Genming Luo

Increasing oxygenation of the early Ediacaran Ocean is thought to have been responsible for the emergence of early animals. Although geochemical studies have suggested periods of oceanic oxygenation in the Ediacaran, direct evidence for seafloor oxygenation has been lacking. Here, we report frequent occurrences of distinctive, sub-millimetric, and...

The Hangenberg Crisis coincided with a large decline of biodiversity and widespread anoxia in the end‐Devonian ocean. Previous research attributed marine anoxia to the spread of deeply‐rooted plants and/or increased volcanism on the continents, but crucial links have not been thoroughly explored. Herein, we propose enhanced weathering as a key trig...

The initial accumulation of atmospheric oxygen is marked by the unprecedented positive δ13Ccarb excursions of the Lomagundi-Jatuli Event (LJE) and records an interval of abnormal O2 production through elevated rates of organic carbon burial. Emerging evidence suggests that the post-LJE atmosphere-ocean system might have suffered a significant deoxy...

Nitrogen (N) is an essential element for living organisms that limits the productivity of biospheres through time. It has been suggested that ferruginous anoxic waters could enhance the fraction of dissimilatory nitrate reduction to ammonium (DNRA) and conserve the biologically available N in the ecosystems. However, the role of mixed-valent iron [...

It is not well understood how, in the immediate aftermath of the Sturtian Snowball Earth, marine sulfur cycling resulted in a global distribution of sedimentary pyrite with δ³⁴S values higher than coeval seawater. Here, we analyze the quadruple sulfur isotope systematics of organic-bound sulfur (OS) from the lowermost post-Sturtian Datangpo Formati...

This paper briefly introduces the conception and research history of the Great Oxidation Event (GOE) in the early Paleoproterozoic and summarizes the primary geological and geochemical records of this event. On the basis of these, we overview the significant progress in three fields of the GOE: the timing and process of its startup, its mechanisms,...

Char and polycyclic aromatic hydrocarbons (PAHs), which can serve as proxies for wildfire frequency and/or intensity, are widely present in Permian-Triassic boundary (PTB) strata, providing information on volcanism or on climatic control of fuel availability (linked to vegetation type and density) or combustibility (linked to aridity). Here, we pre...

The late Mesoproterozoic Era (1300–1000 Ma) was a critical period that witnessed the origin and early evolution of multicellular eukaryotes. Multiple studies have reported observations that the carbon isotope composition of carbonate (δ¹³Ccarb) underwent a substantial increase after ca. 1250 Ma. The high δ¹³Ccarb values suggest that the fraction of...

Significance The permanent disappearance of mass-independent sulfur isotope fractionation (S-MIF) from the sedimentary record has become a widely accepted proxy for atmospheric oxygenation. This framework, however, neglects inheritance from oxidative weathering of pre-existing S-MIF–bearing sedimentary sulfide minerals (i.e., crustal memory), which...

The evolution of deep-time marine biological pumps (BPs) is critical to our understanding of the processes and mechanisms of the present-day carbon cycle. The Late Paleozoic-Early Mesozoic was a key period for the formation of modern marine biological pumps. Two types of Phanerozoic biological pump have been recognized: Paleozoic (Paleozoic-Middle...

The Ediacaran Period (~635-539 Ma) witnessed the largest negative inorganic carbon isotope (δ 13 C carb) excursion in Earth's history (i.e., the Shuram Excursion), which is characterized by decoupling from the organic carbon isotope (δ 13 C org) record. The cause(s) of this event remains highly debated. Here, we report a major (~8-9-Myr-long) episo...

Biotic carbon pumps in marine systems discussed here mainly include the well-known biological pump (BP) and microbial carbon pump (MCP). Through these carbon pumps, microorganisms have made a great contribution to rising atmospheric oxygen levels, the sequestration of atmospheric carbon and the decrease of air temperature in Earth history, which fi...

The largest mass extinction since the advent of animals occurred during the Permian-Triassic (P-Tr) transition, ca. 252 Ma, and is commonly attributed to the eruption of the Siberian Traps large igneous province. However, the direct killing mechanism is still debated. In this study, we investigated marine redox conditions of the intermediate water...

Combustion-derived polycyclic aromatic hydrocarbons (PAHs) are frequently used as molecular proxies for wildfire in recent and ancient sediments. Here, we document the abundances of four hydrocarbon compounds, i.e., phenanthrene (Phe), benzo[e]pyrene (BeP), benzo[ghi]perylene (Bpery), and coronene (Cor), across the Permian–Triassic boundary (PTB) i...

Significance Massive Paleozoic and Precambrian dolostone successions have long puzzled geologists in light of the kinetic barriers that inhibit low-temperature dolomite nucleation and precipitation (i.e., the “dolomite problem”). Significantly, the widely accepted hypothesis that such massive dolomites are the product of burial–hydrothermal dolomit...

The end-Devonian mass extinction (~359 Ma) substantially impacted marine ecosystems and shaped the roots of modern vertebrate biodiversity. Although multiple hypotheses have been proposed, no consensus has been reached about the mechanism inducing this extinction event. In this study, I/Ca ratio of carbonate was used to unravel the changes in local...

The unprecedented positive δ¹³C excursion in carbonates deposited between 2.2 and 2.0 Ga, known as the Lomagundi-Jatuli Event (LJE), has been documented globally and linked to the rise of atmospheric oxygen. Increasing oxidation inevitably changed the atmosphere-hydrosphere system, but few chemostratigraphic or quantitative constraints for the afte...

Dolomite nucleation and subsequent crystallization are kinetically-controlled processes. Modern dolomite-forming environments provide clues to the trigger factors that facilitate dolomite formation under Earth surface conditions. It has been documented that certain types of benthic microorganisms promoted the precipitation of protodolomite from sed...

The Late Paleozoic (Early Devonian to Middle Permian) was an interval of profound changes in Earth-surface systems, reflected in dynamic interplay among the biosphere, hydrosphere, atmosphere, and geosphere. Major events transpired, including the colonization of landmasses by vascular plants, the assembly of the supercontinent Pangea, two first-ord...

Rising oceanic and atmospheric oxygen levels through time have been crucial to enhanced habitability of surface Earth environments. Few redox proxies can track secular variations in dissolved oxygen concentrations ([O2]) around threshold levels for metazoan survival in the upper ocean. We present an extensive compilation of iodine to calcium ratios...

The cause of the Triassic-Jurassic (Tr-J) boundary biotic crisis, one of the ‘Big Five’ mass extinctions of the Phanerozoic, remains controversial. In this study, we analyzed multiple sulfur-isotope compositions (δ³³S, δ³⁴S and δ³⁶S) of pyrite and Spy/TOC ratios in two Tr-J successions (Mariental, Mingolsheim) from the European Epicontinental Seawa...

The marine nitrogen cycle is dominated by redox-controlled biogeochemical processes and, therefore, is likely to have been revolutionised in response to Earth-surface oxygenation. The details, timing, and trajectory of nitrogen cycle evolution, however, remain elusive. Here we couple nitrogen and carbon isotope records from multiple drillcores thro...

Lipids can survive long geological intervals within sediments and provide a unique tool that allows the reconstruction of past organismic diversity and environmental conditions. The lipids discussed in this review include all substances produced by organisms that are insoluble in water but extractable by organic solvents. Lipid biomarkers refer to...

The Ediacaran Shuram Excursion (SE) was a major negative δ¹³Ccarb excursion (to-12‰) thought to reflect significant atmosphericoceanic oxidation, although direct evidence is limited. Here, we model changes in seawater sulfate concentrations ([SO²⁻4]sw) during the SE by using paired S-isotope data of cogenetic sedimentary pyrite and carbonate-associ...

Microbial communities are known to expand as a result of environmental deterioration during mass extinctions, but differences in microbial community changes between extinction events and their underlying causes have received little study to date. Here, we present a systematic investigation of microbial lipid biomarkers spanning ∼20 Myr (Middle Perm...

Records of the Ediacaran carbon cycle (635-541 million years ago) include the Shuram excursion (SE), the largest negative carbonate carbon isotope excursion in Earth history (down to -12‰). The nature of this excursion remains enigmatic given the difficulties of interpreting a perceived extreme global decrease in the δ(13) C of seawater dissolved i...

The sponge biomarker hypothesis argues that 24-isopropylcholestanes preserved in Neoproterozoic-age rocks are "molecular fossils" left behind by marine sponges. Despite genetic and geologic support for this hypothesis, 24-isopropylcholestane has never been reported from a sponge body fossil. This lack of direct evidence regarding the source of spon...

The incursion of euxinic waters into the ocean-surface layer is hypothesized to have been an important killing agent during the end-Permian mass extinction. However, both the causes and extent of oceanic euxinia during this crisis remain poorly known, making assessment of its role in the mass extinction difficult. Here, we document the distribution...

Molecular oxygen (O[subscript 2]) is, and has been, a primary driver of biological evolution and shapes the contemporary landscape of Earth’s biogeochemical cycles. Although “whiffs” of oxygen have been documented in the Archean atmosphere, substantial O2 did not accumulate irreversibly until the Early Paleoproterozoic, during what has been termed...

Zhang et al. (1) recently proposed atmospheric oxygen levels of ∼4% present atmospheric levels (PAL) based on modeling a paleoenvironment reconstructed from trace metal and biomarker data from the 1,400 Ma Xiamaling Formation in China. Intriguingly, this pO2 level is above the threshold oxygen requirements of basal animals and clashes with evidence...

Oxygenation has widely been viewed as a major factor driving the emergence and diversification of animals. However, links between early animal evolution and shifts in surface oxygen levels have largely been limited to extrapolation of paleoredox conditions reconstructed from unfossiliferous strata to settings in which contemporaneous fossils were p...

To improve regional and intercontinental correlation of the uppermost Devonian–lowermost Carboniferous, we examined the conodont faunas and carbon isotopic records of the Tangbagou Formation in the Qilinzhai section, southern Guizhou, South China. The Tangbagou Formation is a succession of mixed carbonate–siliciclastic rocks that accumulated on a s...

Unresolved complex mixtures (UCM) in shales have important implications for organic matter formation and diagenesis. However, their origin is not well understood, one important reason for this is lacking the knowledge of their molecular compositions. Here, using the comprehensive two-dimensional gas chromatography (GC×GC) coupled with time-of-fligh...

Long-term secular variation in seawater sulfate concentrations ([SO42−]SW) is of interest owing to its relationship to the oxygenation history of Earth's surface environment. In this study, we develop two complementary approaches for quantification of sulfate concentrations in ancient seawater and test their application to late Neoproterozoic (635...

The composition of microbial communities and their relationship to ocean redox structure in the Precambrian are topics of continuing interest in geobiology. Our knowledge of organismic diversity and environmental conditions during this time are mostly based on fragmentary paleontological and geochemical records and might be skewed accordingly. In N...

The conodont faunas of Tournaisian shallow-water carbonates from central Guangxi are described mainly for biostratigraphic purposes. A complete series of samples was collected from the Long’an and Du’an formations in the Long’an section. These formations are characterized by lime-mudstone, skeletal and peloidal wackestone, packstone and grainstone...

Long-term secular variation in seawater sulfate concentrations ([SO42–]SW) is of interest owing to its relationship to the oxygenation history of Earth's surface environment, but quantitative approaches to analysis of this variation remain underdeveloped. In this study, we develop two complementary approaches for assessment of the [SO42–] of ancien...

The Late Paleoproterozoic to Early Mesoproterozoic (from ∼1700 Ma to ∼1300 Ma) was highlighted by the assembly of the Nuna supercontinent, expansion of euxinic marine environments and apparent stasis in the diversity of eukaryotes. The isotopic composition of carbonate carbon (δ13Ccarb) was surprisingly constant during this interval, but little is...

The biosphere interacts and co-evolves with natural environments. Much is known about the biosphere’s response to ancient environmental perturbations, but less about the biosphere’s influences on environmental change through earth history. Here, we discuss the roles of microbes in environmental changes during the critical Permian-Triassic (P-Tr) tr...

Following the Ediacaran metazoan radiation, the “Cambrian Explosion” set up the major framework of todays’ animal phyla as well as modern marine ecosystem. Here, we present a preliminary investigation on the temporal and spatial (from shallow to deep waters) variations of the early Cambrian ocean chemistry in South China through analyzing a Fe-S-C...

The marine sulfur cycle is intimately linked to global carbon fluxes, atmospheric composition, and climate, yet relatively little is known about how it responded to the end-Permian biocrisis, the largest mass extinction of the Phanerozoic. Here, we analyze carbonate-associated-sulfate (CAS) from three Permo–Triassic sections in South China in order...

An integrated study of the litho-, bio-, and chemostratigraphy of the Devonian–Carboniferous boundary at four sections (Qilinzhai, Malanbian, Gedongguan and Long'an) in South China was undertaken in order to better understand paleoenvironmental changes and controls on δ13Ccarb variation during the Hangenberg Crisis. Sedimentological data record a m...

Microbialites flourished globally immediately following the latest Permian mass extinction. In this study, lipid biomarker records were analyzed in the Cili section (Hunan Province, South China) in order to determine the types of microbes involved in microbialite formation and their response to contemporaneous environmental changes. Various biomark...

High-resolution stratigraphic records through the Permian–Triassic boundary (PTB) interval of the global stratotype section and point (GSSP) at Meishan, Zhejiang Province, China reveal that the PTB crisis was not a single, abrupt catastrophe. A bed-by-bed analysis of environmental and biotic changes makes clear that the crisis can be resolved into...

The significant achievements and future research orientation of biogeochemistry during the decade of 2001 to 2010 are briefly reviewed. Some carbon pools and related flux have been quantified in modern marine/ocean and land ecosystems. New microbial functional groups involved in sulfur and nitrogen cycles of modern ecosystems have been identified....

The leaf waxes of 23 woody bamboo species of three subgenera, Dendrocalamus, Bambusa and Dendrocalamopsis, from the Xishuangbanna tropical rain forest in Southwest China were analyzed by gas chromatography and coupled gas chromatography–mass spectrometry. The waxes of the Dendrocalamus species are dominated by C27 and C29n-alkanes and their average...

High-resolution oxygen isotope records document the timing and magnitude of global warming across the Permian-Triassic (P-Tr) boundary. Oxygen isotope ratios measured on phosphate-bound oxygen in conodont apatite from the Meishan and Shangsi sections (South China) decrease by 2 parts per thousand in the latest Permian, translating into low-latitude...

Microbes are well-known for their great diversity and abundance in modern natural environments. They also are believed to provide critical links among higher organisms and their associated environments. However, the low diversity of morphological features and structures of ancient microbes preserved in sediments and rocks make them difficult to ide...

Previous work indicates that a variety of microbes bloomed in the oceans after the end-Permian faunal mass extinction, but evidence is sporadically documented. Thus, the nature and geographic distribution of such microbes and their associations are unclear, addressed in this study using a series of biomarker groups. On the basis of microbial biomar...

The stable isotope record of marine carbon indicates that the Proterozoic Eon began and ended with extreme fluctuations in the carbon cycle. In both the Paleoproterozoic [2500 to 1600 million years ago (Ma)] and Neoproterozoic (1000 to 542 Ma), extended intervals of anomalously high carbon isotope ratios (δ(13)C) indicate high rates of organic matt...

The carbon (delta C-13(org)) and nitrogen (delta N-15) isotopic compositions of bulk organic matter were analyzed in two high-resolution Permian-Triassic transitional sections containing microbialite in south China. The results from these shallow-marine sections show that an abrupt negative shift in delta N-15, from similar to+3% to similar to 0%,...

Large perturbations to the global carbon cycle occurred during the Permian–Triassic boundary mass extinction, the largest extinction event of the Phanerozoic Eon (542Ma to present). Controversy concerning the pattern and mechanism of variations in the marine carbonate carbon isotope record of the Permian–Triassic crisis interval (PTCI) and their re...

The cataclysmic end-Permian mass extinction was immediately followed by a global expansion of microbial ecosystems, as demonstrated by widespread microbialite sequences (disaster facies) in shallow water settings. Here we present high-resolution carbonate carbon (δ13Ccarb) and carbonate-associated sulfate–sulfur isotope (δ34SCAS) records from the m...