An evaluation of different methods of preparation of quartz grains for study of their surface features by scanning electron microscopy
- Lewis, Colin A, Armstrong, Glynis A S
- Authors: Lewis, Colin A , Armstrong, Glynis A S
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6705 , http://hdl.handle.net/10962/d1006741
- Description: Sediments from periglacial and glacial environments were subjected to initial preparation and portions were subsequently further prepared using either the dichromate or the hydrogen peroxide method before being examined by scanning electron microscopy. Statistically significant differences did not occur in the results obtained for samples subjected only to initial or to initial and either of the two further preparations: it is concluded that initial preparation is satisfactory and further preparation unnecessary.
- Full Text:
- Date Issued: 1994
- Authors: Lewis, Colin A , Armstrong, Glynis A S
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6705 , http://hdl.handle.net/10962/d1006741
- Description: Sediments from periglacial and glacial environments were subjected to initial preparation and portions were subsequently further prepared using either the dichromate or the hydrogen peroxide method before being examined by scanning electron microscopy. Statistically significant differences did not occur in the results obtained for samples subjected only to initial or to initial and either of the two further preparations: it is concluded that initial preparation is satisfactory and further preparation unnecessary.
- Full Text:
- Date Issued: 1994
Promotion of the Etendeka Formation to Group status: a new integrated stratigraphy
- Milner, Simon C, Duncan, Andrew R, Ewart, A, Marsh, Julian S
- Authors: Milner, Simon C , Duncan, Andrew R , Ewart, A , Marsh, Julian S
- Date: 1994
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145482 , vital:38442
- Description: The Etendeka volcanic rocks of northwestem Namibia are currently defined as the upper part of the Karoo Sequence in Namibia and have thus been represented as stratigraphically equivalent to the volcanic rocks of the Karoo Sequence in South Africa, Botswana, Lesotho, Swaziland and Zimbabwe. However, the Etendeka volcanic rocks (130-135 Ma) are considerably younger than those of the Karoo Sequence (180-190 Ma) in the areas mentioned above. They are compositionally distinct from Karoo volcanic rocks, and constitute an eastern portion of the Parana Igneous Province of Brazil. Stratigraphic studies have shown the Etendeka Formation to be made up of several definable volcanic successions and it is suggested that these successions now be formally recognized as Formations within an Etendeka Group which itself should no longer be part of the Karoo Sequence. Prominent quartz latite units and sequences of basalt flows are defined as Members within the new Formations.
- Full Text:
- Date Issued: 1994
- Authors: Milner, Simon C , Duncan, Andrew R , Ewart, A , Marsh, Julian S
- Date: 1994
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145482 , vital:38442
- Description: The Etendeka volcanic rocks of northwestem Namibia are currently defined as the upper part of the Karoo Sequence in Namibia and have thus been represented as stratigraphically equivalent to the volcanic rocks of the Karoo Sequence in South Africa, Botswana, Lesotho, Swaziland and Zimbabwe. However, the Etendeka volcanic rocks (130-135 Ma) are considerably younger than those of the Karoo Sequence (180-190 Ma) in the areas mentioned above. They are compositionally distinct from Karoo volcanic rocks, and constitute an eastern portion of the Parana Igneous Province of Brazil. Stratigraphic studies have shown the Etendeka Formation to be made up of several definable volcanic successions and it is suggested that these successions now be formally recognized as Formations within an Etendeka Group which itself should no longer be part of the Karoo Sequence. Prominent quartz latite units and sequences of basalt flows are defined as Members within the new Formations.
- Full Text:
- Date Issued: 1994
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