Scientists are interested in what the future may be like and how the Earth may eventually look. What will its climate be like? How will its ecosystems function? How many of the changes will be natural, and how many will be human caused? In the case of plate tectonics, geologists have been able to trace the movement of the Earth's plates backward in time in order to determine the geographic positions of the continents and the resulting climates that affected them, such as tropical, polar, or temperate.
The Earth's plate tectonic process continues today, and scientists wonder what the geographic configuration of the continents will one day become. Although these projections are theoretical, they present an intriguing view of what may lie in the future and what role climate may play.
Dr. Christopher R. Scotese, a geologist at the University of Texas, believes that projecting the locations of continents 50 million years from now is not difficult. Projecting beyond that, however, is much more problematic because unpredictable cause-and-effect incidents can drastically change results. "Fifty million years is fairly straightforward. It's like you're driving on the highway and you want to know where you're going to be in 10 minutes. You check the speedometer, do a calculation, and project your present motion. But beyond 50 million years—like on the highway, unexpected things can happen."
Projecting further into the future is more difficult because it involves far more than simple extrapolations. Instead, rules must be developed that govern not only their movements but also where subduction zones and deep ocean trenches will form. They may change shape but seldom disappear altogether because bedrock weighs little compared to the dense ocean crust. Continents literally float, as do mountains. Once formed, they tend to persist and disappear only after ages of erosion wear them down. The difficult part is to predict the development of new subduction zones in the seafloor and to calculate how rapidly such zones will rearrange the continents. "It's hard
(opposite page) Dr. Christopher R. Scotese's Paleomap Project. (A) This is what the Earth's distribution of continents may look like in 50 million years from now. The Atlantic may widen, Africa will collide with Europe closing the Mediterranean, Australia will collide with Southeast Asia, and California will slide northward up the coast to Alaska. (B) This is Pangaea Ultima 250 million years from now. It will form as a result of the subduction of the ocean floor of the North and South Atlantic beneath eastern North America and South America. This supercontinent will have a small ocean basin trapped at its center. (Source: www.scotese.com)
to understand all the forces down there," Scotese says. "There's probably some input from the mantle. It probably has some say on which way the plates go."
O Future world +50 Ma
East Pacific Rise
O Future world +250 Ma
PACIFIC OCEAN
3 Ancient landmass \ Modern landmass
Subduction zone (triangles point in the direction of subduction) — Seafloor spreading ridge
Baja California
PACIFIC
O Future world +50 Ma
Baja California
PACIFIC
OCEAN
East Pacific Rise
O Future world +250 Ma
OCEAN
PACIFIC OCEAN
3 Ancient landmass \ Modern landmass
Subduction zone (triangles point in the direction of subduction) — Seafloor spreading ridge
Several geologists have predicted that in 50 million years, the tectonic movement of the San Andreas fault will have moved Los Angeles northward to the area of San Francisco. Eventually, Los Angeles will move north as far as Anchorage, Alaska.
In 1998, Dr. Scotese created a project called the Paleomap Project (www.scotese.com), which projects what the continents may look like 50 million years from now and 250 million years from now. He calls the configuration predicted for 250 million years from now Pangaea Ultima. In order to figure out the eventual location of continents, Dr. Scotese used a computer algorithm to simulate the mechanisms that move the plates, such as where subduction zones recycle and melt the plates, where trenches in the ocean floor tear continents apart, where ridges in the ocean floor tear the ocean floor apart and move continents away from one another, and where other continents are being pushed together, creating new mountain ranges.
Dr. Scotese believes the most difficult part of modeling the future distribution of the continents is predicting the development of new subduction zones and determining how aggressive they will be in moving the plates compared to older subduction zones. In addition to the forces on the crust, forces deep inside the Earth's mantle play a part in plate tectonics and are difficult to model.
Dr. Scotese predicts that the processes that will lead to the Earth 250 million years from now, Pangaea Ultima, will begin with the closing of the Mediterranean. Then, 25 to 75 million years from now, Australia will migrate north, collide with Indonesia and Malaysia, then turn counterclockwise and collide with the Philippines and Asia, eventually merging them all together. In addition, Antarctica will migrate northward, upon which its icecap will melt. About 100 million years from now, it will enter the Indian Ocean. Then, 50 million years later, it will settle between Madagascar and Indonesia, making the Indian Ocean an inland sea.
The most drastic change by far will be the closing of the Atlantic Ocean. Then, 200 million years from now, Newfoundland will collide with Africa, and Brazil will butt up against South Africa. Finally, 250 million years from now, all the continents will have merged into a new super continent, Pangaea Ultima, that will encircle the remnants of the old Indian Ocean.
This is just one prediction of what the Earth may look like in the future. Other scientists have projected that instead of the Atlantic Ocean disappearing, the Pacific Ocean may disappear instead, pushing both North and South America into Asia and forming a hypothetical new continent called Amasia.
These are nevertheless hypothetical projections of the Earth's future created by computer models. While no one knows for sure what the Earth will look like in the distant future, it does bring up interesting questions about what the Earth's climate may be like. If the bulk of the continents are located near the equator, what will have happened to those ecosystems that were not tropical? Likewise, what about tropical habitats that now may reside in the mid-latitudes? In addition, if Antarctica migrates north and its ice cap completely melts, what will sea levels be? What will be the composition of seawater, and what will be the new configuration of the major ocean currents?
With a new spatial arrangement of the continents, there will undoubtedly be a new distribution of ocean currents, which in turn will affect global heat distribution. This will affect vegetation distributions, which, in turn, will affect the carbon cycle. Finally, in light of all these hypothetical changes and their effects on energy, heat, and the carbon cycle, what role will global warming have had on all this? Will global warming have been controlled 250 million years earlier so that there are still productive civilizations left to see what the actual Pangaea Ultima will look like? These are the questions climate scientists are working diligently to answer today.
the geological timescale
ERA |
period |
EPocH |
(millions of years) |
first life-forms |
geology | |
Quaternary |
Holocene |
0.01 |
Humans |
Ice age | ||
Pleistocene |
3 | |||||
Neogene |
Pliocene |
11 |
Mastodons |
cascades | ||
cenozoic |
Miocene |
26 |
saber-toothed tigers |
Alps | ||
Tertiary |
oligocene |
37 | ||||
Paleogene |
Eocene |
54 |
Whales | |||
Paleocene |
65 |
Horses, Alligators |
Rockies | |||
cretaceous |
135 |
Birds | ||||
Mesozoic |
Jurassic |
210 |
Mammals |
sierra Nevada Atlantic | ||
Triassic |
250 |
Dinosaurs | ||||
Permian |
280 |
Reptiles |
Appalachians | |||
Pennsylvanian |
310 |
Trees |
ice age | |||
carboniferous |
Mississippian |
345 |
Amphibians Insects |
Pangaea | ||
Paleozoic |
Devonian |
400 |
sharks | |||
silurian |
435 |
Land plants |
Laursia | |||
ordovician |
500 |
Fish | ||||
cambrian |
544 |
sea plants shelled animals |
Gondwana | |||
Proterozoic |
700 |
Invertebrates | ||||
2500 |
Metazoans | |||||
3500 |
Earliest life | |||||
Archean |
4000 |
oldest rocks | ||||
4600 |
Meteorites |
IA |
Periodic Table of the Elements i-Atomic number |
18 VINA | ||||||||||||||||||||||||||||||
1.00794 |
IIA |
6.941 — |
- Symbol |
13 14 15 16 17 IIIA IVA VA VIA VIIA |
2 He 4.0026 | |||||||||||||||||||||||||||
6.941 |
9.0122 |
-Atomic weight |
11 12 IB IIB |
10.81 |
6c 12.011 |
14.0067 |
15.9994 |
18.9984 |
20.1798 | |||||||||||||||||||||||
22.9898 |
24.3051 |
3 4 5 6 7 HIB IVB VB VIB VIIB |
8 9 10 VIIIB VIIIB VIIIB |
26.9815 |
28.0855 |
30.9738 |
32.067 |
39.948 | ||||||||||||||||||||||||
40.078 |
44.9559 |
47.867 |
50.9415 |
51.9962 |
54.938 |
55.845 |
58.9332 |
58.6934 |
63.546 |
65.409 |
69.723 |
72.61 |
74,9216 |
78.96 |
79.904 |
85.4678 |
87.62 |
88.906 |
92.9064 |
95.94 |
(98) |
106.42 |
112.412 |
114.818 |
121.760 |
127.60 |
126.9045 |
131.29 | ||||
132.9054 |
137.328 |
70ir |
174.967 |
178.49 |
180.948 |
183.84 |
186.207 |
190.23 |
192.217 |
195.08 |
196.9655 |
200.59 |
207.2 |
208.9804 |
(209) |
(210) |
(222) | |||||||||||||||
(226) |
102 * |
(260) |
(261) |
(262) |
(2öü |
(263) |
(271) |
(277) |
(284) |
(285) |
Uus Uuo ? ? | |||||||||||||||||||||
-^Lanth Actin |
Numbers in parentheses are atomic mass numbers of most stable isotopes. | |||||||||||||||||||||||||||||||
anoids oids |
138.9055 |
140.115 |
144.24 |
150.36 |
151.966 |
157.25 |
158.9253 |
66 162.^00 |
164.9303 |
167.26 |
168.9342 |
173.04 | ||||||||||||||||||||
(227) |
232.038 |
231.036 |
238.028« |
(237) |
(244) |
243 |
(247) |
(247) |
(251) |
(259) | ||||||||||||||||||||||
O Infobase Publishing |
(g) none | |
(c) nonmetallics | |
element symbol |
a.n. |
carbon C |
6 |
hydrogen H |
1 |
(g) chalcogen | |
(c) nonmetallics | |
element symbol |
a.n. |
oxygen o |
8 |
polonium Po |
84 |
selenium Se |
34 |
sulfur s |
16 |
tellurium Te |
57 |
ununhexlum Uuh |
116 |
(g) alkali metal | |
(c) metallics | |
element symbol |
a.n. |
cesium cs |
55 |
francium pr |
87 |
lithium y |
3 |
potassium < |
19 |
rubidium Rb |
37 |
sodium Na |
11 |
(g) alkaline earth metal | |
(c) metallics | |
element symbol |
a.n. |
barium Ba |
56 |
beryllium Be |
4 |
calcium Ca |
20 |
magnesium Mg |
12 |
radium Ra |
88 |
strontium Sr |
38 |
© Infobase Publishing
The Chemical Elements
element |
symbol |
a.n. |
element |
symbol |
a.n. |
aluminum |
Al |
13 |
scandium |
Sc |
21 |
bohrium |
Bh |
107 |
seaborglum |
Sg |
106 |
cadmium |
Cd |
48 |
silver |
Ag... |
47 |
chromium |
Cr |
24 |
tantalum |
Ta |
73 |
cobalt |
Co |
27 |
technetium |
Tc |
43 |
copper |
Cu-. |
29 |
thallium |
Tl |
81 |
darmstadtium Ds |
110 |
titanium |
Ti |
22 | |
dubnlum |
Db |
105 |
tin |
Sn |
50 |
gallium |
Ga |
31 |
tungsten |
W |
74 |
gold |
Au... |
79 |
ununbium |
Uub |
112 |
hafnium |
Hf |
72 |
ununtrlum |
Uut |
113 |
hassium |
Hs |
108 |
ununquadium |
Uuq |
114 |
Indium |
In |
49 |
vanadium |
V |
23 |
iridium |
lr **** |
77 |
yttrium |
Y |
39 |
iron |
Fe |
26 |
zinc |
Zn |
30 |
lawrencium |
Lr |
103 |
zirconium |
Zr |
40 |
lead lutetium manganese meitnerium mercury molybdenum nickel niobium osmium palladium platinum rhenium radium roentgenlurm ruthenium rutherfordlum
111 44 104
(g) pnictogen (c) metallics element_symbol a.n.
arsenic antimony bismuth nitrogen phosophorus
ununpentium Uup
33 51 83 7 15 115
(g) none (c) semimetallics element symbol a.n. boron B 5
germanium Ge 32 silicon Si 14
(g) pnictogen (c) metallics element_symbol a.n.
(g) actinoid (c) metallics | ||
element |
symbol |
a.n. |
actinium |
Ac |
89 |
americium |
Am |
95 |
berkelium |
Bk |
97 |
californium |
Cf |
98 |
curium |
Cm |
96 |
einsteinium |
Es |
99 |
fermlum |
Fm |
100 |
mendelevium |
Md |
101 |
neptunium |
Np |
93 |
nobelium |
No |
102 |
Plutonium |
Pu |
94 |
protactinium |
Pa |
91 |
thorium |
Th |
90 |
uranium |
U |
92 |
(g) halogens (c) nonmetallics | ||
element |
symbol |
a.n. |
astatine |
At* |
85 |
bromine |
Br |
35 |
chlorine |
CI |
17 |
fluorine |
F |
9 |
iodine |
I |
53 |
ununseptium |
Uus* |
117 |
a.n. = atomic number (g) = group (c) = classification
(g) lanthanoid (c) metallics | ||
element |
symbol |
a.n. |
cerium |
Ce |
58 |
dysprosium |
Dy |
66 |
erbium |
Er |
68 |
europium |
Eu |
63 |
gadolinium |
Gd |
64 |
holmium |
Ho |
67 |
lanthanum |
La |
57 |
neodymium |
Nd |
60 |
praseodymium Pr |
59 | |
Promethium |
Pm |
61 |
samarium |
Sm |
62 |
terbium |
Tb |
65 |
thulium |
Tm |
69 |
ytterbium |
Yb |
70 |
(g) noble gases (c) nonmetallics | ||
element |
symbol |
a.n. |
argon |
Ar |
18 |
helium |
He |
2 |
krypton |
Kr |
36 |
neon |
Ne |
10 |
radon |
Rn |
86 |
xenon |
Xe |
54 |
ununoctium |
Uuo |
118 |
* = semimetallics (c) ** = nonmetallics (c) *** = coinage metal (g) **** = precious metal (g)
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