The origin of the acidic and basic rocks of the Tichka Massif, Morocco, based on rare earth elements

✍ Scribed by Greg B. Scott; Thomas A. Vogel

• Book ID: 104745665
• Publisher: Springer
• Year: 1980
• Tongue: English
• Weight: 557 KB
• Volume: 75
• Category: Article
• ISSN: 0010-7999
• DOI: 10.1007/bf00371892

✦ Synopsis

The Tichka Massif is one of many late-Paleozoic massifs emplaced in northwestern Africa. It consists of granitic pods surrounded by a complex assemblage of dioritic and gabbroic rocks. Previous workers have suggested an independent origin for the granitic and gabbroic rocks and this study evaluates this suggestion using REE data.

The Ce/Yb ratio versus Ce plot for the gabbro shows a large Ce/Yb variation for small changes in Ce, whereas the granites show a linear increase of Ce/Yb with Ce. In the granites, the samples with the highest Ce/Yb ratio have the lowest SiO2, whereas in the gabbros the Ce/Yb ratio is lowest in the low SiO 2 rocks. The diorites show a tightly clustered pattern.

Based on the REE data the granite-diorite-gabbro sequence cannot be related by fractional crystallization. Partial melting of a garnet bearing mantle is consistent with the gabbroic trends. Partial melting of a crustal source with small amounts of apatite and abundant hornblende can produce the granitic rocks.