Transcript Geology

Science and Creationism
12. Geology
© Colin Frayn, 2008-2011
www.frayn.net
Pangea
• One single large land mass
– Existed around ~250-150Myr ago
• Evidence
– Geological strata
• Rock beds often seem to correspond with
extraordinary accuracy in distant countries.
– Similar fossils
• Similar fossils are found on coastal regions
of continents thousands of miles apart
– Glacial deposits
• Similar glacial deposits of similar age occur
on many of the continents, suggesting that
they were all polar at a similar time
– Shapes
• Continents seem to fit together
© Colin Frayn, 2008-2011
www.frayn.net
Ocean Floor Magnetic Reversals
• Basalt on the ocean floor records the
direction of the Earth’s magnetic field
– The pattern of this is symmetrical
• Impossible to create such a pattern without tectonic
separation
– Indicates that mid-ocean ridges slowly create
oceanic plates
• Does it lose its magnetism?
– No, basalt is not magnetic
– The structure of the rock records the magnetic
field when it cools
© Colin Frayn, 2008-2011
www.frayn.net
Oil Pressure
• Oil pressure is so high that it can only have been
in place for a few thousand years
• No, oil & gas are usually trapped by impermeable
rocks
– They can easily be held for millions of years
• An oil field can be much younger than the oil
– Oil can migrate into new reservoirs
– A weak reservoir may be young
© Colin Frayn, 2008-2011
www.frayn.net
Ice Core Science
• Ice cores
– Taken in areas of low snowfall
– Longest are over 3km long!
• Dating methods
– Counting layers (for shallow cores)
– Aligning with known global events
• E.g. volcanic eruptions
– Chemical analysis
• Looking at element ratios over time
– Modelling accumulation rates
• Deep core layers are too compressed to count individually
– Modelling ice flow
• Examine how deep levels flow over time
© Colin Frayn, 2008-2011
www.frayn.net
Greenland Lost Squadron
• Planes forced to land on ice in 1942
• Discovered in 1985-88, 80m deep in ice
– Near the coast, where snowfall rates are very
high (several metres/year)
– In a glacier that had moved ~2km
• Ice cores are taken in the inner parts of
Greenland
– Snowfall rates are much lower
• …or in Antarctica
– Antarctica is technically a desert!
– ~2-3cm of water falls annually
© Colin Frayn, 2008-2011
www.frayn.net
Ocean Salination
• Salt enters the oceans from the land
• If Earth is Old, then should oceans be saltier?
• No, because:
– Salt is also removed from the oceans to balance the
input
Sea spray
Cation Exchange
Burial of pore water
Halite deposition
Alteration of Basalt
Zeolite Formation
Biogenic output
Collective Small outputs
Total
6.7 x 1010 kg/yr
5.2 x 1010 kg/yr
3.9 x 1010 kg/yr
4.0 x 1010 kg/yr
14 x 1010 kg/yr
2 x 109 kg/yr
5 x 109 kg/yr
3.6 x 1010 kg/yr
38.1 x 1010 kg/yr.
© Colin Frayn, 2008-2011
www.frayn.net
Niagara Falls
• How old are Niagra falls?
– Probably less than 10,000 years
• So?
• Age of Niagara is not age of the Earth
• Age of Earth is at least the age of the
oldest thing in Earth not the youngest!
• Some rocks date to over 4 billion years
© Colin Frayn, 2008-2011
www.frayn.net
Erosion Rates of Mountains
• Are erosion rates too high?
• Mountains erode quickly
– Should last <14 million years
– Present erosion rates are likely far higher than average
• We have more mountains than average
• … but new mountains are always being formed
– Colliding continents create uplift
• New continental crust is always being formed
– Volcanic activity
– Sediment deposition
© Colin Frayn, 2008-2011
www.frayn.net
Stalactites and Stalagmites
• How long do they take to form?
– They can grow very quickly
– …with different chemistry e.g. gypsum
– However, calcium carbonate stalactites take a
very long time to form
• ~10cm / 1000 years maximum
• ~0.1cm / 1000 years minimum
• Limestone caverns
– These are etched out slowly by weak acid
erosion
– They are not formed by physical erosion
© Colin Frayn, 2008-2011
www.frayn.net
Water under the crust
• Where did the flood water come from?
– And where did it go?
• The Hydroplate theory suggests it was mainly under the crust,
and went back there
– Water would be easily detected by seismic surveys
• Water behaves very differently from rock
• We don’t detect any large bodies of water under the crust
– Rock is much denser than water
• The water would not be able to remain at depth
– At this depth, the water would be superheated
• The ‘flood’ would have cooked everyone
– The water burrowing through the rock would erode fissures
• The deposits would be scattered on the surface
• Such sediments would be easy to find, and extremely obvious
• Of course, they do not exist
© Colin Frayn, 2008-2011
www.frayn.net
Antarctic Leaves
• Hovind quotes Webb, Harwood, McKelvey
– Found fossilised forests in Antarctica
• What Hovind doesn’t say…
– They date to the late Pliocene
• Roughly 2 million years ago
• This is consistent with current models of tectonic
drift
– Antarctica would have been at warmer latitudes at this
time
© Colin Frayn, 2008-2011
www.frayn.net
The Geologic Column
• The accumulated layers of deposition over
geological time
• Is the column real?
– It exists in its entirety in at least 26 locations worldwide
• How do we know this was not made by a flood?
– Wind-deposited sediments
•
•
•
•
Such as desert sandstone
These grow very slowly
They can be hundreds of metres thick
They aren’t deposited by water
– Multiple salt beds within the column
• Grow slowly by evaporation
• Couldn’t have been formed by a rapid flood
© Colin Frayn, 2008-2011
www.frayn.net
Diatomaceous Earth
• A fossilised whale was found in this
sedimentary rock
– Near Lompoc, CA
– Apparently cutting through the layers
– Suggesting rapid deposition
• However…
– The whale was at roughly 45 degrees
– So were the rock beds
– i.e. the whale fossilised flat on the beds
• It did not cut through them
– The beds were later lifted tectonically
© Colin Frayn, 2008-2011
www.frayn.net
Rapid Petrification
• Flour, Charcoal, Trees etc.
• Petrification can happen quickly
• So?
© Colin Frayn, 2008-2011
www.frayn.net
Burlingame Canyon
• A canyon formed in 6 days
– Formed by a burst irrigation canal in 1926
– Approximately 90 million times smaller than the Grand
Canyon
• Part of the 16,000 year old Touchet formation
– Dated by looking at ash from periodic eruptions of
Mount St Helens between layers
– Gravel and fine sediment (not solid rock)
• It is obvious, from looking at this canyon, that it
has been created rapidly
– It is reasonably straight (The Grand Canyon meanders)
– It has no side channels (The Grand Canyon has perpendicular
tributaries)
© Colin Frayn, 2008-2011
www.frayn.net
Coal Formation
• How long does it take to form coal?
– ‘Low quality’ Coal may form fairly quickly,
given the right conditions
• Up to 1 metre in 100 years
– However, real coal deposits usually formed
slowly
• We see evidence for slow deposition
• River channels and root systems
• High-quality anthracite coal requires much longer
timescales to form
– Coal usually occurs bedded with sandstones,
limestones, shales
• All of which form very slowly
© Colin Frayn, 2008-2011
www.frayn.net
Oil Formation
• Oil forms between 4-6 km underground
– Requires temperatures between 50-120 celsius to form
• It migrates very slowly upwards
– Millions of years per km
– Depends on the permeability of the rock
• Some oil reaches the surface
– E.g. Alberta tar sands
• Some oil gets trapped
– Forms a reservoir
© Colin Frayn, 2008-2011
www.frayn.net
Earth was never Molten
• Why are dense elements (e.g. gold) found at the
surface?
– They should have ‘sunk’ to the core
• They probably did
– There isn’t much gold in the crust
– Though the mixing was probably not very thorough
• Elements are being continually mixed by
convection, volcanism etc.
– Lots of gold deposits are in igneous rocks
– Even though creationists often claim the opposite!
© Colin Frayn, 2008-2011
www.frayn.net
Anecdotal Stories
• Anecdotal evidence is totally worthless as a basis
for science.
• Newton Anderson
– Allegedly found a bell inside some coal
• Max Han
– Allegedly found a hammer head in sedimentary rock
© Colin Frayn, 2008-2011
www.frayn.net