Changes in Paleosol Morphology and Geochemistry Associated with Mid-Paleozoic Afforestation and Decline in Atmospheric pCO2

与中古生代造林和大气 pCO2 下降相关的古土壤形态和地球化学变化

• 批准号: 9418183
• 负责人: Claudia Mora
• 金额: $ 18.56万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-02-01 至 1999-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9418183&HistoricalAwards=false
• 关键词: Changes; Paleosol; Morphology; Geochemistry; Associated

9418183 Mora The proposed research investigates changes in paleosol and pedogenic carbonate morphology and geochemistry preserved during the Siluro-Devonian time period, a period of rapid evolution and diversification of terrestrial ecosystems. Land plant evolution led to progressively more robust plant size and deeper rooting capabilities and more widespread afforestation of the land surface. The development and increasing abundance of vascular land plants may have contributed to increased weathering rates and draw down of atmospheric pCO2 from very high levels in the middle Paleozoic to near-present day levels in the Permo-Carboniferous. The proposed research will evaluate the hypothesis that afforestation, increased weathering profiles and also contributed to changes in the stable isotope composition of pedogenic carbonate. The proposed study will emphasize morphological and geochemical analysis of Siluro-Devonian paleosols from ten stratigraphic units (chiefly red-beds) exposed in outcrop in the U.S. and maritime Canada Appalachians. Detailed macro- and micromorphological characterization of the paleosols, estimation of paleosol thickness, mass balance evaluation of soil major and trace element geochemistry and stable isotopic analyses of pedogenic carbonates phases will be combined with existing paleontological information for these units to characterize the "pedological signature" of afforestation of the land surface by vascular plants. The results will permit a detailed evaluation of atmospheric pCO2 during this period of profound change using Cerling's soil carbonate paleobarometer. The results will contribute to our understanding of the distribution and preservation of paleosols and pedogenic carbonate deposits and their usefulness (or limitations) as monitors of paleoenvironments and paleoclimate. The results are relevant to models which predict the response of the Earth's lithosphere and biosphere to significant changes in atmospheric pCO2.

9418183 MORA提出的研究调查了古罗罗 - devonian时期内保留的古溶质和碳酸盐形态和地球化学的变化，这是陆地生态系统的快速发展和多样化的时期。 土地工厂的进化导致植物尺寸和更深的生根能力逐渐增强，并更广泛地造林。 血管土地植物的发展和丰富性可能导致风化率提高，并使大气中的PCO2从中古生代的高水平中降低到碳酸盐含量的近乎近代的一天。 拟议的研究将评估以下假设：造林，增加风化概况，还导致了稳定的成源碳酸盐同位素组成的变化。 拟议的研究将强调来自美国和加拿大海上opparime opparachians在露头中暴露的十个地层单元（主要是红床）的志留罗 - 德文尼亚古质的形态和地球化学分析。 详细的宏观和微观形象特征，对古溶质厚度的估计，土壤主要和痕量元素地球化学的质量平衡评估以及稳定的Pedenocic碳酸盐阶段的同位素分析，将与这些单元的现有古生物学信息相结合，以表征“ Pedological Signature签名”的特征。血管植物对土地表面的造林。 结果将允许在此期间使用Cerling的土壤碳酸盐古生物计对大气PCO2进行详细评估。 结果将有助于我们理解古质碳酸盐矿床的分布和保存及其作为古环境和古气候的监测器的有用性（或局限性）。 结果与预测地球岩石圈和生物圈对大气PCO2发生重大变化的响应的模型有关。