Solid bitumen in calcite veins from the Oman Mountains : a structural, microstructural and geochemical study on hydrocarbon migration in the Natih

Fink, Reinhard; Urai, Janos L.

doi:999910296617

Solid bitumen in calcite veins from the Oman Mountains : a structural, microstructural and geochemical study on hydrocarbon migration in the Natih

Fink, Reinhard

2013

ImpressumAachen : Publikationsserver der RWTH Aachen University 2013

Umfang93 S., Anh.

Aachen, Techn. Hochsch., Masterarbeit, 2013

Veröffentlicht auf dem Publikationsserver der RWTH Aachen University

Hauptberichter/Gutachter
Urai, Janos L. (Thesis advisor)

Online
URN: urn:nbn:de:hbz:82-opus-45029
DOI: 10.18154/RWTH-CONV-143452
URL: https://publications.rwth-aachen.de/record/206220/files/4502.pdf

Einrichtungen

Inhaltliche Beschreibung (Schlagwörter)
Bitumen (Genormte SW) ; Migration <Geologie> (Genormte SW) ; Oman (Genormte SW) ; Kohlenwasserstoffe (Genormte SW) ; Geowissenschaften (frei) ; Kluftfüllungen (frei) ; bitumen (frei) ; hydrocarbon migration (frei) ; Natih (frei) ; Oman Mountains (frei)

Thematische Einordnung (Klassifikation)
DDC: 550

Kurzfassung
Fractures are important pathways for hydrocarbon migration in the Earth’s crust. This study shows that there was hydrocarbon migration in the Oman mountains, which has not been recognized until now. Solid bitumen in calcite veins from Natih limestone on the southern flank of the Jebel Akhdar Anticline, situated in the Oman Mountains, are remnants of fossil petroleum migration pathways. To understand the role of Natih veins during migration, field work was combined with microscopic analysis including cathodoluminescense, transmitted, and reflected light microscopy. For this purpose, highly polished thin sections were prepared to simultaneously examine solid bitumen in reflected light and its microstructural context in transmitted light. Straight and en échelon arranged, black impregnated, bedding-normal Natih A calcite veins strike 120 and are cross-cut by all other veins. They contain solid bitumen as small (<10 μm) intracrystal inclusions arranged as trails, high-reflective intracrystal mosaic type particles and angular low reflective particles at pressure solution sites. Solid bitumen formed in multiple events after the first vein growth and was most likely derived from the now highly overmature Natih B source rock. During the first event, intracrystal solid bitumen inclusion trails formed by micro-cracking of the existing vein. Simultaneously or later, mosaic type solid bitumen formed in reactivations. Solid bitumen reflectance (BRr) of mosaic type solid bitumen (BRr = 3.40 - 3.76 %) give evidence for high temperatures (T = 317 - 325 C) which only affect the veins. These temperatures exceed maximum burial temperatures (T = 206 - 238 C) derived from BRr measurements of the Natih B source rock. Formation of low reflective solid bitumen (BRr = 0.86 - 0.92 %) along pressure solution sites postdates all events. They may be important hydrocarbon migration pathways and may not only affect veins, but the whole Natih sequence.

OpenAccess:
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