Abyss of Time

Lyle Paul

Description

Geologists are among that group of scientists who must factor the passage of time into their investigations and they thus have a perspective on time that sets them apart from many other researchers. The proposition that geological time is vast, encompassing thousands of millions of years, is relatively recent. It is a concept that remains controversial and unacceptable to many people today who still consider the Earth to have been made to a timetable covering no more than ten thousand years.Paul Lyle examines how our fascination with time has developed from our earliest ancestors recognition of the cycles of the sun and the moon. It considers the passage of time as a series of non-repeatable events, Times Arrow, in contrast to time as a series of repeated processes, Times Cycle, both of which can be used to explain geological features on the Earths surface.The author argues for a greater understanding of geological or deep time as society becomes more aware of the vulnerability of the Earths resources to over-exploitation by an expanding consumer society. This debate and the controversy surrounding global warming emphasises the importance of geological time to the process of economic and political decision-making. It is a book for those interested in the intellectual challenge presented by the extent of geological time. It is written for environmentalists and policy-makers who wish to better place their concerns and decisions in proper context but, above all, it is a book that offers to share a geologists appreciation of time with the widest possible audience.

Sujets

• Sciences et techniques
• Earth science
• Historical geology
• Popular science

Informations

• Publié par: Dunedin Academic Press
• Date de parution: 05 novembre 2015
• Nombre de lectures: 0
• EAN13: 9781780465432
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Contents
Acknowledgements
Preface
Chapter 1: In good time
Chapter 2: Tempus fugit – time flies
Chapter 3: The importance of understanding time
Chapter 4: The early chronologers
Chapter 5: Time’s arrow and time’s cycle
Chapter 6: The determination of relative time – beds in order
Chapter 7: Measurement of absolute time – the age of the Earth
Chapter 8: Archaeological time
Chapter 9: Time future
References and further reading
Index
Illustration credits
To Sylvia with love and gratitude – bon ton roulet – let the good times roll…
Acknowledgements
It is a pleasure to acknowledge those many people who have encouraged and helped me during the course of this project. Principal among those was John Arthurs; his comprehensive and perceptive comments on an early draft of the manuscript did much to improve the content and layout of the book and I thank him for his efforts. The comments from an anonymous reviewer were also extremely useful in the final revision of the text. I am grateful to Edward and Isa Ferguson for their helpful comments on parts of the manuscript and for again allowing me to use Anrhin as a writing retreat. My thanks go also to Rachel and Gary Smylie who provided invaluable photographic and computer support without which I would have been floundering.
My friends and colleagues among the diverse geological community in Ireland have always been free with opinions and comments, gratefully received in the spirit in which they were delivered, and I feel privileged to be part of such a vibrant network. My thanks to you all, you know who you are.
As always the contribution made by Sylvia Lyle has been immense and I thank her again for her constant support and encouragement. I appreciate her consistent willingness to pass comment on whatever piece of text I happen to be working on, even if I don’t always subscribe to her analysis!
They also serve who cheer me on from over the water, so thanks to Gareth and Yvonne and Simon and Jen. Future time belongs to Beth and Jack.
Irrespective of all such support, any errors or omissions are solely my responsibility.
Preface
The idea for this book originated in a series of lectures for the general public which I gave in the Ulster Museum in Belfast in the autumn of 2005, on the theme of time and the geological history of Ireland. These lectures were well attended and the numbers of those turning up stayed high, even as the nights grew longer and the weather became more inclement. This suggested there was an interest in the concept of time in geology that was not being met elsewhere at that time. Hutton’s famous phrase – ‘we see no vestige of a beginning, no prospect of an end’, although flawed, clearly struck a chord with many of the audience. Perhaps for the first time they were thinking directly about the extent of time in Earth history, of time passing and of their place in the continuum of time, if indeed it is a continuum. Geologists, by the nature of their training, perceive time in a different way from non-geologists. A view of any landscape is automatically interpreted in terms of the age of the rocks that form that scenery and the landscape is also interpreted as a sequence of events in Earth history. This ability to ‘read the landscape’ adds a further dimension to the appreciation of the world around us but also allows a greater understanding of our place in the grand scheme of things, on Earth, in the Solar System and in the universe. It is clear that there is a poor understanding in general of the extent of geological time.
Recent surveys taken in the USA have shown that almost half the population there believe that human beings were created in their present form around 10,000 years ago. There is also a poor understanding of the order in which events in Earth history took place. Many people believed that certain events had occurred simultaneously when in fact they were separated by a considerable amount of time. A good example of this is the widespread belief that dinosaurs and humans were on the Earth simultaneously. A further cause for surprise is that, as well as this level of ignorance about time, there was also no apparent concern over their lack of knowledge among those polled. It seems that those enthusiasts who turned out for my lectures were very much an interested minority.
It is not just for aesthetic reasons that people should appreciate geological time, its extent and its ramifications. The world we find ourselves living in today is one of expanding populations using increasing amounts of resources in the form of fuels, often fossil derived and carbon based, to the extent that if present trends continue there will be insufficient resources to sustain the Earth’s population. The importance of understanding geological time is that many of the world’s resources result from cyclical processes. These cycles are sometimes relatively short term, for example the water cycle whereby water evaporates from the oceans to form clouds that come over land and produce rainfall which makes its way back to the ocean via streams and rivers and so completes the cycle. This occurs over periods as little as a few months in some places but over hundreds or thousands of years for some of the large-scale underground water sources such as the Ogallala Aquifer in the mid-western states of the USA. This aquifer, like many such reserves worldwide, is being over-used. The rate of discharge from the aquifer is greater than the rate of recharge, and so the cycle is not being completed. Water can probably be considered as a ‘renewable resource’, but that term cannot be applied to resources such as copper or oil which result from geological cycles which take hundreds or thousands of millions of years to complete. The oil and gas being so greedily consumed in the world’s vehicles and central heating boilers mostly began to form over 100 million years ago and when the reserves are used up we will have to wait a very long time for their replacements to be available.
A greater appreciation of these timescales by politicians and their constituents might help them to agree measures to ameliorate the catastrophe we seem to be heading for. To understand whether or not we are heading into a period of human-induced climate change, with perhaps disastrous effects for the whole of Earth’s population, it is essential that we examine major climate changes that have occurred throughout geological time. This requires an appreciation of geological history, with time measured not just in a relative way – this rock is older or younger than that rock – but also a time framework that tells us the age of a bed of rock, or a mud layer on a lake bed, or a layer of ice in the Greenland ice cap, in as precise a number of years as possible.
So, who is this book aimed at? One obvious interest group is the cohort of people such as those who came to my lectures. They were people who are interested in their surroundings and their environment, who are seeking the intellectual challenge presented by confronting the extent of geological time and the implications that may have for their view of themselves and their place in the universe. If I am feeling optimistic I think that perhaps these people are not such a small minority after all. There is clearly great interest in matters geological, archaeological and astronomical, to judge from the diet of popular television programmes available, and the numbers of books on popular aspects of science that are published and purchased every year. If it is possible to popularize the concept of ‘black holes’ in astronomy, then the idea of an Earth that formed 4.5 billion years ago is not so daunting.
However, engaging with that particular constituency could be regarded as preaching to the converted. The challenge is to engage the majority of the population who up to now have shown little interest in the topic. I believe this group is as big as it is because geologists as a profession have not been as good at communicating with non-geologists (the rest of the world!) as they have been at talking to other geologists. They have been guilty of a lack of outreach and if people do not fully appreciate the role of geologists in society, then geologists themselves are partly to blame for keeping their professional secrets too much to themselves. So this book is an attempt at that outreach to those members of the population who have been previously neglected by our profession, people who are concerned about many of the environmental problems we are facing today and in the near future, but who do not as yet have all the information they need to make an informed judgement on the best way forward. It is also aimed at decision-makers, those members of the legislative and executive branches of governments who are required to make and administer the laws. Such legislation is quite often drawn up with a shocking level of ignorance about the longer term implications of what is being proposed. The book is aimed at raw material producers and those in the manufacturing industries, the suppliers and users of precious resources. An appreciation of the workings of geological time and processes must surely be helpful when balancing the needs of consumption and conservation.
There are many academic and professional fields nowadays that have a peripheral engagement with geology – environmental scientists, geophysicists, water scientists and civil engineers for example – for whom a grasp of the role of the fourth dimension would be useful. For students or practitioners in these areas this book deals with the principles of relative and absolute time, treatment of which is often absent from conventional university courses.
And then there are those people who know little or nothing about geological time, who have never thought about it and furthermore see no reason why they should. Some of these people resist the idea of a very old Earth because of their religiou