The problem with the info in this article is the "precisely to 13,800 years ago" part.  Here's what I mean, speaking simply.

All archeological dating is based on actually finding some element of a civilization - pottery, flint arrow or spear tips, remains of living quarters, etc. - that can be shown at dig sites to have pre-dated other similar finds at the same or similar sites. The farthest we have been able to go back based on this kind of dating alone, is 5,000 years or so.

If we want to go back further, we use carbon-14 dating, or possibly some other molecule that we can measure radioactivity in. We base our dating on the amount co C-14 in the 5,000 year-old dig materials that we have dated using non-C-14 methods, and compare it with today's C-14. This gives us an extendable "rate" that we can use to date all kinds of things that must be older than 5,000 years.

The problem with this kind of dating is that we must assume that the amount of C-14 in older materials and substances fits our established rate. If geological and atmospheric conditions were different pre-5,000 years ago, our rating system wouldn't be accurate.

Until we can find material that we can date older than 5,000 years using non-C-14, standard archeological dating methods, we have nothing on which to base our older-than-5,000-years calculations with any kind of certainty.

We are finding out that there have been some tremendous upheavals in the earth in the past - upheavals of all different kinds, from gigantic earthquakes, to huge volcanoes, to meteor crashes, and who knows what else. What this means is that the C-14 rate probably was extremely different in the ancient past.

All C-14 dating that goes beyond about 5,000 years is at best a guestimation.