GEOLOGY PPT.pptx1 (1).pptx

bowen reaction series

1. DEPARTMENT OF APPLIED GEOLOGY DR. HARISINGH GOUR VISHWAVIDYALAYA, SAGAR(M.P.) PRESENTATION ON “BOWEN REACTION SERIES AND REACTION PRINCIPLES”

2. PRESENTED BY: 1- YASH KUMAR RAJAK. 2- MOHIT KUMAR. 3- DIPENDRA KUMAR NAMDEV. 4- ANKIT PANDEY. 5- RAJEEV DEWANGAN. 6- ABHISHEK TRIPATHI. 7- ANKIT PANDIT. UNDER GUIDANCE OF: DR. HAREL THOMAS PROFESSOR,DEPARTMENT OF APPLIED GEOLOGY

3. INDEX ….. INTRODUCTION. WHAT IS BOWEN REACTION SERIES ? DIAGRAM CONTINUOUS REACTION SERIES. DISCONTINUOUS REACTION SERIES. FRACTIONATION. TYPES OF MAGMA. BOWEN REACTION PRINCIPLE.

4. INTRODUCTION ….. BACK IN THE EARLY 1900’s, N.L.BOWEN AND OTHER AT THE GEOPHYSICAL LABORATORIES IN WASHINGTON D.C. BEGAN EXPERIMENTAL STUDIES INTO THE ORDER OF CRYSTALLIZATION OF THE COMMON SILICATE MINERALS FROM A MAGMA. THE IDEALIZED PROGRESSION WHICH THEY DETERMINED IS STILL ACCEPTED AS THE GENERAL MODEL FOR THE EVOLUTION OF MAGMA DURING THE COOLING PROCESSES. IT DESCRIBES THE FORMATION OF IGNEOUS ROCKS FROM DIFFERENT STARTING TEMPERATURES AND MAGMA COMPOSITIONS.

5. WHAT IS BOWEN REACTION SERIES ? IT IS THE WORK OF PETROLOGIST, NORMAN BOWEN WHO WAS ABLE TO EXPLAIN WHY CERTAIN TYPES OF MINERALS TEND TO FOUND TOGETHER WHILE OTHER ARE ALMOST NEVERASSOCIATED WITH ONE ANOTHER. THE BOWEN REACTION SERIES IS HAVING TWO BRANCHES-THE CONTINUOUS AND DISCONTINUOUS SERIES. THE BRANCH ON THE RIGHT IS THE CONTINUOUS. THE MINERALS AT THE TOP OF THE ILLUSTRATION ARE FIRST TO CRYSTALIZE AND SO THE TEMPERATURE GRADIENT CAN BE READ TO BE FROM HIGH TO LOW WITH THE HIGH TEMPERATURE MINERALS BEEN ON THE TOP AND THE LOW TEMPERATURE ONES ON THE BOTTOM.

6. DIAGRAM ….

7. IT IS DIAGRAMED AS “Y”. THE FIRST HORIZONTAL LINE – USUALLY PLACED JUST ABOVE THE TOP OF THE “Y” – REPRESENTS A TEMPERATURE OF 1800°C. THE NEXT HORIZONTAL LINE REPRESENTS A TEMPERATURE OF 1100°C AND IS LOCATED ONE-THIRD OF THE WAY BETWEEN THE TOP OF THE “Y” AND THE POINT WHERE THE TWO ARMS JOIN THE BASE. A THIRD LINE REPRESENTING A TEMPERATURE OF 1900°C IS LOCATED TWO-THIRDS OF THE WAY FROM THE TOP OF THE “Y” TO THE JUNCTION OF THE UPPER ARMS.

8. A FOURTH HORIZONTAL LINE REPRESNTING A TEMPERATURE OF 600 ° C INTERSECTS THE TRIPLE POINT JUNCTION WHERE THE UPPER ARMS OF THE”Y” MEET THE BASE PORTION. THE HORIZONTAL TEMPERATURE LINES DIVIDE THE “Y”INTO FOUR COMPOSITIONAL SECTIONS. MINERAL FORMATION IS NOT POSSIBLE ABOVE 1800C. BETWEEN 1100 ° C AND 1800 ° C, ROCKS ARE ULTRAMAFIC IN COMPOSITION. BETWEEN 900 ° C AND 1100 ° C, ROCKS ARE MAFIC IN COMPOSITION. BETWEEN 600 ° C AND 900 ° C, ROCKS ARE INTERMEDIATE IN COMPOSITION. BELOW 600 ° C, FELSIC ROCKS FORM.

9. CONTINUOUS REACTION SERIES …… IT STARTS FROM THE RIGHT. EARLIER FORMED MINERALS SLOWLY AND STEADILY CHANGE INTO NEW MINERALS. THE HIGHEST TEMPERATURE PLAGIOCLASE HAS ONLY CALCIUM {C a }. THE LOWEST TEMPERATURE PLAGIOCLASE HAS ONLY SODIUM {N a }. CRYSTALLIZATION OF PLAGIOCLASE FELDSPAR DEPLETES CALCIUM FROM THE PARENT MAGMA AND REPLACES THE MISSING ELEMENT WITH SODIUM AS NEW MINERALS ARE FORMED. FELDSPAR MINERALS FORM CONTINUALLY AT THE SAME TIME AS MINERALS SHOWN OPPOSITE IN THE DISCONTINUOUS SERIES.

10. DISCONTINUOUS REACTION SERIES ….. IT STARTS FROM THE LEFT. EARLIER FORMED CRYSTALS REACT WITH THE REMAINING MAGMA IN A SERIES OF STEPS TO FORM A NEW MINERAL.

11. THESE ARE GROUP OF MAFIC OR IRON MAGNESIUM BEARING MINERALS LIKE OLIVINE, AMPHIBOLES, AND BIOTITE. FROM AN INITIAL BASALTIC MAGMA, THE FIRST FORMED MINERAL IS OLIVINE[M g₂SiO₄ ]. REMOVAL OF OLIVINE INCREASES THE SILICA CONTENT AND DECREASES THE IRON AND MAGNESIUM IN THE PARENT MAGMA. AS THE TEMPERATURES LOWERS, A NEW CHAIN SILICATE MINERAL, PYROXENE [Ca Mg(SiO3)₂] IS FORMED.

12. AS THE TEMPERATURE DROP FURTHER FROM 1100 ° C-850 ° C, THE MAGMA BECOMES EVEN RICHER IN SILICATES. AMPHIBOLE BEGINS TO FORM. THE ORIGINAL BASALTIC MAGMA BECOMES ANDESITIC MAGMA.

13. As temperature cools to 800 ° c and silica increases further, the sheet silicate biotite forms. Andesitic magma now evolves into rhyolitic magma. rhyolite

14. Quartz forms last at low temperature. Muscovite mica and potassium feldspar also form at this temperature. All of these minerals are poor in mafic components which were removed from the melt by minerals that formed earlier. quartz muscovite potassium feldspar This Photo by Unknown Author is licensed under CC BY-SA

15. Fractionation …. it is the process by which minerals are formed and removed from the molten rock. As the magma cools, higher temperature, mafic minerals crystallizes, and more felsic magma is left. Systematic crystal fractionation .

16. Types of magma ….. Igneous rock come in four basic varieties: ultramafic, mafic, intermediate, and felsic. Bowen reaction series shows the relationship among the 8 rock forming minerals. Minerals from the bottom of Bowen reaction series tend to be more sodium and potassium rich, high in silica, cooler in temperature and light colour. Bowen’s reaction series describes the temperature depicts mineral formation in a cooling magma. The continuous side depicts a solid solution series. The discontinuous side depicts mineral formation at decreasing temperatures. Viscosity increases as the temperature cools.

17. The temperature of the magma and the rate of cooling determines which minerals are stable. Slower the magma cools, larger the crystal size. Bowen reaction series allows the geologists to predict chemical composition and texture based upon the temperature of the magma cooling.

18. Bowen reaction principle …… A concept, first propounded in 1928 by norman bowen, which explains how minerals can respond to the changing equilibrium conditions when a magma is cooled, either by a continuous, diffusion-controlled exchange of elements with the magma or discontinuous melting of minerals. IN A CONTINUOUS EXCHANGE, SOLIDS SOLUTION MINERALS SUCH AS FELDSPAR ADJUST THEIR COMPOSITION DURING COOLING BY A CONTINUOUS DIFFUSION OF ELEMENTS BETWEEN MAGMA. IN ADICONTINUOUS REACTION, MINERALS SUCH AS OLIVINEUNDERGO MELTING AT A SPECIFIC TEMPERATURE DURING COOLING AT THE SAME TIME AS A NEW MINERAL IN EQUILIBRIUM WITH THE MAGMA BEGINS TO CRYSTALLIZE.

19. HOPE YOU ENJOYED IT ……