Sedimentation at Democrat Point- John Bucaro

To the south, Long Island is bordered by Fire Island. Fire Island is a series of Barrier beaches that provide the south shore of Long Island with some protection from hurricanes and other storms. The formation of these barrier beaches can be approached in two different theories.
“The most widely held hypothesis is that of ‘shoreface retreat’. This view states that as sea level rises, the barriers migrate continuously landward, mainly through the combined effects of shoreface erosion and washover on the landward sides of the barriers. During the migration, the breaker zone traverses the entire area submerged... The contrasting view, that of in place ‘drowning’, states that as sea level rises, the barrier may remain in place, while the lagoon on it’s landward side deepens and widens.

Eventually, the breaker zone reaches the level of the top of the barrier, the sea drowns the barrier, and the breaker zone oversteps landward to form a new barrier shoreline along the landward edge of the former lagoon” (Rampino and Sanders, 1981).

The barrier beaches of Long Island are often undergoing analysis to understand how much they are eroding and at what rate. It is a difficult task because often times the sand may not be gone from the barrier simply moved to another are of the island. Currents and long shore transport move sediment along the beach and in and out of inlets.

“Circulation patterns are specific to each inlet, but certain properties are common to many inlets. Common properties include ebb or flood dominance, preferred channel on ebb and flood tide, eddy formation and migration, and jetty control on flow patterns” (Militello and Hughes, 2000). At Democrat
Point, near the Fire Island inlet, a large jetty was constructed to prevent sediment being transported into the inlet and filling in the inlet. Since the predominant sediment transport direction is from east to west the east side of the jetty has filled in with sediment.

There is also a jetty across the inlet from Democrat Point. The two jetties are not parallel and can thus be classified as offset jetties. In this situation the current is affected and becomes strongest on the sides with the shorter jetty and water enters the inlet at an angle to the inlet center line Militello and Hughes, 2000). Since the tidal currents combined with longshore transport effect sediment distribution one would think that the jetties effect on the currents would result in unexpected sedimentation patterns.

This study attempts to analyze the sedimentation patterns around the jetty at Democrat Point through grain size analysis. As currents slow down the larger, heavier grains will fall out of solution first. Smaller, lighter grains are still able to be transported by a slow moving current. Since the jetty effects the currents around the inlet a grain size analysis should allow one to determine the jetties effect on sedimentation processes.
Results


Phi size is a useful measurement when doing grain size analysis. The larger phi sizes correlate with smaller grains; therefore a phi size measurement of
4 is a smaller grain than a phi size measurement of 0. Sorting by phi size also allows one to separate the grains out and measure the percentage of the sample within each phi size. By dividing the weight of the sediment in a particular phi size by the total weight of the sediment in the sample one can determine the percentage of the sample in that grain size. Using the percent composition of each phi size is useful because it allows us to see what size most of the grains are. If a higher percentage of the grains are large than we know we’re looking at a coarse sediment where as if the majority of the grains are smaller than we have a finer sediment. Whether the sediment is coarse or fine allows one to determine the type of depositional environment.

In conclusion, we can see that all of the samples are dominated by grains in the larger phi sizes. However, it is worth noting that in the sample furthest east we saw dominance in the top two phi sizes and very little grains in the smaller phi sizes. As one moves further west the grains are more evenly distributed throughout the phi sizes although still the majority are in the larger phi sizes. (See attached spread sheet and graph).
There is also a pattern that is noticeable in the smaller phi sizes. As one moves from location 1 to location 4 (east to west) there is an increase in the percent of grains contained in the smaller phi size category (See attached spread sheet and graph). One would think that the locations closer to the inlet would have a small percentage of grains in the small phi size category because of the increased current. However, this did not occur in this study. One possible reason for this could be that the locations were still too far from the inlet to be greatly effected by the currents.
One might think that the large jetty built at Democrat Point would have an effect on the distribution of sediment and grain sizes. In this study there is very little evidence that the jetty had much effect at all on the distribution of grain sizes. There is an overall general pattern that as one moves from location 1 to location 4, east to west and closer to the inlet that the grain sizes become more evenly distributed throughout the phi sizes.
The jetty does not seem to have any significant effect on this general pattern. The jetty was originally built to keep sediment out of the inlet and prevent the filling in of the inlet. It seems to be succeeding in some degree in this area. The beach on the east side of the jetty (away from the inlet) is significantly larger than the beach on the west side of the jetty. On the east side of the jetty the beach extends approximately 10-15 meters further seaward.

References
Militello, A. and Hughes, S.A. (2000). “Circulation Patterns at Tidal Inlets
with Jetties,” ERDC/CHL
CETN-IV-29, U.S. Army Engineer Research and Development Center. Vicksburg,
MS.
Rampino, R. and Sanders, JE. (1981). Evolution of the Barrier Islands of
Southern Long Island, New York.
Sedimentology 28. pp 37-47.

The Jurassic As Observed in the Deerfield Basin

By John Bucaro

When the super continent Pangea broke apart a series of rift basins were created along what is now the east coast of the United States and down through Central America. The focus of this work is on the northeastern U.S. along the rift zone and more specifically the Newark super group. The Newark super group formed in the late triassic-early jurassic as a result of sedimentation in the rift basins created by the rifting of Pangea. The outcrop studied in this paper is found in the Deerfield basin in Turner Falls, Massachusetts and is of jurassic age (Rasbury 2005).
Certain cycles can be found in the exposed strata of the rift basins. These strata can be used as clues to determine the history of the area, its climate and tectonic activity. All of these findings give one an insight to the depositional processes of the late triassic-early jurassic time period. The sedimentation appears to be lacustrine in nature and the cycles are of a dry-wet-dry nature (Olsen 1997). These cycles are referred to as Van Houten cycles and they suggest the rising and falling of sea level, seasonality, tectonic activity, uplift and various other processes effecting water levels (Olsen 1997). Observation of the Van Houten cycles and further studies of the strata in general can give evidence to transgressive or regressive shorelines and allow for an interesting look at climate changes, plate tectonics and plate positioning during the late triassic-early jurassic.
“The basins show strong vertical changes in overall facies reflecting an interplay of large-scale tectonic and climatic changes with time.” The vertical progression of a cycle consists of a lower area of fluvial deposits and progresses upward to an area of deeper water facies and then transitions back to shallow water fluvial facies again. The Van Houten cycles suggest a cyclical change in climate. The most compelling theory for the climatic change is that of the milankovich cycles, especially the eccentricity of the Earths orbit (Olsen 1997).
In the Newark Basin the Van Houten cycles suggest the deepening and shallowing of lakes. The laminate organic rich layers are representative of a deep stratified lake environment. To have chemical stratification of the lake the depth must be significant approximately 80+ meters. The other end of the cycle is the shallowing of the lake to a playa lake environment(Olsen 1986). In the playa lake thin red, iron rich mudstone and sandstone should be prevalent. There may be some fluvial structures as well indicative of paleocurrents and other fluvial processes. Mudcracks found in any of the strata are indicative of a periodic drying up of the lake once again showing evidence for climatic changes.

I believe this area was lacustrine in nature. It was probably predominantly a playa lake for most of the time as red mudstones and sandstones are most prevalent. The lake must have been shallow enough to allow for oxidation of the iron minerals present. Also the presence of fluvial features in some of the layers suggests that currents were able to have some effect on the bottom sediment of the lake. We also see a few periods where mudcracks are present. The climate must have at one point been arid enough to dry up the lake, also the lake must have been shallow enough to allow for drying up which leads me to believe it was no more than 5-10 meters deep during the playa stage(Olsen 1997). The presence of burrows in some of the layers also leads one to believe that it wasn’t very deep and fairly low energy because animals were able to live in the environment or plants were able to take root in the environment and the burrows remained after the organisms were gone.
The grey material and especially the black fish beds suggest a period in which there must have been a deep stratified lake. Stratification is significant as it suggests the lake was probably at least 80 meters deep (Olsen 1997). Without the stratification the organic material in the fish beds probably would not have been preserved. Oxidation of iron material is less in the deeper stratified lake and we see less of the red coloration at this point in the section.
The overall Van Houten cycle seen in the section is evidence of the changing of climate and environment through the milankovich cycles, plate movement, and tectonics. The fault found in the section suggests active plate tectonics which cause some local low grade metamorphism. Also as the plate drifted through different latitudes climate changes and environment changes will occur. The milankovich cycles obviously change the climate as they are the primary reason for the Earth’s transition in and out of ice ages (Olsen 1997). The overall Van Houten cycle reinforces these theories but we also see smaller changes within the section.
The transitions from mudstone to sandstone and differences in grain sizes suggest the area went through changes in flow regime. Possibilities include river, glacial melts, turbidites and various others however i think the most important information we can take from this is the idea of seasonality. There must have been some seasonality in the area because of the differing flow regimes we see and there occurrence in cycles. Even if one argues that it was due to river influx the differing flow regimes suggest that the river had different flow rates at different times. I think the sandstones and higher flow regime areas are representative of the spring and summer snow melt and run off from the mountains where as the mudstones and lower flow regime structures represent fall and winter periods of less water influx.

Reference:
Olsen, Paul E. Palisades, NY Science 234, (1986). A 40-Million-Year Lake Record of Early
Mesozoic Orbital Climatic Forcing. Pp 842-848.
Olsen, Paul E. Columbia University, Palisades, NY Science 25 (1997) STRATIGRAPHIC RECORD
OF THE EARLY MESOZOIC BREAKUP OF PANGEA IN THE LAURASIA-GONDWANA
RIFT SYSTEM. Pp 337-401.
Rasbury, Troy. Geo 403/543 FIELD TRIP TO JURASSIC OF DEERFIELD BASIN. Class handout.
2005.

Newsday.com: Ancient Indian burial site found in Riverhead park

Posted by Liz
To read the original article click here.
I had to comment on this article because it was extremely interesting to me for more than one reason. For one thing, I have lived on Long Island my whole life and was always interested in Indians and artifacts. Also I live down the street from this park and I have always camped there growing up. It so weird that these remains were found because before this happened I was at the park about a week early right around were the remains were found.

A park in Riverhead “Indian Island Park” is a park open to the public for camping hiking golfing or any leisure activity. Recently bones, a pipe piece and bowl were found. The heavy rains we had in October must have brought the remains to the surface. The bones are believed to be from Indians, dating as far back as 800 BC to 800 AD. The bones were obviously burned, there was a piece of a jaw bone and skull, said to be from two or three different Indians. The pipe was still nearly perfect and said to have geometric detail on it. People said that it was obvious that these people were burned or cremated, which leads us to believe that this was a burial place. But why were they burned? Maybe they were cremated or maybe it was some sort of belief. Officials are not sure what to do with the remains yet. They feel that they should put them back and bury them because of the cultural beliefs. Right now they are being studied so they can be dated and find out exactly who they came from. If it was my decision I would probably bury them back up because it was obvious to be a burial ground from years ago. It’s so interesting to me. there are probably so many more bones and artifacts in that same spot. I wonder if the officials will go ahead and dig up more out of curiosity or let it go in peace. Right now police are watching this place very carefully, they don’t want any intruders.

Where did the Moon come from? Part 2 - The Big Whack by Joe Leddy

Where did the Moon come from? (Part 2 " The Big Whack")

In my last post we looked at the Origins of the Moon and the "Big Three', theories that tried to answer the question of the Moons beginnings. All three had at least some scientific basis behind them, although they all turned out to fall short in one manner or another. So where does that leave the discussion? If the "Big Three" doesn't answer the question, what does?

Enter the currently accepted theory,"The Big Whack". In the mid 1970’s this new theory started to come together. William Hartman (from the Planetary Science Institute in Tucson, Arizona) and Don Davis (a colleague from the PSI) determined that a roaming planetoid of significant enough size could theoretically knock enough of the mantle off of the Earth if it struck early enough after the formation of the planet.

Meanwhile at Harvard University, Alistair Cameron and William Ward determined independently of Hartman and Davis's work that a planetoid of at least the size of Mars could have provided the needed force to supply enough raw materials for the Moon.

Putting these two pieces of work together, "The Big Whack" Theory was born. It was not without its detractors, scientists tend to frown on outlandish answers to problems. So the theory sat without much work being put into it until 1984. In Kona, Hawaii a conference was held to discuss the origins of the moon, and research started to move forward on the Giant Impact Theory as it was know known. (Apparently Astronomers have a rough life with conferences in Hawaii, as apposed to digging in the middle of Montana like a Geologist)

Robin Canup, an astrophysicist from the Southwest Research Institute, modeled what such an impact would look like. Her calculations arrived at the conclusion that the impacting object would have to have been two to three times the size of Mars. She arrived at this conclusion based on her assumptions that only 20 to 50% of the material ejected from an impact would make it to form the Moon.

The Moon is less dense than the Earth, a moon forming from a cloud of debris from the impactor and the Earth' mantle would explain this. The Big Whack also explains the Moon’s tiny core; models show that the Earth would have absorbed any core within the impactor. And the Big Whack explains while the Earth rotates about an axis on a 23.5-degree tilt.

So far so good, however there are still holes in the Big Whack that need to be worked out. For instance, if the Moon is made up from a combination of an impactor and the Earth, why is there such an oxygen-isotope similarity between the two? Wouldn’t you expect more of a difference? A second problem is the resulting spin of the Earth that would have resulted. If such a large object hit at an angle resulting in all of this debris, the planet would have a significant increase in its rotational speeds. How do we account for the lack of this spin? A second impact slowing the Earth down seems incredibly unlikely.

While there are still questions to be answered, the Big Whack is still the favored theory of lunar development.

For more information on the Moon and its origins
please see the following websites:

www.nasa.gov

www.pbs.org/wgbn/nova (origins by Peter Tyson)

Origin of the Moon by William Hartman published in
1984

www.space.com (Torn Away: The Moon’s Violent Birth
September 1 2000)

Where did the Moon come from (part 1 - The Big Three) by Joe Leddy

Where did the Moon come from? (part 1 The Big Three)

Since the beginning of civilization man has been fascinated by the Moon. It has been worshiped,
feared, and studied. For centuries we have theorized how the Moon came to be.

The first modern scientific” studies we conducted by Galileo in 1610, when he discovered that the light and dark spots were plains and mountains. Galileo was on the right path in his discoveries of how the Earth/Sun system worked, until the Church tried him for heresy and all published thoughts along these lines (at least within the influence of the Church) stopped.

Charles Darwin’s son George put the first theory of the origins of the Moon to gain some measure of acceptance forth. George Darwin theorized the Earth spun the Moon into existence. According to Darwin, the Earth in its infancy spun so rapidly that a chuck was pulled of an elongated Earth”. Darwin initially put forth his theory in 1878. Four years later geologist Osmond Fisher added to the theory by stating the scar left behind from this fission was in the
Pacific Ocean. The Fission Theory was widely accepted well into the 20th century.

In 1909, some competition enters the Moon origins discussion. Thomas Jefferson Jackson See, an astronomer with quite possibly the most American name of all time, advocated the Capture Theory. According to See, the Moon was really a wandering planet that was captured by the Earths gravity.

There was still another theory that entered the fray. Edouard Roche, an astronomer advocated a co-accretion theory that the Earth and the Moon formed simultaneously from the same material that all of the planets formed from. This would come to be known as the Co-accretion Theory.

These theories were dubbed the Big Three, and were a source of much debate. Selenology, the study of the moons origins, really gained some footing after the Apollo missions (and corresponding Russian missions) brought over 800 pounds of lunar rock to study.

Studies of these rocks showed some remarkable similarities between the Earth and the Moon. Studies of the isotopes present in the rocks showed both bodies to be roughly 4.5 billion years old, and the quantity of stable oxygen isotopes showed a similarity in the distance both bodies formed from the Sun. The Earth and Moon were shown to be a system. This still does not tell us which of the Big Three was correct, if any.

The Fission Theory falls apart under study. It might explain the lack of a core in the Moon and the Moons similarity to the Earths Mantle, however it stops there. The physics behind the Fission Theory does not work. The speed at which the Earth would have had to been spinning is off the charts. Add that to the fact that the Pacific Basin is 70 million years old, not 4.5 billion and the theory is dead.

The Capture Theory also fails under a combined geological and physics based study. Geologically the chances that a planet developed elsewhere in the galaxy/solar system would have the same properties as the mantle, but no core, does not work. In addition the chances of an object the size of the Moon being captured by the Earth, at just the right angle and speed, are so small they are statistically impossible.

The Co-accretion Theory does not explain the lack of a core in the Moon. In addition, the chances that the Earth develops with all of the iron while the Moon has none make this theory very improbable.

If the Big Three are out, what's left? In part two of this post I'll look at a new theory that is leading the way…"The Big Whack'.

Major Events in the 4 Sciences by Joe Leddy

Events that change a scientific field

What are the major branches of scientific study today? For the purposes of this discussion I will break science as a whole into 4 major branches: Biology, Chemistry, Physics, and the “Earth Sciences. People can and probably will argue that these classifications are too general, especially Earth Sciences. When you look at it from the perspective of unifying theories, discoveries, and events that bring the branch together, it starts to make sense.

Before we look at the theory/discovery that unifies the Earth Sciences, lets take a look at the other sciences to establish what these events look like.

In the field of Biology, Darwins Theory of Evolution changed the face of biological studies and gives direction to why things happen the way that they do. With evolution a biologist can uncover what mechanisms the species developed that make it suited for its environment. This line of questioning leads to how the species adapted, and ultimately the genetics behind the adaptation.

Chemistry started to take off as a science with the discovery of the atom. Prior to this discovery
chemists were nothing more than alchemists trying to turn lead into gold. With the atom, chemists eventually uncovered the structure behind the atom (protons, neutrons, and electrons) and how this structure allows all elements to interact.

Sir Isaac Newton made the major contribution to physics with his Laws of Motion. It is from these laws that modern physics (a.k.a. Newtonian Physics) came to be. By far this is the most important event in physics.

Now we come to the branch that seems to be the catch all for all other types of science. The Earth Sciences are made up of four distinct sciences in and of themselves. These sciences are geology, astronomy, oceanography, and atmospheric science.

Some might ask why these four are grouped together, after all isn't atmospheric sciences really a combination of physics and chemistry? And couldn't you argue that Oceanography has a large biological component to it? Well the short answer is yes, you can make those arguments, and however if you look at the theory that brings these sciences together you might change your mind.

Plate Tectonics is that theory; it unifies the four into the umbrella of the “Earth Sciences”. As you know, the theory of Plate Tectonics is concerned with the movement of lithospheric plates along the asthenosphere. These movements occur along divergent, convergent, and transform plate boundaries.

The real question is how Plate Tectonics ties geology, oceanography, astronomy, and atmospheric sciences together. It is a very clear connection for some and not so clear for others. Lets look at the clear ones first.

Geology is the obvious Earth Science; by definition is the study of the Earth. Plate tectonics explains a large portion of geology, from the development and recycling of older rock all the way to mountain building and earthquakes. Similar to Newton, plate tectonics offers a cornerstone in which geology can be built and grow.

Oceanography is another obvious Earth Science; a large part of it is similar to geology just
underwater. Plate tectonics explains the development of the world ocean and how it changes over time. Which oceans are growing and which are shrinking as well where new oceans may develop. In addition, plate tectonics gives rise to hydrothermal vents and the chemosynthetic organisms that have developed around them.

Atmospheric Science is tied into the Earth Sciences and plate tectonics in a round about way. The weather is a very complex system that is affected by a great many factors, however at its core it deals with the movement of air masses and the amount of moisture within that air mass.

Not seeing a connection between the movement of air and plate tectonics? Lets look at how air moves, parcels of air will either move above or below another parcel or rise and sink based on the air temperature. Air temperature is based on a number of factors, primarily the exchange of the heat from the land/water mass it was developed above. Plate tectonics affects the development of oceans and mountains, oceans and mountains greatly affect how these masses move and their moisture content. So, plate tectonics plays an indirect roll in an areas weather patterns on a geologic scale rather than a small time frame. Finally we come to Astronomy. This connection is not a simple as the others. Plate tectonics has nothing to due with Astronomy on a macro scale; rather it deals with a specific division within Astronomy. The study of planets and the search for live within the universe. Understanding how the Earth behaves gives astronomers a base on which to work with. Whether it is explaining quakes on another planet or looking for life, understanding plate tectonics and how it affects the Earth is a big help in their studies.

For more information on the Earth Sciences please
visit the following web sites:

www.nasa.gov
www.noaa.org
www.weather.com

Or look into classes at Suffolk dealing with these
subjects.

Ice Ages by Joe Leddy

Ice Ages

Hollywood has developed an image of an Ice Age that is catastrophic and in the case of the movie "The Day After Tomorrow" sudden. There are many questions to be studied in order to understand what an Ice Age is. What exactly is an Ice Age? How are they caused? Are there Ice Age Cycles? And can global warming cause an Ice Age?

You can define an Ice Age as a period of a long-term downturn in the temperature of the Earth’s Climate, resulting in the expansion/growth of continental ice sheets/polar ice sheets, and the growth of mountain glaciers (taken from Wikipedia.com) this is also known as glaciation. It should be noted that you could still be in an Ice Age if the Glaciers are retreating; you are just in the process of coming out of the Ice Age. The term Glacial Periods refers to the colder period of the Ice Age and Interglacial refers to the warmer periods. (We are technically in an interglacial period following a retreat of ice roughly
10,000 years ago)

There are three generally accepted factors that cause
Ice Ages:

• Atmospheric Composition - Carbon Dioxide and Methane
  being the chief gases of concern (Decreases in
  concentrations within the atmosphere)
• Variations in the Earths orbit around the Sun (This
  is known as the Milankovitch Theory - The Earth
  wobbles as it orbits the Sun and it takes
  approximately 41,000 years to complete one wobble.
  The wobble is roughly 22 degrees. This tilt of the
  Earth is the cause of our seasons. If the tilt
  varies, say to 25 degrees, we could in theory have
  dramatic shifts in our climate)
  
• The Arrangement of the continents places a part as
  well. If there are landmasses near the poles there is
  a place for the ice to build.

Ice Ages do appear to come and go in a cycle. They generally occur at 100,000-year frequencies however they have been known to occur every 40,000 years. Geologists know the time line by the scrapes the ice leaves behind in the rock. This pattern has held for the last few million years. Within this time there has been 4 major Ice Ages.

The earliest is theorized to have taken place between 2.7 and 2.3 billion years ago, this would have placed it in the early Proterozoic Age. Next comes the Snowball Earth Ice Age, this took place 800 to 600 million years ago. It is referred to as Snowball Earth because permanent sea ice extended to or quite close to the equator. This Ice Age would have taken place in the Cryogenian period.

Roughly 460 to 430 million years ago, during the Late Ordovician Period, another one occurred. And finally there were quite extensive polar ice caps 350 to 260 million years ago during the Carboniferous and Early Permian Periods.

The last Ice Age began 40 million years ago and intensified during the Pleistocene with ice sheets spreading in the Northern Hemisphere. The last glacial period of this Ice Age ended roughly 10,000 years ago.

As you can see, if Ice Ages occur every 40,000 to 100,000 years, it is the “mini ice age” that is far more common than the major Day After Tomorrow types we see in the movies.

It is not global warming that causes the Ice Ages, rather the removal of Carbon Dioxide from the atmosphere. Global warming can indirectly affect this however. In theory, if the greenhouse effect melts the Ice caps the ocean currents could be drastically affected. If the currents are changed the blooming of plankton (photosynthetic organisms) can also be affected. If the bloom is too large, the process of photosynthesis (the conversion of Carbon Dioxide into Oxygen) canremove massive levels of CO2 from the atmosphere. It is that removal that has scientists concerned about another Ice Age. (Please keep in mind this is an over simplified explanation of a very complex process)

For more information please see the following:

Discover Magazine September 2002 - A New Ice Age:
The Day After Tomorrow
www.discover.com

www.ncdc.noaa.gov/paleo/glaciation.html

www.wikipedia.com
Or speak with or review Professor Mandia’s Website