Ever since the collapse of the once powerful Maya civilization, people have been trying to find out what caused it. Authors of the article, "Climate and the Collapse of Maya Civilization", which include Gerald Haug, Detlef Günther, Larry Peterson, Daniel Sigman, Konrad Hughen, and Beat Aeschlimann propose a theory that the Mayans collapsed because of an extended dry period between 760 and 910 A.D.
These scientists set out find the answer as to why the Maya civilization collapsed. This question is fairly popular and is often times answered by an extended drought, but they wanted to find geologic evidence of what the climate was like in the same time period hoping that there is an obvious link between the two. This question may be simple and straightforward, but this was different than using records that paleoclimatologists have been using which record data for the past millennia. These authors were trying to record climate for a short time period which until recently has been assumed to be unchanging for the last 6000 years.
The authors used sediment sequences from two holes drilled in the Cariaco Basin. These sediments were rapidly deposited and were estimated at 30cm per thousand years. They used bulk titanium (Ti) content as a recorder to get an index of the regional hydrologic conditions. High Ti content indicates wet conditions while lower Ti indicates dryer conditions. The authors' results showed Ti content were the lowest between 500 and 200 yr B.P. They also found higher Ti content between 1070 and 850 yr B.P. In addition, the authors found Ti levels were of intermediate value before the sharp rise at approximately 1070 yr B.P.(930 A.D.).
The authors also used a radiocarbon age control for one of the sediment holes on the low Ti content area which confirms that it was in the 800s A.D. This mega drought matched up with the Lake Chichancanab sediment record, giving the authors more confidence in their results. They did this for multiple depths of low Ti content on the sediment cores that resulted in the dates of 910, 860, 810, and 760 A.D.. The intervals between these drought periods were all within approximately 40 to 47 years which also is supported in the Lake Chichancanab sediment record. Beginning with the drought in 760 A.D., a drying trend appeared for approximately the next 40 years until a more severe drought occurred at approximately 810 A.D. Another major drought occurred at roughly 860 A.D. based on very low Ti content results. This was finally capped of with another sever drought in 910 A.D. which lasted roughly 6 years.
After finding these results, the authors linked the growth and collapse of the Maya civilization directly to the climatic results they found. Although the Cariaco can not totally explain the relationship between climate conditions and the Maya collapse, it still supports that the changes in rainfall was an important factor. They first suggest that the enlargement...