Winter solstice observances are something that can be somewhat traced to the early Neolthic period, somewhere around 7,000-10,000 years ago. This coincided with human development of farming and animal husbandry practices, as well as the the organization of primitive communities that needed a method of planning for the year. Solstice was a part of religious practices developed well after the start of the Neolithic period.
Of course Carol Moore, never one to be troubled by facts when advancing her various agendas, should they be unavailable, has what she calls her "guesstimate" to cover any such occasions.
In this case, she's posited that humans began solstice celebrations more than 40,000 years before the need for such observations, absent any facts to support such a ludicrous projection and based on her unfounded "guesstimate."
Way to pull useless shit out of your ass, Carol.