“Precession of the axis of a spinning top and that of the Earth. At present the northern end of Earth’s axis points to what we now call the Pole Star. Around 11.5 ka from now it will point to the star Vega”
A new twist to Pleistocene climate cycles
Climate and tectonics since 250 Ma
A central feature of the Earth’s climate system is the way that carbon bound in two gases – carbon dioxide (CO2) and methane (CH4) – controls the amount of incoming solar energy that is retained by the atmosphere.
Wider traces of the elusive Denisovans
A probable Denisovan molar from 164 to 131 ka old cave sediments in northern Laos. (credit: Demeter, et al.; Fig. 2)
The end of the Carboniferous ‘icehouse’ world
Sedimentary evidence for global climates 320 Ma ago. As well as the large tracts of glaciogenic sediments, smaller occurrences and examples of polished rock surfaces over which ice had passed show the probable full extent (blue line) of ice sheets across the southern, Gondwana sector of Pangaea (Credit: after Fig 7.3, S104, Earth and Space, ©Open University 2007)
Evidence for an early Archaean transition to subduction
A schematic model of transition from Hadean-Eoarchaean lid tectonics to a type of plate tectonics that subsequently evolved to its current form, based on hafnium isotope data in ancient zircons (credit: Bauer et al. 2020; Fig 3)
Evidence for oldest microbes from Arctic Canada
By Steve Drury First PUBLISHED ON April 21, 2022 Among the oldest known rocks are metamorphosed pillow basalts on Nuvvuagittuk Island in Quebec on the east side of Hudson Bay, Canada. They contain […]
Conditions that may have underpinned the ‘Cambrian Explosion’
Artistic impression of the Chengjian Biota
Lower-mantle blobs may reveal relics of event going back to the Hadean
Three-dimensional rendition of seismic tomography results beneath Africa. Mantle with anomalously low S-wave speeds is show in red, orange and yellow. The faint grey overlay represents the extent of surface continental crust today – Horn of Africa at right and Cape Town at the lower margin – the blue areas near the top are oceanic crust on the floor of the Mediterranean Sea. (Image credit: Mingming Li/ASU)
Signs of massive hydrocarbon burning at the end of the Triassic
By Steve Drury First PUBLISHED ON March 25, 2022 One of the ‘Big Five’ mass extinctions occurred at the end of the Triassic Period (~201 Ma), whose magnitude matches that of the more […]
‘Smoking gun’ for Younger Dryas trigger refuted
Colour-coded subglacial topography from airborne radar sounding over the Hiawatha Glacier of NW Greenland (Credit: Kjaer et al. 2018; Fig. 1D)
