Sample SP46 -Apishapa Crag

Two views of Apishapa Crag - Just east of Aquilar, CO - Views are looking northeast (TOP) and east (bottom).

Thin Section from SP46

Thin-section under crossed-nicols (5 mm in diameter). Oscillatory Zoned Titanaugite phenocryst with fine-grained Olivine inclusion. The matrix is primarily very-fine-grained plagioclase lathes.

Another cool thin section showing a titanaugite contact twin with oscillatory zonation. FOV about 5mm

Click here for available geochemistry

Thin Section Description

SP46 (Apishapa Crag). Basalt. (Really a pyroxinode) This rock is holocrystalline, porphyritic-aphanitic, with fine- to medium-grained phenocrysts in a grey groundmass (22%) composed of opaques, augite, apatite, and plagioclase. The olivine (1-4 mm) and the opaque minerals (.5- 1 mm) are subhedral to anhedral The following phenocryst phases are subhedral: orthopyroxene and titanaugite (both 1-3 mm) have conspicuous twinning, some with sieve texture, and some with sector and oscillatory zonation. Several of the pyroxene grains are embayed and are partially resorbed. Ocelli (1 mm) occur rimmed with inward pointing clinopyroxene crystals. The interior of the ocelli are filled with quartz, augite, and zircon. Olivine (<.1 mm) moderately altered to iddingsite occurs as inclusions in augite. Some of this iddingsite is replaced by fluorite. The overall texture is glomeroporphyritic with plagioclase lathes (< .1 mm) rimming some of the larger phenocrysts.