Late Quaternary palaeoenvironment of northern Guatemala: evidence from deep drill cores and seismic stratigraphy of Lake Petén Itzá
Late Quaternary palaeoenvironment of northern Guatemala: evidence from deep drill cores and seismic stratigraphy of Lake Petén Itzá
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危地马拉北部晚第四纪古环境：来自深钻岩芯和佩滕伊察湖地震地层学的证据
DOI：
10.1111/j.1365-3091.2009.01144.x
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发表时间：
2010
期刊：
影响因子：
3.5
通讯作者：
M. Plötze
中科院分区：
文献类型：
--
作者：
A. Mueller;F. Anselmetti;D. Arizteguí;M. Brenner;D. Hodell;J. Curtis;J. Escobar;A. Gilli;D. Grzesik;T. Guilderson;S. Kutterolf;M. Plötze
作为国际大陆科学钻探计划项目的一部分，2006年春季从危地马拉北方的佩滕伊察湖（Lake Petén Itza）采集了水深30至150米的长沉积物岩心。深水的沉积物记录主要由交替的粘土、石膏和碳酸盐单元组成，至少在两个钻探地点，可以追溯到200 kyr以上。 大多数岩石地层单位可沿沿着地震反射在整个盆地内追踪，地震反射可作为地震地层界线，这表明岩石地层学可用于推断区域古环境变化。在综合岩性和地震反射资料的基础上，建立了一个修正的地震地层学。从约200到约85 ka，沉积物主要为碳酸盐-粘土粉砂，通常与桑迪浊积岩互层，表明在相对潮湿的气候中，沉积物体系以碎屑沉积为主。 在约85 ka，暴露层组成的砾石，粗砂和陆生腹足类标志着湖泊低位或部分盆地干燥，表明干燥的气候条件。 从约85到约48 ka，海侵碳酸盐粘土沉积物，被深水粘土覆盖，表明湖平面上升，随后在高阶段稳定。 从约48 ka到现在，岩性的特点是交替粘土和石膏单位。 石膏沉积与海因里希事件（即干燥的气候），而粘土单位符合更潮湿的interstadials。
Long sediment cores were collected in spring 2006 from Lake Petén Itzá, northern Guatemala, in water depths ranging from 30 to 150 m, as part of an International Continental Scientific Drilling Program project. The sediment records from deep water consist mainly of alternating clay, gypsum and carbonate units and, in at least two drill sites, extend back >200 kyr. Most of the lithostratigraphic units are traceable throughout the basin along seismic reflections that serve as seismic stratigraphic boundaries and suggest that the lithostratigraphy can be used to infer regional palaeoenvironmental changes. A revised seismic stratigraphy was established on the basis of integrated lithological and seismic reflection data from the basin. From ca 200 to ca 85 ka, sediments are dominated by carbonate‐clay silt, often interbedded with sandy turbidites, indicating a sediment regime dominated by detrital sedimentation in a relatively humid climate. At ca 85 ka, an exposure horizon consisting of gravels, coarse sand and terrestrial gastropods marks a lake lowstand or partial basin desiccation, indicating dry climate conditions. From ca 85 to ca 48 ka, transgressive carbonate‐clay sediments, overlain by deep‐water clays, suggest a lake level rise and subsequent stabilization at high stage. From ca 48 ka to present, the lithology is characterized by alternating clay and gypsum units. Gypsum deposition correlates with Heinrich Events (i.e. dry climate), whereas clay units coincide with more humid interstadials.