Al/Cr ratios of coexisting pyroxenes and spinellids in some ultramafic rocks
- Eales, Hugh V, Marsh, Julian S
- Authors: Eales, Hugh V , Marsh, Julian S
- Date: 1983
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/133534 , vital:36987 , https://doi.org/10.1016/0009-2541(83)90045-1
- Description: Al/Cr atomic ratios of coexisting spinellids and ortho- and clinopyroxenes show a pattern of sympathetic variation that persists through ultramafic rocks of layered mafic complexes of upper-crustal type, Alpine complexes, and the nodules found in kimberlites and alkaline basalts. Simple expressions are empirically derived to link (Al/Cr) orthopyroxene and (Al/Cr)spinel ratios in putatively equilibrated rocks. Equivalence of spinel compositions in shallow layered complexes and kimberlite nodules of deep-seated origin negates direct crystallochemical control of Al/Cr ratios of spinels by pressure.
- Full Text: false
- Authors: Eales, Hugh V , Marsh, Julian S
- Date: 1983
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/133534 , vital:36987 , https://doi.org/10.1016/0009-2541(83)90045-1
- Description: Al/Cr atomic ratios of coexisting spinellids and ortho- and clinopyroxenes show a pattern of sympathetic variation that persists through ultramafic rocks of layered mafic complexes of upper-crustal type, Alpine complexes, and the nodules found in kimberlites and alkaline basalts. Simple expressions are empirically derived to link (Al/Cr) orthopyroxene and (Al/Cr)spinel ratios in putatively equilibrated rocks. Equivalence of spinel compositions in shallow layered complexes and kimberlite nodules of deep-seated origin negates direct crystallochemical control of Al/Cr ratios of spinels by pressure.
- Full Text: false
Moult in southern African passerine birds: a review
- Authors: Craig, Adrian J F K
- Date: 1983
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447813 , vital:74676 , https://doi.org/10.1080/00306525.1983.9634475
- Description: In the most recent checklist 398 passerine species are recorded for southern Africa. This paper lists information on the moult of 114 species, of which 27 are Palaearctic migrants, or birds for which there are data from European populations only. For 65 additional species data of uncertain relevance to southern African populations are included in appendices. There is much interspecific variation in both pattern and timing, even between members of the same family and genus. Aspects requiring special attention in future studies are discussed.
- Full Text:
- Authors: Craig, Adrian J F K
- Date: 1983
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447813 , vital:74676 , https://doi.org/10.1080/00306525.1983.9634475
- Description: In the most recent checklist 398 passerine species are recorded for southern Africa. This paper lists information on the moult of 114 species, of which 27 are Palaearctic migrants, or birds for which there are data from European populations only. For 65 additional species data of uncertain relevance to southern African populations are included in appendices. There is much interspecific variation in both pattern and timing, even between members of the same family and genus. Aspects requiring special attention in future studies are discussed.
- Full Text:
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