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 pat. wilde. td. 57@aya. yale. edu Mary S. QUINBY-HUNT Lawrence Berkeley Laboratory Berkeley, California 94720 mshunt@sbcglobal. net

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.

Eart h 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/Inner. Plot. 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 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

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/Outer. Plot. 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 Satellit e Jupiter Europa Ganymede Callisto Saturn Mimas Enceladus Tethys Dione Rhea Titan Iapetus Uranus Miranda Ariel Umbriel Titania Oberon Neptun e Triton Diameter (km) 3136 5258 4796 389 500 1049 1120 1529 5150 1438 470 1158 1168 1578 1519 2700 Ice Densit Ratio y 3. 57 0. 25 1. 94 0. 46 1. 86 0. 48 1. 17 0. 77 1. 24 0. 73 1. 26 0. 71 1. 44 0. 63 1. 33 0. 68 1. 88 0. 48 1. 21 0. 74 1. 35 0. 67 1. 66 0. 54 1. 51 0. 60 1. 68 0. 54 1. 58 0. 57 2. 07 0. 43 Ice Vol? # of Earth (km 3) Oceans 4. 07 E+09 3. 53 E+10 2. 79 E+10 2. 37 E+07 4. 75 E+07 4. 32 E+08 4. 60 E+08 1. 27 E+09 3. 42 E+10 1. 16 E+09 3. 62 E+07 4. 41 E+08 4. 97 E+08 1. 10 E+09 1. 05 E+09 2. 97 25. 8 20. 4 0. 017 0. 04 0. 3 0. 9 0. 2 0. 8 0. 03 0. 4 0. 8 4. 48 E+09 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 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/10 e. html

Hydration of basalt Anorthite + Clinopyroxene + Orthopyroxene + Water = Amphibole 2(Ca. Al 2 Si 2 O 8) + 2(Ca. Mg. Si 2 O 6) + 3(Mg 2 Si 2 O 6) +2(H 2 O) = 2(Ca 2 Mg 4 Al 2 Si 7 O 22(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 E 10 Kg over 4. 4 Billion Years Amount Water/Yr needed to convert Basalt to Amphibole 0. 0377 Km 3/Yr A bolide this big per year is enough to maintain the oceans and granitize the basalt Amount H 2 O/Million. Yr 37700 Km 3/Million. Yr Amount H 2 O/100 Million Yr 3770000 Km 3/100 Million. Yr

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 glacioeustatic 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.

3 rd ORDER SEA LEVEL RISE

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 ongoing 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.