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

全新世晚期，伯利兹灯塔礁蓝洞高分辨率风暴和气候档案（中美洲）

• 批准号: 322933508
• 负责人: Professor Dr. Eberhard Gischler
• 金额: --
• 依托单位: Institut für Geologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/322933508?language=en
• 关键词: late; Holocene; resolution; storm; climate

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.

在该项目的第二阶段（2年），从伯利兹蓝洞底部采集了一个连续的30米长的沉积物岩心，随后对该岩心进行了高分辨率的沉积学、古生物学和地质年代学调查。地核包含约12.5 ka，即，从完整的全新世到最晚的冰后期更新世（新仙女木）。沉积序列自上而下可划分为3个单元：（1）事件层发育良好的纹状海相单元（<5.7kaBP），（2）局限海相-半咸水单元（5.7- 7.2kaBP），（3）富有机质湖相单元（7.2- 12.5kaBP）。总共确定了694个事件（气旋）层，这些层用于编制西大西洋独特的、异常长的、每年解析的风暴档案。记录表明，12- 3.5kaBP风暴活动相对较低，只有全新世气候最佳期（6.8- 5.9kaBP）的两个短间隔，而3.5kaBP以来风暴活动较高，在中世纪暖期（MWP）和最近的工业变暖期（IW）有两个极大值。根据与历史风暴记录的比较，可以将风暴床厚度和结构与报告的最大值定量关联起来。风速，即，根据风暴强度标定事件床的沉积学特征。考虑到意外的，很长的回收核心和这个记录的独特性，我们要求为该项目提供最后一年的资金，以进行地球化学分析（d18 O，d13 C，TEX 86）在年度分辨率。最终资助期的目标包括：（1）将每年解析的SST记录扩展到新仙女木;（2）开发同等长度的d13 C记录。目标1将允许组装一个特殊的全新世SST记录，这将使一个全面的解释新的风暴记录在全新世气候变率，包括大西洋年代际振荡（AMO）的影响。根据目标2，气候变化的表现，如气旋频率，降水和土壤侵蚀可能被破译，这反过来又使评估如何中美洲水文气候变化作为催化剂的区域文化发展和玛雅高级文化的最终崩溃在过去的CA。3 ka.