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联合建议的主要科学目标是获得过去350,000年来墨西哥城地区气候和火山活动过去变化的连续、高分辨率记录。我们将分析最近从墨西哥城南郊查尔科湖盆地发现的一个约350米长的岩芯。这一沉积物序列将是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。从这些核心获得的信息将有助于理解导致过去气候变化的机制，这对于评估正在进行的和未来的气候变化的影响至关重要。预计墨西哥在未来几十年或几个世纪内将变得更加干旱，以应对持续的气候变化，这些人为变化将叠加到气候系统中尚未完全了解的自然变异性上。该项目将提取过去35万年的温度和降水信息，以评估气候驱动因素。查尔科沉积序列还提供了墨西哥城地区火山爆发的独特记录，保存了150多次火山喷发的火山灰。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大片单一成因油田。我们将利用这些喷发沉积物来获得地核的年代学，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这一人口稠密地区的灾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.