Collaborative Research in Holocene Geology and Anthropology: Paleoclimate, Landscape Evolution, and Human Occupation of the Western Lake Titicaca Basin, Peru

摘要本研究旨在探讨全新世气候变率对西部的的喀喀湖流域支流流域景观演变的影响，以及这些支流流域全新世景观演变对人类活动的影响。为了实现这一目标，我们将在三个学科的交叉点工作：古气候学、河流沉积学和考古学。我们将通过收集和分析来自小型、高沉积率湖泊的沉积物岩心，为西部的的喀喀湖盆地创建一个基于代理的、高分辨率（年代际）的、正确解释的古气候时间序列。我们将从同一地区的三个河流流域生成新的沉积学和地貌数据，并使用这些数据创建区域气候变化和基准水平背景下的河流演变的全流域模型。而且，我们将产生新的考古数据，这些数据将开始填补我们对盆地早期史前（特别是古代时期的记录，大约10000到3500 cal BP）知识的空白。这些数据将解决有关流域最初占领的特征、定居过程的动态以及定居后农牧住区的扩大等重要问题。在这项研究中，我们的目标是对南美洲热带地区的全新世降水进行最准确的重建。这个记录需要回答重要的古气候问题（如热带大气的海洋表面温度强迫的性质），但它对我们的最终研究目标也是必不可少的。一旦对气候变化有了可靠的了解，我们就可以在适当的气候背景下解决有关河流景观演变的问题。的的喀喀湖盆地西部全新世河流沉积学在很大程度上受降水变率控制，降水变率既影响河流流量，也影响基准面（的的喀喀湖水位）。在对气候和基准面的相关记录有完整了解的情况下，很少有关于河流演化的研究，因此这是一个不同寻常的机会，可以增加我们对沉积物沉积和下降的速率和过程的理解，以及河流对气候和基准面变化的响应中可能存在的非线性。由于河流的变化是景观演变和盆地现代和古代居住者生活的关键因素，因此对气候和景观变化的可靠了解将使我们能够解决与气候变化和人类活动有关的严重问题。我们将收集的新考古数据将补充盆地其他地方正在进行的工作，这些数据是在高度确定的古气候背景下收集的，伴随着对自然景观演变的良好约束重建，这在许多其他研究环境中是无与伦比的，将使我们能够记录环境和文化变化的相对时间。

ABSTRACTThe ultimate goal of this collaborative study is to determine how Holocene climate variability affected landscape evolution in tributary valleys of the western Lake Titicaca basin and how Holocene landscape evolution in those tributaries influenced human activities. To meet this goal we will work at the intersection of three disciplines: paleoclimatology, fluvial sedimentology, and archaeology. We will create a proxy-based, high-resolution (decadal), properly interpreted paleoclimate time series for the western Lake Titicaca basin by collecting and analyzing sediment cores from small, high-sedimentation-rate lakes. We will generate new sedimentologic and geomorphic data, from three river valleys in the same region, and use those data to create a basinwide model of fluvial evolution in the context of regional climate change and base level. And, we will generate new archaeological data that will begin to fill the gaps in our knowledge of the early prehistory (especially the record of the Archaic Period, ca. 10,000 to 3500 cal BP) of the basin. These data will address important questions about the character of the initial occupation of the basin, the dynamics of the sedentarization process, and the expansion of agropastoral settlements following sedentarization.In this study we aim to produce the best-dated and best-understood reconstruction of Holocene precipitation in tropical South America. This record is needed to answer important paleoclimate questions (such as the nature of the sea-surface temperature forcing of the tropical atmosphere), but it also essential to our ultimate research goal. Once climate variability is securely known, we can address questions concerning the evolution of fluvial landscapes within the proper climatological context. Holocene fluvialsedimentology in the western Titicaca basin is largely controlled by precipitation variability, which affects both riverine discharge and base level (the level of Lake Titicaca). Few studies of fluvial evolution have been done with the complete knowledge of the relevant records of both climate and base level, so this is an unusual opportunity to increase our understanding of both the rates and processes of sediment aggradation and downcutting, as well as possible non-linearities in the fluvial response to climate and base-level variability. Because fluvial variability is a key factor in both landscape evolution and the lives of both modern and ancient occupants of the basin, a secure knowledge of climate and landscape variability will allow us to address serious issues relating climate change and human activities. The new archaeological data we will collect will complement ongoing work elsewhere in the basin and the data, gathered within a highly resolved paleoclimatic context accompanied by a well-constrained reconstruction of natural landscape evolution, unrivaled in many other research settings, will allow us to document the relative timing of environmental and cultural change.