Chapter 5The Changing Earth

Mystery in the IceWooly mammoth found in ice in Siberia.

The Earth's Story• No human was present at the beginning• No human records before 5000 years ago• Records before this are incomplete• Must makes assumptions:• 1) the earth always existed or• 2) formed naturally out of pre-existing materials• 3) earth supernaturally created out of nothing

The Nebular Hypothesis• The belief that the solar system formed slowly from a cloud of dust and gas… a nebula.

• Immense pressure formed a star

•Clumps of dust formed small bodies of rock, dust and ice – planetesimals

•Pulled together by gravity to form planets

Earth's FormationAccording to secular worldview:• Earth began 4.5 billion years ago

“planetesimals” collided because of gravity, forming a molten ball

once cooled, another planet collided, re-melting earth’s core

Debris went into orbit, forming the moon

Gases collected to form atmosphere

Ice from comets formed oceans

•As oceans rose, continents formed

Problems with the Nebular Hypothesis theory:• Sun should rotate faster•Mercury is too dense to have formed gradually•Mercury should be solid by now•Venus rotates backward•Uranus and Neptune are too large and too far away to fit with this model•Collisions would have left the earth wobbling•Probability of moon forming this way is almost nonexistent

Young – Earth story…• From the Bible’s account of Creation found in Genesis 1 and 2• God created by the power of His word in six days• He created in a specific order, establishing the processes we see today

A History of Change : Old – Earth Geologist's Story•Rubik’s Earth model – continents grew then broke apart, rejoined like patterns of a Rubik’s cube

Old-Earth …• tectonic plates – pieces of continents• supercontinents – plates repeatedly crashing (2 billion years ago)• Pangaea – last supercontinent to form, broke into pieces 180 million years ago

Old – Earth…•The Ice Ages• Believe that 5 major ice ages

occurred• Glacial period – span of time when a large part of earth covered in deep continental glaciers• Causes???

Causes of ice ages… (according to old-earth model)

• Cycles in sun’s heat output• Less “greenhouse gases” - gases trapping heat in atmosphere• Repeating wobble in earth’s orbit

The Geologic Column

• Building a history from the rock record• Observing “stratum” – multiple rock layers (strata)

• Absolute age – fixed age of rock based on nuclear change

• Relative age - comparing to nearby layers• Principle of superposition – oldest layers at

the bottom

Problems with Old-Earth Story•Finding similar magnetic field lines and fossils on different continents:•Problem: magnetic alignments can actually be different on same piece of crust.

•Multiple ice-ages:• Problem: Glaciers need lots of snow, and oceans

need to be much warmer to produce enough moisture in the air

More problems…•Radiometric Dating Problems:• It’s based on uniformitarian assumptions,

that things have always been changing at the same rate

• Unreliable results – young volcanic rock has been given ancient ages

More problems…

•Fossil Dating Problems:• Assume animals and plants began simple

and became more complex• No transitional fossils have been found• Vertical tree trunks found in many layers of

strata• The very existence of fossils shows problems

– must have been rapid burial

The Young-Earth Geologist's StoryThe Flood –• Most significant physical event in earth’s history after Creation (Genesis 7 & 8)• Heavy rain and break up of earth’s crust

Effects of the Flood • Different world, from mild temperatures to extremes• Volcanic activity from break up of crust •Thick clouds and ash in atmosphere blocked sunlight• Ushering in the ice-age

Ice-Age – Young Earth View• Creationist – Michael Oard’s theory• Only one ice – age, not covering entire earth• Caused from sun’s light being blocked from thick clouds and dust and ash

Ice-Age – Young Earth View

• 500 – 800 years after the flood• Job – one of the oldest books in Bible describes ice, snow, frost• As temperatures warmed, more mobile animals left for warmer places, large trapped•Animals died: lack of food, arctic cold, dust storms• All could be a quick death, preserved in deep freeze

Diluvial Geologic Column• Refers to rock layers from at least one huge continent• Continent foundation – granite rock• Plants at creation – so soil above the rock• Flood caused sediment, rocks, and soil to cover strata• Glaciers moved rocks, sand – creating valleys and more layers

Diluvial Geologic Column• Creationary geologist – Tasman Walker•5 time periods of earth’s history

• 1) Creation – bottom layer, no fossils, no death• 2) Lost World Era – Pre-flood world (1656 years),

some erosion, no fossils• 3) Flood – largest part of geologic column formed,

animals killed and buried quickly, fossils• 4) New World Era – rocks formed after flood, from

volcanoes and local flooding, very few fossils• 5) Recent Sediments – loose sand, gravel from

erosion

Tectonics:Study of Earth’s bedrock, earthquakes, volcanoes, and mountains, and the forces and processes that formed them.

Tectonics:Old-Earth View

Old-Earth view…•Geosyncline theory:

• Strata forms folds like a trough or bowl• Filled with collecting sediment• Pushing up mountains – • Problem! – couldn’t explain the source for

uplifting mountains•Continental drift:

• Continents seemed to fit together (same fossils at edges) and moved apart

• Wegener – single land mass Pangaea• Problem – couldn’t explain the source of the

movement

Old-Earth view…•Sea-floor Spreading: new ocean crust at a mid-ocean ridge

• During WWII – Sonar technology discovered mid-ocean ridges and trenches

• Ocean drilling – found alternating bands of magnetic grains

• Magma oozing up through cracks called rifts• Blobs of hot rock in mantle spreading out,

causing a rift to spread•Plate Tectonics

• Continental and oceanic crust forming plates• What happens to extra crust if sea-floor is

spreading?• Subduction – oceanic plates sliding under

continental plates

•Theory of Plate Tectonics

Old-Earth view…• Plate Tectonics Theory – the key explanation for how mountains formed, cause of earthquakes and volcanoes•Problems? – Dates…???

Young Earth…• Catastrophic Plate Tectonics

• John Baumgardner – plate tectonics fits well with the Flood, shattered Earth into plates

Difference with old-Earth and young-Earth theories – Time!!