WANDERING THE
WATERSHEDS: HACKENSACK MEADOWLANDS
by Michael J.
Passow
The Hackensack Meadowlands contain both
highly developed and wilderness environments, and as such rank among the most
interesting locations to “Wander the Watershed.” One can paddle through a tidal
marsh viewing at snowy egrets and great blue herons one moment, then look up to
see overpasses on the New Jersey Turnpike and Giants Stadium with 70,000 fans
while a jet overhead roars down toward its landing at Newark Liberty Airport!
Geologically, the Meadowlands result from more than 200 million years of
deposition, erosion, and human alterations. It is an oasis of peace and quiet,
fascinating environmental features, and a pollution-abatement success story, all
within the greatest metropolis in the world!
Geological History
The Meadowlands lie within the Newark Basin,
also known as the Newark Lowlands province, a Late Triassic-Early Jurassic
sedimentary feature with several igneous extrusions and intrusions, including
the Palisades along the west shore of the Hudson River. First studies of the
region date back to the earliest days of geology in the 1830s, yet new
techniques within the past decade have revealed much about the history of the
region. These include a set of deep drillings by the LDEO Borehole Group and
Rutgers University.
Olsen (1980) introduced the discussion by
noting:
Far from being the consequences of the last
gasps of the Appalachian Orogeny, Late Triassic and Early Jurassic Newark
Supergroup basins formed in dynamic association with the opening of the Atlantic
Ocean. In addition, Newark Supergroup rocks, once thought to be nearly barren of
fossils, are now known to be exceptionally rich in organic remains,
replete with plants, invertebrates, and vertebrates spanning some 35 millions
years of the Early Mesozoic. Finally, long periods of unusually continuous
deposition coupled with an abundance of laterally extensive stratigraphic
‘marker’ beds makes this deposit ideal for studying time-facies relationships
and evolutionary phenomena. These recent discoveries have focused new interest
on Newark strata.
The Newark Basin is the largest of the
exposed divisions of the Newark Supergroup, covering about 7770 km2
and stretching 220 km along its
long axis. The basin contains the thickest sedimentary sequence of any exposed
Newark Supergroup basin and correspondingly covers the greatest continuous
amount of time.
Olsen
defines the Newark Supergroup as:
… “the
predominantly red clastics and volumetrically minor basaltic igneous rocks
exposed in 13 major and 7 minor elongate basins preserved in the Piedmont,
New England, and Maritime physiographic provinces of Eastern North America….The
rocks of these basins … unconformably overlie (or intrude) Precambrian and
Paleozoic rocks. They are in turn overlain by post-Jurassic rocks of the Coastal
Plain, Pleistocene deposits, or recent alluvium and soils….”
Precambrian
and early Paleozoic rocks of the southwestern prongs of the New England Upland
[“Manhattan” Prong and “Reading” Prong or, locally, “Hudson Highalnds”] border
the Newark Basin along its northeast and northwest margins. The southeastern and
southwestern portions of the Newark Basin overlie and are bordered by Paleozoic
and Precambrian rocks of the Coastal and Piedmont Provinces. Newark Basin
sediments rest with profound unconformity on basement rocks and mostly dip
5o - 25o to the northwest.
For an
earlier guidebook, Van Houten described this region as:
…preserved
in a southwest-trending basin that reaches from Rockland Country, New York, to
northeast Lancaster County, eastern Pennsylvania. This is the largest of six
major (and several minor) Triassic rift valleys in a sinuous belt more than
1,000 miles long, from Nova Scotia to North Carolina (and in subsurface as far
south as Florida).
The Newark
Basin is the largest of three lobes (Newark, Gettysburg, Culpepper connected by
narrow corridors in a 300-mile arcuate tract from southeastern New York to
northeastern Virginia. It is about 40 miles long and a maximum of 32 miles
wide….
Extruded or
intruded through the sedimentary layers are several igneous rock formations.
These include the Watchung lava flows (formally described by Olsen as the Orange
Mountain Basalt, Preakness Basalt, and Hook Mountain Basalt), and diabase
intrusions, the largest of which form the Palisades. A smaller intrusion in the
Meadowlands has been extensively quarried, but still forms a prominent landmark
on any paddle through the Meadowlands. It is variously known as Rocky Hill,
Snake Hill, and Laurel Hill, and is now the site of a Hudson County Park and
common launching site for canoeing and kayaking trips.
The
sedimentary rocks consist mainly of shales, sandstones, and conglomerates.
Earlier studies divided these into the Stockton, Lockatong, and Brunswick
formations, but recent work by Olsen and others now separates the Brunswick into
three formations separated by the basalt flows. Further details of the rocks may
be found in the references.
In summary,
we can generally say that great stresses associated with the breakup of Pangaea
in the Early Mesozoic produced a series of basins into which sediments were
eroded from adjacent higher areas. Many were rich in iron, giving the
distinctive reddish color. Such oxidation and the fossil evidence indicate that
these basins were generally shallow, or even terrestrial. In many places,
“fossil raindrops” preserve a record of brief showers falling on moist muds,
through which worms or other burrowing organisms left churned-up tracks. One of
the earliest dinosaurs, Clepysaurus (Rutiodon), was discovered in 1910
during a field trip of Columbia geology students about half a mile south of
where the George Washington Bridge was later built, and is now on display at the
American Museum of Natural History.
Gradually,
the sediments were eroded southeasterly as the Atlantic opened and the Coastal
Plain formed. There is evidence that changes in sea level during the later
Mesozoic and Cenozoic alternately covered and exposed the region, and probably
deposited sediments over the early Mesozoic rocks.
The next
interesting part of the Meadowlands story involves the Hudson River, which now
flows several kilometers to the east on the other side of the Palisades ridge.
But closer examination of the area has revealed remnants of meandering streams
that crossed a flat surface (sometimes called the “Schooley Peneplain”). These
can be traced to the ancestral Hudson River, which apparently cut through the
Palisades at the Sparkill Gap, west of the Tappan Zee region some twenty km
north of the George Washington Bridge. These streams eroded softer rocks that
may have been deposited as part of the Coastal Plain inundations as the Atlantic
opened, exposing and eroding the harder Triassic and Jurassic rocks. Many
diagrams illustrating the sequence of events during the Mesozoic and Cenozoic
are included in De Lotto (1973) and the other references used in preparing this
account.
Using
borings made for various construction projects in the Meadowlands, it became
possible to identify two pre-glacial rivers flowing in a southerly direction
through what is now the Meadowlands, beds of the ancestral Hudson River (Widmer,
1964). At some point in time, a small stream eroding northward along the base of
the Palisades broke through the sediments and “pirated” the Hudson River,
allowing it to follow a more direct route to the ocean. Subsequently, the Hudson
eroded its existing bed, and the more westerly river beds were abandoned.
With the
advance of the Pleistocene ice sheets, the area was covered by continental
glaciers more than 800 meters thick. But this was close to the limit of their
extent, and much of the materials they transported were left as the terminal
moraine when the ice started to melt, or was strewn over the region as erratics.
The terminal moraine formed a dam blocking the meltwaters, and in what became
the Meadowlands a long, narrow lake formed. Glacial Lake Hackensack apparently
extended more than 30 km northward from the area near where Newark Airport is
now into Rockland County. Clay and other sediments deposited on the lake bottom
covered the ancient river beds and other rocks, beginning the formation of the
Meadowlands. To the west behind the terminal moraine lay the even-larger Glacial
Lake Passaic, the remnant of which is the Great Swamp.
In the 1920s
when clay from these glacial lake deposits were mined in Little Ferry for
ceramics and other uses, geologists counted more than 2000 varves, layers that
formed in the annual freezing and melting as the Ice Ages ended. At some point,
the terminal moraine “dam” broke and Glacial Lake Hackensack emptied. Sea level
rose as water once in the glaciers melted and returned to the ocean, and the
region gradually became the swampy, tidal Meadowlands. More information about
the changes as the Wisconsin glaciation ended and the Holocene began are
provided by Averill et al. (1980.)
Interesting
“windows” into the region’s life as the Ice Ages ended and post-glacial warming
began have been in the form of two mastodont skeletons discovered in the area.
During construction of Interstate-80 in the early 1960s at the edge of
Hackensack, two schoolboys accidentally found a tooth. Subsequent excavation by
paleontologists uncovered a partial skeleton. In February 1974 during clearing
of Dwarskill Creek leading into the Oradell Reservoir near the junction of
Closter, Harrington Park, and Northvale, another skeleton was discovered and
excavated. Both now belong to the Bergen Museum, which is in the process of
re-opening at Bergen Mall. [Note: If you look carefully in Fig. 7 of Averill’s
article, you will see him pointing out some features to me during the
excavation.]
Agron (1980)
provides an excellent overview of the Meadowlands environmental geology, and
this article is strongly recommended. Additional selected field trip guidebook
articles about the geology of this region are provided at the end of this
account.
Human Intervention
The Lenni
Lenapes and other Native Americans survived for many centuries through
lifestyles based on hunting and gathering the animals and plants occupying the
region in post-glacial times. The first Europeans to settle were the Dutch,
beginning around the 1630s. They began to utilize their ditch and dike building
strategies to modify the environment into farmland, just as they had done in
their native Holland.
When the
English took control from the Dutch in the 1660s, many of the early settlers
remained and continued to farm the area. During the early 18th
Century, copper was discovered in the Mesozoic rocks on the western edge of the
Meadowlands in what is now Lyndhurst, and one of the first steam engines in
North America was imported to drain water seeping into the mine. Copper from
this region was used to make brass and bronze fittings during the Revolutionary
War.
In November
1776, Washington led his forces in the Retreat Across the Jerseys after the
Battle of White Plains that ended at Valley Forge. When all his troops had
crossed the river, Washington’s forces burned the “New Bridge” at River Edge and
took all the boats at Little Ferry, thus stymieing the British forces trying to
catch them. The following month was the famous crossing of the Delaware and
victory at Trenton on Christmas Eve. But perhaps without the delay provided by
the barrier of the Hackensack River, events might have turned out quite
differently.
Through the
19th and 20th Centuries, various attempts were made to
develop the marshy areas, but the subsurface geology generally frustrated such
efforts. Modern technology allowed construction of the Meadowlands Sports
Complex, with Giants Stadium, the Continental Arena, and Meadowlands Race Track.
Fortunately, much of the region still remains wetlands. The Meadowlands today
still consists of about 7,000 acres of wetlands, some ten times the size of
Central Park in Manhattan.
In the late
19th and early 20th Centuries, the red sandstones along
the eastern edge of the Meadowlands were extensively quarried to supply basic
materials for the “brownstones” so common in parts of Manhattan and Brooklyn.
The diabase was also extensively quarried at many places along the Palisades and
at Rocky Hill. Around the turn of the 20th Century, various Womens
Clubs led the efforts to end these mining activities and created the Palisades
Interstate Park, stretching north of Fort Lee into Rockland.
Industrial
plants at the edges of the marshes, however, continued to discharge great
amounts of toxic heavy metals and other pollutants until stricter environmental
laws passed beginning in the 1970s required greater attention to the impact of
their actions. Some companies shut down their operations in this sensitive
region, but others continue to have detrimental affects. The damage they
inflicted on water quality and wildlife still remains, although definite signs
of positive progress exist. More birds and other predators inhabit the
marshlands, indicating reduced levels of pollution.
The
Hackensack Meadowlands Environmental Center, part of the New Jersey Meadowlands
Commission, provides educational and recreational programs about the Meadowlands
region (http://www.meadowlands.state.nj.us/ec/environment_center.html).
They offer a variety of school and public activities featuring the Meadowlands,
working together with such groups at Hackensack Riverkeeper (www.hackensackriverkeeper.org).
Hydrology
At its
northern end, the Hackensack is strictly a freshwater stream, supplied by rain
and runoff through many small tributaries draining westward down the Palisades
and eastward from its divide with the Passaic. Since the late 19th
Century, parts of the upper Hackensack have been dammed and used as water
supply. The largest of several water bodies is the Oradell Reservoir, and also
include Woodcliff Lake, Tappan, and Lake DeForest in Rockland County.
South of the
Oradell dam, the river is tidal, with a range of more than a meter. In places
along its banks, the river alternately exposes and covers mud flats on which
live crabs, mussels, and other organisms. Marsh reeds, bog plants, and
vegetation form islands in much of the rest of the area, providing a habitat for
a variety of fish, waterfowl, muskrats, and other organisms. Within the
Meadowlands can be found both freshwater and salt marsh environments.
The tidal
patterns are available at
www.nos.noaa.gov, and should be consulted before planning a paddle. In many
parts of the Meadowlands, the water may drain out fairly quickly, stranding the
unwary wanderer in a vast muddy tract within sight of deeper waters. More
information about the Hackensack watershed is available through the EPA’s “Surf
Your Watershed,”
http://cfpub1.epa.gov/surf/huc.cfm?huc_code=02030103, and related websites
from the U.S. Geological Survey and other sources that may be linked through the
EPA site..
The
Hackensack Meadowlands Environmental Center (http://www.meadowlands.state.nj.us/ec/environment_center.html)
operated by the New Jersey Meadowlands Commission (http://www.hmdc.state.nj.us/)
serves as the focal point for educational programs about the region. They
provide a great variety of school and public activities featuring the
Meadowlands, working together with such groups at the Hackensack Riverkeeper
(http://www.hackensackriverkeeper.org/).
References:
Agron, S.L., 1980, “Environmental Geology of the
Hackensack Meadowlands,” in Manspeizer, W., ed., Field Studies of New
Jersey Geology and Guides to Field Trips. 52nd Annual Meeting of
the New York State Geological Association, Rutgers University-Newark. pp.215 –
242.
Averill, S.P., et al., 1980, “Environmental Geology of
the Hackensack Meadowlands,” in Manspeizer, W., ed., Field Studies of New
Jersey Geology and Guides to Field Trips. 52nd Annual Meeting of
the New York State Geological Association, Rutgers University-Newark. pp.159 –
186.
De Lotto, Sister Doris,
1973, “An Overview of the Hackensack Meadowlands from Its Geological Beginnings
to the Present.” St. Louis University Geography Department, Masters Thesis.
Olsen, P.E., 1980, “Triassic and Jurassic Fomations of
the Newark Basin,” in Manspeizer, W., ed., Field Studies of New Jersey
Geology and Guides to Field Trips. 52nd Annual Meeting of the New
York State Geological Association, Rutgers University-Newark. pp.2 – 40.
Van Houten, F.B., 1969, “Late Triassic Newark Group, North
Central New Jersey and Adjacent Pennsylvania and New York,” in Subitzky, S., ed.
Geology of Selected Areas in New Jersey and Eastern Pennsylvania and
Guidebook of Excursions. Geological Society of merica and Associated
Societies Annual Meeting, Atlantic City, NJ.
Widmer, K., 1964, The Geology and Geography of New
Jersey. Van Nostrand Co., Princeton.
Additional Field Trip Guidebook articles concerning this region
[Note: Over time, many of the locations described in these
articles no longer exist, but the geological information is still of use.]
New York State Geological Association 40th
Annual Meeting (1968, Queens College) Guidebook to Field Excursions
“The Triassic rocks of the
Northern Newark Basin” by E.L. Savage; Road log by F. B. Van Houten, E. L.
Savage
New York State Geological Association 47th
Annual Meeting (1975, Hofstra University) Guidebook to Field Excursions
“Structure and Form of the Triassic Basalts in
North Central New Jersey” by M. Sichko, Jr.
New York State Geological Association 68th
Annual Meeting (1996, College of Staten Island) Guidebook to Field Excursions
“Sedimentary Environments in the Newark Basin
in New Jersey and Contiguous New York” by Gerald M. Friedman
The Geology of North America Volume I-2 The Atlantic
Continental Margin: US, Edited by R. E. Sheridan and J. A. Grow, Geological
Society of America, 1988.
“Late Triassic-Early Jurasic synrift basins of
the U.S. Atlantic margin” by W. Manspeizer and H. L. Cousminer, pp. 197 – 216.
“Mesozoic and Cenozoic magmatism” by J. Z. de
Boer et al., pp. 217 – 241.
Acknowledgement:
For her valuable suggestions and corrections, I appreciate comments received from Kathy Urffer, Hackensack Riverkeeper, Inc.,231 Main Street, Hackensack, NJ 07601; 201-968-0808; 201-968-0336 (fax); www.hackensackriverkeeper.org
Riverkeeper, Inc.,231 Main Street, Hackensack, NJ 07601; 201-968-0808; 201-968-0336 (fax); www.hackensackriverkeeper.org
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