This document discusses basalts, which are volcanic rocks formed from the solidification of magma. It describes two main types of basalts based on their tectonic environment: mid-ocean ridge basalts (MORB) and ocean-island basalts (OIB). MORB comes from the depleted upper mantle, while E-MORB comes from the deeper, more fertile mantle. The document also discusses how basalts are categorized based on their chemical composition and the partial melting of mantle rock that leads to the formation of basaltic magma. Finally, it outlines some industrial uses of basalt, including in fibers that are superior to other fibers for properties like thermal stability and durability.

2. YADU’S

13. Basalts are also categorized according to the tectonic
environment in which they have erupted:
‘ mid - ocean ridge basalt’ (MORB) and
‘ocean - island basalt’(OIB)
A “typical” MORB is an olivine tholeiite with low
K2O (< 0.2%) and low TiO2 (< 2.0%)
 N-MORB (normal MORB) taps the depleted upper
mantle source
 Mg# > 65: K2O < 0.10 TiO2 < 1.0
 E-MORB (enriched MORB, also called P-MORB for
plume) taps the (deeper) fertile mantle
 Mg# > 65: K2O > 0.10 TiO2 > 1.0

14. Wt. % Oxides to Atom % Conversion
Oxide Wt. % Mol Wt. Atom prop Atom %
SiO 2 49.20 60.09 0.82 12.25
TiO 2 1.84 95.90 0.02 0.29
Al2O3 15.74 101.96 0.31 4.62
Fe 2O3 3.79 159.70 0.05 0.71
FeO 7.13 71.85 0.10 1.48
MnO 0.20 70.94 0.00 0.04
MgO 6.73 40.31 0.17 2.50
CaO 9.47 56.08 0.17 2.53
Na 2O 2.91 61.98 0.09 1.40
K2O 1.10 94.20 0.02 0.35
H2O+
0.95 18.02 0.11 1.58
(O) 4.83 72.26
Total 99.06 6.69 100.00

16. Trace Element and Isotope Chemistry
REE diagram for MORBs
Figure 13.11. Data
from Schilling et
al. (1983) Amer. J.
Sci., 283, 510-586.

18. Magma Types Based on Chemistry
gabbro/basalt diorite/andesite granite/rhyolite
50% SiO2 60% SiO2 70% SiO2

19. Partial Melting of Different Starting Materials
Peridotite (mantle rock)  Basaltic Magma
Basaltic (oceanic crust)  Andesitic Magma
Andesitic (continental crust)  Rhyolitic Magma

20. Mantle Melting and the Origin of Basaltic Magma

22. Primary Basaltic Magmas
• Mantle melts with no subsequent modification by
secondary processes (fractional crystallization, assimilation,
mixing).
• Criteria:
• SiO₂ < 50 wt%
• MgO > 7 wt%
• Cr > 1000 ppm
• Ni > 400 ppm
• Rarely observed, “Holy Grail” of basalts, very important for
petrologists and geochemists, fingerprint of mantle source!

24. Uses of Basalt
The industrial applications of basalt are based on the basic
quality properties of basalt such as high abrasion
resistance, compressive strength and chemical resistance.
Basalt can made into fine, superfine and ultra fine fibers,
basalt fibers are considered superior to other fibers in
terms of thermal stability, heat and sound insulation
properties, vibration resistance and durability.
Basalt continuous fibers offer the prospect of a completely
new range of composite materials and products, such
products have no toxic re-action with air or water, are non
combustible and explosion proof, when it contact with
other chemicals they produce no chemical reactions that
may damage health or environment.
Basalt replaces almost all applications of asbestos and has
three times heat reinforced plastics (1 kg. of basalt
reinforcement equal 9 kg. steel).