New K-Ar Age Determinations from the West African Shield in the Niger Republic

Abstract

Research Article| January 01, 1974 New K-Ar Age Determinations from the West African Shield in the Niger Republic Rudolf O. Brunnschweiler Rudolf O. Brunnschweiler 1Bishop Oil & Refining Co., B.P. 383, Niamey, Republic of Niger Search for other works by this author on: GSW Google Scholar Author and Article Information Rudolf O. Brunnschweiler 1Bishop Oil & Refining Co., B.P. 383, Niamey, Republic of Niger Publisher: Geological Society of America First Online: 02 Jun 2017 Online Issn: 1943-2682 Print Issn: 0091-7613 Geological Society of America Geology (1974) 2 (1): 17–20. https://doi.org/10.1130/0091-7613(1974)2<17:NKADFT>2.0.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Rudolf O. Brunnschweiler; New K-Ar Age Determinations from the West African Shield in the Niger Republic. Geology 1974;; 2 (1): 17–20. doi: https://doi.org/10.1130/0091-7613(1974)2<17:NKADFT>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The evolution and consolidation of the Birrimian part of the West African shield covered a much longer time span than is generally believed. K-Ar ages of seven new samples reported here range from 1,206 to 2,487 m.y. old. The Eburnean (Birrimian) orogeny at the end of early Proterozoic time (2,150 to 1,950 m.y. ago) was only one of several events which have shaped the region through Proterozoic time, and western Niger does not even seem to have been affected by it.In the Aïr Mountains of the central portion of northern Niger, no dates older than 660 m.y. have yet been found, although a complex Precambrian history is suspected from geologic studies; the Pan-African event (about 600 m.y. ago) has strongly overprinted earlier features.While the “Younger Granites” of the Jos plateau in northern Nigeria were intruded in Jurassic time, the similar granites of the “young” ring complexes in the Aïr Mountains are not younger than early Carboniferous in age. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.