NSFGEO-NERC: Collaborative Research: MexiDrill: Developing a 350,000 year record of climate and environmental change in tropical North America

这项NSF-GEO/NERC联合提议的主要科学目标是获得墨西哥城地区过去35万年气候和火山活动变化的连续、高分辨率记录。我们将分析最近从墨西哥城南郊的Chalco湖盆地回收的约350米长的岩心。这一沉积物序列将成为目前缺乏此类记录的地区最长的气候、环境和生物群档案之一。从这些岩心中获得的信息将有助于了解导致过去气候变化的机制，这对于评估当前和未来气候变化的影响至关重要。据预测，由于持续的气候变化，墨西哥在未来几十年至几百年将变得更加干燥，而这些人为变化将叠加在气候系统的自然变率上，而这些自然变率尚不完全清楚。该项目将提取过去35万年的温度和降水信息，以评估气候的驱动因素。Chalco沉积序列也为墨西哥城地区的火山爆发提供了独特的记录，保存了150多个火山爆发的灰烬。这些火山灰层很可能来自墨西哥城周围的主要层状火山和位于该市南部的广泛的单成因场。我们将利用这些喷发沉积物来获得岩心的年表，并确定过去喷发的规模和频率。这些关于这些火山长期历史的信息对于这个人口稠密地区的危害和风险评估将是无价的。

The primary scientific objective of this joint NSF-GEO/NERC proposal is to obtain a continuous, high-resolution record of past changes in climate and volcanism in the Mexico City region over the last 350,000 years. We will analyse a recently recovered ~350 metre-long core from the Lake Chalco basin on the southern outskirts of Mexico City. This sediment sequence will be among the longest archives of climate, environment, and biota from a region presently lacking such records. Information obtained from these cores will help understand the mechanisms that caused past climate shifts, which is critical for evaluating impacts of ongoing and future climate change. Mexico is projected to become drier in the coming decades-centuries in response to ongoing climate change, and these anthropogenic changes will be superimposed on natural variability in climate systems that are not fully understood. This project will extract information on the temperature and precipitation over the last 350,000 years to evaluate the drivers of the climate. The Chalco sedimentary sequence also provides a unique record of the explosive volcanism in the Mexico City region, with ash from more than 150 volcanic eruptions preserved. These volcanic ash layers are likely to be from the major stratovolcanoes that surround Mexico City and the extensive monogenetic field situated in the southern part of the city. We will use these eruption deposits to obtain a chronology for the core and establish the magnitude and frequency of past eruptions. This information on the long-term history of these volcanoes will be invaluable for hazard and risk assessments for this densely populated region.