23 Apr 2021

EarthTalks at GEOCENTER Denmark

The Section for Geobiology at GLOBE has helped organizing the spring season of EarthTalks 2021, and we welcome interested students and researchers to participate over Zoom (link below). The talks will not be recorded. Earth Talks Lecture Series – Spring 2021 Friday afternoons 14:00-15:00 DK time (sharp) 23/4 – Prof. Sigur∂ur Gislason, University of Iceland The […]

28 Mar 2021

Did land plants alter erosion rates on Earth?

A discussion arises from the recent review article in Chemical Geology, where Tais W. Dahl and Susanne Arens concluded that land plants did not forever increase the physical weathering rates of the continental crust. This conclusion was reached from the records of preserved sediment rock volume and the timing of plant-assisted weathering as recorded in […]

27 Jan 2021

The Carlsberg foundation supports field work in Siberia

The Carlsberg Foundation is sponsoring field work led by Tais W. Dahl to Arctic Siberia, where an important climate catastrophe is recorded in marine sedimentary rocks. The expedition will bring back data and samples deposited in the oceans during a climate event that caused sulfidic anoxia to suddenly expand in warming oceans and wipe out […]

12 Oct 2020

Press release: Early animals had a shorter day

In a brief story published in Danish on Videnskab.dk, Aske L. Sørensen and Tais W. Dahl explain one of the consequences of their latest EPSL paper: Earth was spinning faster 500 million years ago. The scientific paper entitled “Astronomically forced climate change in the Late Cambrian” documents Milankovitch-cycles in two drill cores through the Alum […]

4 Aug 2020

Tracing global ocean oxygenation from calcitic brachiopods

The uranium isotope composition of seawater provide insights to how much sediment burial occurs globally in anoxia settings. Therefore, it is desirable to measure uranium isotopes to track the oxygenation state of the oceans through geological time. However, there is currently no geological archive that can reliably record the composition of ancient seawater. Calcitic brachiopods […]

3 Jul 2020

Review: Tracing the global ocean oxygenation state with uranium isotopes

May 21, 2020 The stable isotope fractionation of uranium in nature – unrelated to radioactive decay – has led to a profound tool for tracing O2 in the Earth’s oceans from the geological record. Feifei Zhang has gathered many of the leading researchers in the community to provide a summary of how uranium isotopes are […]

14 May 2020

New paper: The impact of land plant evolution on Earth’s climate and oxygenation state

The colonization of land by plantss, fungi and animals has had a profound impact on Earth’s climate and oxygenation state. In a comprehensive review paper, we have summarize the current state of knowledge and compiled available evidence in support that terrestrial life has caused: Atmospheric CO2 decline and climatic cooling (permanent transition) Atmospheric O2 rise […]

18 Apr 2020

New GCA paper: Volcanic eruptions triggered repeated marine anoxia and reveal global-scale feedbacks during the Permian-Triassic mass extinction 250 million yeers ago

The largest animal extinction event in recorded history occurred 251 Ma at the Permian-Triassic boundary coinciding with expansive marine anoxia. In a new study, led by postdoc Feifei Zhang, of a greatly expanded dolomite section from the Carnic Alps, Austria, marine anoxia is found to have expanded in two pulses separated by ~100,000 years. Global […]

1 Mar 2020

Expansive ocean anoxia during the Late Devonian Hangenberg event

Marine animal extinction events have occurred episodically over the past 550 million years with expansive marine anoxia as the proximate kill mechanism. New evidence from a carbonate section in South China (Long’an) shows that the Late Devonian Hangenberg event should be counted as one such events. Postdoc Feifei Zhang have analyzed uranium isotopes in a […]

22 Oct 2019

Forskerzonen: Mystery about animals in ancient anoxic oceans resolved

The newly discovered ocean ventilation events in the 500 million year old Alum shale ocean is described in Danish on Forskerzonen: Videnskab.dk