期刊
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
卷 109, 期 -, 页码 -出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.jsames.2021.103231
关键词
Lake Chalco; Glacial-interglacial; North America; Fire-activity; Palynology; Z-Score analysis
资金
- UNAM DGAPA-PAPIIT [IN103819]
- US NSF [EAR-1462347]
The study found that the Basin of Mexico responded differently to orbital changes from late MIS 6 to MIS 3, including lake productivity, vegetation, and fire events. The paleoenvironmental reconstruction showed that in the past, wetter periods were often accompanied by dry conditions, low forest cover, and low fire activity; while under high spring insolation, the environment suddenly shifted from wet to dry, leading to increased forest cover and fire activity.
The responses of lake productivity, vegetation, and fire events in the Basin of Mexico to orbital changes from late MIS 6 to MIS 3 (146-35 ka) have been studied based on geochemical (Ti, TIC, TOC, C/N), charcoal (CHAR) and pollen data of the sediment core CHA08 from Lake Chalco. The paleoenvironmental reconstruction identifies the MIS 6 as a wetter period with episodes of dry conditions, low forest cover and low fire activity. A sudden change from wetter to dry environments with low to high forest cover and fire activity episodes characterized the end of the MIS 6 (132-130 ka) coincident with high spring insolation. Variations in vegetation composition, with a tendency towards higher forest cover, fire-activity, runoff, and organic matter availability, are recorded during the MIS 5, MIS 4, and MIS 3. However, a reduction in the fire-activity was recorded for the cold and dry MIS 4. Spectral analysis based on the titanium concentration record of Lake Chalco suggests a precessional forcing on runoff variations. We explored the impact of the Intertropical Convergence Zone latitudinal migrations which have been related to the summer insolation at 65 degrees N by comparing runoff data with other sedimentary records from North and Central America. Our results highlight the sensitivity of the high altitude tropical basin to climate variations.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据