How oxygen levels in Earth's atmosphere and oceans evolved has always been a central question in Earth System Science. Researchers have developed numerous tracers to tackle this question, utilizing geochemical characteristics of different elements. Iodine incorporated in calcium carbonate (including biogenic) minerals, reported as I/Ca, is a proxy for dissolved oxygen in seawater. Here we review the rationale behind this proxy, its recent applications and some potential future research directions.
The remarkable scientific story of how Earth became an oxygenated planet The air we breathe is twenty-one percent oxygen, an amount higher than on any other known world. While we may take our air for granted, Earth was not always an oxygenated planet. How did it become this way? Donald Canfield—one of the world's leading authorities on geochemistry, earth history, and the early oceans—covers this vast history, emphasizing its relationship to the evolution of life and the evolving chemistry of the Earth. Canfield guides readers through the various lines of scientific evidence, considers some of the wrong turns and dead ends along the way, and highlights the scientists and researchers who have made key discoveries in the field. Showing how Earth’s atmosphere developed over time, Oxygen takes readers on a remarkable journey through the history of the oxygenation of our planet.
In this thesis we use a model of biogeochemical cycling and laboratory experiments to explore the processes that stabilize pO2 at different levels over Earth history. We find that a suite of negative feedbacks, including the oxygen-sensitivity of organic carbon burial, allow the stability of oxygen at modern levels. These feedbacks leave pO2 very insensitive to most aspects of the biogeochemical system, such that stable, Proterozoic levels of pO2 can only be explained by a smaller supply of phosphorus to the biosphere at that time. Experimental results show that inorganic scavenging processes, which compete with biology for phosphorus, may be more effective in low-oxygen environments due to differences in iron-redox cycling. We explore redox dynamics in the Archean by coupling our biogeochemical model to a hydrogen escape calculation that incorporates the effects of changing oxygen levels on thermosphere composition and temperature. We find that the Archean was characterized by several different steady states of oxygen, each corresponding to a different stage in the evolution of life. Furthermore, interactions between the cycles of carbon, oxygen, iron and calcium give rise to a previously unrecognized positive feedback. Our model results show that this feedback allows Archean pO2 to increase rapidly to a new steady state at Proterozoic levels, given a large enough perturbation. The high levels of atmospheric carbon dioxide following a Snowball Earth glacial event do act as such a trigger in our simulations, providing a hypothesis for the apparent synchronicity between the GOE and the Paleoproterozoic Snowball glacials.
Earth’s present-day environments are the outcome of a 4.5 billion year period of evolution reflecting the interaction of global-scale geological and biological processes. Punctuating that evolution were several extraordinary events and episodes that perturbed the entire Earth system and led to the creation of new environmental conditions, sometimes even to fundamental changes in how planet Earth operated. Volume 3: Global Events and the Fennoscandian Arctic Russia - Drilling Earth Project represents another kind of illustrated journey through the early Palaeoproterozoic, provided by syntheses, reviews and summaries of the current state of our understanding of a series of global events that resulted in a fundamental change of the Earth System from an anoxic to an oxic state. The book discusses traces of life, possible causes for the Huronian-age glaciations, addresses radical changes in carbon, sulphur and phosphorus cycles during the Palaeoproterozoic, and provides a comprehensive description and a rich photo-documentation of the early Palaeoproterozoic supergiant, petrified oil-field. Terrestrial environments are characterised through a critical review of available data on weathered and calichified surfaces and travertine deposits. Potential implementation of Ca, Mg, Sr, Fe, Mo, U and Re-Os isotope systems for deciphering Palaeoproterozoic seawater chemistry and a change in the redox-state of water and sedimentary columns are discussed. The volume considers in detail the definition of the oxic atmosphere, possible causes for the oxygen rise, and considers the oxidation of terrestrial environment not as a single event, but a slow-motion process lasting over hundreds of millions of years. Finally, the book provides a roadmap as to how the FAR-DEEP cores may facilitate future interesting science and provide a new foundation for education in earth-science community. Welcome to the illustrative journey through one of the most exciting periods of planet Earth!
The Earth that sustains us today was born out of a few remarkable, near-catastrophic revolutions, started by biological innovations and marked by global environmental consequences. The revolutions have certain features in common, such as an increase in complexity, energy utilization, and information processing by life. This book describes these revolutions, showing the fundamental interdependence of the evolution of life and its non-living environment. We would not exist unless these upheavals had led eventually to 'successful' outcomes - meaning that after each one, at length, a new stable world emerged. The current planet-reshaping activities of our species may be the start of another great Earth system revolution, but there is no guarantee that this one will be successful. The book explains what a successful transition through it might look like, if we are wise enough to steer such a course. This book places humanity in context as part of the Earth system, using a new scientific synthesis to illustrate our debt to the deep past and our potential for the future.
This book provides a comprehensive treatment of the chemical nature of the Earth’s early surface environment and how that led to the origin of life. This includes a detailed discussion of the likely process by which life emerged using as much quantitative information as possible. The emergence of life and the prior surface conditions of the Earth have implications for the evolution of Earth’s surface environment over the following 2-2.5 billion years. The last part of the book discusses how these changes took place and the evidence from the geologic record that supports this particular version of early and evolving conditions.
Earth’s present-day environments are the outcome of a 4.5 billion year period of evolution reflecting the interaction of global-scale geological and biological processes punctuated by several extraordinary events and episodes that perturbed the entire Earth system. One of the earliest and arguably greatest of these events was a substantial increase (orders of magnitude) in the atmospheric oxygen abundance, sometimes referred to as the Great Oxidation Event. Volume 2: The Core Archive of the Fennoscandian Arctic Russia - Drilling Early Earth Project provides a description of the newly generated archive hosting ICDP's FAR-DEEP drill cores through key geological formations in Russian Fennoscandia. The book contains several hundred high-quality, representative photographs illustrating 3650 m of fresh, uncontaminated core documenting a series of global palaeoenvironmental upheavals linked to the Great Oxidation Event. The core exhibits sedimentary and volcanic formations that record a transition from anoxic to oxic Earth surface environments, the first global glaciation (the Huronian glaciation), an unprecedented perturbation of the global carbon cycle (the Lomagundi-Jatulian Event), a radical increase in the size of the seawater sulphate reservoir, an apparent upper mantle oxidising event, the Earth's earliest documented sedimentary phosphates, one of the greatest accumulations of organic matter (the Shunga Event) and generation of the Earth's earliest supergiant petroleum deposit. The volume highlights the potential of the FAR-DEEP core archive for future research of the Great Oxidation Event and the biogeochemical cycles operating during that time. Welcome to the illustrative journey through one of the most exciting periods of planet Earth! Earth’s present-day environments are the outcome of a 4.5 billion year period of evolution reflecting the interaction of global-scale geological and biological processes punctuated by several extraordinary events and episodes that perturbed the entire Earth system. One of the earliest and arguably greatest of these events was a substantial increase (orders of magnitude) in the atmospheric oxygen abundance, sometimes referred to as the Great Oxidation Event. Volume 2: The Core Archive of the Fennoscandian Arctic Russia - Drilling Early Earth Project provides a description of the newly generated archive hosting ICDP's FAR-DEEP drill cores through key geological formations in Russian Fennoscandia. The book contains several hundred high-quality, representative photographs illustrating 3650 m of fresh, uncontaminated core documenting a series of global palaeoenvironmental upheavals linked to the Great Oxidation Event. The core exhibits sedimentary and volcanic formations that record a transition from anoxic to oxic Earth surface environments, the first global glaciation (the Huronian glaciation), an unprecedented perturbation of the global carbon cycle (the Lomagundi-Jatulian Event), a radical increase in the size of the seawater sulphate reservoir, an apparent upper mantle oxidising event, the Earth's earliest documented sedimentary phosphates, one of the greatest accumulations of organic matter (the Shunga Event) and generation of the Earth's earliest supergiant petroleum deposit. The volume highlights the potential of the FAR-DEEP core archive for future research of the Great Oxidation Event and the biogeochemical cycles operating during that time. Welcome to the illustrative journey through one of the most exciting periods of planet Earth! Earth’s present-day environments are the outcome of a 4.5 billion year period of evolution reflecting the interaction of global-scale geological and biological processes punctuated by several extraordinary events and episodes that perturbed the entire Earth system. One of the earliest and arguably greatest of these events was a substantial increase (orders of magnitude) in the atmospheric oxygen abundance, sometimes referred to as the Great Oxidation Event. Volume 2: The Core Archive of the Fennoscandian Arctic Russia - Drilling Early Earth Project provides a description of the newly generated archive hosting ICDP's FAR-DEEP drill cores through key geological formations in Russian Fennoscandia. The book contains several hundred high-quality, representative photographs illustrating 3650 m of fresh, uncontaminated core documenting a series of global palaeoenvironmental upheavals linked to the Great Oxidation Event. The core exhibits sedimentary and volcanic formations that record a transition from anoxic to oxic Earth surface environments, the first global glaciation (the Huronian glaciation), an unprecedented perturbation of the global carbon cycle (the Lomagundi-Jatulian Event), a radical increase in the size of the seawater sulphate reservoir, an apparent upper mantle oxidising event, the Earth's earliest documented sedimentary phosphates, one of the greatest accumulations of organic matter (the Shunga Event) and generation of the Earth's earliest supergiant petroleum deposit. The volume highlights the potential of the FAR-DEEP core archive for future research of the Great Oxidation Event and the biogeochemical cycles operating during that time. Welcome to the illustrative journey through one of the most exciting periods of planet Earth!
Earth’s present-day environments are the outcome of a 4.5 billion year period of evolution reflecting the interaction of global-scale geological and biological processes punctuated by several extraordinary events and episodes that perturbed the entire Earth system. One of the earliest and arguably greatest of these events was a substantial increase (orders of magnitude) in the atmospheric oxygen abundance, sometimes referred to as the Great Oxidation Event. Volume 1: The Palaeoproterozoic of Fennoscandia as Context for the Fennoscandian Arctic Russia - Drilling Earth Project describes the implementation of the FAR-DEEP drilling project in Arctic Russia. It summarises the knowledge of more than 50 years of largely Russian-led fieldwork, information hitherto virtually unavailable in the west, and provides geological description of drilling areas with an overwhelming illustration of rocks by high-quality, representative photographs. The volume offers a comprehensive review and rich photo-illustration of palaeotectonic, palaeogeographic and magmatic evolution of the Fennoscandian Shield in the early Palaeoproterozoic, and link the evolution of the shield to the emergence of an aerobic Earth system. The volume unfolds the event-based Fennoscandian chronostratigraphy and discusses the chronology of the Palaeoproterozoic global events as the base for a new subdivision of Palaeoproterozoic time. Welcome to the illustrative journey through one of the most exciting periods of planet Earth!
