MORLEY 2014

Anyone who has ever traveled realizes that…. 1. Not all places on Earth are the same 2. Nor are those places remaining unchanged

Geology is not a fundamental science Geology is a 'Multidisciplinary' science This is a $.50 word which says that it draws strength from many different areas of study By the time we're done, you will see how it is interrelated to physics, chemistry, biology, geophysics, geochemistry, etc.

We can’t do many empirical experiments…. Mostly Observe Oh… and beat up rocks!

FIRST QUIZ in GEOLOGY!

And best of all, there are no real "laws" in geology Not like the fundamental sciences which rely on the “natural laws” to help them make sense of the world (and keep them boring and predictable) Uniformitarianism: the present is the key to the past - We assume that earth processes that are working now have probably worked in pretty much the same way throughout geologic time. Original Horizontality: sedimentary layers are initially deposited in horizontal layers Superposition: the layer on the bottom is the oldest, and they get younger as they pile up. Cross-cutting relationships: the thing being cut is older than the thing doing the cutting

Geology is all about CHANGE In Europe, religious dogma effectively put a lid on creative geologic thought until the 1700's creationism and catastrophic natural events to explain the diverse biologic and physical features found on the earth

Fortunately, several free-thinkers attempted to explain natural events in more natural ways James Hutton ( ) and John Playfair ( ) - both were Scottish – Each felt that the geologic features which they observed could have been formed by slow, continuous processes over long periods of time, rather than catastrophic events

Sir Charles Lyell ( ) - Englishman Started doing detailed studies "documented the realities of uniformitarianism“ Called the Father of Geology

Introduction to Geologic Time

The Age of the Earth DO: Make a line from the top of your page to the bottom – How many years? – Place the following events…. First Life First Multicellular Organism Dinosaurs First Fish Humans First Trees Formation of the Appalachian Mountains Flowers

The Age of the Earth Archbishop Ussher ( ) Added up the 'begats' in the old testament The earth was formed on the evening of October 22, 4004 B.C. This date was etched in the cement of church dogma For a hundred years or so, anyone who questioned this date was liable to be denounced as a heretic (or worse) Remember, this was when you could be bar-b-qued for questioning the church Supporters relied on "innumerable catastrophes" to explain the diverse geologic features on earth

The Age of the Earth New insights into geologic processes allowed 'more scientific' attempts Some Questions…. – How fast are sediments deposited – How fast are they eroded – Is sedimentation continuous – And even if we can figure out all the above – No continuous exposure through all of the earth's history

Some new ideas…. William Sollas (1883) – Estimated the earth's age at 26 million years – Far cry from the 6000 years postulated by the church Joly (1899) – Irishman – Measurements of the amount of salt in seawater – Is the rate of salt addition constant? – This is directly related to rates of mountain building and tectonicstectonics – How about salt removed from the sea due to uplift and evaporation – Some of this salt is re-cycled as the salt beds are eroded – Came up with an age of 100 million years

We currently believe that the earth is 4.6 billion years old Absolute vs. Relative Age The Relative Geologic Time Scale Doesn't concern itself with actual ages, only in the RELATIVE order of events

A few thoughts on Fossils Fossils are the best and most commonly used correlation tool This is based on the concepts of natural selection and evolution

The true meaning of fossils, however, hasn't always been recognized Avicenna ( ) - a disciple of Aristotle: they grow within the rocks and resemble bones and plants only by chance Dogma of the middle ages said that they were created by Satan to confuse us William Smith ( ) - English canal builder – Spent 24 years mapping canal routes and observing the rocks of the English countryside – At that time, he failed to recognize the evolutionary significance of the fossils – To him they were essentially just distinctive shapes which allowed him to assign relative orders to the rock units in the area The significance of the fossilized remains has been recognized and used to establish the Relative Time Scale Paleontology - the study of fossils (or "ancient life")

YOUR TASK: Create an accurate time line of significant biologic and geologic events