profile-img
Riya Sen posted an Question
October 16, 2021 • 13:34 pm 30 points
  • IIT JAM
  • Geology (GG)

(1t jam z01 no. the geochemical trends illustrated in the dia- rams for a suite of cogenetic and coeval 18 neous rocks indicate: sio, a. olivine crystallization

(1T JAM Z01 No. The geochemical trends illustrated in the dia- rams for a suite of cogenetic and coeval 18 neous rocks indicate: SiO, A. Olivine crystallization B. Clinopyroxene crystallization C. Plagioclase crystallization D. Alkali feldspar crystallization (11T-JAM 2015)

1 Answer(s) Answer Now
  • 0 Likes
  • 1 Comments
  • 0 Shares
  • comment-profile-img
    Mayank vedwal Vedwal Best Answer

    This problem is based on harker diagram. Here you can see that with the increase in the SiO2 content MgO and CaO content is decreasing and Al2O3 increasing. Harker diagram represents the magmma evolution trend in a particular set of rocks found in an area. So by looking at the given harker diagram we can interpret :- since with the evolution of magma CaO and MgO content is decreasing means the minerals containing CaO and MgO are forming and removing from melt. Olivine contain MgO in its composition and cox contains both CaO and MgO in its composition so these two minerals are formed from the evolution of magma. Plagioclase and alkali feldspar both contain Al2O3 in their composition and here Al2O3 content is increasing so we can say that these two aren't formed from magma. So option A and B are correct.

    eduncle-logo-app

    thank you sir😊

    eduncle-logo-app

    welcome dear 🙂

whatsapp-btn

Do You Want Better RANK in Your Exam?

Start Your Preparations with Eduncle’s FREE Study Material

  • Updated Syllabus, Paper Pattern & Full Exam Details
  • Sample Theory of Most Important Topic
  • Model Test Paper with Detailed Solutions
  • Last 5 Years Question Papers & Answers