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President’s
Corner
Mike Smith,
President
February turned into “minerals road trip month” for several FMC members as Barry
Knapp, Karen Simmons, and yours truly headed off on a 10-day expedition to
the annual Tucson Gem and Mineral Show.
This year’s show theme was “Fluorite: Colors of the Rainbow,” and there were
dozens of showcases full of gorgeous examples of a mineral that we often
tend to ignore because of its relative abundance. Sightseeing and prospecting stops on the
drive down to Tucson included the Mineral Museum at New Mexico Tech in
Socorro (very nice!), exploring the Kelly Mine dump and ghost town site south
of Magdalena, drooling over world-class but pricey Kelly Mine smithsonite in the two small mineral shops at
Magdalena, and a visit to the Very Large Array (http://www.vla.nrao.edu/),
whose 28 radio telescope dishes on the Plains of Saint Augustin
west of Socorro play a central role in the movie “Contact.” Down in Tucson, we also toured the
University of Arizona’s Steward Observatory Mirror Lab
(http://mirrorlab.as.arizona.edu/), where the largest optical telescope
mirrors in the world are currently being built. On the way back, we toured Tombstone AZ
(and yes, Boot Hill as well as the OK Corral ; ), did some successful rockhounding around Fluorite Ridge north of Deming, and
explored Silver City NM, Pinos Altos, and
environs. As usually happens on such
trips, we end up with enough ideas and unfinished business for multiple
return trips…Gotta go back!
I believe there may still be a
couple of open slots for Ed Raines’s upcoming Front Range Geology class…ten
Wednesday evening sessions and four field trips for FMC members only. Contact Gabi Accatino if you are
interested.
And don’t forget our monthly FMC
meeting on Thursday, March 14—see program below.
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Spring Meetings
& Field Trips
The
March program will be Thursday, March 14, and our speaker will be John Widirstky, who will talk on “Gold and Its
Processing.” John has worked in gold
mining and milling since 1974, and is a 25+ year member of the Society of
Mining Engineers. He produced over 4 tons of gold, and ran the largest mine
production in the state for two years.
It promises to be a very interesting evening 1974.
The
April program will be our annual silent auction. A flyer and bid sheets are
attached to this newsletter.
For
May we will have a short program by Ray Horton about the Phoenix Mine near
Idaho Springs, where he works, and Field Trip sign-ups.
The
June program will be Preethi Burkholder, the
presentation is titled "Ghost Towns of the Rockies.”
Preethi is the author of
the book "Ghost Towns of the Rockies" Rocky Mountain ghost towns
are filled with chilling but captivating tales from the mining era when
Gold, Silver, Coal, Copper, and Clay Mining ruled the West. Horace Tabor
the Silver King of Leadville was one of the wealthiest men in the country.
He lost all his fortune in the Silver Panic of 1893 and was shoveling dirt
for $0.65 cents a day at the time of his death. This will be a PowerPoint
presentation, along with storytelling and perhaps some piano music from the
mining era.
For
the first field trip of the year, we will return to North Table Mountain
outside of Golden on Saturday, May 4.
North Table Mountain is a world-renown site for collecting zeolites.
Thomsonite, analcime, chabazite, mesolite, and
calcite are quite common, plus a number of other zeolite minerals can also
be found.
The
hike from the parking area is about a mile, climbing about 700 feet in
elevation. There is a new trail to
the site, so the hike is not as steep as the previous route. This is a great trip to take kids, as
everyone will find specimens to take home.
Children must be accompanied by an adult.
If you would like to come on this trip,
you can sign up at the April meeting or contact Dennis Gertenbach. Details about the trip will be sent to
those who sign up for the trip. Once
again, Dennis Gertenbach will be leading the
trip.
We're
working on the summer trip schedule and I am collaborating with Gary Rowe
of CMS to continue to have joint trips.
--Gabi Accatino
A
chabazite specimen found during a previous year’s
North Table Mountain trip
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Jr. Geologists
Activities
During
January’s meeting, the Jr. Geologists learned about fluorescent minerals as
they earned the Fluorescent Minerals badge.
The children were encouraged to bring specimens from their
collections to see if they fluoresced.
They also chose one fluorescent mineral and learned more about their
chosen mineral. Here is a list of
fluorescent minerals that the Jr. Geologists identified.
Sheelite is a tungsten
mineral that is yellow in natural light and sky blue under ultraviolet
light (Josiah Henning, age 7)
Willemite is a tan color
under normal light and green under UV light. It is found in New Jersey and
Namibia. (Riley Petrone,
age 7)
Botryoidal Fluorite is dark
purple in regular and green in UV light.
It comes from Canon City in Fremont County, Colorado, and is also
found in different parts of Asia like China and India. (Gavin Morrison, age 9)
Fluorescent
Opal is a white mineral that fluoresces green. It is found in Denio,
Nevada. (Andrew Caballero, age 9)
Opal
is white in normal light and green under black light. Opal can be found in Mexico, Brazil, and
the U.S. (Ian Crittenden, age 10)
Zeolites
she found on North Table Mountain are pinkish white in normal light and
greenish under ultraviolet light. (Miu Iwabuchi, age 12)
Gerry
Naugle showing the Jr. Geologists fluorescent
minerals.
Gerry
explaining to the Jr. Geologists how some minerals fluoresce.
Calcite
samples from Wyoming.
The
same calcite samples under shortwave ultraviolet light.
Beginning
in March, the Jr. Geologists will start working on the Fossil Badge. They will learn how fossils are formed,
what fossils tell us about ancient environments, and how to identify
different fossils. The older Jr.
Geologists will learn more advanced information about fossils and the
animals and plants they came from.
The meeting will be at the Boulder Library Reynolds Branch, 3595 Table
Mesa Drive in Boulder, starting at 6:30 p.m.
The
Jr. Geologists program is open to all Flatirons Mineral Club families. Each month we learn more about geology,
plus earn badges for different earth science activities. For information about the Jr. Geologists
program, please contact Dennis Gertenbach.
The
Jr. Geologists program is looking for adults to help with the monthly
programs. If you would enjoy working
with the kids, either for a special activity or at their monthly meeting,
please contact Dennis.
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Front Range Geology Course
Our
club is offering a geology course to its members!
Ed
Raines will teach his Front Range Geology course this spring. The weekly
course will start on Wednesday, April 3 and go through Wednesday, June 5 -
ten sessions of classes.
It
will include 4 field trips on weekends during the term. They will
correspond to the course material. Ed requests that the class members not
miss any classes. The material is cumulative and attendance is imperative.
We
have secured a classroom in the community room of the Boulder Outlook Hotel
at 800 28th Street. Classes will
start at 7PM. The class is limited to the first 12 participants who sign
up. To sign up, contact Gabi
Accatino.
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Get Your Very Own Flatirons Mineral Club Baseball
Cap
The
club now has Baseball caps in a variety of colors for sale. They sport the
newly revised FMC logo. Buy them at any meeting. The member price is $10
each, while the non-member price is $15.
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Fossils
in the News
Dennis Gertenbach
A New Family Tree
for Mammals
The
picture of our mammal ancestors hiding in the underbrush from the dinosaurs
to keep from being eaten may not be correct. Since the 1990s, many scientists thought
that some lineages of modern placental mammals (mammals who give live birth
to well-developed offspring) originated as early as 100 million years ago
when the dinosaurs ruled the earth, based largely on molecular
evidence. However, others have been
skeptical, because no fossils resembling these mammals have been found that
are older than 65 million years, when the dinosaurs went extinct.
A
new study by paleontologist Maureen O’Leary of Stony Brook University in
New York and colleagues related 46 species of living mammals, including
placental, marsupial and egg-laying mammals and 40 extinct species known
from fossils to each other. They
evaluated differences in 27 genes in the living species and 4,541 physical
traits related to bones, teeth and soft tissue. These data were then used to construct a new
family tree for mammals, based on the similarities of both genetic and
physical similarities and differences. The oldest fossils that have similar
characteristics with living placental mammals date to 64.85 million years
ago, after the dinosaur extinction.
An
artist’s rendition of an ancestor of modern placental mammals as a small,
insect-eating creature, based on the reconstructed mammal family tree. (Credit: Carl Buell)
New Theory on the
Origins of Bird Flight
A
new paper authored by Dr. Gareth Dyke of the University of Southampton and
associates describes a new feathered dinosaur which predates the bird-like
dinosaurs that scientists have long thought to be the ancestors of modern
birds. This new fossil, Eosinopteryx, was a 12-inch, flightless dinosaur that
lived 140 million years ago and was found in north-eastern China. The discovery sheds further doubt on the
widely-held theory that Archaeopteryx was pivotal in the evolution of
modern birds. Rather, this new
discovery reinforces the thought that birds evolved from a group of
dinosaurs called theropods from the Early
Cretaceous period, around 120-130 million years ago. Recent discoveries of
feathered dinosaurs from the older Jurassic period have reinforced this
theory. This latest find provides an
additional link between the older feathered dinosaurs and the first true
birds that could fly.
Reconstruction
of Eosinopteryx, a newly discovered bird-like
dinosaur that provides new insight into the origin of flight. (Credit: Royal
Belgian Institute of Natural Sciences)
270 Million Year
Old Tapeworm Egg Fossil
Paula
Dentzien-Dias and colleagues from the Federal
University of Rio Grande, Brazil, have discovered a cluster of tapeworm
eggs in 270-million-year-old fossilized shark feces. These fossilized intestinal parasites
eggs are much older than previously found.
Such remains are quite rare and the fossilized tapeworm eggs were
found in only one specimen of the 500 samples examined during this study.
The fossilized eggs were found in a cluster that is very similar to those
laid by modern tapeworms. Some of
the eggs are unhatched and one contains what
appears to be a developing larva.
This discovery shows that vertebrate intestinal parasites are much
older than was previously thought.
270
million-year-old parasite eggs in a shark coprolite (fossilized feces)
(Credit: Paula C. Dentzien-Dias and co-workers)
Crocodiles Fed On
Baby Dinosaurs
Newly
discovered fossils of a plant-eating baby ornithopod
dinosaur provide evidence that it was frequently dinner for an extinct
relative of the crocodile family. Research by Dr. Clint Boyd of the South
Dakota School of Mines and Technology and his colleagues found bite marks
on bone joints, as well as a crocodile tooth still embedded in a dinosaur
femur. These findings show that
dinosaurs were not always the top predators during the late Cretaceous
period. Four sites within the Grand
Staircase-Escalante National Monument in southern Utah had a large number
of mostly tiny bits of dinosaur bones, indicating that the crocodile
predation was widespread.
Furthermore, the number of bone bits point to small crocodiles, as
large crocodiles would have swallowed the dinosaurs
whole and not broken up the bones of their prey. In the process of their research, the
team discovered that these baby prey are a new, as
yet-to-be-named dinosaur species, which will be described in a separate
paper.
Crocodile
tooth embedded in the femur of a young dinosaur. (Credit: South Dakota
School of Mines and Technology).
****************
Geosciences
column: Iceland spar, or how Vikings used sunstones to navigate
By
Bárbara Ferreira, EGU’s Media and Communications Officer
Nowadays,
we can rely on GPS receivers or magnetic compasses to tell us how to reach
our destination. Some 1000 years ago, Vikings had none of these advanced
navigation tools. Yet, they successfully sailed
from Scandinavia to America in near-polar regions where it can be hard to
use the Sun and the stars as a compass. Clouds or fog and the long twilights characteristic of polar summers complicate
direct observations of these celestial bodies. So how did they find their
bearings? A new study published in Proceeding of Royal Society shows that
they probably used Iceland spar, a “sunstone”.
Centuries-old
Viking legends tell of glowing sunstones that navigators used to find the
position of the Sun and set the ship’s course even on cloudy days. In 1967,
a Danish archaeologist named Thorkild Ramskou speculated that the Viking sunstone could have
been Iceland spar, a clear variety of calcite common in Iceland and parts
of Scandinavia.
This
crystal has an interesting property called birefringence: a light ray
falling on calcite will be divided in two, forming a double image on its
far side. (This double image is easily seen by placing transparent calcite
on printed text.) Further, the Iceland spar is a polarising
crystal, meaning the two images will have different brightnesses
depending on the polarisation of light.
Birefringence
of Iceland Spar seen by placing it upon a paper with written text. Source:
Wikimedia Commons.
Light
is made up of electromagnetic waves with component electric and magnetic
fields. If these components have a specific orientation, the light is said
to be polarised, while in unpolarised
light the orientation of these fields has no preferred direction. Calcite
can appear dark or light depending on the polarisation
of light that falls upon it.
Sunlight
becomes polarised as it crosses the Earth’s
atmosphere, and the sky forms a pattern of rings of polarised
light centred on the Sun. Changing the
orientation of calcite as light passes through it will change the relative
brightness of the projections of the split beams, even when the Sun is
hiding behind clouds or just below the horizon. The beams are equally
bright when the crystal is aligned to the Sun.
It
can be hard to determine when exactly these split beams have equal
brightness. But the new study, led by Guy Ropars
at the University of Rennes 1 in France, suggests Vikings could have built
a simple device to better use the sunstone.
The
technique consists in covering the Iceland spar with an opaque screen with
a small hole in its centre and a pointer. As
light passes through the hole onto the crystal, a dark surface below it
receives the projection of the double image for comparison.
The
authors of the Proceedings of the Royal Society study believe Vikings could
have used a device like this to navigate. The crystal is inside, and the
projection of a double image is seen below it. Credit: Guy Ropars. Source: ScienceNOW.
By
rotating the apparatus and determining the direction at which the two
images were equal in brightness, the team managed to pinpoint the Sun’s
position on a cloudy day with an accuracy of one degree on either side. Researchers
also conducted tests when the Sun was largely below the horizon. “We have
verified that the human eye can reliably guess clearly the Sun direction in
dark twilights, even until the stars become observable,” Ropars’ team writes in the paper.
Although
archaeologists have not yet found Iceland spar among Viking shipwrecks, the
new study adds credence to the idea that Viking seafarers used the crystal
in their travels.
Further,
the recent finding of a calcite crystal on a sixteenth century Elizabethan
ship shows that navigators could have used Iceland spar even after the
appearance of the magnetic compass. Cannons on ships could perturb a
magnetic compass orientation by 90 degrees, so a crystal serving as an
optical compass could be crucial in avoiding navigational errors and get
sailors to a safe port.
****************
Chelyabinsk
Meteorite Papers
Submitted
by Wayne Green
Meteorite
hunters and collectors are all excited about the Feb. 15 Chelyabinsk meteorite. Here
are some early papers describing the event, and the working out of the
orbit of the meteorite:
http://arxiv.org/abs/1302.5377
--Great paper, rounds up some interesting accounts and images in one place.
http://goo.gl/vcG3Y (from the paper) is very visual account
of back-tracking the meteor with handy web tools.
I
got on the trail to this paper from Slashdot: http://science.slashdot.org/story/13/02/26/2240208/russian-meteor-likely-an-apollo-asteroid-chunk.
****************
Upcoming Events
March
11, Mon., Denver Region Exploration Geologists' Society meeting, “To Reactivate
or Not to Reactivate—Nature and Varied Behavior of Structural Inheritance
in the Proterozoic Basement of the Eastern Colorado Mineral Belt--Over 1.7
Billion Years of Earth History”, by Jonathan Caine (USGS), John Ridley and
Zachary Wessel (CSU); Colorado School of Mines, Berthoud Hall Rm. 241;
Social hour 6:30 to 7:00 p.m., Presentation 7:00 p.m. All are welcome to attend. (Pete Modreski says this should be a very good talk about
geologic structures in the Colorado Front Range and their relationship to
ore deposits.)
Mar.
16-17, Sat-Sun, Western Interior Paleontological Society (WIPS) Symposium,
Ice Worlds and Their Fossils; "Discover how glacial climates &
life interact to shape evolution and the biosphere". At the Green
Center, CSM campus, Golden. See
http://www.westernpaleo.org/symposiums/pages_2013/2013.php for full
information. (early registration - $10 discount-
runs through Jan. 7). These symposia, held every other year by WIPS, are GREAT!Mar. 16-17, Sat-Sun,
Western Interior Paleontological Society (WIPS) Symposium, Ice Worlds and
Their Fossils; "Discover how glacial climates & life interact to
shape evolution and the biosphere". At the Green Center, CSM campus,
Golden. See http://www.westernpaleo.org/symposiums/pages_2013/2013.php for
full information. (early registration - $10
discount- runs through Jan. 7). These symposia, held every other year by
WIPS, are GREAT!
Mar
22-24, Fri-Sat-Sun, Fort Collins Rockhounds Gem
and Mineral Show, McKee 4-H Building at The Ranch (Larimer County Fairgrounds),
Loveland, CO; at I-25 exit 259; 4-8 p.m. Fri., 9-6 Sat., 10-5 Sun.
Admission, adults $4/day or $7/3-day pass, students age 12-18 with student
ID $1, children under 12 free with adult. See http://www.fortcollinsrockhounds.org/
March
30, Sat., 10:00 a.m. to 2:00 p.m., Silent Auction (and Bake Sale),
sponsored by the Colorado Springs
Mineralogical Society; held at the Western Museum of Mining and
Industry, 225 North Gate Blvd., Colorado Springs. Regular admission prices apply (members
of CSMS and other WMMI supporting clubs admitted free).
Apr.
6-7, Sat.-Sun., Hands of Spirit's
16th Annual Spring Mineral and Jewelry Open House from 11:00 am to 5:00 pm.
You're sure to find an incredible selection of the finest crystal and
mineral specimens, stone carvings, and a lovely selection of jewelry.
Refreshments will be served. Call 303-541-9727 for directions and further
information.
April
12, Fri., Silent Auction of
Minerals, Gems, etc., sponsored by the North Jeffco
Gem & Mineral Club; APEX Community Center, 6842 Wadsworth Blvd.,
Arvada; auction begins at 6:45 p.m.; see http://www.peaktopeak.com/njeffco/auction.php.
Fri.-Sat.-Sun.,
April 19-21, Colorado Mineral and Fossil Show, Ramada Plaza Hotel [formerly
Holiday Inn - Central Denver], 4849 Bannock St., Denver; 10 a.m. – 6 p.m.
Fri./Sat., 10-5 Sun.; free admission and parking.
April
21 (or 22), on the occasion of Earth
Day (April 22), a geology/natural history hike at some location TBD in the
Lakewood/Golden/Morrison area will be led by USGS Geologist Pete Modreski. Details will be available later (contact pmodreski@usgs.gov).
Fri,
Apr. 26, Public Open-House with guided tours of the Geological Society of
America World H-Q Building at: 3300 Penrose Place Boulder 80301 (for
MapQuest or Google maps) from 3 to 6pm. It's part of their 125th
Anniversary
during 2013.
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Flatirons Mineral Club Annual Picnic
Be
sure to circle 17 Aug on your brand-new 2013 calendars for the FMC Annual
Picnic in August. The picnic will be at the main pavilion of North Boulder
Park, start at 11:00am same as previous years. Grab bags, pot-luck lunch
(club provides sandwiches & beverages) and awards follow the luncheon.
Plan to bring the whole family.
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Rock Saw Available
I
have a very old 14-inch rock saw, circa 1950, built by a machinist, which I
would like to give to a good home. It will take some work to get it
cutting, including a blade and drip pan - it drips a lot. It has a 70-pound
cast iron cutting pan and an incredible 50-pound cone bearing blade arbor.
When a good blade is carefully aligned the cuts are so smooth they look
polished. I have cut many thousands of slabs but it is time to recycle this
warhorse one way or another in early March. Drop me a line soon,
subject “Rock Saw”, if
interested. Thanks - Dean Baldwin,
Longmont.
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Calendar of Events
Mar.
14 - FMC Club Meeting, 7:00 PM, West Boulder Senior Ctr,
9th & Arapahoe John
Widirstky, on “Gold and Its Processing.”
Mar.
16-17 WIPS Symposium, CSM Campus, “Ice Worlds and Their Fossils”
Mar.
21 - Junior Geologists Meeting, Boulder Public Library, Reynolds Branch, 6:30 p.m.
Mar.
22-24 - Fort Collins Rockhounds Annual Gem and
Mineral Show, Larimer County Fairgrounds, Loveland
Mar.
25 - FMC Board Meeting - To be conducted via e-mail
Apr.
11 - FMC
Club Meeting, 7:00 PM, West Boulder Senior Ctr,
9th & Arapahoe. Annual Silent Auction
Apr.
23 – FMC Show Committee meeting Boulder Co. Fairgrounds, Clover Building, 7
p.m. (All interested club members welcome!)
Apr.
25 - Junior Geologists Meeting, Boulder Public Library, Reynolds Branch, 6:30 p.m.
Apr.
29 - FMC Board Meeting - To be conducted via e-mail
May
4 - FMC Field Trip To N. Table Mountain, Golden, For Zeolites
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Updated 3/18/13
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