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首页> 外文期刊>Geological Society of America Bulletin >Stratigraphic record of the asteroidal Veritas breakup in the Tortonian Monte dei Corvi section (Ancona, Italy)
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Stratigraphic record of the asteroidal Veritas breakup in the Tortonian Monte dei Corvi section (Ancona, Italy)

机译：Tortonian Monte Dei Corvi段的小行星Veritas分手的地层记录（安科纳，意大利）

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The discovery of elevated concentrations of the cosmogenic radionuclide 3He in deepsea sediments from Ocean Drilling Program (ODP) Site 926 (Atlantic Ocean) and ODP Site 757 (Indian Ocean) points toward accretion of extraterrestrial matter, probably as a result of the catastrophic disruption of a large asteroid that produced the Veritas family of asteroids at ca. 8.3 +/- 0.5 Ma, and which may have had important effects on the global climatic and ecologic systems. Here, we investigated the signatures possibly related to the Veritas event by performing a highresolution multiproxy stratigraphic analysis through the late Tortonian-early Messinian Monte dei Corvi section near Ancona, Italy. Closely spaced bulk-rock samples through a 36-m-thick section, approximately spanning from ca. 9.9 Ma to ca. 6.4 Ma, show an similar to 5-fold 3He anomaly starting at ca. 8.5 Ma and returning to background values at ca. 6.9 Ma, confirming the global nature of the event. We then analyzed, at 5 cm intervals, bulk-rock samples for sedimentary and environmental proxies such as magnetic susceptibility, calcium carbonate content, total organic carbon, and bulk carbonate delta O-18 and delta C-13, through a 21-m-thick section encompassing the He-3 anomaly. Available high-resolution sea-surface temperature data (via alkenone analyses) for this site show a temperature decrease starting exactly at the inception of the He-3 anomaly. Cyclostratigraphic fast-Fourier-transform spectral analyses of the proxies indicate an age of 8.47 +/- 0.05 Ma for the inception of the He-3 anomaly. A search for impact ejecta (analogous to what is present in the late Eocene, where both a He-3 anomaly and large-scale impact events are recorded) was not successful. Detailed cyclostratigraphic analyses of our data suggest that the changes in the stable isotope series and environmental proxy series through this late Tortonian time interval had a common forcing agent, and that perturbations of orbitally forced climate cycles are present exactly through the interval with the enhanced influx of extraterrestrial He-3. Thus, the chemostratigraphic evidence for a collisional event that created the Veritas family of asteroids, coinciding with climate perturbations on Earth, suggests yet another form of interaction between Earth and the solar system.
机译：从海洋钻井计划（ODP）站点926（大西洋）和ODP网站757（印度洋）的深度沉积物中升高浓度浓度的浓度浓度的浓度沉积物（ODP）和ODP Site 757（印度洋）指向外星物质的积极性，可能是由于灾难性的破坏而产生的一个大的小行星，在加利福尼亚州制作了Veritas家族的小行星。 8.3 +/- 0.5 mA，这可能对全球气候和生态系统产生了重要影响。在这里，我们通过在意大利安科纳附近的晚期Tortonian-Messinian Monte Dei Corvi部分进行了高度研究的多元墨西州Monte Dei Corvi部分，调查了可能与Veritas事件有关的签名。通过36米厚的部分紧密间隔的散装样本，大约跨越CA. 9.9 ma到CA. 6.4 mA，从加利福尼亚州开始类似于5倍3HE异常。 8.5 mA并返回CA的背景值。 6.9 MA，确认事件的全球性质。然后，我们分析为5cm间隔，沉积和环境代理的体积岩石样品，如磁性敏感性，碳酸钙含量，总有机碳和批量碳酸酯δO-18和δC-13，通过21M-包括HE-3异常的厚实部分。可用的高分辨率海表面温度数据（通过链烯酮分析）对于该网站显示温度降低，即时在初始的HE-3异常开始时开始。基金会的CycloStraphicaphic Fout-Transforms谱分析表明HE-3异常的初始为8.47 +/- 0.05 mA。寻找影响EJECTA（类似于后期eocene中存在的东西，其中记录了HE-3异常和大规模的影响事件）并未成功。我们的数据的详细基本数据库分析表明，稳定同位素系列和环境代理系列通过这种晚期Tortonian时间间隔的变化具有常见的强制性代理，并且通过增强涌入的间隔完全通过间隔施用轨道强迫气候循环的扰动外星人He-3。因此，在与地球上的气候扰动恰逢地球扰动的碰撞事件的化疗证据表明了地球和太阳系之间的另一种形式的互动。

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