However, in vivid contrast, the ratio 14N/ 15N indicates only a small loss of atmosphere, 3 mbar, by such sputtering-SW erosion over the last 4.0 Billion years. With a loss of 1/2 bar or greater of Mars atmosphere by diffusive sputtering and erosion by the SW (Solar Wind) in the last 4 Billion years. Both channels are approximately 800 km long. Maadim Vallis (L) on old terrain draining into Gusev Crater. Two of those isotopic features of immediate interest are the ratio of 36Ar/ 38Ar, which consistentįigure 1. The loss of atmosphere by various mechanisms is expected to have created isotopic clues to its mechanisms that can be seen in surface atmospheric measurements and in trapped gases in MMs (Mars Meteorites). Typical of this range of ages of channels are Maadim Vallis on old terrain and showing evidence of precipitation, the other Hradd Vallis on young terrain, which are believed to have been carved by water with magma induced melt water flows being the likely source (see Figure 1). This dense past atmosphere, suppressing vaporization of water and trapping heat, apparently allowed the formation of abundant water channels on terrains of both old and young age and even an apparent Paleo-Ocean on its lightly cratered Northern plains. This is in vivid contrast to the present thin Mars atmosphere of approximately 6 mbar. Mars apparently had a warm dense atmosphere of approximately 1 bar or greater in pressure, that lasted for an unknown fraction of its geologic history. Mars global geomorphologies suggesting a past much different than its present state. In the remainder of this article the salient puzzles of Mars isotopic system will be discussed as will the hypothetical events which caused them. These explosions created the radiogenic excesses of xenon and argon and caused the loss of atmosphere without significant fractionation of nitrogen. It is the aim of this article to explain these salient puzzles with a new hypothesis: that Mars was the site of massive thermonuclear explosions, of unknown cause, in the recent geologic past. Other puzzles are also present, as will be discussed. Mars is a planet with an apparently complex history, manifesting itself in puzzling isotopic features in its atmosphere starkly different from Earth, such as the ratio of 129Xe/ 132Xe, and 40Ar/ 36Ar, both radiogenic and the ratio 15N/ 14N suggesting a loss of only millibars of atmosphere by Solar Wind erosion over Mars geo-history while geomorphology strongly suggests atmospheric pressure 1 bar or greater in the past. Although there is presently no plausible explanation for the nuclear events, the hypothesis can be tested through related nuclear products such as Pu-244. 80Kr and 82Kr are hyperabundant in the Mars atmosphere and in the youngest MMs indicating intense irradiation of Mars surface with neutrons. This LPARE hypothesis is found to explain other isotopic features of Mars atmosphere and surface. The collateral massive and non-mass fractionating atmospheric loss, and the intense neutron bombardment of 14N in the atmosphere primarily created the 14N/ 15N ratio we presently observe, with some mass fractionating erosion of the residual atmosphere. The LPARE (Large Planet Altering R-process Event) hypothesis attempts to explain these major isotopic puzzles at Mars by postulating that two massive, anomalous thermonuclear explosions, rich in R-process physics, occurred over the surface of Northern Mars in the past, approximately 500 million years ago, and that these explosions created the 129Xe/ 132Xe excess, and the accompanying intense neutron bombardment of Mars atmosphere and regolith created the 40Ar/ 36Ar excess off of potassium in the surface rocks. Mars appears to have lost an original atmosphere of pressure 1 bar or greater, yet the ratio 14N/ 15N indicates only a loss of a few millibar by Solar Wind Erosion. Mars data presents a collection of startling and seemly contradictory isotopic data: a glaring excess of the two radiogenic isotopes 129Xe/ 132Xe 2.5 and 40Ar/ 36Ar 3000 enabled identification of MM (Mars Meteorites) because they are so different than any other major Solar System reservoir.
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