image: Image of the sediment core used in this study shown versus depth below the bottom of the lake. The sediment layers consist of dark layers that are composed of organic-rich deposits, and light-colored layers that are composed of the mineral gypsum (calcium sulfate dihydrate; CaSO4·2H2O). Gypsum forms when the lake level was lowered during times of drought. The hydration water in gypsum was used in this study to reconstruct the changes in rainfall of the region. The panel on the right displays the sediment density record of the core. Periods of gypsum precipitation are indicated by density values of >1.1 g/cm3. The interval from 165 to 125 cm spans the time from ~620 to ~1100 CE. The gypsum layers between 154 and 125 cm correspond approximately to the time of the decline of Classic Maya civilization. This material relates to a paper that appeared in the Aug. 3, 2018, issue of Science, published by AAAS. The paper, by Nicholas Evans at University of Cambridge in Cambridge, UK, and colleagues was titled, "Quantification of drought during the collapse of the classic Maya civilization." view more
Credit: <p>Sediment density profile from Hodell et al. (2005) <p><strong>NOTE:</strong> Though this is a publicly listed YouTube video, use of this video to specifically promote this Science Focus paper must not appear in the public domain until embargo lift.