Study on the tufa Thickness and Formation Age of Dyke at Sparkling Lake, Jiuzhaigou Scenic Area, Sichuan Province

Abstract

Abstract Jiuzhai Valley earthquake occurred on August 8, 2017 has resulted in significant impact at Jiuzhai Valley Scenic Area. Some geological landscapes were damaged to different degrees, and the most destroyed landscape at Jiuzhai Valley was the failure of Sparkling Lake’s Dyke, with the shimmering scenery of Sparkling Lake being wiped from the map. Although the earthquake led to the disappear of landscape, it also provides an unusual opportunity to study the formation and evolution of the Sparkling Lake’s Dyke. The author has the honor to participate in the study on the post-earthquake geological changes and reconstruction countermeasures of Jiuzhai Valley World Natural Heritage Site. After conducting comprehensive study on the Sparkling Lake’s Dyke, such as large-scale geological survey, geological profile survey, dronestagram, implementation of minor-caliber backpack drill and formation age, the author finds that the tufa thickness of the Sparkling Lake’s Dyke is 8m-22.78m, with glacial till at the under layer, the age of tufa via carbon-14 dating method (14C) is up to 4.3ka-27ka, and the rate of deposition of tufa is 2.25mm/a-9.35mm/a. The findings that deposition sequence of the Sparkling Lake’s Dyke cannot be attributed to simple bottom-up overlaying relation and no sequential deposition for the deposition of tufa at Jiuzhai Valley area since the very beginning can serve as the complete and accurate scientific basis for ecological restoration of the Sparkling Lake’s tufa dyke.