly Analogues 25
I.4.3.2 Biosignatures 26
I.4.4Oceanography and Climatology 26
I.5 Collection of MISS 27
Concepts 29
II.1 MISS – Products of Life and Environment 29
II.1.1 The Sedimentary Surface – an Interface 29
II.1.1.1 The Three Main Types of Sedimentary Systems 30
II.1.2 Life at the Interface 31
II.1.2.1 Biofilm 32
II.1.2.2 Microbial Mat 37
II.1.2.3 Cyanobacteria for BeginnersBecause microbial mats are coherent 39
II.2 Formation and Preservation of MISS 40
II.2.1 Development and Preservation of Microbial Mats:the Ecological and the Taphonomic Window 40
II.2.1.1 The Ecological Window: Primary Processes of MISS-Formation 40
II.2.1.2 The Taphonomic Window: Primary and Secondary Processes of MISS-Preservation 64
II.2.2 Bringing the Ecological and Taphonomic Window into Alignment:the Search for Biofilms and Microbial Mats in Siliciclastic Settings 70
II.2.2.1 Search 71
II.2.2.2 Detection 72
II.2.2.3 Identification 73
II.2.2.4 Confirmation 74
II.2.2.5 Differentiation 75
II.2.3 The Criteria for Biogenicity of MISS 76
II.2.3.1 List of Criteria 77
II.2.3.2 The Criteria for the Biogenicity of MISS in the Context of the Criteria for Stromatolites 79
Classification 83
III.1 The Classification Diagram of MISS 83
III.2 The Five Categories of MISS 85
III.2.1 Structures Arising from Microbial Growth 85
III.2.1.1 Oriented Grains 85
III.2.1.2 Laminated Leveling Structure 89
III.2.2 Structures Arising from Microbial Binding 91
III.2.2.1 Mat Microfabrics 92
III.2.2.2 Sinoidal Structure 98
III.2.3 Structures Arising from Biostabilization 100
III.2.3.1 Mat Chips 101
III.2.3.2 Roll-up Structure (Mat Curl) 105
III.2.3.3 Shrinkage Cracks 108
III.2.3.4 Petees 110
III.2.3.5 Gas Domes 112
III.2.3.6 Sponge Pore Fabrics 115
III.2.4 Structures Arising from Baffling and Trapping 117
III.2.4.1 Mat Layer-Bound Small Grains 118
III.2.4.2 Mat Layer-Bound Heavy Minerals 119
III.2.5 Structures Arising from the Interference of All Microbial Activities Interactingwith Physical Sediment Dynamics 120
III.2.5.1 Erosional Remnants and Pockets 120
III.2.5.2 Multidirected Ripple Marks 128
III.2.5.3 Microsequences 133
III.2.5.4 Wrinkle Structures 136
III.2.5.5 Polygonal Oscillation Cracks 143
Application 148
IV.1 Ancient Biofilm- and Microbial Mat-Forming ProkaryotesModern microbial mats and MISS are the keys to understanding the nature 148
IV.2 Geobiological Field Trip Sites 150
IV.2.1 Modern and Pleistocene Catena of Benthic Cyanobacteriain the Bahar Alouane, Southern Tunisia, Africa 150
IV.2.2 Earth’s Possibly Oldest Fossil Cyanobacteria Preserved in the Nhlazatse Section,2.9 Ga Pongola Supergroup, South Africa 152
IV.2.2.1 Location of the Outcrop 153
IV.2.2.2 Stratigraph 153
IV.2.2.3 Tectonic Overprint 154
IV.2.2.4 Biofilm-Catena 154
IV.2.2.5 Exceptionally Preserved Structures in the Nhlazatse Outcrop 155
References 173
Index 181