1
24-060
Mineralogy And Geochemistry of Heavy Mineral Beach-Placer
Sandstones in New Mexico
Evan J. Owen
NM Bureau of Geology and Mineral Resources,
New Mexico Tech, Socorro, NM
Virginia T. McLemore
NM Bureau of Geology and Mineral Resources,
New Mexico Tech, Socorro, NM
ABSTRACT
Heavy mineral beach-placer sandstones are accumulations
of high specific gravity, resistant minerals that form from
mechanical concentration by waves, currents, and winds
in marginal-marine environments. These sediments are
enriched in critical minerals such as titanium, zirconium,
and REE. Cretaceous beach-placer sandstones are found
in the Colorado Plateau of northwestern New Mexico.
Originally discovered by airborne radiometric surveys for
uranium in the 1950s, these beach-placer sandstones are
being re-examined with modern methods as potential
sources for critical minerals. Selected beach-placer sand-
stones have been sampled, mapped with ground radiomet-
ric surveys, and analyzed with whole-rock and trace element
geochemical methods. Mineralogy is being determined with
optical methods, XRD, and EMPA. Zircon, rutile, ilmen-
ite, and monazite are the primary heavy minerals of interest
found in the studied deposits. Initial results show that the
sandstones contain up to 1.4% total REE, 29.4% TiO2,
and an estimated 4.9% ZrO2. Chondrite-normalized REE
diagrams show distinct light REE and minor heavy REE
enrichment, as well as pronounced negative Eu anomalies
for each deposit.
INTRODUCTION
Heavy mineral beach-placer sandstones are accumulations
of high specific gravity, resistant minerals that form from
mechanical concentration by waves, currents, and winds in
marginal-marine environments (Van Gosen et al., 2014).
These sandstones contain minerals such as zircon, rutile,
ilmenite, and monazite, sources of critical minerals such
as zirconium, titanium, and rare earth elements (REE).
Critical minerals are mineral commodities that are essen-
tial to the economic and national security of the United
States (Ellis, 2018). The United States is 100% import reli-
ant on many critical minerals and are currently sourcing
them from countries that can easily disrupt supply chains.
These commodities are also required for modern electron-
ics, as well as in technology for the green energy transi-
tion, such as wind turbines, solar panels, and electric cars
(Goodenough, 2018).
Cretaceous heavy mineral sandstones are found in
the Colorado Plateau within the San Juan Basin in north-
western New Mexico (Dow and Batty, 1961 McLemore,
2010 2016 2017). This Upper Cretaceous-Early Tertiary
age structural basin extends into southern Colorado and
contains significant coal, uranium, petroleum, and natural
24-060
Mineralogy And Geochemistry of Heavy Mineral Beach-Placer
Sandstones in New Mexico
Evan J. Owen
NM Bureau of Geology and Mineral Resources,
New Mexico Tech, Socorro, NM
Virginia T. McLemore
NM Bureau of Geology and Mineral Resources,
New Mexico Tech, Socorro, NM
ABSTRACT
Heavy mineral beach-placer sandstones are accumulations
of high specific gravity, resistant minerals that form from
mechanical concentration by waves, currents, and winds
in marginal-marine environments. These sediments are
enriched in critical minerals such as titanium, zirconium,
and REE. Cretaceous beach-placer sandstones are found
in the Colorado Plateau of northwestern New Mexico.
Originally discovered by airborne radiometric surveys for
uranium in the 1950s, these beach-placer sandstones are
being re-examined with modern methods as potential
sources for critical minerals. Selected beach-placer sand-
stones have been sampled, mapped with ground radiomet-
ric surveys, and analyzed with whole-rock and trace element
geochemical methods. Mineralogy is being determined with
optical methods, XRD, and EMPA. Zircon, rutile, ilmen-
ite, and monazite are the primary heavy minerals of interest
found in the studied deposits. Initial results show that the
sandstones contain up to 1.4% total REE, 29.4% TiO2,
and an estimated 4.9% ZrO2. Chondrite-normalized REE
diagrams show distinct light REE and minor heavy REE
enrichment, as well as pronounced negative Eu anomalies
for each deposit.
INTRODUCTION
Heavy mineral beach-placer sandstones are accumulations
of high specific gravity, resistant minerals that form from
mechanical concentration by waves, currents, and winds in
marginal-marine environments (Van Gosen et al., 2014).
These sandstones contain minerals such as zircon, rutile,
ilmenite, and monazite, sources of critical minerals such
as zirconium, titanium, and rare earth elements (REE).
Critical minerals are mineral commodities that are essen-
tial to the economic and national security of the United
States (Ellis, 2018). The United States is 100% import reli-
ant on many critical minerals and are currently sourcing
them from countries that can easily disrupt supply chains.
These commodities are also required for modern electron-
ics, as well as in technology for the green energy transi-
tion, such as wind turbines, solar panels, and electric cars
(Goodenough, 2018).
Cretaceous heavy mineral sandstones are found in
the Colorado Plateau within the San Juan Basin in north-
western New Mexico (Dow and Batty, 1961 McLemore,
2010 2016 2017). This Upper Cretaceous-Early Tertiary
age structural basin extends into southern Colorado and
contains significant coal, uranium, petroleum, and natural