Computer model of Quartz lattice structure (Courtesy of Steven Dutch, Univ. of Wisconsin-Green Bay)		Hexagonal Quartz Crystal (Photo by Ken Casey)

     Notice the hexagonal grouping of ions.  This translates to our seeing the hexagonal crystal
system shapes of crystal facets.  This tight structure also gives it the attribute of 6.5-7.5 on the
Moh’s Hardness Scale--a relatively hard mineral.  This is a good thing, since the ground we
stand on is in majority composed of silicate minerals!

     Also giving us a firm foundation for our study of quartz are the older two-dimensional drawings. 
This is how crystallographers of the past viewed their subjects.  This author is no stranger to them. 

This is how crystallographers of the past viewed their subjects. (Drawing from The Changing Earth -- Introduction to Geology, 2 ed., Mears, Jr, D. Van Nostrand Co. 1977.)

     Before computer modeling, students had to rely upon drawing and constructing models for
themselves.  This author recalls his early use of materials he employed in the making of his
constructs.  The handiest were Doritos.  Surprisingly, their flat triangular shape fit well into a
graphic representation of silicon tetrahedra.

Take 4 flat Doritos, lay them out in a larger triangle, flip up the sides until they touch: you have a "Doritohedron"! (Photos and concept by Ken Casey)

Grab "Doritohedron"...		One drawback, though--my hungry dorm mates ate them immediately upon completion of my lattice structure!  I had to resort to poster board for a more lasting model.  All of this helped me prepare for my mineralogy exam with Dr. Peter Leavens, Prof Emeritus at the University of Delaware.      I guess that's just the way the "Doritohedron" tumbles!       Now that we've entertained the notions of a college- level understanding of quartz structure, let us move on to Delaware Quartz geology.
...and eat!		(Doritohedron animation by Ken Casey)

Foot Hills (or Piedmont)

     As we visit the more rugged terrain of northern New Castle County from the Maryland,
Pennsylvania, and Delaware border, we can travel east to Wilmington and find mega-boulders
covering much of the surface.  As we stand atop of any of our favorite skyscrapers, we can can
see three aspects of our geology: the Delaware River, the Delaware Memorial Bridge spanning
it, and the marshlands, denoting the fall line. 

Topographic Map of northern New Castle County (Note the red arrow showing the slight dip in both surface elevation at the fall line and the differentiation of Piedmont and Coastal Plain.  (The fall line is roughly denoted as a green dashed line.) (Map courtesy of the USGS, modified by Ken Casey)

     Yes, the land does seem to fall from the city on down, from about 250 feet above sea level
just northwest of the city limit to just above sea level on the banks of the Delaware River.  The
topography does approach sea level as we exit the city to the southeast; however, the subsurface
bedrock dips, as well.  What we see from the marshes on on through our trek downstate are
sediments that have washed down from the mountains and foothills, which have filled up the
continental shelf over eons, thus raising land, which make up southeastern New Castle, and all
of Kent and Sussex Counties.

Heading south-southeast on I-95		Marshy wetlands of Old New Castle
(Photos by Ken Casey)

    Below us, sedimentary rocks have formed under heat and pressure from the earth's mantle and crust,
thus creating a sturdy state upon which to carry out our business.  The fall line just delineates the
area at which the igneous and metamorphic layers dip a bit, and sediments have filled in the dip south
of the greater Wilmington area.  So, Delaware is fortunate enough to have all three major rock types
at the surface (and below it) for us to study--hoorah! 

This is not to say the the land in lower Delaware is not solid ground--it is.  We couldn't build houses upon it or important structures, like our newly  renovated Old State House in Dover, if it wasn't.  To the contrary, the sediments are only on the surface; sedimentary rock lies beneath.     This historic edifice still stands proud today, since it's original completion in 1791.  Over two hundred years old, and solidly anchored in our soil and in our hearts, it served Delawareans in government service for 140 continuous years!      This is, of course, only one example of long-standing structures that dot our First State today. (Left): Renovated Delaware State House (Photo courtesy of The Great State of Delaware)

     Now that we are oriented geographically, let's turn our attention to the higher ground.  If we
turn around, and look north from our urban perch, we can see the land rise in elevation, especially
on the far side of the Brandywine Creek.  There are boulders here at Brandywine Park, some
of which are quartz, others contain quartz, like our Brandywine Blue Gneiss.  Why not check out
this DGS GeoAdventure when we are done today. 

View looking on Brandywine Park		View looking southeast from northern bank of Brandywine Creek
(Photos by Ken Casey)

     Now, to our canoes to paddle some ten miles upstream to witness the gentle rapids, which
erode rocks to the Atlantic Coastal Plain.  If you like, you can hike the creek bank to study the
geology more closely.  We'll meet you at the rendezvous point, Brandywine Creek State Park.

We'll park our canoes at Brandywine Creek State Park, and proceed uphill on foot to the  Woodlawn Quarry.  It'll be good to stretch out our muscles, after sitting.  You hikers of the previous leg, groan as you will, and take a pit stop.  See you there. Watch out for the schist.      Yes, you see it.  From the parking lot at Woodlawn Quarry, we still have to hike further uphill.  That's the piedmont experience.  Don't fret, after the quarry, it's all downhill from here!  Just look for the big white boulder (see: left). (Left): White boulder (Photo by Ken Casey)

     At last, we are here!  Our landmark is the white graphic granite boulder along the trail, just
about 50 feet downhill on the tailings pile.  At the top, we can look down into the quarry proper. 
I won't ask you to climb, as we have visited this excavation on previous excursions.  Let's brush
away some leaves to find massive clear and smoky quartz remnants from mining a century ago. 
We can see the igneous textures; some pieces are even gemmy, small as they might be.

Massive milky quartz on forest floor  (Photo by Ken Casey)		Smoky quartz grains in graphic granite (Photo by Ken Casey)

    Have a look at the boulders here.  We can observe the large pegmatite grains in the graphic
granite.  In these igneous rocks, quartz shares a place with feldspar, mica, garnet, and beryl.

     It's a good time to stop for lunch, then discuss the igneous rocks at Woodlawn Quarry.  Then,
we'll take the easy way down by canoe, or tube, whichever you prefer.  Pass the Doritos, please?

The Kalmar Nyckel docking		The Kalmar Nyckel docked at Battery Park, Old New Castle, Delaware
(Photos by Ken Casey)

      Next, we'll glide back down the creek and dock our small boats over to Swede's Landing at the
confluence of Christina River.  We will come upon the Kalmar Nyckel, Delaware's Official Tall Ship.  
After booking passage, we'll sail into the Delaware River at the fall line, until we reach the port of
Old New Castle on Battery Park.  Watch out for the ships!  We're likely to encounter ocean-going
vessels, as well as personal craft and locally-moored sailboats. 

     We'll follow the Delaware safe boating rules, of course.

Erosion

Brandywine Park, Wilmington, Delaware (Video and photo by Ken Casey)

     As we float downstream, notice the energy that propels us southeast, and downhill.  It's
gravity, of course, acting upon the massive volume of water, which has no resistance, unless
it is contained.  You know the axiom, water finds its lowest point at which to rest.  Scientifically,
high-energy to low-energy stream currents result in large rocks being deposited upstream; while,
smaller particles, like sand, are carried further downstream.  That is why we find more rocks at
the narrowing of the Delaware River and Brandywine Creek, respectively. 

     Imagine first, the jagged remnants freed from the bedrock by earthquakes, erosion, and the
freeze-thaw cycle, as they are tumbled into, then down, the river or creek.  Bumping against
each other in the high-energy current, their bumpy edges break off into smaller rocks, while the
larger get polished, then dropped, as the current looses energy at stretches of small elevation
changes.  When winter mountain snow meltwaters swell the river and creek in springtime, a
larger volume of water is drawn downhill, thus exacerbating erosion by its floodwaters--a problem
for property owners.

Jagged and rounded stream boulders at BP		Freeze-thaw releases new material to stream at BP
(Photos by Ken Casey)

     Next, the rounding and polishing continues further downstream for the smaller particles, until
such point as individual mineral grains are broken free of their matrix in the case of our prolific
graphic granite.  Quartz sand and rock crystals are already extant, and will continue as they are. 
Sometimes, we can find a partially rounded crystal of Amethyst from Pennsylvania, before it
becomes broken down into pebbles or sand.  Chert is also a quartz candidate for making sand.

     Once the pebbles and sand either feed from the creek into the Delaware, and as upper
Delaware River rocks and sediment continue down to tidal areas, they polish even further.  The
smaller grains act as progressively finer grit sandpaper, as used by a craftsperson, to give each
grain its distinctive shine and glow.  Though not as finished as a lapidary would tumble them,
they are still a natural beauty to behold. 

     We will visit some upper Delaware River rocks to our north on a future visit.  This basic
alluvial process shows us also why we discover of the bulk of marshy sediments and sand down
river and downstate.  We'll see this mucky marsh sediment and sand, as we sail on the tall ship
Kalmar Nyckel underneath the Delaware Memorial Bridge down to New Castle City.

     Notice now the Delaware River beach sand at Battery Park, as we disembark from our ship.

Sand beach at bulkhead, Battery Park, New Castle		Typical beach sand of Delaware River area
(Photos by Ken Casey)

     After becoming part of the Delaware River, Bay, or ocean coast, the erosional process takes
a literal turn.  Acted upon by tidal waters and ocean waves, the beach sands move.  It is never
in the same place twice!  The tides pull and redeposit some sand.  It is especially prominent in
summer and winter.  The difference is that the bulk of beach sand is pulled away to a gentler
slope in winter by storm activity, and is usually replenished naturally by summer, which is most
prominently shown at the ocean and bay fronts.

Ocean beach in July with larger sand area		Ocean beach in April with smaller sand area
(Photos b Ken Casey)

(Above): Ocean wave angle to shore diagram (Drawing by Ken Casey)

And, as you can see as we sit on the beach, that ocean waves hit the coast not head on here, but at an angle to the shoreline, depending on the prevailing wind.  As each wave hits, it sweeps up and carries a parcel of sand further down the beach, a process known as beach evolution.       Yes, the sand all looks the same, but the process has been measured by geologists.  If you like this area of study, you can specialize in hydrology, sedimentology, or marine geology, if you have a mind to.  The University of Delaware at both Newark and the College of Marine Studies & Earth Studies at Lewes have programs from which to choose.

Aerial photo of Rehoboth Beach, Delaware near Silver Lake Note the wave action occurring at angles to the shoreline (Image courtesy of Microsoft Terraserver)

     Let's complete our observations of the sand process for this trip as we visit in depth one of the
sources of Delaware beach sand.  We'll cross the fall line in pursuit of the dip that fills as new
and is added.  We'll revisit the topic of the larger pebbles in January in "Delaware Quartz: Part 2:
Colorful Pebbles and Products of Erosion".  Don't worry, we'll come back to the beaches later in
our fieldtrip to study sand grains.

The Delaware Fall Line

     The fall line is a geologic nonconformity after which sedimentary rocks have formed over
previously eroded metamorphic and igneous rocks.  This hard-to-see escarpment runs hundreds
of miles along our nation's coast.  Our state has about twenty miles running through New Castle
County.  In Delaware, Taconic orogeny-created metamorphic rocks have eroded to create sandy
Cretaceous and Tertiary sediments, which have been deposited over eons.  It took millions of
years of  to remove most of the surface traces of major elevation changes by creating a more
gradual slope.

     In Delaware, the eons of alluvial sediments deposited upon one another to form the Coastal
Plain Province over the trailing edge of the North American continent.  America's eastern
Piedmont Upland Region slopes down from the Appalachian and Pocono mountain ranges
from Pennsylvania and Maryland down to Delaware.  Rivers and creeks, such as the Brandywine
River, Brandywine Creek, and Delaware River, have all contributed to the eroding of alluvium to
create a geomorphologically crooked coastline. 

Generalized Delaware Surficial Quartz Map and Fall Line Designation (Map by Ken Casey)

     Fall line points under the waters have historically acted as geographical and practical limits
of further upriver navigation; therefore, prominent ports were established at these headwater
locales.  I bet the Swedes and other early settlers discovered this shipping anomaly, as they
settled on the Christina River, Brandywine Creek and Delaware River. 

     One can imagine the 'good luck' dolphins swimming of the bow of masted tall ships.  As the
water turns fresh near Wilmington, these sea mammals turn with the tide for deeper waters and to
saltier fare.  This is because currents on the Delaware switch from ocean and bay saltwater tidal
to freshwater river downhill, gravity-fed stream right around the Delaware Memorial Bridge and the
Port of Wilmington.  Of course, the bathos changes with environmental and geological conditions,
such as droughts, storm surges, or earthquakes and continental drift.

View of fall line area from NJ to DE		Shipping at fall line area near the Delaware River
(Photos by Ken Casey)

     It is also interesting to note that in modern times, U. S. Route 1 and Interstate 95 roughly trace
this line, thus linking by road the major port cities in the United States.  Later, inland industrial
cities to the west paralleled the ports, and were joined to the ports by railways, then highway. 

  (Sources: http://en.wikipedia.org/wiki/Fall_line,  http://www.infoplease.com/ce6/sci/A0818202.html)

Map of Fall Line running through New Castle County, Delaware (Map by Richard N. Benson, DGS)

     In the First State, the fall line is what made possible our creation of a solidly-based port city
on the hill, successful marine commerce, and recreational beaches in the same state.  It did help
for William Penn and the founding fathers to establish a political boundary of the "circle" which
protected port waters under the Governor.  That is why the top of Delaware is a semi-circle on the
map.

     Geography does somehow dictate areas covered by a political subdivision.  For example, early
colonial property deeds, like those land grants given to William Penn to disperse, describe land
boundaries from the bank of one stream to another.  Further study might give us clues to how our
 local ancestors saw the geology of the area.  I am certain the Delaware Geological Survey has
consulted those deeds and maps in their earliest work.

Map of Delaware "12-Mile Circle" Border with fall line border  (Map by Ken Casey)

     As an exercise, why not take a Delaware map copy and complete the circle with a drawing
compass (as above).  Note how the area includes the Delaware River up to and past the New
Jersey shoreline.  (Of course, we minus out the landmass of our neighboring New Jersey.)  In
fact, in Pennsville Township, Salem County, based upon William Summerill's original land grant
from Mr. Penn, the boat docks attached to New Jersey soil, which jut out into the waters of the
Delaware River violate the 2005 revised statute, and are a controversy until this day. 

     Since they are built on adjacent tideland's lithos/ bathos interface, the boundary changes with
the tides.  That means that the old rule governing where the state line between New Jersey and
Delaware exists is still at issue to some degree.  That is also why Pea Patch Island falls squarely
within Delaware's jurisdiction.

     Good thing for Fort Delaware, Fort DuPont, and Fort Mott fans that a clear state line is drawn! 
See how geology can affect society?  Cool, huh?

     There is no issue with this in Kent and Sussex Counties, Delaware, or south of Salem
County, New Jersey.  So, our visit to Newark next, then our return to Delaware Beaches will be a
lot more fun.

     We'll come ashore in Old New Castle at Battery Park to skip traveling the shipping channel
towards the C & D Canal.  (There are sand and fossils at the mouth of the canal, but that is
another fieldtrip.  And, there are gravel quarries here and there, but we'll visit those in January
in "Delaware Quartz, Part 2: Colorful Pebbles and Products of Erosion".)  Our club bus is waiting
for us at the park, so portage your canoes to the boat trailer, and stow your oars.  Let's climb
aboard!

     As we drive towards Newark, Delaware, note the flatness of the land on Route 273 West. 
Newark is at the bottom end of the fall line area.  We can find quartzes and pegmatites, many
of which are in one our member's backyard.  Our host, Tom Pankratz, is a kindly mineral
collector and gemstone faceter.  He is also our club's Vice-President of Programs.  Let's have
a look at some of his quartzes!

Quartz crystal vug, Newark, Delaware		Perhaps a pod quartz, Newark, Delaware
(Photos by Tom Pankratz)

    We have here vugs of rock crystal, massive quartzes and quartzite rocks the size of
basketballs, and the odd stream crystal.  'What is quartzite?', you might ask.  Well, it is "[a]
metamorphic rock consisting largely or entirely of quartz. Most quartzites are formed from
sandstone." 

  (Source: http://www.delawarequarries.com/glossary.html)

Large quartzite boulder in Tom's backyard		Metamorphosed remnants of an ancient sand beach
(Photos by Tom Pankratz)

     High metamorphism of sands in the Setters Formation during the Taconic Orogeny created
an impure quartzite.  The sand once rolled upon an ancient sandy beach.  It is likely that some
of Tom's rocks originated there.  At one time, Tom's yard was beachfront property.  Oh how
geology changes "location, location, location".   

Tom's Quartzes and Quartzites		Close-up of reddish quartz
(Photos by Tom Pankratz)

     Tom gave a presentation recently to our club on this phenomenon (among other processes)
at our November 12, 2007 meeting, called "The Land Beneath Our Feet".  He took us on a virtual
geological tour of Delaware from the Big Bang to modern times.  Why not take a look at the
summary later, when you are free.

Collected pile of quartzes and other area rock		Were turtles around when this rock was formed?
(Photos by Tom Pankratz)

     The quartzes he has, however, most likely were formed as vein or as sutured quartz.  Some are
quartz pods, or "bulls" in other rock types.  Ancient fractures in Piedmont country rock commonly
filled with quartz via either precipitation from solution, or by a melt.

  (Source: http://www.dgs.udel.edu/publications/pubs/specialpublications/sp20.pdf)

     There are gneisses, amphibolites, and migmatites, all hosting quartz.  Some of these become
sands as they erode down the Red Clay Creek north of Newark.  Then, the process begins again
in the Rock Cycle.

    Tom has another passion--faceting gemstones.  One of his hobbyist goals is to facet at least
one of every major gemstone, up to and including Delaware Smoky Quartz!

Large Faceted Delaware Smoky Quartz		Table view of Tom's faceted Quartz
(Faceting and Photos by Tom Pankratz)

     As we say thank you to our host Tom, and say goodbye, we'll adjourn to our bus for a trip
down to the beach.  What is your pick: Rehoboth, Bethany, Lewes, Fenwick Island?  We'll head
out from Newark on Route 896 South to connect to U. S. Route 13 South and bear left onto
Route 1 near Milford.  This route takes us through Smyrna and Dover and over aquifers.

Aquifers

What are aquifers?  They are underground beds of sand or porous rock that conduct or store groundwater.  Either you, a well-driller, or Artesian Water will setup a hole and pump system that will bring that water to your home or building.  An important aquifer is right underneath us as we jostle down the road.       According to the Delaware Geological Survey Open Report 45, "Fluvial sands of the subsurface Cretaceous Potomac Formation form a major aquifer system used by a growing population in the northern Coastal Plain of Delaware."  So, the study of sand facies is obviously required in Delaware to support a good local water supply.  Become a geologist, and maybe you can help.  (Source: DGS Open File Report 45)       Enough talk about sand (until we reach the beach).  Let's discuss a snack.  How about boardwalk fries at Thrasher's?  Or, a big hot Nic-O-Boli at Nicola's Pizza?  (Left): Photo of Delaware's Potomac Formation aquifer sands and sediments  (Photo courtesy of DGS)

     There are three major sources of this sand: the Delaware River sediment flow, bay and
ocean rock and sediments in the bathymetry of the Coastal Plain dip into the ocean, and
beach replenishment trucks.

Delaware Bay fine white sands		Wind-blown sand dunes
Brown angular Delaware beach sand		Fine white Delaware beach sand
(Photos by Ken Casey)

     Up and down the Delaware coast, we can find this mix of sands.  From aeolian dune system
berms to tidal inlets, and from the rough and granular beach sand and pebbles to the north at Fowlers
Beach to the smooth, natural white sugar-grain type sands to to the south at Fenwick Island to
the bathymetrically-derived beach replenishment material, different sand types arrive at their shore
locations.   

     And, sand has its own geology.  It makes up the major headlands of the Delaware coast at
Rehoboth, Bethany, and South Bethany beaches.   Coastal geogmorphology includes bay
barriers and lagoons, too.  "Between the headlands, bay barriers separate the waters of the
Atlantic Ocean from the waters of the coastal lagoons of Rehoboth Bay, Indian River Bay, and
Little Assawoman Bay."

  (Source: http://www.dgs.udel.edu/publications/pubs/reportofinvestigations/ri63.pdf)

Aerial photo of Cape Henlopen, Delaware		Picturesque 360°-view of Cape Henlopen State Park beach
(Photo by Microsoft Terraserver)		(Photo by 360 Visions and Coastal Images, Inc.)

 

     For example, major geographical changes have been observed and logged over the years
on the spit complex of Cape Henlopen. 

     DGS Special Publication 26 "Historical Coastline Changes of Cape Henlopen, Delaware"
shows photos of the massive migration of sand since 1926, and chronicles topography since
1842.

     There are issues that revolve around the use of externally supplied sand added to the beach
 to protect against or recover from beach erosion.  The gamut of topics run from the cost to
wildlife, the efficacy of the proposed and current programs, and the financial cost to taxpayers. 
Aside from these goings on, the geology works itself out, for better or for worse.

We'll just enjoy the beach and study quartz sand grains today.  Though, as scientists and enthusiasts, we must exercise great care into the resolution of these issues by underwriting new proposals with good science.  In other words, government relies on us to provide it evidence and data that can be utilized by our officials to make good decisions for the people and for the environment. (Left): Horseshoe crab shell at the Delaware Bay (Photo by Ken Casey)

     One way to learn about Delaware coastal geology is to visit the University of Delaware's
College of Marine Studies in Lewes.  The nice folks there host an Open House on "Coast Day"
in early October each year.  Check the U of D website for information.

		Today, we'll employ a stress free way to learn about the textures of sand and its angle of repose is to build a sand castle.  You can decide upon which sand, large angular or fine grain, packs the best.  What a novel and fun experiment, eh?  So, take a deep breath of salt air, and let's enjoy our stay!   (Left): Sand castle from Ocean City, Maryland's Sandcastle Contest 2005 (Photo courtesy of OceanCity.com)

 

Sand-sculpting Links 

http://www.sandcastlecentral.com/

http://www.festivalofsand.com/

http://www.wssa.info/

 

 

Beach Art

     At the Delaware beaches, there is no shortage of marine and nautical art for us to peruse. 
Upon researching sand, I came across a local artist who paints pictures of it.  He is Daniel
Coston, formerly of Georgetown, Delaware.  While in residence, Daniel painted some
magnificently detailed and lifelike beach scene close-ups.  From horseshoe crabs to clam
shells on the sand, his renditions capture well both the textures and colors of Delaware beach
sand.  While most artists paint more panoramic shorescapes, Daniel focused upon details
and our favorite sands.  Thanks, Daniel.

Acrylic Painting "Cat's Eye Bubble"		Acrylic Painting "Crashed Spaceship/Dead Horseshoe Crab" by Daniel Coston

    Now that we've visited sand and quartz throughout the state, it's time to board the bus for
our return trip back to the clubhouse.  Dusk is falling, so let's take one last look at the sunset,
and go home.

 

     Our first museum is The Rice Northwest Museum of Rocks and Minerals.  It is situated near
Portland, and has a vast collection of common quartz and Oregon beach agates.  Two other
exhibits are the "Flowers of the Mineral Kingdom" and displays of extraordinary lapidary works,
such as polished petrified wood and gem minerals.  They offer tours and classes, as well as
rental of private party facilities for meeting.  You can even get married there, if you have a mind to.

     Our online choice this month is The Virtual Sandbox Museum of World Sands, which hosts a
myriad selection of magnified sand grains from locations around the globe.  Our hosts encourage
the trading of sand specimens for fun and educational purposes.  Virtual trading of photos of sand
are happily carried out, as well.  They post tips on how to collect sand, identification, and projects
you can do with sand.  I'm thinking of sending a few samples to share with others.  How about you?

 

Uses

     As Delaware quartz occurs in commercial quantities as gravel and sand, these most easily
accessible forms are readily used in construction and landscaping.  Our large stretches of bay and
ocean beaches are for recreation, and as nature preserves.

     Sidelight: Under heat and pressure, nature fuses quartz and mica together to metamorphose
into Sillimanite, our Official State Mineral. 

Delaware Quartz Crystals in vug (Photo by Tom Pankratz)

 

Links