Environmental changes during MIS6-3 in the Basin of Mexico: A record of fire, lake productivity history and vegetation
Environmental changes during MIS6-3 in the Basin of Mexico: A record of fire, lake productivity history and vegetation
复制标题
DOI：
10.1016/j.jsames.2021.103231
复制
发表时间：
2021-08
影响因子：
1.8
通讯作者：
L. R. Martínez-Abarca-;S. Lozano-García;B. Ortega‐Guerrero;C. M. Chávez-Lara;Esperanza Torres-Rodríguez;M. Caballero;E. Brown;Susana Sosa-Nájera;C. Acosta-Noriega;V. Sandoval-Ibarra
中科院分区：
文献类型：
--
作者：
L. R. Martínez-Abarca-;S. Lozano-García;B. Ortega‐Guerrero;C. M. Chávez-Lara;Esperanza Torres-Rodríguez;M. Caballero;E. Brown;Susana Sosa-Nájera;C. Acosta-Noriega;V. Sandoval-Ibarra
基于Chalco湖沉积物岩芯CHA08的地球化学（Ti、TIC、TOC、C/N）、炭（CHAR）和花粉资料，研究了墨西哥盆地湖泊生产力、植被和火灾事件对MIS 6 ~ MIS 3晚期（146 ~ 35 ka）轨道变化的响应。古环境重建将MIS 6确定为一个湿润期，伴有干旱、低森林覆盖率和低火灾活动。从湿润环境到干燥环境的突然转变，森林覆盖率从低到高，火灾活动事件的发生与春季高日照同时发生。在MIS 5、MIS 4和MIS 3期间记录了植被组成的变化，其趋势是森林覆盖、火灾活动、径流和有机质可利用性增加。然而，在寒冷和干燥的MIS 4中，火灾活动有所减少。基于Chalco湖钛浓度记录的光谱分析表明，进动强迫对径流变化有影响。通过对比径流数据与北美和中美洲其他沉积记录，探讨了热带辐合带纬向迁移对65°N夏季日照的影响。我们的研究结果强调了高海拔热带盆地对气候变化的敏感性。
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° 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.