Collaborative Research: Documenting the Global Middle Miocene Climatic Optimum in the High-Latitude North Pacific

MarincovichOPP-0095147这是加州科学院和佛罗里达大西洋大学的合作提案。阿拉斯加和堪察加的浅水海洋软体动物动物群是高纬度北太平洋中新世早期全球变暖的最北端的经验证据。首席调查员将根据新的和现有的软体动物采集和对阿拉斯加和堪察加选定的软体动物物种的稳定同位素分析，记录气候最佳时期(1,450万至1,700万年前)该区域浅水海洋变暖和古季节性的程度。它们还将为这些地区的地层序列中证明的四次或更多气候最佳暖水期提供地层和年龄限制。该项目将侧重于两个浅水软体动物动物群的动物群和稳定同位素研究，这两个动物群清楚地证明了中新世早期气候最佳，这两个动物群分别位于科迪亚克岛狭窄的开普组和堪察加西北部的卡夫兰斯卡亚系列。首席调查员以前从阿拉斯加半岛熊湖组收集的软体动物分析将纳入这项研究。暖水双壳类Anadara、Dosinia、Glycymeris、Macoma和Nutiallia以及腹足类Fulgoraria(Musashia)、GibBula、Nassariuv、Turritella和Tyrannoberingius的普遍出现，将为使用动物群和同位素标准估计古温度提供基础。研究应建立太平洋气候最佳北端的温暖程度和古季节性，并将这一古气候事件置于生物和年代地层背景中。这些数据将首次使将高纬度北太平洋地区的浅水海洋气候纳入数值气候和海洋模式成为可能。

AbstractMarincovichOPP-0095147This is a collaborative proposal between the California Academy of Sciences and Florida Atlantic University. Shallow-water marine molluscan faunas in Alaska and Kamchatka are the northernmost empirical evidence of early middle Miocene global warming in the high-latitude North Pacific. The Principal Investigators will document the degree of shallow-water marine warming and paleoseasonality in this region during the Climatic Optimum (14.5 to 17 million years ago), based on new and existing mollusk collections and stable isotope analyses of selected mollusk species from Alaska and Kamchatka. They will also provide stratigraphic and age constraints for the four or more Climatic Optimum warm-water episodes evidenced in stratigraphic sequences in these regions. This project will focus on faunal and stable isotope studies of two shallow-water molluscan faunas that exhibit clear evidence of the early middle Miocene Climatic Optimum, in the Narrow Cape Formation of Kodiak Island and the Kavranskaya Series in northwestern Kamchatka. Analyses of mollusks previously collected by the Principal Investigators from the Bear Lake Formation on the Alaska Peninsula will be incorporated into the study. The common occurrences in these formations of the warm water bivalves Anadara, Dosinia, Glycymeris, Macoma and Nutiallia, and the gastropods Fulgoraria (Musashia), Gibbula, Nassariuv, Turritella, and Tyrannoberingius will provide a basis for paleotemperature estimates using both faunal and isotopic criteria.The research should establish the degree of warmth and paleoseasonality at the northern limit of the Climatic Optimum in the Pacific and put this paleoclimatic event in bio-and chronostratigraphic contexts. These data will make it possible, for the first time, to include the shallow-water marine climate of the high-latitude North Pacific region into numerical climatic and oceanographic models.