Category Archives: Geology

A Gastropod and Macrostrat

On occasion, cleaning out that old box of leftover and generally forgotten minerals from a past trip can provide an unexpected reward.  Last month I uncovered a box of rather ordinary wavellite specimens from the club visit to Mount Pleasant Mills, PA in April of 2016.  Among the cruddy and generally less than desirable wavellite discards I found a fossil gastropod that I had remembered collecting, but had pretty much forgotten.  It was time to clean it up and do a little research.  After all, that is what the winter months are for in western New York.

Continue reading

Micro-micro minerals

Some rockhounds like to collect rocks and minerals the size of small cars, or at least motorcycles.  You know who you are (and so do the rest of us!).  Others settle for samples that can be carried, a size that seems to decrease with each collecting season.  But we also know of those who collect thumbnail specimens (less than 1”) and stick them into tiny boxes.  There are even folks who like to collect specimens that require microscopes to be seen; these collectors are called micromounters.  But I am going to tell you a bit about some “mineral specimens” that are even smaller.  And I am even going to make up a new name for them.  I am calling them micro-micro minerals.

Continue reading

The Origin of the Elements

Have you ever sat down to think about where the chemical elements in all those neat minerals we collect came from?   I mean in the grand scheme of things, like as the universe forms and evolves.

We collect metallic minerals, like copper (Cu) in chalcopyrite and bornite and in colorful carbonate secondary minerals like malachite and azurite.  The latter require carbon (C) as does calcite with its calcium (Ca) cation and dolomite when there is sufficient magnesium (Mg).  WCGMC has travelled to Cobalt, Ontario in search of silver (Ag) in its pure form as well as cobalt in arsenic minerals (Co, As).

Continue reading

Measuring Specific Gravity

This note was published in the the Sept. 2017 WCGMC Newsletter

How do you try to identify an unknown mineral?  If you are like most folks you start with color, which can help, but can also mislead.  Trace elements and other types of inclusions can alter the color or many minerals.  Does it have crystal faces?  Maybe, but often not.  Can you see a cleavage direction?  Can you even distinguish crystal faces from cleavage?  Calcite has rhombohedral cleavage, galena is cubic, but then fluorite is a cubic crystal with octahedral cleavage.  That isn’t even fair.  Luster helps with metallic minerals.  Hardness can be helpful, but no one wants to scratch a prize find.

What about density, or more accurately specific gravity (sg).  If it is magnetite or galena you can tell it is dense when you pick it up, but what about other minerals with specific gravity closer to the common minerals? Or heavy minerals that are not magnetic? Is there a method to easily measure specific gravity?

Continue reading

Rutter Pluton, French River, Ontario

For the second consecutive year, members of Wayne County Gem and Mineral Club joined with the Niagara Peninsula Geological Society for a several day trip to mineral sites in Ontario.  We thank Ashley Pollock for organizing the trip and I thank Ashley for writing this short summary of one of the sites we visited and allowing me to publish it in the September, 2017 WCGMC newsletter and also this this blog. 

It rained and then it stopped and then it rained again as we drove north to start our week long summer collecting trip.  But when we met our Wayne County Club friends at our first collecting stop along the French River south of Sudbury, the clouds had parted and the week of fun began.

The Rutter Pluton is a nepheline-syenite intrusion within/ straddling the border of the Grenville Front Tectonic Zone (GFTZ) of the Grenville Province.  The 10 km long, 2 km wide igneous body is dated at 975 million years.  Like much of the Precambrian terrain in Ontario, the igneous rocks have been metamorphosed to a gneissic texture.  Mineralogically, the pluton consists of nepheline, albite (plagioclase feldspar), potassium-feldspar, and biotite mica.  Quartz is absent.

Continue reading

Calcite-Vein Dikes in Tory Hill, Ontario

The annual test of aging bones and muscles that we call the Wayne County Gem and Mineral Club quest for really old Ontario rocks was in July this year.   The event lasted  five days for several and eight days for four of us who continued on to Cobalt, Ontario.  I am happy to report that all of us survived, and we have the pictures, stones, bruises, and mosquito bites to prove we were there.  The whirlwind trip included collecting beryl and rose quartz in two pegmatites, a day in Eganville for apatite and biotite, a quarry stop for fossils, Princess Mine for sodalite,  Schickler Mine for fluorite, Desmont Mine for mosquitoes, and Essonville Line roadcut for fluoro-richterite.  Four of us carried on to Cobalt, grabbing some garnets along the way and finding one very nice silver-laced boulder at a mine dump in Cobalt.

The highlight of the trip had to be the day we spent with Canadian collector George Thompson on his mineral claims off Gibson Road in Tory Hill.  We all thank him for sharing his calcite vein-dikes with us and allowing us to carry home memories of a fine day in the field.  Oh, we took home some minerals also.  And thus this note focuses on George’s property and the fifth day of our adventure. Continue reading

Unakite

In late June, Wayne County Gem and Mineral Club visited  St. Lawrence County. One stop on the  three day field trip was at the Valentine Mine in Harrisville where the quarry/mine operators, Gouverneur Talc Co., graciously permitted us our annual visit.  Naturally all were drawn to the bright blue calcite and the brilliantly white wollastonite (the site’s economic resource), but there is another interesting rock to be collected there.  Bright orange and green unakite can also be found.

Continue reading

Basalt Porphyry “Flowerstone”

The door prizes at the June meeting of the Wayne County Gem and Mineral Club consisted of a bucket of miscellaneous unpolished slabs from the club collection.  Linda Schmidtgall had scoured the club collection and accumulated a wide variety of colorful and unique pieces.  She set them in water for folks to make their selection.  When my number was called I picked out a unique volcanic rock slab.  It was an end cut, which meant one surface was raw.

Continue reading

CCE Outdoor Education Day

I’d like to thank Julie Daniels for providing my name to the Seneca County 4-H Cornell Cooperative Extension for their Outdoor Education Field Day.  When they called a couple months ago, it was with some trepidation that I accepted visiting with over 300 sixth graders rotating through ten 18 minute sessions at Sampson State Park on May 17th. The big yellow buses rolled in about 9:30 and by 9:48 AM the rotations began:  five sessions in sequence, a 30 minute lunch period, and then five more sessions.  Incredibly, the whole thing went like clockwork. Continue reading

Gotthard Base Tunnel

My favorite rock hound club (Wayne County Gem and Mineral Club) loves to dig and we are always looking for new places to dig and new tools to use while digging.  But there are some folks in Switzerland that we must acknowledge have done a little more digging than us while deploying more sophisticated and larger tools.  In fact, they have been digging on the same project for 17 years.  And in June of 2016 they completed their mission.  All they had done was dig a 57 km (35 mile) railway tunnel through the Alps in south-central Switzerland: the Gotthard Base Tunnel.

All told this massive project removed 28 million tons of igneous and metamorphic rock (dominantly gneiss). That is enough rock to build a rectangular regular pyramid that is 5200’ high.  Think about that! At its deepest points the Alps tower more than 2000m (6500’) above the tunnel floor.

Continue reading

Reeder Creek: Fossil Hunting Meets History

Article was published in the February 2017 WCGMC Newsletter

Sometimes it is fun to just explore for fossils or minerals by visiting an unknown location, perhaps one with potentially appropriate geology, but not a site with documented fossils or minerals.  One may not find much, but occasionally one stumbles onto something completely unexpected and equally interesting.  In the fall of 2015 Stephen Mayer and I had such an experience when we decided to investigate the geology along Reeder Creek in Varick, NY.

Continue reading

Classifying Geologists and Rockhounds

Column written for the WCGMC Newsletter, January 2017

Everyone likes to classify things: by shape, by color, by cost, by size.  You name something to sort by, and someone is busy classifying with it.  So, it should be no surprise that geologists get classified.  And perhaps the first way they get labeled is as either a soft rock geologist or a hard rock geologist.  No, it has nothing to do with the character of their head (although some might disagree) and it has nothing to do with their taste in music.  Rather it relates to the type of rocks they study.

Continue reading

Classifying Geologists (and Rock Hounds)

Everyone likes to classify things: by shape, by color, by cost, by size.  You name something to sort by, and someone is busy classifying with it.  So, it should be no surprise that geologists get classified.  And perhaps the first way they get labeled is as either a soft rock geologist or a hard rock geologist.  No, it has nothing to do with the character of their head (although some might disagree) and it has nothing to do with their taste in music.  Rather it relates to the type of rocks they study.

Continue reading

Collecting Thin Sections

People come in all sizes and so do collectible rocks and minerals.  There are collectors who prefer garden rocks, as big as they can carry (or even bigger).  These people will do this until their yards or patios are completely covered by rocks.  And then they start building piles.  You know who you are!  There are folks who like cabinet specimens of several inches.  You need space to display these also and typically quality cabinet specimen can deplete the wallet all too quickly.

Me, I prefer mineral specimens that are called miniatures, no longer than 2” in their longest dimension.  A few dozen can fit on a display shelf or in a drawer.   Of course there are thumbnail collectors who specialize in specimens that can fit into a one inch cube.    They even have neat little special boxes, called Perky boxes named after the collector/dealer that popularized the theme.  And then there are the micromounters.  These collectors can purchase much of their material less expensively and the number of available minerals seems endless, but then they require binocular microscopes and perhaps close-up camera lens to best view their prized possession.

But what about collecting minerals on thin section.  Is there a place for that?  OK, first off what is a thin section?  According to the bible of the internet, Wikipedia tells us that a thin section is a “laboratory preparation of a rock, mineral, soil, bone, or even metal for use with a polarizing microscope”.  Fine, but what is it?  Let me try: a thin section is a tiny sliver of rock, typically mounted/glued onto a microscope slide that permits light to pass through all the transparent mineral phases.  As it turns out if you mount a polished rock surface onto a glass microscope slide and grind/polish the surface down to 30 microns in thickness (that’s about 1/800th of an inch for the metrically challenged) then many minerals will display characteristic colors and properties upon the transmission of polarized light.  In this way minerals can be identified under the microscope.  Further-more their textures and how they are intergrown with each other can be used to interpret how the minerals grew and how a rock might have formed.

Continue reading

Collecting Minerals on Mercury

Published in the July WCGMC Newsletter

Admittedly, some of the Wayne County Gem and Mineral Club collecting trips are out of this world.  However, that’s figurative speech as we have not yet actually figured out how to visit any true planetary bodies.  No, Cobalt, Ontario does not count, not even Sudbury.  But suppose we could travel to another planet to collect.  What might we find?  Let’s consider Mercury for starters.

Continue reading

Drumlins in Wayne County

Published in the June 2016 WCGMC Newsletter

All of us who live or travel in Wayne County in western New York State  know it is easier to travel north-south than east-west.  Most of us know that is due to the elongated hills called drumlins that cover much of the region.  And we also know that those geomorphological features were formed by the continental glaciation that covered western New York with ice a mile thick until their final retreat 12,000 years ago.

BUT, did you know that until very recently, glacial geologists could not agree on exactly how these elongated parallel hills came into existence.  It was known that the drumlin fields were aligned with the glacial flow and retreat, but it was unclear whether they represent debris built up progressively during glacial advance and retreat or whether they were sculpted out of older sediment from previous glacial deposits.  The debate has raged for over 150 years.

Continue reading

A Little Local History: Geologic History That is

It was not that long ago that Wayne County and the rest of western New York were located just south of the equator while basking in tropical temperatures.  A large and shallow inland sea dominated the region with high mountains to the east and a shallow continental margin to the west.  The sea was replete with life.  Invertebrates dominated the sea bottom, corals and brachiopods filtered nutrients from the seawater to survive, while trilobites, cephalopods (squid), and a host of other scavenger and predator species roamed the benthic (sea bottom) region feeding on them.  Numerous species of gastropods (snails) and bivalves (clams) were abundant also.  The seas above were dominated by large armored fish (i.e. Dunkleosteus) and a multitude of smaller fish.  It was the Devonian Period of earth’s history.  It was the age of fish.

Continue reading

Cobalt Silver District, Ontario

During the third week in July, seven WCGMC members spent 7 days and 6 nights collecting in Ontario.  The first three days in Cobalt, Ontario are summarized here.  Part 2, three days near Eganville, will be reviewed in a subsequent entry.  Modified from August, 2015 WCGMC newsletter article. 

From its discovery in 1903 until around 1920, Cobalt, Ontario was a hotbed of silver mining and the center of Ontario’s economic mining industry as over 10,000 inhabitants opened more than 100 mines in search of silver.  Over 100 years later, and for 2 days in July, 2015, seven eager rockhounds from WCGMC followed in the old timers footsteps.

A typical scene from Cobalt:   Remains from the Crown Reserve Mine in the foreground, and mine dumps from the Kerr Lake Mine across the lake.

A typical scene from Cobalt: Remains from the Crown Reserve Mine in the foreground, and mine dumps from the Kerr Lake Mine across the lake.

Continue reading