In all geologic time, the responsibilities are on our generation ... including you ...

Highlands vs. Lowlands Geologies

Like on all planetary crusts and the dirt under your feet here on Earth, lunar material consists predominantly of silicate minerals, i.e., silicon and oxygen molecularly bonded to various metal atoms. However, the lunar highlands differ from the lunar lowlands mainly in their concentrations of the metal oxides.

The early lunar crust formed a "magma ocean" which solidified into a crust of the lightest minerals which had floated to the top, predominantly aluminum calcium silicates ("anorthositic material") about 4.5 billion years ago. In fact, this crust is quite rich in aluminum and calcium compared to Earth's crust. (Earth's crust is split into two layers, the top being richer in aluminum silicates, "SiAl", with an underlying layer of magnesium rich silicates, "SiMg".)

However, the period between 4.5 and 4.0 billion years ago was marked by heavy bombardment by meteors and asteroids, causing intense cratering.

The highlands geology is mostly composed of overlapping layers of material ejected from craters, predominantly the initial anorthosite (aluminum rich) crust. Rocks brought back from the highlands vary in age between 3.84 and 4.48 billion years old.

Today's flat lowlands "mare" regions ("mare" is Latin for "sea") formed about 4 billion years ago when immense asteroid impacts fractured the crust, allowing the lavas from 300 kilometers deep (200 miles) to erupt through the impact fractures and form vast seas of lava. (For comparison, Earth's crust today is 50 kilometers, or 30 miles, thick in most places.) This material was poor in aluminum and calcium, but rich in iron and magnesium. However, the lavas melted preexisting aluminum-rich surface materials and mixed with them. The lava was rich in the heavier radioactive elements which had initially settled well below the crust, and the radioactivity kept the molten seas of lava hot for millions upon millions of years. Mare rocks have been measured to be between 3.15 and 3.77 years old. The last molten lakes are thought to have finally solidified about 3 billion years ago.

The resulting material which makes up the surface of these ancient lava seas is rich in iron and magnesium minerals, with a remarkably high content of titanium minerals.

When you look at the moon, the mares are the darker areas, and tend to be circular in shape because they formed in giant asteroid impact spots.






PERMANENT.com > Lunar Resources (Mining The Moon) > Origin and Composition > Geology, Highlands vs. Lowlands




To get updates on PERMANENT (occasional, not frequent), get on our mailing list.

For general or specific e-mail regarding PERMANENT, please use our Feedback page.

Leave information about yourself in our people, companies, and organizations database.

If you are interested in hiring our expertise, anywhere in the world, please contact us.
We have people in the USA and Thailand, and can travel or consult by internet.
You can call anytime, 24/7, at +66-8-1135-7977

Text by Mark Prado, Copyright © 1983-2013, All Rights Reserved.
Many website artistic design elements by Sam Fraser, Copyright © 1999-2013, All Rights Reserved.

Except where specifically stated otherwise,
Copyright © 1983-2013 by Mark Evan Prado, All Rights Reserved

Source: http://www.permanent.com

PERMANENT logo
P rojects to E mploy R esources of the M oon and A steroids N ear E arth in the N ear T erm

Menu:
please see our

Site Map

to navigate.

For PCs, this righthand
side has a floating menu,
but if your tablet
or your PCs web browser
do not run
-- javascript --
then you must
-- navigate --
using the Site Map above.