Sedimentary record from Patagonia, southern Chile supports cosmic-impact triggering of biomass burning, climate change, and megafaunal extinctions at 12.8 ka
YOUNGER DRYAS BOUNDARY
; LAST GLACIAL MAXIMUM
; GREENLAND ICE CORE
; INTERTROPICAL CONVERGENCE ZONE
; NANODIAMOND-RICH LAYER
; EXTRATERRESTRIAL IMPACT
; LATE PLEISTOCENE
; BLACK MATS
; NORTHWESTERN PATAGONIA
; INDEPENDENT EVALUATION
WOS学科分类:
Multidisciplinary Sciences
WOS研究方向:
Science & Technology - Other Topics
英文摘要:
The Younger Dryas (YD) impact hypothesis posits that fragments of a large, disintegrating asteroid/ comet struck North America, South America, Europe, and western Asia -12,800 years ago. Multiple airbursts/impacts produced theYD boundary layer (YDB), depositing peak concentrations of platinum, high-temperature spherules, meltglass, and nanodiamonds, forming an isochronous datum at >50 sites across similar to 50 million km(2)of Earth's surface. This proposed event triggered extensive biomass burning, brief impact winter, YD climate change, and contributed to extinctions of late Pleistocene megafauna. In the most extensive investigation south of the equator, we report on a similar to 12,800-year-old sequence at Pilauco, Chile (similar to 40 degrees S), that exhibits peak YD boundary concentrations of platinum, gold, high-temperature iron- and chromium-rich spherules, and native iron particles rarely found in nature. A major peak in charcoal abundance marks an intense biomass-burning episode, synchronous with dramatic changes in vegetation, including a high-disturbance regime, seasonality in precipitation, and warmer conditions. This is anti-phased with northern-hemispheric cooling at the YD onset, whose rapidity suggests atmospheric linkage. The sudden disappearance of megafaunal remains and dung fungi in the YDB layer at Pilauco correlates with megafaunal extinctions across the Americas. The Pilauco record appears consistent with YDB impact evidence found at sites on four continents.
1.Univ Austral Chile, Inst Ciencias Tierra, Valdivia, Chile 2.Univ Austral Chile, Transdiciplinary Ctr Quaternary Res TAQUACH, Valdivia, Chile 3.Univ Catolica Temuco, Dept Antropol, Temuco, Chile 4.Univ Austral Chile, Lab Pilauco, Valdivia, Chile 5.Elizabeth City State Univ, Ctr Excellence Remote Sensing Educ & Res, Elizabeth City, NC 27909 USA 6.Elizabeth City State Univ, Dept Nat Sci, Elizabeth City, NC 27909 USA 7.Univ South Carolina, South Carolina Inst Archaeol & Anthropol, Savannah River Archaeol Res Program, Columbia, SC 29208 USA 8.No Arizona Univ, Sch Earth Sci & Environm Sustainabil, Geol Program, Flagstaff, AZ 86011 USA 9.North Carolina State Univ, Analyt Instrumentat Facil, Raleigh, NC 27695 USA 10.DePaul Univ, Dept Chem, Chicago, IL 60614 USA 11.Comet Res Grp, Prescott, AZ 86301 USA 12.Univ Calif Santa Barbara, Dept Earth Sci, Santa Barbara, CA 93106 USA 13.Univ Calif Santa Barbara, Inst Marine Sci, Santa Barbara, CA 93106 USA
Recommended Citation:
Pino, Mario,Abarzua, Ana M.,Astorga, Giselle,et al. Sedimentary record from Patagonia, southern Chile supports cosmic-impact triggering of biomass burning, climate change, and megafaunal extinctions at 12.8 ka[J]. SCIENTIFIC REPORTS,2019-01-01,9