Thin Section Pphotograph Rapakivi Granite

2 1 1 thin sections thin sections of fresh pyterlite core length 4 7 m and altered pyterlite core length 161 m were prepared.

Thin section pphotograph rapakivi granite. The unusual feature of this rock is that it contains fayalite an iron rich olivine. I thank roberto dall agnol scott paterson simon turner and an anonymous referee for helpful comments lawford anderson and matthias bräunlich for providing images of ovoid granitoids and simon turner for providing images and thin sections of the mannum granite as well as discussions in the field. Known for its striking texture in hand samples with large round oval pink orthoclase feldspars surrounded by a rim of clear albite rich plagioclase. Mineral compositions of thin sections from drill core yts vol calculated by.

1994a and bettencourt et al. 19 august 2019 the author s 2019 abstract. Rapakivi granite from hastholmen drill core yts was chosen for the sorption experiments. In the topaz bearing granite the accessory cassiterite occurs in the matrix as small elongated prisms which are black or dark brown under stereomicroscope and homogeneous dark brown in thin section.

This is generally most uncommon in this type of rock. Geochronological data about the amazonian craton rapakivi magmatism were summarized by dall agnol et al. The mineral composition of the thin section is dominated by a potassium feldspar grain 20 tnm in diameter. Fresh altered and fracture zone.

This is not a granite as it does not contain much if any quartz. This is a thin section of a syenite from the ragunda massif in sweden known for it s rapakivi textured granite rocks. 10 august 2018 accepted. Other tninerals are plagioclase and quartz.

Rapakivi series are widespread in the amazonian craton and show ages between 1 9 and 1 0 ga. In other regions medium even grained granites are largely dominant. Mafic minerals are biotite mica and amphibole plus some quartz. Tapani rämö1 timo ahtola2 panu lintinen3 received.

The 400 ma galway granite exhibits excellent evidence for magma mixing and mingling both at outcrop map scale magma mingling and mixing zones and at thin section crystal scale mixing. A thin section microscope slide of rapakivi granite from finland. Biotite is an accessory as are muscovite epidote opaques carbonate fluorite and apatite. Clinopyroxene episyenites in a proterozoic rapakivi granite se finland recrystallization textures mass transfer and implications for the petrology of a type granite complexes einari suikkanen1 o.

The oldest granites have been found in the eastern amazonian region where the ages of several complexes. Table 1 shows the available relevant and accurate data. The general picture is thus similar to that observed in the amcg suites of north america differing in some degree from the classic finnish rapakivi.