Cretaceous volcanic rocks of the Namibe Basin, southern Angola: report on a reconnaissance field and geochemical investigation
- Authors: Marsh, Julian S
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67301 , vital:29070
- Description: publisher version , Mafic alkaline lavas and intrusions occur in the onshore Namibe Basin in southern Angola. The distribution and field relationships of these igneous rocks have been mapped and described by Carvalho (1961). During a reconnaissance field visit in June 2009 a suite of samples was collected for further investigation.
- Full Text:
- Date Issued: 2010
- Authors: Marsh, Julian S
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67301 , vital:29070
- Description: publisher version , Mafic alkaline lavas and intrusions occur in the onshore Namibe Basin in southern Angola. The distribution and field relationships of these igneous rocks have been mapped and described by Carvalho (1961). During a reconnaissance field visit in June 2009 a suite of samples was collected for further investigation.
- Full Text:
- Date Issued: 2010
The geochemistry and evolution of Palaeogene phonolites, central Namibia:
- Authors: Marsh, Julian S
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145000 , vital:38399 , https://doi.org/10.1016/j.lithos.2010.02.012
- Description: Phonolites of Palaeogene age occur at two different localities in central Namibia, occurring as clusters of eroded monogenetic lava domes. Six phonolites at Aris collectively exhibit a narrow compositional range and represent a single magma system of highly evolved phonolite with high concentrations of Na2O, Rb, Th, Zr, Zn, Pb, and REE and very low abundances of MgO, P2O5, Sr and Ba. No mafic rocks are associated with the Aris phonolites and their ultimate petrogenetic origin remains obscure. The more abundant Staalhart phonolites exhibit more variable but scattered compositional variation consistent with fractional crystallization dominated by sanidine (and nepheline) and pyroxene. The behaviour of REE is decoupled from Zr, Nb, and Th in this suite indicating a controlling role for minor phases in their evolution. The least evolved phonolites have initial 87Sr/86Sr 0.7043, which is identical to a small occurrence of associated plagioclase-bearing nephelinite indicating a possible petrogenetic link.
- Full Text:
- Date Issued: 2010
- Authors: Marsh, Julian S
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145000 , vital:38399 , https://doi.org/10.1016/j.lithos.2010.02.012
- Description: Phonolites of Palaeogene age occur at two different localities in central Namibia, occurring as clusters of eroded monogenetic lava domes. Six phonolites at Aris collectively exhibit a narrow compositional range and represent a single magma system of highly evolved phonolite with high concentrations of Na2O, Rb, Th, Zr, Zn, Pb, and REE and very low abundances of MgO, P2O5, Sr and Ba. No mafic rocks are associated with the Aris phonolites and their ultimate petrogenetic origin remains obscure. The more abundant Staalhart phonolites exhibit more variable but scattered compositional variation consistent with fractional crystallization dominated by sanidine (and nepheline) and pyroxene. The behaviour of REE is decoupled from Zr, Nb, and Th in this suite indicating a controlling role for minor phases in their evolution. The least evolved phonolites have initial 87Sr/86Sr 0.7043, which is identical to a small occurrence of associated plagioclase-bearing nephelinite indicating a possible petrogenetic link.
- Full Text:
- Date Issued: 2010
The largest volcanic eruptions on Earth
- Bryan, Scott E, Peate, Ingrid Ukstins, Peate, David W, Self, Stephen, Jerram, Dougal A, Mawby, Michael R, Marsh, Julian S, Miller, Jodie A
- Authors: Bryan, Scott E , Peate, Ingrid Ukstins , Peate, David W , Self, Stephen , Jerram, Dougal A , Mawby, Michael R , Marsh, Julian S , Miller, Jodie A
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/132887 , vital:36902 , https://doi.org/10.1016/j.earscirev.2010.07.001
- Description: Large igneous provinces (LIPs) are sites of the most frequently recurring, largest volume basaltic and silicic eruptions in Earth history. These large-volume (> 1000 km3 dense rock equivalent) and large-magnitude (> M8) eruptions produce really extensive (104–105 km2) basaltic lava flow fields and silicic ignimbrites that are the main building blocks of LIPs.
- Full Text: false
- Date Issued: 2010
- Authors: Bryan, Scott E , Peate, Ingrid Ukstins , Peate, David W , Self, Stephen , Jerram, Dougal A , Mawby, Michael R , Marsh, Julian S , Miller, Jodie A
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/132887 , vital:36902 , https://doi.org/10.1016/j.earscirev.2010.07.001
- Description: Large igneous provinces (LIPs) are sites of the most frequently recurring, largest volume basaltic and silicic eruptions in Earth history. These large-volume (> 1000 km3 dense rock equivalent) and large-magnitude (> M8) eruptions produce really extensive (104–105 km2) basaltic lava flow fields and silicic ignimbrites that are the main building blocks of LIPs.
- Full Text: false
- Date Issued: 2010
- «
- ‹
- 1
- ›
- »