Sökning: "fossil meteorites"

Hittade 4 uppsatser innehållade orden fossil meteorites.

  1. 1. Chrome spinel grains from the Komstad Limestone Formation, Killeröd, southern Sweden : a high-resolution study of an increased meteorite flux in the Middle Ordovician

    Master-uppsats, Lunds universitet/Geologiska institutionen

    Författare :Ellinor Martin; [2014]
    Nyckelord :chrome spinel; fossil meteorites; Komstad Limestone; winonaites; Middle Ordovician; carbonate sedimentology; Earth and Environmental Sciences;

    Sammanfattning : I mellersta ordovicium var inflödet av kosmiskt material till jorden högre än idag, i sviter-na efter uppbrytningen av den L-kondritiska asteroidkroppen i asteroidbältet mellan Mars och Jupiter, vilket beri-kade den forna havsbottnen med meteoriter och kosmiskt damm. Komstadformationen i Killeröd, Skåne, innehåller ett lager särskilt rikt på L-kondritiska kromitkorn vilket indikerar en hög grad av kondensation. LÄS MER

  3. 2. Cosmic ray tracks in chondritic material with focus on silicate mineral inclusions in chromite

    Master-uppsats, Lunds universitet/Geologiska institutionen

    Författare :My Riebe; [2012]
    Nyckelord :extraterrestrial chromite; cosmic rays; cosmic ray tracks; ordinary chondrites; Ordovician; kosmisk strålning; spår efter kosmisk strålning; extraterrestrisk kromit; ordinära kondriter; ordovicium; Earth and Environmental Sciences;

    Sammanfattning : It has been suggested that the cosmic ray flux varies as Earth moves relative to the spiral arms in the galaxy. However, no satisfying record over the cosmic ray flux over long time scales has been presented. LÄS MER

  4. 3. A Russian record of a Middle Ordovician shower : extraterrestrial chromite in Volkhovian-Kundan (lower Darriwilian) strata at Lynna River, St. Petersburg Region

    Master-uppsats, Lunds universitet/Geologiska institutionen

    Författare :Anders Lindskog; [2011]
    Nyckelord :Lynna River; extraterrestrial chromite; fossil meteorites; Volkhov; Kunda; Darriwilian; heavy minerals; Lenodus variabilis; Lynna; utomjordisk kromit; fossila meteoriter; tungmineral; Earth and Environmental Sciences;

    Sammanfattning : Numerous fossil meteorites and high concentrations of sediment-dispersed extraterrestrial chromite (EC) grains with typical ordinary chondritic composition have previously been documented from 467±1.6 Ma Ma lower Kundan (Middle Ordovician) strata. LÄS MER

  5. 4. Spinel group minerals in carbonaceous and ordinary chondrites

    Kandidat-uppsats, Lunds universitet/Geologiska institutionen

    Författare :My Riebe; [2009]
    Nyckelord :spinel group minerals; carbonaceous chondrites; ordinary chondrites; spinellgruppmineral; kolkondriter; ordinära kondriter; Earth and Environmental Sciences;

    Sammanfattning : Meteorites are easily altered in the oxygen-rich environment on the Earth surface. Fossil meteorites are thus uncommon and in the ones, which are found, almost all minerals are secondary. However, the spinel group mineral chromite is resistant to alteration and has successfully been used as a proxy for ordinary chondrites in sediment. LÄS MER