Prehistoric Mongolia

[TransformerRobot]

What was it like during the days of Velociraptor and Protoceratops? Was it all just one large, harsh dessert? Or did it have any lush tropical areas like classic depictions of dinosaur-age Earth?

[Greg H.]

In summary,

 

 

 

We interpret the Suihent conifers to have grown in a monsoonal climate with cool, dry winters and warm, rainy summers. The relatively low variability in interannual growth of the wood is likely the result of consistent annual conditions during the rainy season. The lack of false rings reflects a warm and wet, rather than hot and dry, summer. In a warm summer with moderate evaporation rates, temporary decreases in rainfall would not be as likely to result in a drought than in hot summer conditions. Common summertime droughts would have produced false rings in the Suihent woods, as they likely did in the Purbeck woods and as reported by J. Yao (pers. comm.) for Late Jurassic trees from the Junggar basin of northwestern China. The presence of false rings in trees from the Junggar basin is consistent with its more inland position, relative to the Suihent study area, and the likelihood that the Junggar basin would have experienced a somewhat more continental climate during the Late Jurassic. The

sharp transition between earlywood and latewood in the Suihent trees reflects rain-limiting conditions that started and ended abruptly, as is commonly the case with monsoonal climates and was particularly true of megamonsoonal climates common during the early Mesozoic (e.g., Kutzbach and Gallimore, 1989; J.T. Parrish, pers. comm.). In addition, it is possible that a rapid decrease in temperature at the end of the growing season contributed to the abrupt transition from earlywood to latewood as well as the narrowness of the latewood. ¹

 

 

---

1. Keller, A.M. and Hendrix, M.S. (1997). Paleoclimatologic Analysis of a Late Jurassic Petrified Forest, Southeastern Mongolia. Retrieved on 09-25-2013 from http://origins.swau.edu/misc/paleocurrents/pdf/china-not%20so%20good-references%20etc/paleoclimatologic%20mongolia-keller.pdf

Edited September 25, 2013 by Greg H.