Still the question was how would we recognize a venusian meteorite?
Great question to ponder.
As a "lay" astrogeologist here is "an" answer as I see it. So far we only have the direct sampling of the Venusian atmosphere by the Soviet mission. The isotope ratios of the Venusian atmosphere will help in confirming meteorites from the Mercury Venus Zone. The analysis will initially lie in the differences in isotopic ratios between Mars and Venus, I feel. Age of formation will be equally important. We need a mission to Venus again!
We know that there is a gradient of " heavy to light" elements produced by a presolar shockwave(s) that swept elements outward from the center. This is why the inner planets are stony-irons and the outer ones are gaseous. Having higher "momentum / inertia"moments, the heavier elements tended to remain in the inner solar system while lighter elements rode the bow wave to the outer edges. Of course all the atoms of each element were not completely segregated, none-the -less there was a measurable sorting. We know this from measuring values against the elemental abundance of the solar system. The"elemental abundance" is a calculation of all elements against each other such that we know the ratio of each individual element to all the others or, in another way, we know their individual percentage in the entire mass of the soar system.
Along with the afore mentioned distribution/concentration of elements, is a subset distribution within the isotopes of individual elements. For example, from each area of concentration in the solar system for oxygen, the ratio of isotopes such as Oxygen 16, 17, and 18 as they relate to each other vary. Specifically, they vary with the distance they are from the center of the solar system. The lighter the isotope, the more distantly it moved toward the outer edge of the solar system. The Earth Moon ratio has been determined. This is one of the means we used to identify lunar meteorites. Similar ratios were used to identify Martian meteorites based on Viking Lander measurements.
Igneous rocks from Earth and Mars pretty much contain the same minerals so we rely on isotopic ratios and radioisotope ages to shore up our findings. In like manner, that is how the determination of a Veneusian meteorite will happen. While the jurry is out on Mercury, some think it was captured and its orbit of formation lies elsewhere, (isotopic ratios may not be what is expected from a planetoid forming close to the solar center), Venus is another story. It is certianly a differenteated body and recently volcanicaly active. Any Enstatite chondrite (E,EH,EL) can't be from Mercury nor Venus. Likewise the age of formation/crystallization for Venuisan material will likely be much less younger than asteroidal material.
So Venusian material will likely be isotopically weighted toward Oxygen 18 and will have a crystallization age closer to Martian material but I am guessing under 2 but less than 3-3.5 billion years.
Regards, Elton
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