CENTAURS AND ICY PLANETARY BODY IMPACTS ON OCEAN VOLUMES AND CHEMISTRY THROUGH TIME

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CENTAURS AND ICY PLANETARY BODY IMPACTS ON
OCEAN VOLUMES AND CHEMISTRY THROUGH TIME

• Pat WILDE
• Pangloss Foundation
• 1735 Highland Pl. 28
• Berkeley, California 94709
• pat.wilde.td.57_at_aya.yale.edu
• Mary S. QUINBY-HUNT
• Lawrence Berkeley Laboratory
• Berkeley, California 94720
• mshunt_at_sbcglobal.net

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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.
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Mercury (orbit)
Earth
Venus (orbit)
Mars (orbit)
Jupiter (orbit)
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Plot of the Inner Solar SystemThe 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.htm
l
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
multiple-apparition/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
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Jupiter (orbit)
Uranus (orbit)
Saturn (orbit)
Pluto
Neptune
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Plot of the Outer Solar SystemThe plot below
shows the current locations and orbits of the
Jovian planets (Jupiter through Neptune) and the
current locations of various distant minor
bodiesSource http//cfa-www.harvard.edu/iau/list
s/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 23 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.
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Icy Satellites
Ice Ratio
Ice Vol? (km3)
of Earth Oceans
Planet
Satellite
Diameter (km)
Density
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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
granite-oceanic 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.
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Source http//www.physicalgeography.net/fundament
als/10e.html
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Molecular Weight of Amphibole 814 Molecular
Weight of Water 18 Molar Ratio
0.022
Continental Crust 5 e22 Kg Oceans
1.3 e21 Kg For 15 Amphibole
7.5 e21 Kg Water needed to produce amphibole
0.0221 x 7.5 e21 1.658 e20 Kg
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Input Water 3.77 E10 Kg over 4.4 Billion Years
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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.
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3rd ORDER SEA LEVEL RISE
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3rd ORDER SEA LEVEL RISE
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Effect of adding the mass of water in impacting
objects
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Estimated potential maximum sea level rise from
the total melting of present-day glaciers
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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.
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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
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CHEMICAL CHANGE
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Effect of adding the mass of C in impacting
objects
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CHEMICAL CHANGE
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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.
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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.