NEW FACTS: Komatiite magma cannot reach the surface
of the Earth because it is very dense and it has very high
melting point temperature. This fact is contradicted
by evidence that 4.5 billion years ago (Hadean eon)
oceanic crust was made of komatiite and basalt.
(Continental crust was made of tonalite and granodiorite,
and later, granites.) Some komatiite rocks formed later,
in the Archean eon. The Archean komatiites were altered
by metamorphism and water. 4.5 billion years ago the
average wind speed was about 800 kilometers per hour.
Anhydrous komatiite containing 28% MgO has a density
of about 2800 kg/m3 at atmospheric pressure, but at
pressures greater than 8 GPa (which correspond to a mantle
depth of about 250 km) komatiite is more dense than olivine
and pyroxene because komatiite is very compressible.
(source: Rigden et al, 1984; Agee and Walker, 1988; Miller
et al, 1991) The viscosity of komatiite magma is very low,
one to two orders of magnitude less than that of basalt.
(source: N.T. Arndt and C.M. Lesher, Komatiite,
http://hal.archives-ouvertes.fr/docs/00/10/17/12/PDF/Arndt_Lesher.pdf)
Its melting point temperature is between 1560 and about
1600°C. (source: Bickle et al. 1977; Green 1974; Nisbet
1982) Spinifex is a texture unique to komatiite. It is
a texture characterized by large, skeletal, dendritic,
platy, bladed or acicular grains of olivine or pyroxene
found in the upper parts of komatiitic flows, or, less
commonly, at the margins of sills and dikes.
(source: Kent C. Condie, "Archean crustal evolution,"
Elsevier Science, November 11, 1994, page 37)
Basalt melts at about 984° to 1260° and granite at
about 1215°C to 1260°C. (source: American Mineralogist,
Volume 14, pages 81-94, 1929, THE TEMPERATURES OF
MAGMAS, ESPER S. LARSEN, Harvard University)
The unique spinifex texture has been explained by
turbulent flow of the komatiite. The turbulent flow
inhibited the settling of olivine grains. (source:
Turner, J.S., Huppert, H.E. and Sparks, R.S.J, 1986.
Komatiites II: Experimental and theoretical investigations
of post-emplacement cooling and crystallization. J.
Petrol., 27: 397-437) Convection in the Komatiite
magma is sluggish or absent (source: Renner, R.
Cooling and crystallization of komatiite flows from
Zimbabwe, Ph.D Thesis, University of Cambridge, 1989,
162 pp.) so convection could not produce the turbulent
flow. Most komatiite rocks formed in a dry environment
(source: N. Arndt, C. Ginibre, C. Chauvel, F. Albarède,
M. Cheadle, C. Herzberg, G. Jenner and Y. Lahaye, Were
komatiites wet?, Geology, August 1998, v. 26, p.
739-742) so the turbulent flow was not produced by the
presence of water. Some geologists claim that komatiite
rocks formed because the Archean mantle sources of
komatiite were 200-300 °C hotter than modern mid-ocean
ridge mantle. (sources: R.I. Hill, I.H. Campbell, G.H.
Davies and R.W. Griffiths, "Mantle plumes and continental
tectonics" Science 256:186-93, 1992; Nisbet, E. G.,
Cheadle, M.J., Arndt, N.T., and Bickle, M.J., 1993,
Constraining the potential temperature of the Archaean
mantle: a review of the evidence from komatiites.:
Lithos, v. 30, p. 291-307. Ohtani, E., 1984, Generation)
This claim is not convincing because 4.4 billions years
ago zircons formed from magmas containing a re-worked
continental crust that formed in the presence of liquid
water near the Earth's surface. The presence of liquid
water implies low temperature of the Earth's surface.

HYPOTHESIS: Extremely high pressure inside the Earth's
crust is the only plausible reason for the presence of
komatiite on the Earth's surface. When Theia's
atmosphere collided with the Earth, the collision
deformed the Earth's crust, cracked the crust, and
generated extremely high pressure deep inside the crust.
It took a few days for the pressure to relax. During
that time the komatiite magma flowed up to the Earth's
surface because its viscosity was very low. The
komatiite magma was a supercritical fluid; it had the
viscosity of gas but the density of rock. The collision
between Theia's atmosphere and the Earth produced
extremely high pressure but it did not melt the Earth's
surface because it was soft collision, similar to a
collision between a motorist's head and the airbag. The
hurricanes produced turbulent flow of the komatiite
magma, which explains the unique spinifex texture of
the komatiite. The rising komatiite plumes froze inside
the mantle and expanded due to high compressibility of
komatiite. The plumes did not sink back to the depth of
250 km because the expanded komatiite had low density.
The movement of tectonic plates in the Archean eon
pushed some komatiite plumes up to the Earth's surface
and gradually sunk the remaining plumes.