Sökning: "Paleozoic rocks"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden Paleozoic rocks.

1. 1. Geophysical studies in the western part of the Siljan Ring Impact Crater

   Författare :Harbe Muhamad; Christopher Juhlin; Alireza Malehmir; Daniel Sopher; Lars Nilsen; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Siljan ring impact structure; Seismic reflection; Down-hole logging; Gravity; Magnetic; Tomography; Paleozoic rocks;

   Sammanfattning : This thesis utilizes several geophysical methods to study the Siljan Ring impact structure, focusing on the western part of the structure. This thesis, and the three papers upon which it is based, reports on attempts to delineate the Paleozoic rocks at depth within the annular ring graben and characterize their structure. LÄS MER

3. 2. Early land plant spores from the Paleozoic of Sweden – taxonomy, stratigraphy and paleoenvironments

   Författare :Kristina Mehlqvist; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Spores; early land plants; taxonomy; stratigraphy; biostratigraphy; Silurian;

   Sammanfattning : The Silurian through earliest Devonian, between ca 444 and 412 million years ago, was characterized by significant changes in global climate and environment. At that time, plants and animals had begun to expand the colonization of previous relatively desolate terrestrial landscape. LÄS MER

4. 3. Tectonic Evolution of Taimyr in the Late Paleozoic to Mesozoic from Provenance and Thermochronological Evidence

   Författare :Xiaojing Zhang; Victoria Pease; Arild Andresen; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Taimyr; sandstones; provenance; heavy mineral analysis; detrital zircon; apatite fission track; tectonic setting; uplift; Geology; geologi;

   Sammanfattning : The Taimyr Peninsula is a key element in the circum-Arctic region and represents thenorthern margin of the Siberian Craton. The Taimyr Peninsula is a late Paleozoic fold andthrust belt and preserves late Paleozoic through Mesozoic siliciclastic sedimentarysuccessions and providing an ideal location to investigate the Paleozoic to Mesozoictectonic evolution associated with the Uralian orogeny, the Siberian Trap magmatism andopening of Amerasia Basin within a circum-Arctic framework. LÄS MER

5. 4. Crustal evolution of the Arabian–Nubian Shield : Insights from zircon geochronology and Nd–Hf–O isotopes

   Författare :Fitsum Girum Yeshanew; Victoria Pease; Martin J. Whitehouse; Robert J. Stern; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Gondwana; Arabian–Nubian Shield; Azania; zircon U–Pb–O–Hf isotopes; Nd isotopes; Cambrian Sandstones; juvenile; pre–Neoproterozoic; reworking; Geology; geologi;

   Sammanfattning : The Arabian–Nubian Shield (ANS) represents a major site of juvenile Neoproterozoic crustal addition on Earth and documents Neoproterozoic tectonics bracketed by two supercontinent cycles, namely the fragmentation of Rodinia and the amalgamation of Gondwana. There is general consensus that the ANS formed by juvenile magmatic arc accretion and subsequent shield–wide post–tectonic magmatism. LÄS MER

7. 5. An integrated study of geological, magnetic and electromagnetic data for mineral exploration in the Jameson Land Basin, central East Greenland

   Författare :Anaïs Brethes; Thorkild Maack Rasmussen; Florian Wellmann; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; central East Greenland; Jameson Land Basin; base metal mineralization; geological structures; magnetic data; electromagnetic data; Prospekteringsgeofysik; Exploration Geophysics;

   Sammanfattning : The Jameson Land Basin, located in central East Greenland, initiated in Devonian time with the collapse of the over-thickened Caledonian Orogen. The basin developed during different phases of rifting from the late Paleozoic to the Mesozoic and has accumulated between 16-18 km of sediments. LÄS MER