Earth’s habitability

Stephanie Pappas writes: Fossils called stromatolites from Western Australia were created by microbes 3.48 billion years ago. Layered rocks in Western Australia are some of Earth’s earliest known life, according to a new study.  The fossils in question are stromatolites, layered rocks that are formed by the excretions of photosynthetic microbes. The oldest stromatolites that scientists agree were made by living organisms date back 3.43 billion years, but there are older specimens, too. In the Dresser Formation of Western Australia, stromatolites dating back 3.48 billion years have been found.  However, billions of years have wiped away traces of organic matter in these older stromatolites, raising questions about whether they were really formed by microbes or whether they might have been Read More ›

New research led by Curtin University geologists suggests that regions of space with dense interstellar clouds may send more high-energy comets crashing to the surface of the Earth, seeding enhanced production of continental crust. The findings challenge the existing theory that Earth’s continental crust was solely formed by processes inside our planet. Earth is unique among the known planets in having continents, whose formation has fundamentally influenced the composition of the mantle, hydrosphere, atmosphere, and biosphere. Cycles in the production of continental crust have long been recognized and generally ascribed to the periodic aggregation and dispersal of Earth’s continental crust as part of the supercontinent cycle. However, such cyclicity is also evident in some of Earth’s most ancient rocks that Read More ›