Tag Archives: robert hazen

15 million-year-old mollusk protein found

Washington, D.C.— A team of Carnegie scientists have found “beautifully preserved” 15 million-year-old thin protein sheets in fossil shells from southern Maryland. Their findings are published in the inaugural issue of Geochemical Perspectives Letters. (more…)

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Ancient Minerals: Which Gave Rise to Life?

Washington, D.C.— Life originated as a result of natural processes that exploited early Earth’s raw materials. Scientific models of life’s origins almost always look to minerals for such essential tasks as the synthesis of life’s molecular building blocks or the supply of metabolic energy. But this assumes that the mineral species found on Earth today are much the same as they were during Earth’s first 550 million years—the Hadean Eon—when life emerged. A new analysis of Hadean mineralogy challenges that assumption. It is published in American Journal of Science.

Carnegie’s Robert Hazen compiled a list of every plausible mineral species on the Hadean Earth and concludes that no more than 420 different minerals—about 8 percent of the nearly 5,000 species found on Earth today—would have been present at or near Earth’s surface. (more…)

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Evidence of 3.5 billion-year-old bacterial ecosystems found in Australia

Washington, D.C.— Reconstructing the rise of life during the period of Earth’s history when it first evolved is challenging. Earth’s oldest sedimentary rocks are not only rare, but also almost always altered by hydrothermal and tectonic activity. A new study from a team including Carnegie’s Nora Noffke, a visiting investigator, and Robert Hazen revealed the well-preserved remnants of a complex ecosystem in a nearly 3.5 billion-year-old sedimentary rock sequence in Australia. Their work is published in Astrobiology.

The Pilbara district of Western Australia constitutes one of the famous geological regions that allow insight into the early evolution of life. Mound-like deposits created by ancient photosynthetic bacteria, called stromatolites, and microfossils of bacteria have been described by scientists in detail. However, a phenomenon called microbially induced sedimentary structures, or MISS, had not previously been seen in this region. These structures are formed from mats of microbial material, much like mats seen today on stagnant waters or in coastal flats. (more…)

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