Download Calculating the Radiometric Ages of USGS samples

RL Hanna
Radiometric Dating
Calculate the ages of the samples from the info given below.
Compare your answers to those presented on the USGS webpage
http://pubs.usgs.gov/gip/geotime/radiometric.html
no=amount of parent material left
n t = amount of parent material at the beginning
Calc Age
Years
Sample
14
14
Cloth wrappings from a mummified bull
P-D C -N
Samples taken from a pyramid in Dashur, Egypt. This date agrees with
Y=no/nt = 0.7803719661
the age of the pyramid as estimated from historical records
Charcoal
P-D C14-N14
Sample, recovered from bed of ash near Crater Lake, Oregon, is from
a tree burned in the violent eruption of Mount Mazama which created
Crater Lake. This eruption blanketed several States with ash, providing Y=no/nt = 0.447880803
geologists with an excellent time zone.
Charcoal
Sample collected from the "Marmes Man" site in southeastern
Washington. This rock shelter is believed to be among the oldest
known inhabited sites in North America
Spruce wood
Sample from the Two Creeks forest bed near Milwaukee, Wisconsin,
dates one of the last advances of the continental ice sheet into the
United States.
Bishop Tuff
Samples collected from volcanic ash and pumice that overlie glacial
debris in Owens Valley, California. This volcanic episode provides an
important reference datum in the glacial history of North America.
Volcanic ash
Samples collected from strata in Olduvai Gorge, East Africa, which
sandwich the fossil remains of Zinjanthropus and Homo habilis -possible precursors of modern man.
Monzonite
Samples of copper-bearing rock from vast open-pit mine at Bingham
Canyon. Utah.
Quartz monzonite
Samples collected from Half Dome, Yosemite National Park,
California.
Conway Granite
Samples collected from Redstone Quarry in the White Mountains of
New Hampshire.
Rhyolite
Samples collected from Mount Rogers, the highest point in Virginia.
Pikes Peak Granite
Samples collected on top of Pikes Peak, Colorado.
Gneiss
Samples from outcrops in the Karelian area of eastern Finland are
believed to represent the oldest rocks in the Baltic region.
The Old Granite
Samples from outcrops in the Transvaal, South Africa. These rocks
intrude even older rocks that have not been dated.
Morton Granite
Samples from outcrops in southwestern Minnesota are believed to
represent some of the oldest rocks in North America.
?
?
14
14
P-D C -N
Y=no/nt = 0.293638225
?
14
14
P-D C -N
Y=no/nt = 0.244615273
?
P-D Ur235 -Pb207
Y=no/nt = 0.999311029
?
P-D K40-Ar40
Y=no/nt = 0.999030065
?
P-D K40-Ar40
Y=no/nt = 0.979420298
?
P-D K40-Ar40
Y=no/nt = 0.956608158
40
?
40
P-D K -Ar
Y=no/nt = 0.905006463
238
?
206
P-D Ur -Pb
Y=no/nt = 0.880597595
238
206
P-D Ur -Pb
Y=no/nt = 0.85238372
P-D Th 232 -Pb208
Y=no/nt = 0.874871391
?
?
?
P-D Th 232 -Pb208
Y=no/nt = 0.853479598
87
?
87
P-D Rb -Sr
Y=no/nt = 0.9501515238
?
RL Hanna
Radiometric Dating
Answers
Sample
Cloth wrappings from a mummified bull
P-D C14-N14
Samples taken from a pyramid in Dashur, Egypt. This date agrees with
Y=no/nt = 0.7803719661
the age of the pyramid as estimated from historical records
Charcoal
P-D C14-N14
Sample, recovered from bed of ash near Crater Lake, Oregon, is from
a tree burned in the violent eruption of Mount Mazama which created
Y=no/nt = 0.447880803
Crater Lake. This eruption blanketed several States with ash, providing
Charcoal
Sample collected from the "Marmes Man" site in southeastern
Washington. This rock shelter is believed to be among the oldest
known inhabited sites in North America
Spruce wood
Sample from the Two Creeks forest bed near Milwaukee, Wisconsin,
dates one of the last advances of the continental ice sheet into the
United States.
Bishop Tuff
debris in Owens Valley, California. This volcanic episode provides an
Volcanic ash
Samples collected from strata in Olduvai Gorge, East Africa, which
sandwich the fossil remains of Zinjanthropus and Homo habilis -possible precursors of modern man.
Monzonite
Samples of copper-bearing rock from vast open-pit mine at Bingham
Canyon. Utah.
Quartz monzonite
Samples collected from Half Dome, Yosemite National Park,
California.
Conway Granite
Samples collected from Redstone Quarry in the White Mountains of
New Hampshire.
Rhyolite
Samples collected from Mount Rogers, the highest point in Virginia.
Pikes Peak Granite
Samples collected on top of Pikes Peak, Colorado.
Gneiss
Samples from outcrops in the Karelian area of eastern Finland are
believed to represent the oldest rocks in the Baltic region.
The Old Granite
Samples from outcrops in the Transvaal, South Africa. These rocks
intrude even older rocks that have not been dated.
Morton Granite
Samples from outcrops in southwestern Minnesota are believed to
represent some of the oldest rocks in North America.
Calc Age
Years
2,050
6,640
P-D C14-N14
Y=no/nt = 0.293638225
10,130
P-D C14-N14
Y=no/nt = 0.244615273
235
11,640
207
P-D Ur -Pb
Y=no/nt = 0.999311029
P-D K40-Ar40
Y=no/nt = 0.999030065
700,000
1,750,000
P-D K40-Ar40
Y=no/nt = 0.979420298
37,500,000
P-D K40-Ar40
Y=no/nt = 0.956608158
40
80,000,000
40
P-D K -Ar
Y=no/nt = 0.905006463
P-D
Y=no/nt =
P-D
Y=no/nt =
P-D
238
180,000,000
206
Ur -Pb
0.880597595
Ur238 -Pb206
0.85238372
232
208
Th -Pb
Y=no/nt = 0.874871391
820,000,000
1,030,000,000
2,700,000,000
P-D Th 232 -Pb208
Y=no/nt = 0.853479598
3,200,000,000
P-D Rb87-Sr87
Y=no/nt = 0.9501515238
3,600,000,000