Transcript CENTAURS AND ICY PLANETARY BODY IMPACTS ON OCEAN …

CENTAURS AND ICY PLANETARY BODY IMPACTS
ON OCEAN VOLUMES AND CHEMISTRY
THROUGH TIME
Pat WILDE
Pangloss Foundation
1735 Highland Pl. #28
Berkeley, California 94709
[email protected]
Mary S. QUINBY-HUNT
Lawrence Berkeley Laboratory
Berkeley, California 94720
[email protected]
The number of icy bodies reported in the solar system has
increased dramatically in the past few years suggesting
their potential importance in Earth history via impacts.
Wilde (1987) proposed that icy bodies may be a significant
source of the oceans during the later stages of accretion.
Wilde and Quinby-Hunt (1997) discussed the chemical
consequences of impacts of ice-volatile bolides of various
compositions. The 'rain' of icy bodies hitting the Earth
throughout time suggests implications for the following
Earth processes.
Earth
Mercury
(orbit)
Venus
(orbit)
Mars
(orbit)
Jupiter
(orbit)
Plot of the Inner Solar System
The plot shows the current location of the major planets (Mercury through
Jupiter) and the minor planets that are in the inner region of the solar system.
Source: http://cfa-www.harvard.edu/iau/lists/InnerPlot.html
Light Blue: The orbits of the major planets
Large Colored Dots: the current location of the major planets
Green Circles: The locations of the minor planets, including numbered and multipleapparition/long-arc unnumbered objects
Red Circles Objects with perihelia within 1.3 AU are shown by red circles.
Objects observed at more than one opposition are indicated by filled circles, objects
seen at only one opposition are indicated by outline circles.
Deep Blue Circles: The two "clouds" of objects 60° ahead and behind Jupiter (and at
or near Jupiter's distance from the sun) are the Jupiter Trojans
Filled Light-Blue Squares - Numbered periodic comets
Unfilled Light-Blue Squares - Other comets
Jupiter (orbit)
Uranus (orbit)
Saturn (orbit)
Pluto
Neptune
Plot of the Outer Solar System
The plot below shows the current locations and orbits of the Jovian planets (Jupiter through
Neptune) and the current locations of various distant minor bodies
Source: http://cfa-www.harvard.edu/iau/lists/OuterPlot.html
Light Blue: The orbits of the planets
Dark Blue Symbol: the current location of each object
The current location of the minor bodies of the outer solar system are shown in
different colors to denote different classes of object.
Cyan triangles: Unusual high-e objects
Orange triangles: Centaur objects
White circles: Plutinos (objects in 2:3 resonance with Neptune)
Large white symbol: Pluto
Magenta circles: scattered-disk objects
Red circles: "classical" or "main-belt" objects
Objects observed at only one opposition are denoted by open symbols, objects with
multiple-opposition orbits are denoted by filled symbols.
Filled light-blue squares Numbered periodic comets.
Unfilled light-blue squares: Other comets.
Icy Satellites
Planet
Satellite
Jupiter
Europa
Ganymede
Callisto
Mimas
Enceladus
Tethys
Dione
Rhea
Titan
Iapetus
Miranda
Ariel
Umbriel
Titania
Oberon
Triton
Saturn
Uranus
Neptune
Diameter (km)
3136
5258
4796
389
500
1049
1120
1529
5150
1438
470
1158
1168
1578
1519
2700
Ice Vol?
Density
Ice
Ratio
3.57
1.94
1.86
1.17
1.24
1.26
1.44
1.33
1.88
1.21
1.35
1.66
1.51
1.68
1.58
2.07
0.25
0.46
0.48
0.77
0.73
0.71
0.63
0.68
0.48
0.74
0.67
0.54
0.60
0.54
0.57
0.43
4.07E+09
3.53E+10
2.79E+10
2.37E+07
4.75E+07
4.32E+08
4.60E+08
1.27E+09
3.42E+10
1.16E+09
3.62E+07
4.41E+08
4.97E+08
1.10E+09
1.05E+09
4.48E+09
(km3)
# of Earth
Oceans
2.97
25.8
20.4
0.017
0.04
0.3
0.3
0.9
0.2
0.8
0.03
0.3
0.4
0.8
0.8
3.3
PLATE TECTONICS AND
THE EVOLUTION OF GRANITIC CRUST
Earliest sediments thus found are greenstones, basically basaltic
sediments suggesting lack of a granite source. Without a graniteoceanic basaltic crustal difference, early surface terrains would
be limited to a relatively low relief consisting of abyssal plains,
seamounts, and the ridge-rise system.
Incrementally the impact of icy objects would provide fluid for the
then shallow ocean basins. During subduction at depth the
pressure and temperature plus fluids could hydrate the basaltic
crust producing granitic compositions. With time the production
of granite could produce the continental blocks raising the
present freeboard of the continents and the relief of the ocean
basins. Chondritic compositions are too water poor to support
Rubey's (1951) theory that volatile components such as water
largely come from expression from the mantle.
Source: http://www.physicalgeography.net/fundamentals/10e.html
Hydration of basalt
Anorthite + Clinopyroxene + Orthopyroxene + Water = Amphibole
2(CaAl2Si2O8) + 2(CaMgSi2O6) + 3(Mg2Si2O6) +2(H2O) = 2(Ca2Mg4Al2Si7O22(OH)2)
Molecular Weight of Amphibole = 814
Molecular Weight of Water
= 18
Molar Ratio = 0.022
Continental Crust = 5 e+22 Kg
Oceans
= 1.3 e+21 Kg
For 15% Amphibole = 7.5 e+21 Kg
Water needed to produce amphibole: 0.0221 x 7.5 e+21 = 1.658 e+20 Kg
Input Water = 3.77 E10 Kg over 4.4 Billion Years
Amount Water/Yr needed to convert
Basalt to Amphibole
0.0377 Km3/Yr
A bolide this big per year is enough
to maintain the oceans and
granitize the basalt
Amount H2O/MillionYr
37700 Km3/MillionYr
Amount H2O/100 Million Yr
3770000 Km /100 MillionYr
3
SEISMIC STRATIGRAPHY AND
TIME SCALE OF ICY IMPACTS
Third-order sea level rises of durations of a few million
years can not be related to known glacio-eustatic climatic
events. These sea level rises may be the result of impacts of
icy Centaur-like bodies briefly adding to the ocean volume
and eventually being absorbed in the granitizing process of
subduction. The frequency of the third-order events could
record the timing of icy impacts of significant size.
3rd ORDER SEA LEVEL RISE
Centaurs
100000
100,000,000
1000
1,000,000
10
10,000
0.1
100
0.001
1
0.00001
1 13 25 37 49 61 73 85 97 109121133145
Number in decreasing volume
Apparent Sea Level
rise in Meters
Volume in Km^3
10,000,000,000
3rd ORDER SEA LEVEL RISE
Centaurs
10,000,000,000
1,000,000,000
Volume in Km^3
100,000,000
100,000,000
10,000,000
10,000,000
1,000,000
1,000,000
100,000
100,000
10,000
10,000
1,000
1,000
100
100
10
10
1
1
1 15 29 43 57 71 85 99113127141
Time in Yrs to absorb by
subduction
1,000,000,000
Effect of adding the mass of water in impacting objects
Estimated potential maximum sea level rise
from the total melting of present-day glaciers
VARIATIONS IN OCEANIC COMPOSITION
Berner (2004) and others have discussed changes in the
bulk composition of the oceans during Phanerozoic time. A
potential contribution to such variations would be the
introduction of icy planetary bodies with the variation a
function of bolide composition. Such events may be seen in
the delta spike of C and S isotope values against the
background of terrestrial isotopic processes.
Permian
Triassic
Carbon, organic carbon and sulfur isotope variability
across the PTB in the Idrijca Calley (W. Slovenia)
From: Carbon and Sulfur isotope anomalies across the
Permian-Triassic boundary (PTB) in W. Slovenia
Matej Dolenec and Barbara Vokal
CHEMICAL CHANGE
Effect of adding the mass of C in impacting objects
CHEMICAL CHANGE
TESTS OF CONJECTURES
Upcoming missions to analyze the composition of comets
and other icy bodies, thought to be remnants of original
solar system building blocks, will be useful in discerning
the contributions of icy extraterrestrial bodies to on-going
Earth processes.
REFERENCES
Berner, R. A., 2004, A model for calcium, magnesium and sulfate in sea
water over Phanerozoic Time: American Journal of Science, v. 304, p.
438-453.
Rubey, W. W., 1951, Geologic history of seawater: an attempt to state the
problem: Geological Society of America Bulletin, v. 62, p. 1111-1147.
Wilde, P., 1987, Primordial origin of the oceanic Rubey Volatiles as a
consequence of accretion of ice-sulfur planetesmals, (abst.): EOS, 68:
no. 44, p. 1337.
Wilde, P. and M. S. Quinby-Hunt, 1997, Collisions with ice/volatile
objects: Geological implications- A qualitative treatment:
Palaeogeography, Palaeoclimatology, Palaeoecology, v. 132, p. 47-63.