The relative influences of tectonics, continental weathering and seafloor weathering in controlling the geological carbon cycle are unknown. Here we develop a new carbon cycle model that explicitly captures the kinetics of seafloor weathering to investigate carbon fluxes and the evolution of atmospheric CO2 and ocean pH since 100 Myr ago.
by Yama Tomonaga et al., March 22, 2017, Nature
In closed-basin lakes, sediment porewater salinity can potentially be used as a conservative tracer to reconstruct past fluctuations in lake level. However, until now, porewater salinity profiles did not allow quantitative estimates of past lake-level changes because, in contrast to the oceans, significant salinity changes (e.g., local concentration minima and maxima) had never been observed in lacustrine sediments. Here we show that the salinity measured in the sediment pore water of Lake Van (Turkey) allows straightforward reconstruction of two major transgressions and a major regression that occurred during the last 250 ka.
by University of California – Davis, May 16,2017 in ScienceDaily
Chronicling Earth’s past temperature swings is a basic part of understanding climate change. One of the best records of past ocean temperatures can be found in the shells of marine creatures called foraminifera
by Yair Rosenthal et al., January 1, 2017
Here we review proxy records of intermediate water temperatures from sediment cores in the equatorial Pacific and northeastern Atlantic Oceans, spanning 10,000 years beyond the instrumental record.
These records suggests that intermediate waters were 1.5–2 °C warmer during the Holocene Thermal Maximum than in the last century.
Intermediate water masses cooled by 0.9 °C from the Medieval Climate Anomaly to the Little Ice Age.
by University of Queensland, May 10, 2017, in DailyScience
Ms Korpanty said global climate underwent significant change about 14 million years ago when the Antarctic ice sheet expanded.
« The new study presents shallow-marine sediment records from the Australian continental shelf, providing the first empirical evidence linking high-altitude cooling around Antarctica to climate change in the subtropics during the Miocene era, » she said.