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首页> 外文期刊>Canadian journal of earth sciences >Fossil biotas from the Okanagan Highlands, southern British Columbia and northeastern Washington State: climates and ecosystems across an Eocene landscape
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Fossil biotas from the Okanagan Highlands, southern British Columbia and northeastern Washington State: climates and ecosystems across an Eocene landscape

机译：欧肯娜根高原，不列颠哥伦比亚省南部和华盛顿州东北部的化石生物群：始新世景观的气候和生态系统

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摘要

The late Early to early Middle Eocene Okanagan Highlands fossil sites, spanning ~1000 km north-south (northeastern Washington State, southern British Columbia) provide an opportunity to reconstruct biotic communities across a broad upland landscape during the warmest part of the Cenozoic. Plant taxa from these fossil sites are characteristic of the modern eastern North American deciduous forest zone, principally the mixed mesophytic forest, but also include extinct taxa, taxa known only from eastern Asian mesothermal forests, and a small .number of taxa restricted to the present-day North American west coast coniferous biome. In this preliminary report, paleoclimates and forest types are reconstructed using collections from Republic in Washington State, USA., and Princeton, Quilchena, Falkland, McAbee, Hat Creek, Horsefly, and Driftwood Canyon in British Columbia, Canada. Both leaf margin analysis (LMA) and quantitative bioclimatic analysis of identified nearest living relatives of megaflora indicated upper microthermal to lower mesothermal moist environments (MAT ~10-15 deg C, CMMT > 0 deg C, MAP > 100 cm/year). Some taxa common to most sites suggest cool conditions (e.g., Abies, other Pinaceae; Alnus, other Betulaceae). However, all floras contain a substantive broadleaf deciduous element (e.g., Fagaceae, Juglandaceae) and conifers (e.g., Metasequoia) with the bioclimatic analysis yielding slightly higher MAT than LMA. Thermophilic (principally mesothermal) taxa include various insects, the aquatic fern Azolla, palms, the banana relative Ensete, taxodiaceous conifers, Eucommia and Gordonia, taxa which may have occurred near their climatic limits. The mixture of thermophilic and temperate insect and plant taxa indicates low-temperature seasonality (i.e., highly equable climate).
机译：中新世早期至早期的欧肯那根高地化石遗址，横跨南北约1000公里（北华盛顿特区，不列颠哥伦比亚省南部），为新生代最温暖地区的广阔山地景观中的生物群落的重建提供了机会。来自这些化石场所的植物类群是北美现代东部落叶林带的特征，主要是混合中生森林，但也包括灭绝的类群，仅东亚中热森林才知道的类群，以及仅限于现在的少量类群天北美西海岸的针叶生物群系。在这份初步报告中，古气候和森林类型是使用美国华盛顿州的Republic以及加拿大不列颠哥伦比亚省的普林斯顿，Quilchena，福克兰，McAbee，Hat Creek，Horfly和Driftwood Canyon的集合重建的。叶缘分析（LMA）和确定的最近的巨型植物近缘亲属的定量生物气候分析均显示了上微热到下中热湿润环境（MAT〜10-15摄氏度，CMMT> 0摄氏度，MAP> 100厘米/年）。大多数地点共有的一些分类单元表明天气凉爽（例如，冷杉，其他松科; Al木，其他桦科）。但是，所有植物区系均包含实质性的阔叶落叶元素（例如，菊科，菊科）和针叶树（例如，水杉），其生物气候分析得出的MAT略高于LMA。嗜热（主要是中温）类群包括各种昆虫，水生蕨类植物Azolla，棕榈树，香蕉亲缘种，分类针叶树，杜仲和Gordonia，这些类群可能在其气候极限附近发生。嗜温和温带昆虫与植物类群的混合物表明低温季节性（即高度均等的气候）。

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