EXERCISE 5.8 Insights from Melting Experiments Name: Course: Section Date:-- Res

Question

EXERCISE 5.8 Insights from Melting Experiments Name: Course: Section Date:-- Results from melting experiments help explain several aspects of igneous rock texture and composition. Remember that crystallization is the exact opposite of melting. Answer the following questions (a) The figure below shows textural features displayed by plagioclase feldspar (left) and pyroxene and amphibole (right) found in many igneous rocks. Considering the continuous and discontinuous legs of Bowen's reaction series, suggest an explanation for the origin of these textures Photomicrographs of common mineral textures in igneous rocks Compositionally zoned plagioclase feldspar with Ca-rich core and progressively richer Na rims Pyroxene grain (px; dark green) with amphibole rim (am; light green). (b) From Bowen's reaction series, is it likely that minerals with high melting points will occur in rocks with minerals with low melting points?Explain 5.4 ORIGIN AND EVOLUTION OF MAGMAS 121

Explanation / Answer

a)left part is normal zonning because the core is calcic rich where as rim is sodium rich.This is continuous reaction series in which anorthite which is calcic is the high temperature mineral and gradually it becomes sodic as temperature decreases.

right side figure is of discontinuous reaction in which pyroxene has formed fast and followed by amphibole.

b)

the more high temperature of a mineral the more will it prone to instability,so quartz and olivine rarely coexist.so it is very to exist a high temperature with a lower one.

c)lowet maga temperature to highest -

granite (granitic,felsic) ,andesite (intermediate),gabbro(mafic) ,peridotite(ultramafic)

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.