The Fuchuan Ophiolite in South China: Evidence for modern‐style plate tectonics during Rodinia breakup

Plate tectonics on early Earth? Weighing the paleomagnetic evidence

Paleomagnetism is the only quantitative method available to test for lateral motions by tectonic plates across the surface of ancient Earth. Here, we present several analyses of such motions using strict quality criteria from the global paleomagnetic database of pre–800 Ma rocks. Extensive surface motion of cratons can be documented confi dently to older than ca. 2775 Ma, but considering only t...

Balancing the force budget of plate tectonics along the Nazca/South America plate margin

A high-quality mid-Neoproterozoic paleomagnetic pole from South China, with implications for ice ages and the breakup configuration of Rodinia

Neoproterozoic (Sinian) sediments are exceptionally well preserved in the Three Gorges region (western Hubei Province) of the South China block. We report new paleomagnetic results, obtained independently by two separate laboratories, from a total of 157 samples of the 748±12 Ma, basal Sinian Liantuo Formation at its type locality. Detailed thermal demagnetization procedures and least-squares l...

Snowball Earth ocean chemistry driven by extensive ridge 1 volcanism during Rodinia breakup

During Neoproterozoic Snowball Earth glaciations, the oceans gained 8 massive amounts of alkalinity, culminating in the deposition of massive 9 cap carbonates upon deglaciation. Changes in terrestrial runoff associ10 ated with both breakup of the Rodinia supercontinent and deglaciation 11 can explain some, but not all of the requisite changes in ocean chem12 istry. Submarine volcanism along sha...

Comment on "Intermittent plate tectonics?".

Silver and Behn (Reports, 4 January 2008, p. 85) proposed that intermittent plate tectonics may resolve a long-standing paradox in Earth's thermal evolution. However, their analysis misses one important term, which subsequently brings their main conclusion into question. In addition, the Phanerozoic eustasy record indicates that the claimed effect of intermittency is probably weak.