The 50th anniversary of Geology provides not only a welcome occasion to celebrate past decades of extraordinary advances in geoscience knowledge but also the impetus to cast our gaze forward and envision what new directions and discoveries will guide geoscience research through the next 50 years and beyond. My research broadly concerns reconstructing the factors that have shaped the emergence and evolution of complex life on our planet, as well as the fidelity of archives of past environmental and ecological change. This is an area that, in my view, is currently undergoing a renaissance—fueled by efforts leveraging multidisciplinary approaches; exploring increasingly highly resolved spatial and temporal scales; and harnessing the power of large, stratigraphically grounded data sets.Many of our most pressing questions regarding Earth's early history concern interactions between past life and environments and how these have co-evolved. To address these questions, which are truly multidisciplinary in scope, we need a multidisciplinary toolkit. In recent years there have been major strides forward in the realm of combining paleontological, sedimentological, paleoclimatic, and geochemical approaches—particularly for the Neoproterozoic and lower Paleozoic eras, the interval bracketing the emergence and initial radiations of complex animal life. Geochemical and paleontological investigations of this interval, in particular, have historically occurred within disciplinary silos, even when motivated by questions centered on environmental-biotic feedbacks. Paleontological and geochemical data sets have commonly been collected from different units, facies, and even paleocontinents. For instance, many paleoredox proxy records, such as iron speciation, sulfur isotopes, and trace element analyses, are generated from muddy lithologies that are particularly susceptible to diagenesis and weathering and thus more tractably sampled from drill core than outcrop (Ahm et al., 2017). In contrast, certain body and trace fossils more commonly occur or are more readily recognized in non-muddy lithologies, and their preservation in outcrop may even be accentuated by early diagenetic cementation, dolomitization, or preferential weathering (Savrda, 2012). Additionally, Neoproterozoic successions suffer from substantial chronostratigraphic uncertainties relative to younger intervals—compounded by a paucity of robust index fossils suitable for biostratigraphic correlation as well as lingering questions regarding the syngeneity and synchroneity of potential chemostratigraphic markers such as carbon isotope excursions (cf. Xiao et al., 2016). Integrating these disparate data sets on time scales that are ecologically and evolutionarily meaningful therefore remains a major hurdle. However, a growing body of studies that provide new chronostratigraphic constraints on key intervals in Earth's early life history (Pu et al., 2016; Rooney et al., 2020) and attempt to compile paleoenvironmental, paleoclimatic, biogeochemical, and paleontological data in tandem (Li et al., 2015; Wood et al., 2019) offers promise for future multidisciplinary efforts.At the same time, higher-resolution data are clearly critical to addressing questions of biological-environmental interactions through this interval—in part because geochemical, paleontological, and geochronological proxies can all be subject to alteration. Bulk samples, as palimpsests of primary, diagenetic, metamorphic, and recent weathering processes (Hood et al., 2016; Tarhan et al., 2018), may not serve as faithful archives of seawater and sea-floor conditions. Additionally, recent work has highlighted that finer stratigraphic and spatial scales frequently correspond to the biological and ecological time scales of greatest interest. For instance, petrographic-scale geochemical analyses are shedding new light on short-term redox fluctuations in the Neoproterozoic seawaters inhabited by some of our earliest biomineralizing and potentially reef-forming complex organisms (Hood and Wallace, 2015; Wood et al., 2017). Application of both older and emerging microscale analytical techniques with the capability to target geologic and fossil materials at a truly granular scale—from cathodoluminescence microscopy and electron microprobe analyses to laser ablation and secondary ion mass spectrometry—provides a powerful toolkit to tackle both longstanding and emerging questions in Earth's early environmental and life history (Tarhan et al., 2016; Trower et al., 2021). Likewise, studies coupling fossil records with biogeochemical modeling are allowing us to reevaluate the feasibility of longstanding conceptual frameworks for environmentalbiotic coevolution. For instance, some of my recent work has used this approach to assess whether animals emerged against a backdrop of high seawater dissolved organic carbon levels (Fakhraee et al., 2021), or whether the expansion of well-bioturbated sediments drove shifts in marine productivity and oxygen concentrations (Tarhan et al., 2021). Direct integration of stratigraphic and modeling observations ensures that paradigms of early life-environment coevolution have been rigorously tested and are grounded in a mechanistic understanding of physical, chemical, and biological processes. Similarly, research seeking to quantitatively apply insights gleaned from modern natural and experimental geobiological systems (as well as sedimentary geochemical modeling of these systems) directly to the fossil record is shedding new light on the role of preservational processes (and their inherent biases) in shaping the fossil record (Slagter et al., 2021; Westacott et al., 2021).Recent work has also highlighted the need to be clear-eyed when it comes not only to the extraordinary opportunities offered by burgeoning proxy-based geochemical and paleontological data sets but also their limitations. Statistical and probabilistic tools increasingly offer means to constrain confidence in these data sets and guide how we can use them to robustly reconstruct major trends in evolutionary and environmental history (Sperling et al., 2015; Anderson et al., 2018). And although few would dispute the imperfect nature of the stratigraphic and shelly fossil records (Sadler, 1981), we must not overlook that even extraordinary, Lagerstättengrade fossils have undergone decay and alteration—in fact, many pathways of exceptional preservation necessitate decay—and are shaped by taphonomic processes that can obfuscate original anatomical and ecological information and introduce morphological variability (Briggs, 2003). Exceptional fossils can undeniably yield exceptional insights into past life. However, as a community, we must continue to recognize that, if we hope to distinguish outliers from patterns truly representative of Earth's history, scrutiny of all components of the fossil record—body or trace, skeletal or soft-tissue—should be premised on characterization of extensive sample sets rather than isolated examples (Evans et al., 2017; Tarhan, 2018). And if our aim is to reconstruct how changing conditions across Earth's surface environments have shaped the evolutionary trajectory of life—and how, in turn, the emergence of new ecological novelties and innovations has engineered Earth's landscapes (cf. Erwin, 2015)—any consideration of fossil data must occur in a geologic context and be grounded in a paleoenvironmental and taphonomic framework.

中文翻译：

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重建地球上早期动物生命历史的多学科方法

地质学 50 周年不仅为庆祝过去几十年在地球科学知识方面取得的非凡进步提供了一个可喜的机会，而且也提供了推动我们向前看的动力，并展望未来 50 年及以后的地球科学研究将有哪些新方向和发现。我的研究广泛涉及重建影响地球上复杂生命出现和进化的因素，以及过去环境和生态变化档案的保真度。在我看来，这是一个正在经历复兴的领域——在利用多学科方法的努力推动下；探索越来越高分辨的空间和时间尺度；并利用基于地层的大型数据集的力量。我们关于地球的许多最紧迫的问题 早期的历史关注前世与环境之间的相互作用，以及它们是如何共同进化的。为了解决这些真正涉及多学科范围的问题，我们需要一个多学科工具包。近年来，在古生物学、沉积学、古气候和地球化学方法相结合的领域取得了重大进展——特别是在新元古代和下古生代，这一时期包含了复杂动物生命的出现和初始辐射。尤其是对这一区间的地球化学和古生物学研究，历史上一直发生在学科孤岛内，即使是在以环境-生物反馈为中心的问题的推动下。古生物和地球化学数据集通常是从不同的单元、相甚至古大陆收集的。例如，许多古氧化还原记录，如铁形态、硫同位素和微量元素分析，都是由特别容易受到成岩作用和风化影响的泥质岩性产生的，因此从钻芯中取样比从露头中取样更容易（Ahm 等人， 2017）。相比之下，某些身体和痕迹化石在非泥质岩性中更常见或更容易识别，早期成岩胶结、白云石化或优先风化甚至可能加强它们在露头中的保存（Savrda，2012）。此外，相对于较年轻的间隔，新元古代演替存在大量的年代地层不确定性——再加上缺乏适合生物地层相关性的稳健指数化石，以及关于潜在化学地层标记（如碳同位素偏移）的同源性和同步性的挥之不去的问题（参见 Xiao et al. , 2016)。因此，在具有生态和进化意义的时间尺度上整合这些不同的数据集仍然是一个主要障碍。然而，越来越多的研究为地球早期生命历史中的关键间隔提供了新的年代地层限制（Pu 等人，2016 年；鲁尼等人，2020 年），并试图将古环境、古气候、生物地球化学和古生物学数据串联起来（李等人，2015 年；伍德等人，2019）为未来的多学科努力提供了希望。与此同时，更高分辨率的数据对于解决这一区间的生物-环境相互作用问题显然至关重要——部分原因是地球化学、古生物学和地质年代学代理都可能发生变化。散装样本作为原始、成岩、变质和近期风化过程的重述（Hood 等人，2016 年；Tarhan 等人，2018 年），可能无法作为海水和海底条件的忠实档案。此外，最近的工作强调了更精细的地层和空间尺度通常对应于最感兴趣的生物和生态时间尺度。例如，岩相尺度的地球化学分析为新元古代海水中的短期氧化还原波动提供了新的线索，这些海水中居住着一些我们最早的生物矿化和可能形成礁石的复杂生物（Hood 和 Wallace，2015；Wood 等，2017）。应用旧的和新兴的微尺度分析技术，能够以真正的颗粒尺度定位地质和化石材料——从阴极发光显微镜和电子探针分析到激光烧蚀和二次离子质谱——提供了一个强大的工具包来解决长期存在和新兴的问题地球早期环境和生命史中的问题（Tarhan et al., 2016; Trower et al., 2021）。同样地，将化石记录与生物地球化学模型相结合的研究使我们能够重新评估长期存在的环境生物协同进化概念框架的可行性。例如，我最近的一些工作使用这种方法来评估动物是否在海水溶解有机碳含量高的背景下出现（Fakhrae 等人，2021 年），或者生物扰动良好的沉积物的扩张是否推动了海洋生产力的变化和氧气浓度（Tarhan 等人，2021 年）。地层和建模观测的直接整合确保了早期生命-环境协同进化的范式已经过严格测试，并以对物理、化学和生物过程的机械理解为基础。相似地，旨在将现代自然和实验地球生物学系统（以及这些系统的沉积地球化学模型）收集的见解定量应用到化石记录的研究正在揭示保存过程（及其固有偏见）在塑造化石中的作用记录（Slagter 等人，2021 年；Westacott 等人，2021 年）。最近的工作还强调，不仅要注意新兴的基于代理的地球化学和古生物学数据集所提供的非凡机会，而且还需要保持清醒的头脑。还有它们的局限性。统计和概率工具越来越多地提供了限制对这些数据集的信心的方法，并指导我们如何使用它们来稳健地重建进化和环境历史的主要趋势（Sperling 等人，2015 年；安德森等人，2018 年）。尽管很少有人会质疑地层和贝壳化石记录的不完美性（Sadler，1981），但我们不能忽视即使是非凡的 Lagerstättengrade 化石也经历了腐烂和改变——事实上，许多特殊保存的途径都需要腐烂——并且是由可以混淆原始解剖和生态信息并引入形态变异性的埋藏过程形成（Briggs，2003）。不可否认，非凡的化石可以对过去的生活产生非凡的见解。然而，作为一个社区，我们必须继续认识到，如果我们希望将异常值与真正代表地球历史的模式区分开来，仔细检查化石记录的所有组成部分——身体或痕迹，骨骼或软组织——应以广泛样本集的表征而不是孤立的样本为前提（Evans 等人，2017；Tarhan，2018）。如果我们的目标是重建地球表面环境不断变化的条件如何塑造了生命的进化轨迹——以及反过来，新的生态创新和创新的出现如何改造了地球的景观（参见 Erwin，2015 年）——任何考虑化石数据必须发生在地质背景下，并以古环境和埋藏学框架为基础。