Sökning: "Impact cratering"

Hittade 5 avhandlingar innehållade orden Impact cratering.

  1. 1. Geochronology of impact structures - constraining syn- and post-impact processes using the 40Ar/39Ar and U-Pb techniques

    Författare :Maria Herrmann; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Impact structure; Dating impact events; 40Ar 39Ar dating; U-Pb dating; Siljan impact structure; Mien impact structure; Hummeln impact structure; Puchezh-Katunki impact structure;

    Sammanfattning : The discovery, at the beginning of the 20th century, that elements can transform into other elements, due to the spontaneous decay of an instable to a stable atomic nuclei, gave rise to a powerful source for age information in many fields of earth science. For impact structures, it is crucial to establish well-defined and precise ages in order to understand how impact events affect the Earth’s geo and biosphere and also with regard to possible future events that can have devastating effects on our civilization. LÄS MER

  3. 2. Impact cratering at sea

    Författare :Jens Ormö; Richard A.F Grieve; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; allmän och historisk geologi; General and Historical Geology;

    Sammanfattning : .... LÄS MER

  4. 3. Terrestrial consequences of hypervelocity impact – shock metamorphism, shock barometry, and newly discovered impact structures

    Författare :Sanna Alwmark; Berggrundsgeologi; []
    Nyckelord :Impact cratering; Impact structure; Shock metamorphism; Shock barometry; Quartz; Planar deformation features; Siljan; Målingen; Hummeln;

    Sammanfattning : Impact cratering was once considered a rare geological process of no, or little, importance to the evolution of the Solar System and planet Earth. After more than 50 years of space exploration and the discovery of numerous (~190 as of October 2016) impact structures on Earth, this view has changed, and it is now clear that impact craters are in fact one of the most common morphological features on solid bodies in the Solar System. LÄS MER

  5. 4. Leave no trace: A non-destructive correlative approach providing new insights into impactites and meteorites

    Författare :Josefin Martell; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; impact cratering; Mars; Mien impact structure; X-ray tomography; Neutron tomography; Shock metamorphism; Impact structure;

    Sammanfattning : Impact cratering is today recognized as a fundamental geological process on all rocky bodies in the solar system. On Earth, however, processes such as plate tectonics and erosion have eradicated most craters from the geological record, or they may be buried under sediments, oceans, and vegetation. LÄS MER

  7. 5. The origin of the marine Lockne impact structure, Jämtland

    Författare :Erik Sturkell; Christian Keoberl; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lockne; Jämtland; Earth sciences; Geovetenskap; allmän och historisk geologi; General and Historical Geology;

    Sammanfattning : The Lockne impact structure in Jämtland (63o00'20"N, 14o49'30"E), formed in the Middle Ordovician at approximately 455 Ma. The structure is a concentric crater with a total diameter of 13.5 km. The impact took place in a marine environment. LÄS MER