BYU

Abstract by Haley Mosher

Personal Infomation


Presenter's Name

Haley Mosher

Degree Level

Undergraduate

Abstract Infomation


Department

Geological Sciences

Faculty Advisor

Bart Kowallis
Eric Christiansen

Title

What Happens When Magmas Mix?: Titanite in Mafic Enclaves in the Little Cottonwood Stock, Utah

Abstract

            Titanite is an accessory mineral found in many granites that is useful when studying petrogenic processes. The Little Cottonwood (LC) granite in western Utah was sampled for titanite as were the mafic enclaves found in the LC stock. Both enclave and LC titanite grains tend to have primary mottled cores with abundant inclusions of rounded ilmenite, surrounded by mantles with oscillatory and sector zoning. Enclave grains tend to be larger and have more ilmenite inclusions. Several enclave grains have a poikilitic or spongey texture, indicative of late-stage titanite growing around feldspar and quartz grains; these have only been found in enclaves. Chemically, enclave titanite has slightly lower REEs (0.01-0.04 vs 0.02-0.05 apfu) and Fe (0.02-0.05 vs 0.03-0.07) than titanite in LC granite, although enclave grains tend to have a wider chemical range. Both texturally and chemically, these titanite grains  indicate at least one magma mixing event between a granitic  and more mafic magma triggered titanite crystallization in the enclave magma.