"But all of this is just speculation, of course. I would never speak as if it were fact."
FYI, an important statement and observation here I feel. The meteorite Allan Hills 84001 in this report has a long history of reworked radiometric dating using different isotopes to identify the object's *true age*. Early ages were 4.63E+9 years old, and others 4.5 billion years old or older. More recent dating accepted for ALH84001 was 4.09E+9 years old. The 4.09E+9 age fits better with the *Noachian* period interpreted for Mars past and when life could be there. All Martian meteorites, wikipedia reports 99, other reports I have claim 200 Martian meteorites, have various radiometric ages reported along with different CRE ages too.
10 % uncertainty seems not much considering the difficulties, even though individual radiometric dating techniques can be much more precise and self calibrating (isochron techniques) for robustness. The map datings rely on impact dating to a large degree, and they are much more uncertain - Curiosity gave the first "on the ground" calibration point for Gale crater environment.
Mostly, of the found meteorites thus far [
https://en.wikipedia.org/wiki/Martian_meteorite ] - almost all seems to derive from three ejecta events. "... as of April 2019, 266 meteorites have been identified as Martian, out of over 61,000 known meteorites. ... As of April 25, 2018, 192 of the 207 Martian meteorites are divided into three rare groups of
achondritic (stony)
meteorites:
shergottites (169),
nakhlites (20),
chassignites (3), and ones otherwise (containing the orthopyroxenite (OPX) Allan Hills 84001, as well as 10 basaltic breccia meteorites).
[1] Consequently, Martian meteorites as a whole are sometimes referred to as the
SNC group. "
- "Roughly three-quarters of all Martian meteorites can be classified as shergottites. ... The shergottites appear to have crystallised as recently as 180 million years ago ...".
- "Nakhlites are
igneous rocks that are rich in
augite and were formed from
basaltic magma from at least four eruptions, spanning around 90 million years, from 1416 ± 7 to 1322 ± 10 million years ago. ... It has been shown that the nakhlites were suffused with liquid water around 620 million years ago and that they were ejected from Mars around 10.75 million years ago by an asteroid impact. They fell to Earth within the last 10,000 years."
- "Chassigny is particularly important because, unlike most
SNCs, its
noble gas composition differs from that in the current Martian
atmosphere. These differences are presumably due to its cumulate (mantle-derived) nature.
[4] " [
https://en.wikipedia.org/wiki/Chassigny_(meteorite) ]
IIRC chassignites are also recently ejected. But in any case, there is lot of radiometric (and other geologic) ages to keep track of (formation age, environment change ages, ejection age, impact age, discovery date). And some dating processes affect the others (such as weathering on Mars and Earth). Are there any cases where dating uncertainties has had a huge impact on the science lately? The last time around has been crater dating (suggesting a "late heavy bombardment" that now seems fictional), and cosmological dating before that (suggesting universe ages younger than some stellar model ages, before the LCDM physics was discovered).