Baozeng Xie currently studies at the Institute of Earth Sciences, China University of Geosciences (Beijing). Baozeng does research in Paleontology, Geochemistry and Oceanography.
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1.44 Ga Oxygenation Event: Evidence From the Southern Margin of North China
Journal of geophysical research. Biogeosciences, Apr 1, 2024
Mineralogy-based stepwise dissolution of dolomitic limestone reveals high iodine content in water-column precipitated calcite and well‑oxygenated shallow seawater during the ~1.57 Ga oxygenation event
Enhanced Weathering Triggered the Transient Oxygenation Event at ∼1.57 Ga
Geophysical Research Letters, Aug 9, 2022
The mid‐Proterozoic (∼1.8–0.8 Ga) is characterized by low atmospheric oxygen and pervasive oceani... more The mid‐Proterozoic (∼1.8–0.8 Ga) is characterized by low atmospheric oxygen and pervasive oceanic anoxia, with transient oxygenation events. One of the oxygenation events happened at ∼1.57 Ga, during which atmospheric O2 may have reached ≥4% present atmospheric level (PAL) and thus promoted the evolution of multi‐cellular eukaryotes. The cause of this oxygenation event, however, remained unknown. Here, we report δ202Hg, ∆199Hg, P concentration, Rb/Al, and εNd(t) data across the ∼1.57 Ga oxygenation event in the Gaoyuzhuang Formation of North China. The positive δ202Hg, εNd(t), and negative Δ199Hg shifts, plus the accompanied peaks in Rb/Al, P, and I/(Ca + Mg), suggest that this oxygenation event was likely resulted from enhanced weathering of intermediate to mafic rocks, which may have promoted primary production via increasing P influx to the ocean and led to the rise in oxygen levels. The data indicate that enhanced weathering input could trigger transient oxygenation events during the mid‐Proterozoic.
Enhanced weathering triggered the transient oxygenation event at ~1.57 Ga
The mid‐Proterozoic (∼1.8–0.8 Ga) is characterized by low atmospheric oxygen and pervasive oceani... more The mid‐Proterozoic (∼1.8–0.8 Ga) is characterized by low atmospheric oxygen and pervasive oceanic anoxia, with transient oxygenation events. One of the oxygenation events happened at ∼1.57 Ga, during which atmospheric O2 may have reached ≥4% present atmospheric level (PAL) and thus promoted the evolution of multi‐cellular eukaryotes. The cause of this oxygenation event, however, remained unknown. Here, we report δ202Hg, ∆199Hg, P concentration, Rb/Al, and εNd(t) data across the ∼1.57 Ga oxygenation event in the Gaoyuzhuang Formation of North China. The positive δ202Hg, εNd(t), and negative Δ199Hg shifts, plus the accompanied peaks in Rb/Al, P, and I/(Ca + Mg), suggest that this oxygenation event was likely resulted from enhanced weathering of intermediate to mafic rocks, which may have promoted primary production via increasing P influx to the ocean and led to the rise in oxygen levels. The data indicate that enhanced weathering input could trigger transient oxygenation events during the mid‐Proterozoic.
Banded iron formations (BIFs) are iron-rich marine chemical sedimentary rocks, and their mineralo... more Banded iron formations (BIFs) are iron-rich marine chemical sedimentary rocks, and their mineralogy and geochemistry can be used to gain insights into ancient ocean chemistry and biospheric evolution. Magnetite is the major iron-bearing mineral in many BIFs (particularly in the Archean) and is variably interpreted to be of primary, early diagenetic, or metamorphic origin. Different genetic interpretations for magnetite lead to divergent pictures of the Precambrian Earth system and its evolutionary models through time. The Baizhiyan Formation of the Neoarchean Wutai Group (Shanxi, North China) features magnetite-bearing, Algoma-type BIFs deposited ca. 2.52 Ga, in the lead-up to a major period of global iron formation deposition in the Paleoproterozoic. Abundant magnetite crystals found in the silica-rich bands of these BIFs show euhedral, hexagonal morphology. We suggest that this hexagonal magnetite likely represents pseudomorphs after green rust, a mixed-valence iron hydroxy-salt f...
Mesoproterozoic oxygenation event: From shallow marine to atmosphere
GSA Bulletin
Oxygen availability is crucial for the evolution of eukaryotes in geological history, but the red... more Oxygen availability is crucial for the evolution of eukaryotes in geological history, but the redox conditions of the mid-Proterozoic atmospheric-oceanic system remain vigorously debated. Previous geochemical studies suggested a very low mid-Proterozoic atmospheric oxygen level of probably below 0.1−1% of the present atmospheric level (PAL) with weakly oxygenated surface ocean, which may have suppressed the early evolution of eukaryotes in the ocean. A recent study, however, revealed a pulsed oxygenation event that was recorded in shallow marine carbonate of the middle Gaoyuzhuang Formation (at ca. 1.57 Ga, North China) with atmospheric pO2 of up to ≥4% PAL based on iodine speciation. This event is associated with the earliest known multi-cellular eukaryotic fossils. To elucidate whether this pulsed oxygenation was limited to shallow local seawaters or could also reflect an increase in atmospheric oxygen, chromium (Cr), and carbonate-associated sulfate (CAS), sulfur isotopes in the ...
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