Meteorite Impact!: The Danger from Space and South Africa's Mega-Impact The Vredefort Structure / Edition 3

Meteorite Impact!: The Danger from Space and South Africa's Mega-Impact The Vredefort Structure / Edition 3

by Wolf Uwe Reimold, Roger Lawrence Gibson

ISBN-10: 3642104630

ISBN-13: 9783642104633

Pub. Date: 09/10/2010

Publisher: Springer Berlin Heidelberg

The impact of large extraterrestrial bolides (asteroids and comets) with Earth is an ever-present danger that humanity has only recently begun to recognise. Of the 175 impact craters found thus far on Earth, three giants stand out – Chicxulub in Mexico, Sudbury in Canada, and the Vredefort Impact Structure in South Africa. Each of these impact events

…  See more details below


The impact of large extraterrestrial bolides (asteroids and comets) with Earth is an ever-present danger that humanity has only recently begun to recognise. Of the 175 impact craters found thus far on Earth, three giants stand out – Chicxulub in Mexico, Sudbury in Canada, and the Vredefort Impact Structure in South Africa. Each of these impact events catastrophically altered the global environment and was strong enough to drastically change life on our planet. The Vredefort Structure is the oldest and largest of these three giants and at about 300 km diameter it is nearly twice the size of the Chicxulub crater that was formed by an impact that wiped out approximately 75% of all known life on Earth 65 million years ago. In the more than 2000 million years since its formation, water, wind and ice have slowly eroded away the original Vredefort crater, exposing its roots in a series of spectacular rocks. The outcroppings in the region around the towns of Vredefort and Parys, known as the Vredefort Dome, show the scars of the cataclysmic forces that accompanied the impact event. The rocks, ripped from the depths of the crust by the impact, also tell a far older story that stretches back to more than 3500 million years ago, when the first continents formed on the primitive Earth, and to the time when fabulous gold deposits accumulated on the margins of the ancient Witwatersrand sea. The Vredefort Structure is truly one of the geological wonders of the world. While the rocks of the Vredefort Dome, and the story they have to tell, lie at the heart of this book, it is by no means the full story. The Dome is an area of spectacular scenic beauty and biodiversity, dominated by 40 kilometre-wide crescent of hills incised by the Vaal River and its tributaries. This area has also been home to humans for many thousands of years. Together, the rich geological, biological and archaeological heritage has led to the recognition of the most scenic part of the Vredefort Dome as a World Heritage Site.

Read More

Product Details

Springer Berlin Heidelberg
Publication date:
Geoparks of the World, #1
Edition description:
3rd ed. 2010
Product dimensions:
8.27(w) x 10.63(h) x 0.02(d)

Table of Contents

Foreword 10

Part I

Chapter 1 The Early History of Earth --- Impact, Volcanoes, and Early Life 15

Introduction 16

Geological change --- the answers within, and without 18

Man on the Moon 24

Back to the beginning --- from the Big Bang to early Earth 29

Impact --- the ubiquitous process 31

The oldest rocks 32

Time to cool --- birth of the Kaapvaal continent 35

Old crust in the Vredefort Dome 37

Rifting, oceans, volcanism 38

Mountains, fire and ice 44

The Unique Bushveld magmatic event 46

Chapter 2 Chaos and Catastrophe 49

Introduction 50

Extinction or survival --- our restless Earth 53

Meteorite-impact catastrophes 67

Normal (background) versus mass extinctions 72

A brief look at the impact record in the Solar System 76

What are the projectiles capable of causing an impact catastrophe? 87

What is an impact crater? 90

How can we identify impact structures? 92

Shock metamorphism 97

Chapter 3 The Impact Heritage of Southern Africa 101

Tswaing meteorite crater 102

Does Tswaing have a twin? (Kalkkop Crater, Eastern Cape Province) 108

South Africa's other Giant Impact --- Morokweng impact structure, North West Province 109

Our Southern African neighbours 111

Testimony of earliest impact catastrophe --- Barberton and the Northern Cape Province 113

Traces of catastrophe in the Karoo? 115

Chapter 4 Vredefort: The Largest and Oldest Impact Structure in The World 117

The Vredefort Structure revealed 118

Getting to know the giant: By road through the Vredefort Structure 120

Traversing the outer parts of the Vredefort Dome (Fochville to Parys) 125

The geology of the Vredefort Dome 130

The Unique rock formations and deformations in the Vredefort Dome 134

The findings of the early Vredefort geologists 138

The second phase: evidence of impact? 141

Shock metamorphism --- the undeniable evidence! 145

The Vredefort Structure in the 1970s and 1980s: a time of confusion... but hard work! 148

What do dead elephants in Leningrad have to do with the Vredefort Structure? 151

The third phase --- solving the riddle, at last! 153

Vredefort research in the 21st Century 159

Vredefort --- an open book about the history of Earth and the nature of Earth's interior 161

Chapter 5 The Recent History of The Vredefort Dome Area 163

Section 1 Travelling Through Time: Archaeology and The Vredefort Dome 164

Introduction 164

Stone Age Vredefort Dome 165

The Iron Age 168

Archaeological research on the Askoppies Late Iron Age site 170

Archaeology of the historical period on the dome 175

Section 2 Beyond The Frontier History of The Vredefort Dome Area 179

The geographic setting 181

Development of towns 183

Treading on territorial toes 185

Mineral resources 187

The Second Anglo-Boer War (1899-1902) 189

After the war 195

20th Century development and growth 196

Development of infrastructure 198

Development of tourism 199

Workers and forced removals 199

Section 3 Flora and Fauna of The Vredefort Dome --- What, Where and Why? 201

The Vredefort Dome plants (flora) in a geographical context 201

The composition of the flora 201

Which biome occurs on the Vredefort Dome? 203

Veld types on the Vredefort Dome 203

Factors that affect the vegetation 205

The habitats on the Vredefort Dome 207

The effect of geology on the vegetation of the Vredefort Dome 207

Recent changes in habitats on the Vredefort Dome 208

Woody vegetation in the Vredefort Dome 210

Fauna in the Vredefort Dome 210

Chapter 6 Frequently Asked Questions 215

Frequently asked questions about the Vredefort impact event 216

Where is the projectile responsible for the Vredefort impact? 216

Do we know from which direction the Vredefort bolide came? 216

Do we know how large the bolide was that caused the Vredefort catastrophe? 218

Could any life forms have perished in this catastrophe? 219

Would this impact have influenced further development of life? 219

Can there be other impact structures of the size of Vredefort, not yet discovered on Earth? 219

Major diamond, gold and platinum resources lie close to the Vredefort Dome. Why have no major ore deposits been found in the dome itself? 220

Is Vredefort truly unique? 221

Is the Cradle of Humankind related to the impact structure? 222

Chapter 7 What Does The Future Hold For Humankind? 225

What does the future hold for humankind? 226

Chapter 8 Tourism in The Vredefort Dome 233

Outlook: the Vredefort Dome's potential to become an international heritage asset 234

Part II Tour Guide Through the Vredefort Dome 242

Stop 1 Vredefort Dome World Heritage Site Visitor Centre 244

Stop 2 Inlandsee pan and the centre of the Vredefort impact structure 246

Stop 3 Ancient oceanic crust at Greenlands 247

Stop 4 Broodkop shear zone and bentonite mines 249

Stop 5 Steynskraal pelitic granulites---a thermal record 251

Stop 6 Pseudotachylitic breccia and gneisses, Parys 252

Stop 7 Pseudotachylitic breccia and gneisses in the outer core 252

Stop 8 Vredefort Granophyre and Bushman petroglyphs, Daskop 257

Stop 9 Vredefort Granophyre and Dominion Group lavas, Iniekom 258

Stop 10 Rocks and metamorphism of the Central Rand Group (Witwatersrand Supergroup), Donkervliet valley 262

Stop 11 Vaal River view site and alkali granite 265

Stop 12 Gold mining in the Venterskroon area 266

Stop 13 Shatter cones in Booysens formation, Rooderand 267

Stop 14 Amazon gold reef, Rooderand 270

Stop 15 Ventersdorp lavas, Askoppies iron Age settlement and Anglo-Boer War sites on Tygerfontein farm 271

Stop 16 Stromatolites and cave in Transvaal rocks of the western collar 272

Stop 17 Schoemansdrift Bridge shatter cones 273

Stop 18 Dwarsberg (Steenkampsberg) View site 274

Stop 19 Rocks and metamorphism of the lower Witwatersrand Supergroup, Kommandonek Nature Reserve 275

Stop 20 Impact-induced fold and view site, Parson's Rus 275

Stop 21 Coesite-stishovite-bearing quartzite Kromellenboog Stream 276

Stop 22 Witwatersrand Supergroup quartzite, impact fault and Bobbejaanrant viewpoint, Smilin' Thru Resort 277

Acknowledgements 278

Bibliography 279

Glossary 288

Appendices 305

Index 324

Read More

Customer Reviews

Average Review:

Write a Review

and post it to your social network


Most Helpful Customer Reviews

See all customer reviews >