Crazy. Cannabis grew up here???
But today it likes 78F???
Thank you! This got me to thinking... was the Tibetan Plateau always so high, dry, and cold? In other words, what was the climate of this area like 28 MILLION YEARS AGO? I.e. the time period of the cannabis "center of origin" theory proposed in the
2019 study. (Which by the way I have only skimmed through!)
Note that the divergence or "split" of cannabis from humulus (hops) also occurred right around 28 million years ago, so the dating of the pollen (fossils?) in the 2019 study points to the very beginning of cannabis as a separate genus.
Well, according to
this scientific article published in Jan. 2021, they draw the following conclusions...
(mya = million years ago)
- The geology and climate of the region came together during the Mesozoic era, 252-66 mya
- The landscape was comprised of mountains and deep valleys
- The deep valleys contained subtropical plants and animals
- The area "did not rise as a pre-formed plateau... driven solely by the India–Eurasia collision"
- "The Tibetan Plateau did not form until the Neogene", 23 mya to 2.58 mya
So if the 2021 article is correct, I take this to mean that, at 28 mya, the region was at much lower elevation, much warmer, and much wetter. Makes sense in terms of the cannabis origin story!
The period including 28 mya is called the Oligocene Epoch, 33.7 mya to 23.8 mya. I believe 28 mya would be considered "mid Oligocene". Late Oligocene is called the Chattian age, 28 mya to 23 mya.
From the above article (underlines added)...
Among the fossil finds from the Chattian (late Oligocene) lower Dingqing Formation is a climbing perch [a kind of fish], Eoanabas thibetana (Anabantidea) [71], whose modern relatives occupy tropical lowlands of South Asia and sub-Saharan Africa below 1000 m [3280 ft], while higher in the succession (early Miocene–Aquitanian) a primitive form of the cyprinid fish Plesioschizothorax macrocephalus has been recovered, whose modern relatives are restricted to elevations below 2500 m. These and other discoveries [40] suggest low elevations in marked contrast to the >4000 m derived from isotope studies.
• • •
As the Himalaya [rose past] 5 km [16400 ft], they imposed an increasing rain shadow effect on central Tibet**. By the late Oligocene, this caused the central valley lake margin vegetation to become more xerophytic [i.e. adapted to dry climate], while Neogene uplift and ‘bathtub sedimentation’ [7] raised the valley floor to its present elevation of ∼5 km exacerbating the drying process. [** Meaning the "area occupied by the modern plateau"]
So, at 28 mya the valleys were likely still subtropical, and began "drying out" over the period of the next 5 million years. And by 23 mya, the high-elevation, cold, dry plateau was formed.
Wow, this is really fascinating, because it could mean that cannabis branched from humulus (hops) in a subtropical climate (think San Diego, Calif.) If so, the original cannabis emerged not in the high-altitude, dry, cold climate associated with some of the original indicas, but in a lower-elevation, moderate climate with warm/hot summers and mild winters.
So, in another strange twist, the original cannabis from the Oligocene may have been like the sativas that evolved on the steppes of Central Asia—i.e tall and with low THC. And then, due to the transformation of the climate in the region of the Tibetan Plateau, cannabis morphed into its high-altitude, dry-climate-adapted, high-THC indica form.
But I wonder, how definitive is the science at this point, that the original cannabis indeed originated from this one geographic region? If it did originate in this one region, then this seems to point to a strange sativa-indica-sativa evolution sequence. If this one region isn't the true "center of origin", then there could have been a much older pattern of emergence. In other words, the original sativas of 1-1.8 million years ago may have descended from the Oligocene cannabis, just as the indicas did. For that to be the case, the Oligocene cannabis may have had an ancestor that was spread over a wider range including Central Asia.
Indeed, one ancestor is humulus (hops), but I'm talking about a cannabis ancestor that emerged from hops around 27.8 million years ago. Surely, that emergence must have had a specific, single point. Or is that just an assumption?
Let's take a look at the abstract of the
2019 study (underlines and bold added):
Biogeographers assign the Cannabis centre of origin to “Central Asia”, mostly based on wild-type plant distribution data. We sought greater precision by adding new data: 155 fossil pollen studies (FPSs) in Asia. Many FPSs assign pollen of either Cannabis or Humulus (C–H) to collective names (e.g. Cannabis /Humulus or Cannabaceae). To dissect these aggregate data, we used ecological proxies. C–H pollen in a steppe assemblage (with Poaceae, Artemisia, Chenopodiaceae) was identified as wild-type Cannabis. C–H pollen in a forest assemblage (Alnus, Salix, Quercus, Robinia, Juglans) was identified as Humulus. C–H pollen curves that upsurged alongside crop pollen were identified as cultivated hemp. Subfossil seeds (fruits) at archaeological sites also served as evidence of cultivation. All sites were mapped using geographic information system software. The oldest C–H pollen consistent with Cannabis dated to 19.6 [mya], in northwestern China. However, Cannabis and Humulus diverged 27.8 [mya], estimated by a molecular clock analysis. We bridged the temporal gap between the divergence date and the oldest pollen by mapping the earliest appearance of Artemisia. These data converge on the northeastern Tibetan Plateau, which we deduce as the Cannabis centre of origin, in the general vicinity of Qinghai Lake. This co-localizes with the first steppe community that evolved in Asia. From there, Cannabis first dispersed west (Europe by 6 [mya]) then east (eastern China by 1.2 [mya]). Cannabis pollen in India appeared by 32.6 thousand years (ka) ago. The earliest archaeological evidence was found in Japan, 10,000 bce, followed by China.
Ah ha, key sentence there: "co-localizes with the first steppe community that evolved in Asia". That would be Central Asia, and I take that to mean the authors are suggesting a co-center of origin, and I take that to mean a common ancestor, and that ancestor being the Oligocene cannabis "newly" diverged from humulus. The range of this wild, primordial cannabis was from Central Asia to East Asia. And apparently it was sativa-like. This was ~28 mya. Then it took 22 million years for it to disperse west to the area of Europe, and 26.8 million years to disperse to the area of eastern China. [Humans didn't domesticate cannabis until 10,000 to 12,000 years ago.]
There's lots of wild cannabis growing in Central Asia, but I wonder if any strains have been identified that haven't been contaminated with cultivated cannabis.
good stuff!
I think we disagree on some points. We are attempting to look back at ancient China and make some guesses as to what was going on with cannabis and their developing system of medicine. What happened early on in China is obviously different than what developed let's say in the past 500 to 1000 years, up to modern day teaching and practice of TCM. One thing is for sure—the traditional medicine of China is very focused on the use of herbs. So, it's kind of hard to believe that they wouldn't fully explore and put to use what is probably the most powerful herb there is. You may be right that, due to cultural and government influences, there was an avoidance of cannabis as an intoxicant (i.e. they perceived the intoxicating effects as outweighing the medicinal effects). Perhaps that view intensified in more modern times.
