Robert Frei

TL;DR: A continuous record of atmospheric lead since 12,370 carbon-14 years before the present (14C yr BP) is preserved in a Swiss peat bog, indicating the beginning of lead pollution from mining and smelting, and anthropogenic sources have dominated lead emissions ever since.

TL;DR: The greatest lead sux (15.7 milligrams persquare meter per year in A.D. 1979) was 1570 times the natural, backgroundvalue (0.01 milligram per square meters per year from 8030 to 5320.

TL;DR: The findings suggest that the Great Oxidation Event did not lead to a unidirectional stepwise increase in atmospheric oxygen, and strong positive fractionations in Cr isotopes in the late Neoproterozoic era provide independent support for increased surface oxygenation at that time, which may have stimulated rapid evolution of macroscopic multicellular life.

TL;DR: The findings suggest that there were appreciable levels of atmospheric oxygen about 3 billion years ago, more than 600 million years before the Great Oxidation Event and some 300–400 million years earlier than previous indications for Earth surface oxygenation.

TL;DR: In this article, age-corrected Nd, Pb, and Sr isotopic data for 46-150 Ma seafloor lavas from sites in the western Indian Ocean and ocean-ridge-type Tethyan ophiolites (Masirah, Yarlung-Zangpo) reveal the presence of both Indian-Ocean-type compositions and essentially Pacific-North Atlantic-type signatures.