Astronomical Periodicity Signals from Lamina Growth Rhythm Records of Lacustrine Stromatolites
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摘要: 对采自青藏高原北部渐新统雅西措组中的叠层石样品进行了研究，通过切面观察和薄片鉴定，确定这些叠层石具有典型的富藻生物纹层和富屑碎屑纹层交替的显微结构特征，纹层生长带呈阶段式波状和柱状产出。采用样品数字图像的灰度值作为计量纹层个数和纹层厚度变化的指标，提取了4件样品的显微纹层厚度变化序列。根据功率谱分析结果，认为叠层石纹层层偶为年际生长纹层，纹层层偶的厚度变化与太阳黑子活动的11年天文周期具有一定的联系，提出湖相环境中叠层石的生长节律记录了太阳活动驱动的气候与环境变化的信息。
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关键词:
- 湖泊环境叠层石生长周期频谱分析太阳活动
Abstract: The lacustrine stromatolite samples was collected from the Oligocene Yaxicuo Formation in northern Tibetan Plateau. The microtexture features of alternative dark organicrich lamination and light mineralrich lamination distinctly display on polished sections and under microscope observation. The lamination bands occur as wavy and column shapes with step growth episodes. The grayscale values to extract from digitized photographs can be used as a method of lamination couplet counts and thickness measurements. The lamination couplet thickness series are obtained from four sample segments. Individual lamination couplet is interpreted to correspond to annual growth patterns. The periodicities in lamination couplet thickness variations are detected by power spectral analysis. Its significant spectral peaks about 11 years periodicities are related to 11 years sunspot cycle. It is suggested that regular growth rhythms of lacustrine stromatolites may record climate and environmental oscillations forced by sunspot activity. -
Key words:
- Lacustrine environment
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