Paleozoic astrochronologies are limited by uncertainties in past astronomical configurations and the availability of complete stratigraphic sections with precise, independent age control. We show it is possible to reconstruct a robust Paleozoic ~104-yr-resolution astrochronology in the well-preserved and thick Upper Ordovician reference record of Anticosti Island (Canada). The clear imprint of astronomical cycles, including ~18 k.y. precession, potential obliquity, and short and long eccentricity, constrains the entire Vauréal Formation (~1 km thick) to only ~3 m.y. in total, representing ~10 times higher accumulation rates than previously suggested. This ~104 yr resolution represents an order of magnitude increase in the current standard temporal resolution for the Katian and even allows for the detection of sub-Milankovitch climate-scale variability. The loss of a clear precession signal in the uppermost Vauréal Formation might be related to contemporaneous global cooling prior to the Hirnantian glacial maximum as indicated by the δ18O record. Complementary to the study of cyclostratigraphy of longer and often simplified records, it is important to recognize stratigraphic hiatuses and complexities on the ~104 yr scale to achieve robust sub-eccentricity-scale Paleozoic astrochronologies.The theory of astronomical climate forcing has revolutionized our understanding of Cenozoic climate systems and is the basis for unprecedented continuous time scales (astrochronologies) with precision down to ~104 yr (Zachos et al., 2001). Pre-Cenozoic astrochronologies face several challenges relating to (1) uncertainties in the deep-time astronomical solutions and parameters (Berger and Loutre, 1994; Waltham, 2015); (2) less-complete and less-well-preserved strata; and (3) the sparsity of geochronologic anchor points. Consequently, Paleozoic astrochronologies are typically based on identification of the stable 405 k.y. eccentricity cycle instead of shorter astronomical cycles, which have the potential to provide an order-of-magnitude increase in temporal resolution. However, the prevalence of eccentricity-based astrochronologies is mechanistically difficult to explain because most of the insolation power lies in the obliquity and precession bands—not in the eccentricity.Several researchers have interpreted the record of eccentricity (~100 and ~405 k.y.) and long obliquity (~1.2 m.y.) cycles in the Upper Ordovician reference outcrop sections of Anticosti Island, Québec, Canada (Fig. 1; Long, 2007; Elrick et al., 2013; Ghienne et al., 2014; Mauviel et al., 2020). However, extrapolating these interpreted accumulation rates for the relatively homogeneous upper Katian subsurface lithology results in total time spans of tens of millions of years, which is inconsistent with integrated stratigraphic constraints indicating an estimated duration of only 4–5 m.y. (Cooper and Sadler, 2012; McLaughlin et al., 2016). While acknowledging challenges to pre-Cenozoic astrochronologies, our study makes use of new subsurface records from recent drilling on Anticosti Island and explores several astrochronological scenarios within the available stratigraphic constraints. Pre-Hirnantian glacial buildup is well established (Vandenbroucke et al., 2010; Pohl et al., 2016), and correctly documenting Late Ordovician astronomical cycles is crucial for constructing high-resolution time scales and studying dynamic changes in climate and biodiversity (Saupe et al., 2020). In general, reliable identification of high-frequency Paleozoic astronomical cycles can pave the way toward a greatly enhanced understanding of the interplay between biotic evolution and environmental change.The lower Paleozoic mixed siliciclastic-carbonate succession of Anticosti Island contains some of the thickest, most fossiliferous, well-exposed, and little-altered Upper Ordovician sections preserved on Earth (Fig. 1; Desrochers et al., 2010; Finnegan et al., 2011). The succession was deposited within a structural embayment along the eastern margin of Laurentia on the distal portion of a Taconic-Acadian foreland located in the paleo(sub-)tropics (10°S–25°S; Fig. 1B; Blakey, 2013). Our study focuses on the subsurface part of the upper Katian Vauréal Formation, consisting of predominantly gray, interbedded micrite, calcarenite, and marl deposited in a mid- to outer-shelf environment (Fig. S1 in the Supplemental Material1; Long, 2007). The lithological variations of interest in this study are multimeter bed bundles, and not the centimeter- to decimeter-thick limestone-marl couplets that are potentially early diagenetic in origin (Fig. 1C; Nohl et al., 2019). Previous outcrop studies suggested that eccentricity is the dominant astronomical signal in the Vauréal Formation (Long, 2007; Elrick et al., 2013; Mauviel et al., 2020). Updated biostratigraphy together with new chemostratigraphy indicate that the Vauréal Formation belongs to Ka4, a stage slice estimated at a total duration of 4–5 m.y. (Fig. 1D; see the Supplemental Material; McLaughlin et al., 2016).The La Loutre #1 core (LL1; 49°35′18″N, 63°38′14″W) was drilled by Consortium Hydrocarbures Anticosti ~10 km southwest of the well-studied New Associated Consolidated Paper (NACP) core (49°37′20″N, 63°26′18″W; Fig. 1A; McLaughlin et al., 2016). The two cores were correlated using the informal lithological units V2–V5 defined by McLaughlin et al. (2016) (see also Figs. 1A and 2; Fig. S2; see the Supplemental Material). The greater thickness of lithological units in the LLI core is attributed to separation by ~10 km along the south-directed depositional dip of the Anticosti Basin. The NACP core and the western outcrop sections were correlated based on their bulk δ13Ccarb (carb—carbonate) records (Figs. 1A and 2; Mauviel and Desrochers, 2016; McLaughlin et al., 2016). Additionally, 472 new NACP samples were measured for bulk δ13Ccarb and δ18Ocarb to increase the resolution of the record (see the Supplemental Material). The LL1 potassium (40K perent) record as measured by natural gamma-ray (NGR) logging was used as proxy for time-series analyses. This proxy reflects the multimeter cycles of carbonate versus clay lithology of interest and is continuously recorded with the highest available resolution (10 cm). Evolutive harmonic analysis (EHA) (Thomson, 1982) and TimeOpt, eTimeOpt, and timeOptTemplate (Meyers, 2015, 2019) analyses were done with “Astrochron” (https://cran.r-project.org/web/packages/astrochron/index.html; Meyers, 2014) in R (R Core Team, 2017). TimeOpt is a statistical optimization method that can simultaneously consider power spectra distributions and amplitude modulation patterns (Meyers, 2015, 2019). Accumulation rate reconstructions were also done in MATLAB using ACEv.1 and spectral moments (Sinnesael et al., 2016, 2018). Code and data are available in the Supplemental Material.The initial target for analysis was the V4–V5 stratigraphic interval of the Vauréal Formation, given that deeper intervals contained multiple hardgrounds and sharp contacts (e.g., the V2–V3 limit), and given that the overlying Ellis Bay Formation shows a pronounced facies shift toward more calcareous shales and was not completely recorded by the LL1 logging (Fig. 2; McLaughlin et al., 2016). Most lithological variation in the V4–V5 interval of LL1 (1030–335 m) is characterized by 5–10-m-thick cycles of clay-rich and clay-poor beds (Figs. 3B and 3C; Fig. S3), with a gradual decrease in thickness up section. These cycles are less clear in the lowermost (1030–880 m) and uppermost (403–335 m) intervals of the record (Fig. S3). Therefore, our analysis focused on the 880–403 m interval, which shows clear uninterrupted regular cycles (Figs. 2 and 3). Parallel to the decrease in cycle thickness up section, the amplitude changes attenuate, suggesting a gradual decrease in accumulation rate. The NGR signatures also appear to be bundled (5–6) into larger ~25–50-m-thick packages, with more clearly developed 5–10 m cycles occurring in the middle of the bundles (Fig. 3E).Integrating the biostratigraphic (conodont, graptolite, and chitinozoan) and chemostratigraphic (87Sr/86Sr and δ13Ccarb isotope) constraints with the numerical Ordovician 2012 Geological Time Scale (Cooper and Sadler, 2012; see the Supplemental Material), McLaughlin et al. (2016) inferred that the entire ~1100-m-thick Vauréal Formation represents a few million years, implying that the 5–10 m cycles each represents a few tens of thousands of years. This interpretation is also consistent with the 2020 Ordovician Geological Time Scale (Goldman et al., 2020). These independent time constraints exclude eccentricity time scales for the 5–10 m cycles. However, they do not allow us to discriminate between precession and obliquity. Nonetheless, both precession and obliquity should be amplitude modulated by eccentricity and long-obliquity, respectively. A bundling of 5–6 cycles into larger cycles could be an indication of a Late Ordovician precession (~16–21 k.y.; Berger and Loutre, 1994; Waltham, 2015) and short eccentricity (~100 k.y.) ratio. However, a similar ratio exists between Late Ordovician obliquity (~30–33 k.y.) and the 173-k.y.-long obliquity cycle (Boulila et al., 2018). An independent astronomical characteristic that can distinguish between both bundling scenarios is the identification of the longer 100 and 405 k.y. eccentricity cycles in a precession-eccentricity–dominated record. This hypothesis can be tested statistically using TimeOpt.The eTimeOpt analysis supports a precession-eccentricity–dominated signal with accumulation rates decreasing from ~60 to 30 cm k.y.–1 (Fig. 3A). This trend agrees with visual inspection (manual tuning) and additional independent numerical accumulation rate reconstructions (Fig. S4). We used this trend to additionally constrain the timeOptTemplate analysis, statistically testing a precession-eccentricity signal and reconstructing precession and eccentricity in the time domain. The resulting precession band-pass filters and reconstructed eccentricity (combined fitting of the precession-band amplitude and a user-defined eccentricity model containing the 405, 125, and 95 k.y. periods) show clear precession amplitude modulations by the ~100 and 405 k.y. eccentricity periods (Fig. 3D). Changes in accumulation rates follow the 25–50 m (~100 k.y. eccentricity) cycles, with times of high eccentricity corresponding with higher accumulation rate (Fig. 3; Fig. S4). Such an interpretation suggests a positive phase relationship between the occurrence of thicker clay-rich layers and eccentricity maxima. Located at the southeast margin of the large Laurentian landmass at paleo(sub-) tropical latitudes (Fig. 1B), the Anticosti Basin could have been prone to monsoons. We suggest a monsoon-driven climatic control on the input of siliciclastic detrital material to explain the observed variations in clay content on astronomical time scales, as commonly documented throughout the Phanerozoic (cf. De Vleeschouwer et al., 2012; Wang et al., 2014).We estimated the total duration of the 880–403 m interval in several ways. The timeOptTemplate approach, optimizing the precession-eccentricity relationship, resulted in a total duration of 1138 k.y. (Fig. S5), whereas the short-long eccentricity optimization gave a total duration of 1245 k.y. (Fig. S6). Manually counting 66 lithological cycles multiplied by an average precession duration of 18.725 k.y. for 445 m.y. ago (Waltham, 2015) led to a total duration of 1236 k.y. A possible explanation for this slight offset might be that some exceptionally thick cycles are not single precession cycles; instead, they are obliquity cycles that become more prominent during eccentricity minima when the amplitude of the climatic precession is relatively low (Fig. 3E; Fig. S3).Overall, the studied 477-m-thick subsurface interval is interpreted to represent ~1.2 m.y., recording three 405 k.y. eccentricity cycles, 12 ~100 k.y. eccentricity cycles, and 60–66 precession cycles of ~18 k.y., with a potential imprint of obliquity cycles during eccentricity minima. Extrapolating the resulting accumulation rates across the entire Vauréal Formation suggests a represented total duration of ~3 m.y. This interpretation is in closer agreement with the available integrated stratigraphic constraints (McLaughlin et al., 2016) compared to the previous outcrop-based cyclostratigraphic interpretations assigning eccentricity-scale durations to comparable meter-scale lithological cycles.Interestingly, the clear precession imprint disappears at ~400 m LL1 core depth toward the top of the Vauréal Formation (Fig. 2; Fig. S3). This interval coincides with a period of cooling (Fig. 2). Although caution is needed while interpreting Paleozoic bulk δ18O records, the trends in the Anticosti Island bulk δ18O record are consistent with results of studies using clumped oxygen isotopes and well-preserved brachiopod and conodont δ18O data (Finnegan et al., 2011; Goldberg et al., 2021), as well as with the averaged δ18Oconodont apatite data from Elrick et al. (2013) (Fig. 2). Late Katian cooling could have shifted the position of the Intertropical Convergence Zone and monsoon circulation so that the paleolocation of the Anticosti Basin was less influenced by monsoon climate forcing (Armstrong et al., 2009). Additionally, the increasingly large ice buildup on Gondwana could have shifted the dominant global astronomical signature toward stronger obliquity (Herrmann et al., 2003) or eccentricity imprints as suggested for the uppermost Vauréal Formation or Hirnantian Ellis Bay Formation (Long, 2007; Mauviel et al., 2020). Thus, the weakened precession signal might reflect a stronger nonlinear response of the climate system to the precession forcing, thereby enhancing the strength of the modulating eccentricity signal. In such a scenario, the δ18Oconodont apatite variations interpreted by Elrick et al. (2013) could reflect glacio-eustatic fluctuations.Alternatively, the δ18Oconodont apatite variations could include more than glacio-eustatic fluctuations. Next to a control on supply of siliciclastic material, a strong monsoon circulation could have had an important influence on the continental runoff of freshwater and local evaporation rates. Simulations for the late Carboniferous North American Midcontinent epicontinental sea, a setting that could be compared with the Late Ordovician Laurentian epicontinental sea (Fig. 1B), demonstrate how such seawater freshening might considerably impact marine biogenic δ18O proxy interpretations (Macarewich et al., 2021). An additional possibility is a link with sub-Milankovitch climate variability. Our reconstructed accumulation rates result in some of the highest-time-resolution windows on the Ka4 slice worldwide. Spectral analyses of the precession-calibrated time series as shown in Figure 3E demonstrate a consistent cycle of ~1–1.5 k.y. (see the Supplemental Material), corresponding with the Pleistocene Dansgaard-Oeschger oscillation period (Dansgaard et al., 1989). Even though Paleozoic boundary conditions were fundamentally different compared to the Cenozoic (Elrick and Hinnov, 2007), evidence for a Paleozoic record of millennial-scale climate variability is growing (e.g., Da Silva et al., 2018).We demonstrated how identification of the unique amplitude modulation characteristic of precession and eccentricity can be used as a powerful tool to develop Paleozoic ~104-yr-resolution astrochronologies. Using such astronomical signal properties in combination with integrated stratigraphic constraints allowed us to move beyond the limits of stable 405 k.y. eccentricity astrochronologies, while recognizing the stratigraphic limitations imposed by the occurrences of unconformities or hiatuses and intervals where cycles might not be clearly expressed. Such an approach is complementary to longer, but less precise, cyclostratigraphic studies. Our unprecedented temporal resolution provides a snapshot into late Katian climate dynamics, paving the way for future “Cenozoic-style” scenario reconstructions.We thank the Research Foundation–Flanders (M. Sinnesael: Ph.D. fellowship FWOTM782), the King Baudouin Foundation (Brussels) (T. Vandenbroucke and J. De Weirdt: Professor T. Van Autenboer Fund), Bijzonder Onderzoeksfonds—Universiteit Gent (BOF-UGent) (T. Vandenbroucke: BOF17/STA/013), the Natural Sciences and Engineering Research Council of Canada (A. Desrochers: NSERC Discovery Grant), and the Vrije Universiteit Brussel (VUB) Strategic Research Program (P. Claeys) for funding, and M. Elrick and F. Hilgen for constructive reviews. This work contributes to International Geoscience Programme projects IGCP 652 (Reading geologic time in Paleozoic sedimentary rocks) and IGCP 653 (The onset of the Great Ordovician Biodiversification Event).

中文翻译：

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在 Hirnantian 冰川最大值之前岁差驱动的气候周期和时间尺度

古生代天体年代学受到过去天文配置的不确定性以及具有精确、独立年龄控制的完整地层剖面的可用性的限制。我们表明，在安蒂科斯蒂岛（加拿大）保存完好且厚厚的上奥陶世参考记录中，可以重建强大的古生代~104 年分辨率的天文年代学。天文周期的清晰印记，包括~18 ky 岁差、潜在倾角和短长偏心，将整个Vauréal 组（~1 公里厚）限制在总共只有~3 my 的范围内，代表着比以前高出~10 倍的积累率建议。这个~104 年的分辨率代表了卡蒂安当前标准时间分辨率的一个数量级增加，甚至可以检测到亚米兰科维奇气候尺度的变化。δ18O 记录表明，在最上层的 Vauréal 组中失去清晰的进动信号可能与 Hirnantian 冰川最大值之前的同期全球冷却有关。作为对较长且通常简化的记录的旋回地层研究的补充，重要的是要识别 ~104 年尺度上的地层间断和复杂性，以实现强大的亚偏心率尺度古生代天体年代学。天文气候强迫理论彻底改变了我们对新生代气候系统的理解，并且是前所未有的连续时间尺度（天体年代学）的基础，精度低至 104 年（Zachos 等，2001）。新生代前的天体年代学面临着与 (1) 深时天文解和参数的不确定性相关的几个挑战（Berger 和 Loutre，1994 年；Waltham，2015 年）；(2) 地层不完整、保存较差；(3)地质年代学锚点的稀疏性。因此，古生代天体年代学通常基于对稳定的 405 ky 偏心率周期的识别，而不是较短的天文周期，后者有可能在时间分辨率上提供一个数量级的增加。然而，基于偏心率的天体年代学的盛行在​​机械上难以解释，因为大部分日照力位于倾斜和进动带中，而不是偏心率。几位研究人员已经解释了偏心率（~100 和~405 ky）和长倾斜的记录(~1.2 my) 加拿大魁北克安蒂科斯蒂岛上奥陶世参考露头剖面的循环（图 1；Long，2007 年；Elrick 等人，2013 年；Ghienne 等人，2014 年；Mauviel 等人，2020 年） . 然而，对相对均质的上卡蒂安地下岩性推断这些解释的积累率导致总时间跨度为数千万年，这与综合地层限制不一致，表明估计持续时间仅为 4-5 米（Cooper 和 Sadler，2012 年） ；麦克劳克林等人，2016 年）。在承认新生代前天体年代学面临挑战的同时，我们的研究利用了最近在 Anticosti 岛上钻探的新地下记录，并在可用地层限制内探索了几种天体年代学情景。Pre-Hirnantian 冰川积聚已经确立（Vandenbroucke 等人，2010 年；Pohl 等人，2016 年），正确记录晚奥陶世天文周期对于构建高分辨率时间尺度和研究气候和生物多样性的动态变化至关重要（Saupe等人，2020 年）。一般来说，对高频古生代天文周期的可靠识别可以为大大增强对生物进化与环境变化之间相互作用的理解铺平道路。Anticosti 岛的下古生界混合硅质碎屑-碳酸盐岩系列包含一些地球上保存的最厚、含化石量最多、出露良好且几乎没有变化的上奥陶统剖面（图 1；Desrochers 等，2010；Finnegan 等，2010）。 , 2011)。该系列沉积在位于古（亚）热带（10°S-25°S；图 1B；Blakey，2013）的 Taconic-Acadian 前陆远端部分的 Laurentia 东缘的构造海湾内. 我们的研究侧重于上 Katian Vauréal 地层的地下部分，主要由沉积在中到外陆架环境中的灰色、互层泥晶、方解石和泥灰岩组成（补充材料中的图 S1；Long，2007 年）。本研究中感兴趣的岩性变化是万用表床束，而不是厘米到分米厚的石灰岩-泥灰岩对，它们可能起源于早期成岩作用（图 1C；Nohl 等，2019）。先前的露头研究表明，偏心率是 Vauréal 组中的主要天文信号（Long，2007；Elrick 等，2013；Mauviel 等，2020）。更新的生物地层和新的化学地层表明 Vaureal 组属于 Ka4，估计总持续时间为 4-5 my 的阶段切片（图 1D；参见补充材料；McLaughlin 等人，2016 年）。 La Loutre # 1 个岩心（LL1；49°35′18″N，63°38′14″W）由 Consortium Hydrocarbures Anticosti 钻探，位于研究充分的 New Associated Consolidated Paper (NACP) 岩心 (49°37'20) 西南约 10 公里处“N, 63°26'18”W；图 1A；McLaughlin 等人，2016 年）。使用 McLaughlin 等人定义的非正式岩性单元 V2-V5 将两个岩心关联起来。（2016 年）（另请参见图 1A 和 2；图 S2；参见补充材料）。LLI 岩心中岩性单元的厚度较大归因于沿 Anticosti 盆地向南的沉积倾角分离约 10 公里。NACP 岩心和西部露头剖面基于它们的大量 δ13Ccarb（碳水化合物-碳酸盐）记录进行了关联（图 1A 和 2；Mauviel 和 Desrochers，2016 年；McLaughlin 等人，2016 年）。此外，还测量了 472 个新 NACP 样品的大体积 δ13Ccarb 和 δ18Ocarb，以提高记录的分辨率（参见补充材料）。通过自然伽马射线 (NGR) 测井测量的 LL1 钾 (40K perent) 记录用作时间序列分析的代理。该代理反映了碳酸盐与感兴趣的粘土岩性的万用表循环，并以最高的可用分辨率（10 厘米）连续记录。演化谐波分析 (EHA)（Thomson，1982 年）和 TimeOpt、eTimeOpt 和 timeOptTemplate（Meyers，2015 年、2019 年）分析是使用“Astrochron”完成的 (https://cran.r-project.org/web/packages/astrochron /index.html; Meyers, 2014) in R (R Core Team, 2017)。TimeOpt 是一种统计优化方法，可以同时考虑功率谱分布和幅度调制模式 (Meyers, 2015, 2019)。还在 MATLAB 中使用 ACEv.1 和谱矩（Sinnesael et al., 2016, 2018）完成了累积率重建。补充材料中提供了代码和数据。 分析的初始目标是 Vaureal 组的 V4-V5 地层区间，考虑到更深的层段包含多个硬地和尖锐的接触（例如，V2-V3 限制），并且考虑到上覆的 Ellis Bay 组显示出明显的相向更多钙质页岩移动并且没有被 LL1 测井完全记录（图 2） ；麦克劳克林等人，2016 年）。LL1 的 V4-V5 层段（1030-335 m）的大部分岩性变化的特征是 5-10 米厚的富粘土层和贫粘土层旋回（图 3B 和 3C；图 S3），其中向上部分的厚度逐渐减小。这些循环在记录的最低（1030-880 m）和最高（403-335 m）间隔中不太清楚（图S3）。因此，我们的分析集中在 880-403 m 区间，该区间显示了清晰的不间断规律周期（图 2 和图 3）。平行于循环厚度向上部分的减小，幅度变化衰减，表明积累率逐渐下降。NGR 特征似乎也被捆绑 (5-6) 成更大的~25-50 米厚的包裹，在捆绑中间出现更清晰的 5-10 米循环（图 3E）。整合生物地层（牙形石、笔石和几丁质动物）和化学地层学（87Sr/86Sr 和 δ13Ccarb 同位素）约束与数值奥陶纪 2012 地质时间尺度（Cooper 和 Sadler，2012；参见补充材料），McLaughlin 等人。(2016) 推断整个约 1100 米厚的 Vaureal 地层代表几百万年，这意味着 5-10 米的周期每个代表几万年。这种解释也与 2020 年奥陶纪地质年表一致（Goldman 等，2020）。这些独立的时间限制不包括 5-10 m 周期的偏心率时间尺度。然而，它们不允许我们区分岁差和倾角。尽管如此，进动和倾角都应该分别通过偏心距和长倾角进行幅度调制。将 5-6 个周期捆绑成更大的周期可能表明晚奥陶世岁差（~16-21 ky；Berger 和 Loutre，1994；Waltham，2015）和短偏心率（~100 ky）比率。然而，晚奥陶世倾角（~30-33 ky）和 173 ky 长的倾角旋回之间存在类似的比率（Boulila 等，2018）。可以区分这两种捆绑方案的独立天文特征是识别进动偏心率主导记录中较长的 100 和 405 ky 偏心率周期。该假设可以使用 TimeOpt 进行统计测试。 eTimeOpt 分析支持进动偏心率主导的信号，累积速率从 ~60 到 30 cm ky-1（图 3A）。这种趋势与目视检查（手动调整）和额外的独立数值累积率重建（图 S4）一致。我们使用这种趋势来额外约束 timeOptTemplate 分析，统计测试进动偏心率信号并在时域中重建进动和偏心率。由此产生的进动带通滤波器和重建的偏心率（进动带幅度的组合拟合和包含 405、125 和 95 ky 周期的用户定义的偏心率模型）显示了 ~100 和 405 ky 偏心率的清晰进动幅度调制期间（图 3D）。积累率的变化遵循 25-50 m（~100 ky 偏心率）循环，高离心率的时间对应于更高的积累率（图 3；图 S4）。这种解释表明较厚的富含粘土层的出现与偏心率最大值之间存在正相关系。Anticosti 盆地位于古（亚）热带纬度的大型劳伦大陆的东南边缘（图 1B），可能容易受到季风的影响。我们建议对硅质碎屑物质的输入进行季风驱动的气候控制，以解释观察到的天文时间尺度上粘土含量的变化，正如整个显生宙中普遍记录的那样（参见 De Vleeschouwer 等，2012；Wang 等， 2014）。我们以多种方式估计了 880-403 m 间隔的总持续时间。优化进动-偏心关系的 timeOptTemplate 方法导致总持续时间为 1138 ky（图 S5），而短长偏心优化的总持续时间为 1245 ky（图 S6）。手动计算 66 个岩性旋回乘以 445 年前的平均进动持续时间 18.725 ky (Waltham, 2015) 导致总持续时间为 1236 ky 这种轻微偏移的可能解释可能是一些异常粗的旋回不是单个进动旋回; 相反，当气候进动的幅度相对较低时，它们是在偏心率最小值期间变得更加突出的倾角循环（图 3E；图 S3）。总体而言，所研究的 477 米厚的地下间隔被解释为代表 ~1.2我的，记录三个 405 ky 偏心率周期，12 ~100 ky 偏心率周期，以及 60-66 个~18 ky 的进动周期，在偏心率最小值期间带有倾斜周期的潜在印记。推断整个 Vauréal 地层的堆积速率表明总持续时间约为 3 米。与先前基于露头的旋回地层解释相比，该解释与可用的综合地层限制（McLaughlin 等，2016）更接近一致。 -尺度持续时间与可比的米尺度岩性循环相比。有趣的是，清晰的进动印记在朝向 Vaureal 组顶部的 LL1 岩心深度约 400 米处消失（图 2；图 S3）。该间隔与冷却期相吻合（图 2）。尽管在解释古生代大块 δ18O 记录时需要谨慎，Anticosti Island 大块 δ18O 记录的趋势与使用聚集氧同位素和保存完好的腕足动物和牙形石 δ18O 数据的研究结果一致（Finnegan 等人，2011 年；Goldberg 等人，2021 年），以及平均值来自 Elrick 等人的 δ18Oconodont 磷灰石数据。（2013 年）（图 2）。Katian 晚期降温可能已经改变了热带辐合带和季风环流的位置，从而使 Anticosti 盆地的古地理位置受季风气候强迫的影响较小（Armstrong 等，2009）。此外，冈瓦纳大陆上越来越大的冰堆积可能已经将占主导地位的全球天文特征转移到更强的倾斜度（Herrmann 等人，2003 年）或如最上面的 Vauréal 组或 Hirnantian Ellis 湾组所建议的偏心率印记（Long，2007 年；Mauviel 等人）等，2020）。因此，减弱的进动信号可能反映了气候系统对进动强迫的更强非线性响应，从而增强了调制偏心率信号的强度。在这种情况下，Elrick 等人解释的 δ18Oconodont 磷灰石变化。(2013) 可以反映冰川 - 静海波动。或者，δ18Oconodont 磷灰石变化可能包括更多的冰川 - 静静波动。除了控制硅质碎屑材料的供应外，强烈的季风环流可能对大陆淡水径流和局部蒸发率产生重要影响。晚石炭纪北美中陆陆表海的模拟，可以与晚奥陶世劳伦大陆表海相比较（图 1B），证明了这种海水淡化可能如何显着影响海洋生物 δ18O 替代解释（Macarewich 等人，2021 年）。另一种可能性是与亚米兰科维奇气候变率的联系。我们重建的累积率导致全球 Ka4 切片上的一些最高时间分辨率窗口。如图 3E 所示，对进动校准时间序列的光谱分析表明，周期为 ~1-1.5 ky（见补充材料），对应于更新世 Dansgaard-Oeschger 振荡周期（Dansgaard 等，1989）。尽管古生代边界条件与新生代有着根本的不同（Elrick 和 Hinnov，2007），但有关千年尺度气候变率的古生代记录的证据正在增加（例如，Da Silva 等，2018）。我们展示了如何识别进动和偏心率的独特幅度调制特征可以用作开发古生代~104 年分辨率天体年代学的有力工具。将此类天文信号特性与综合地层约束结合使用，使我们能够超越稳定的 405 ky 偏心率天体年代学的限制，同时认识到由不整合或中断和间隔的发生所施加的地层限制，其中周期可能无法清楚地表达。这种方法是对时间较长但精度较低的旋回地层研究的补充。我们前所未有的时间分辨率提供了对晚期 Katian 气候动态的快照，为未来的“新生代”情景重建铺平了道路。我们感谢研究基金会 - 佛兰德斯 (M. Sinnesael：博士 奖学金 FWOTM782）、博杜安国王基金会（布鲁塞尔）（T. Vandenbroucke 和 J. De Weirdt：T. Van Autenboer 教授基金）、Bijzonder Onderzoeksfonds-Universiteit Gent (BOF-UGent)（T. Vandenbroucke：BOF17/STA/013） , 加拿大自然科学和工程研究委员会 (A. Desrochers: NSERC Discovery Grant) 和布鲁塞尔自由大学 (VUB) 战略研究计划 (P. Claeys) 提供资金，M. Elrick 和 F. Hilgen 提供建设性评论. 这项工作有助于国际地球科学计划项目 IGCP 652（读取古生代沉积岩的地质时间）和 IGCP 653（大奥陶纪生物多样性事件的开始）。Bijzonder Onderzoeksfonds-Universiteit Gent (BOF-UGent) (T. Vandenbroucke: BOF17/STA/013)、加拿大自然科学和工程研究委员会 (A. Desrochers: NSERC Discovery Grant) 和 Vrije Universiteit Brussel (VUB) 战略研究计划 (P. Claeys) 提供资金，M. Elrick 和 F. Hilgen 提供建设性评论。这项工作有助于国际地球科学计划项目 IGCP 652（读取古生代沉积岩的地质时间）和 IGCP 653（大奥陶纪生物多样性事件的开始）。Bijzonder Onderzoeksfonds-Universiteit Gent (BOF-UGent) (T. Vandenbroucke: BOF17/STA/013)、加拿大自然科学和工程研究委员会 (A. Desrochers: NSERC Discovery Grant) 和 Vrije Universiteit Brussel (VUB) 战略研究计划 (P. Claeys) 提供资金，M. Elrick 和 F. Hilgen 提供建设性评论。这项工作有助于国际地球科学计划项目 IGCP 652（读取古生代沉积岩的地质时间）和 IGCP 653（大奥陶纪生物多样性事件的开始）。Hilgen 提出建设性意见。这项工作有助于国际地球科学计划项目 IGCP 652（读取古生代沉积岩的地质时间）和 IGCP 653（大奥陶纪生物多样性事件的开始）。Hilgen 提出建设性意见。这项工作有助于国际地球科学计划项目 IGCP 652（读取古生代沉积岩的地质时间）和 IGCP 653（大奥陶纪生物多样性事件的开始）。