Seismic survey of the Blue Hole, Belize: a pre-study for ICDP-drilling

伯利兹蓝洞地震勘探：ICDP 钻探预研究

• 批准号: 59921461
• 负责人: Professor Dr. Eberhard Gischler
• 金额: --
• 依托单位: Arbeitsgruppe Biosedimentologie
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/59921461?language=en
• 关键词: Seismic; survey; Blue; Hole; Belize

A core study of the proponent has revealed that sediments at the bottom of the Blue Hole, a 125 m deep Pleistocene sinkhole located in the lagoon of Lighthouse Reef Atoll, Belize, consist of undisturbed, annually layered biogenic carbonate muds and silts with intercalated coarser grained storm beds. Sedimentation-rate of layered sections is 2.5 mm/yr on average, and our 6 m long core spans the past 1400 yrs. Oxygen isotopes of laminated sediment provide a late Holocene climate proxy: a highresolution 18O time series traces the Medieval Warm Period, the Little Ice Age, and the industrial temperature rise. Carbon isotopes (13C) decrease upcore and show the impacts of the decline of the Maya culture and the anthropogenic combustion of fossil fuel. Storm event beds are most common during AD 650-850, around AD 1000, during AD 1200-1300, and AD 1450-1550. Storm beds are rare during the past 500 years BP. Given the average sedimentation rate and the early Holocene marine inundation of the Lighthouse Reef lagoon, the total Holocene marine sediment record in the Blue Hole alone can be expected to cover about 8 kyrs. and more than 20 m of annually layered sediment. We plan to core this sediment package in the framework of the ICDP, and, therefore, need to perform a seismic pre-study in order to validate the layered nature and thickness of the late Quaternary sediments.

对提议者进行的岩心研究表明，蓝洞底部的沉积物是一个125米深的更新世天坑，位于伯利兹灯塔礁环礁的泻湖内，由未受扰动的、每年分层的生物成因碳酸盐泥和淤泥组成，其间夹有较粗粒度的风暴床。分层剖面的沉积速率平均为2.5 mm/yr，我们的6 m长的岩心跨越了过去的1400 yrs. Oxygen同位素的分层沉积物提供了一个晚全新世气候代理：高分辨率的18 O时间序列跟踪中世纪温暖期，小冰期，和工业温度上升。碳同位素（δ 13 C）的减少显示了玛雅文化衰落和人类化石燃料燃烧的影响。风暴事件床最常见于公元650-850年，公元1000年左右，公元1200-1300年和公元1450-1550年。在过去的500年里，风暴床是罕见的。考虑到灯塔礁泻湖的平均沉积速率和全新世早期的海洋淹没，仅蓝洞的全新世海洋沉积物记录就可以预计约为8 kyrs。以及每年超过20米的层状沉积物。我们计划在ICDP的框架内对该沉积物包进行取芯，因此，需要进行地震预研究，以验证晚第四纪沉积物的分层性质和厚度。