"Sedimentary phosphorite, fertilizer ore, and the evolving phosphorus cycle: an integrated approach"

磷矿是一种富含磷的海洋化学沉积物，是一种不可再生的化肥矿石。磷是一种形成骨骼和DNA的生物必需元素，对细胞能量转移至关重要，并在地质时间尺度上限制生物生产力。由于其降水与生物密切相关，磷岩不仅是地质过程的记录器，而且与生命的进化和海洋-大气的发展密切相关。研究的重点是新元古代-古生代的生磷幕，这是地球上第二个主要的磷矿沉积时期。认识到与地球系统的重大重组相对应的四个主要的磷矿沉积事件。研究位于加拿大东部和西部的寒武纪和奥陶系地层，以及巴西的新元古代、志留纪和泥盆纪岩石。这些沉积物是磷循环系统的一部分，在海洋-大气氧化的最后阶段之前、期间和之后，与动物的出现和多样化有关。确切的原因尚不清楚，但关于P周期变化的猜测被归因于戏剧性的气候波动、生物进化、超大陆的合并和解体以及海洋-大气成分和环流的变化。了解生物有效磷、海洋氧化还原状态和埃迪卡拉纪和寒武纪辐射之间的关系是一个主要的焦点。这将使用沉积学、层序地层学和地球化学相结合的综合方法来完成，以约束磷矿的沉积和沉积后背景。最近的大多数研究都是基于地球化学指标，这些指标是在沉积学、海洋学、成岩和变质作用之外解释的。对加拿大来说意义重大的是，这种独特的方法将通过开发对新不伦瑞克、魁北克和不列颠哥伦比亚省鲜为人知的矿藏的专业知识，提高我国获得稳定和安全的磷矿来源的能力。

Phosphorite is a marine chemical sediment rich in phosphorus and a non-renewable fertilizer ore. Phosphorus is a bioessential element that forms skeletons and DNA, is essential for cellular energy transfer, and limits biologic productivity over geologic timescales. Since its precipitation is so closely tied to biology, phosphorite is not simply a recorder of geologic processes, but intimately involved in the evolution of life and ocean-atmosphere development. Research is focused on the Neoproterozoic-Paleozoic phosphogenic episode, Earth's second major period of phosphorite deposition. Four major episodes of phosphorite deposition are recognized that correspond to significant reorganizations of the Earth system. Studies are located in Cambrian and Ordovician strata of eastern and western Canada, and in Neoproterozoic, Silurian, and Devonian rocks of Brazil. These deposits are part of a system of P cycling prior to, during, and after the final stages of ocean-atmosphere oxygenation related to the emergence and diversification of animals. Precise causes remain unclear, but speculation about variations in the P cycle have been attributed to dramatic climate fluctuations, biologic evolution, supercontinent amalgamation and breakup, as well as changing ocean-atmosphere composition and circulation. Understanding the relationship between bioavailable P, ocean redox state, and the Ediacaran and Cambrian radiations is a primary focus. This will be done using an integrated approach combining sedimentology, sequence stratigraphy, and geochemistry to constrain the depositional and postdepositional context of phosphorites. Most recent studies are based on geochemical proxies, which are interpreted outside the sedimentologic, oceanographic, diagenetic, and metamorphic aspects of hosting sedimentary rocks. Significant to Canada is that this unique approach will enhance our nation's ability to acquire a stable and secure source of phosphorite by developing expertise on poorly understood deposits in New Brunswick, Quebec, and British Columbia.