The late Holocene, high-resolution storm and climate archive of the Blue Hole, Lighthouse Reef, Belize (Central America)

在项目的第二阶段（2年），从伯利兹蓝洞底部提取了一个连续的30米长的沉积物岩心，随后对其进行了沉积学、古生物学和地质年代学方面的高分辨率调查。地核包含了大约12.5 ka，即从完整的全新世到最新的冰期后更新世（新仙女木期）。沉积演替从上至下可划分为3个单元，分别为(1)事件层发育良好的海相单元（<5.7 ka BP）、(2)限制海相-半咸淡水单元（5.7 ~ 7.2 ka BP）和(3)富有机质湖相单元（7.2 ~ 12.5 ka BP）。总共确定了694个事件（气旋）层，用于准备一个独特的、特别长的、每年解决的西大西洋风暴档案。记录表明，12 ~ 3.5 ka BP期间风暴活动相对较低，除了全新世气候最适期（6.8 ~ 5.9 ka BP）有2个短间隔外，3.5 ka以来风暴活动较高，其中在中世纪暖期（MWP）和最近的工业暖期（IW）有2个最大值。根据与历史风暴记录的比较，可以定量地将风暴床厚度和质地与报告的最大值联系起来。风速，即根据风暴强度校准事件床的沉积学特征。鉴于该岩心的长度出乎意料，且该记录的独特性，我们要求为该项目提供最后一年的资金，以便以年度分辨率进行地球化学分析（d18O, d13C, TEX86）。最后一个资助期的目标是(1)将每年解决的海温记录扩展到新仙女木期(2)发展同样长度的d13c记录。目标1将允许组装一个特殊的全新世海温记录，这将使新的风暴记录在全新世气候变率的基础上得到全面的解释，包括大西洋多年代际涛动（AMO）的影响。基于目标2，气候变率的表现，如气旋频率、降水和土壤侵蚀可以被破译，这反过来又可以评估中美洲水文气候变化如何在过去约3 ka期间作为区域文化发展和玛雅高级文化最终崩溃的催化剂。

In the second phase of the proj2ect (2 years), a continuous, 30 m long sediment core was retrieved from the bottom of the Belize Blue Hole, which was subsequently investigated at high resolution with regard to sedimentology, paleontology, and geochronology. The core encompasses some 12.5 ka, i.e., the complete Holocene into the latest, postglacial Pleistocene (Younger Dryas). The sedimentological succession may be subdivided in three units from top to base including (1) a varved marine unit with well-developed event beds (<5.7 ka BP), (2) a restricted marine to brackish unit (5.7-7.2 ka BP), and (3) an organic-rich lacustrine unit (7.2-12.5 ka BP). In total, 694 event (cylone) layers were identified that were used to prepare a unique, exceptionally long, annually resolved storm archive of the western Atlantic. The record indicates that storm activity was relatively low from 12-3.5 ka BP, with the exception of two short intervals during the Holocene Climate Optimum (6.8-5.9 ka BP), and high since 3.5 ka, with two maxima during the Medieval Warm Period (MWP) and the recent time of Industrial Warming (IW). Based on comparisons with historical storm records, it was possible to quantitatively relate storm bed thickness and texture to reported max. wind speed, i.e., to calibrate sedimentological characteristics of event beds based on storm intensity. Given the unexpected, great length of the retrieved core and the uniqueness of this record, we ask for a final year of funding for the project in order to conduct geochemical analyses (d18O, d13C, TEX86) at annual resolution. The objectives of the final funding period include (1) the extension of the annually resolved SST-record to the Younger Dryas and (2) the development of a d13C-record of equal length. Objective 1 will allow to assemble an exceptional Holocene SST-record, which will enable a comprehensive interpretation of the new storm record in the light of Holocene climate variability, including the influence of the Atlantic Multidecadal Oscillation (AMO). Based on objective 2, manifestations of climate variability such as cyclone frequency, precipitation, and soil-erosion may be deciphered, which in turn enable an evaluation as to how Mesoamerican hydro-climate changes operated as a catalyst for the regional cultural development and eventual collapse of the Maya high culture during the past ca. 3 ka.