“…2000-year period between ~12 and 10 ka.”
KA is a new one to me, obviously a time period. Definition?
I had to look it up before posting:
“In the end, it is mostly accepted (although not precise and not backed by standards) to use “kyr” for time periods or durations and for time in the future and “ka” for age (or negative time) thus a period from 10.7 ka to 9.7 ka would be assumed to be in the past and have a duration of 1 kyr. “
e.g., “It is quite common that “ka” is used for “kiloyears ago”, so the “a” somehow stands for both, “annus” and “ago” (??!!)”
“If we could make a suggestion we recommend (like NIST ) to use “a” for “annus / anni” which is Latin for “year / years”. Normally events before today should extend to the left of a time axis and be negative time. Since this is impractical for most paleo-records, we suggest to consequently use “age [ka]” as the label of an age axis and use expressions such as “14.6 ka ago” in the text if you want to avoid negative time like “at -14.6 ka”.”
https://www.sedgeochem.uni-bremen.de/kiloyears.html
It seems to have been adopted. I’ve seen this reference numerous times and made the presumption prior that it referred to a negative time axis, aka ‘before present (BP).”