Celebrating Marie Tharp: The Queen of the Oceans!
Apeksha Srivastava and Aniruddha Mukherjee
See through the sea!
July 30, 2020, marked the 100th birth anniversary of the
very inspirational Marie Tharp,
the woman who 'decoded' the oceans. While several
other scientists remain at the forefront of academic media,
not many people know about the woman who showed us, for the
first time, that the ocean bottom has a range of
geographical features, similar to what we see on land.
Before the early 1950s, the world knew very little about the
ocean floor structure. It was her revolutionary work that
not only opened doors to previously unknown and amazing
terrain of the ocean floor, but also made it possible for us
to understand our planet better. Marie Tharp was one of the
creators of the
first detailed map of the Atlantic Ocean floor, and
she definitely did not stop just there.
A Series of ‘Fortunate’ Events
Born in Ypsilanti (Michigan) in 1920, Marie Tharp was the
daughter of William Tharp, a surveyor who mapped soils for
the United States Department of Agriculture. A possible
reason that influenced her growing interest in science was
that, as a child, Marie loved to accompany her father during
his fieldwork. Her school trips to explore nature seemed to
add fuel to the fire of her scientific curiosity as well.
However, since women were not encouraged to work in the
‘male-dominated’ scientific fields at that time, Tharp never
even considered taking up science for her bachelor’s degree.
She graduated from Ohio University with English and Music
instead. The 1941 attack on Pearl Harbor that led the U.S.
to enter World War II was the turning point in Marie Tharp’s
scientific career. During this time, women were being
recruited to fill many ‘men-only’ positions because men went
to war. The University of Michigan, thus, opened its doors
to girls, promising them jobs in the petroleum industry if
they earned a degree in geology. Studying the earth resulted
in Tharp getting a job at the Stanolind Oil and Gas Company,
Oklahoma. The deep-rooted gender bias in society resulted in
her collecting information and maps to assist men, the only
ones allowed to go for fieldwork at that time. In the face
of all challenges, Tharp completed her bachelor’s in
Mathematics while working here. One thing led to another,
and she became one of the first women to work at the Lamont
Geological Observatory (now known as the Lamont-Doherty
Earth Observatory at Columbia University) in 1948.
Bringing Oceans to Life
During her time at Lamont Geological Observatory, Tharp
started working with Bruce Charles Heezen, another American
geologist, to locate drowned military aircraft from the war.
With time, they began to map the ocean floor. For about 18
years, Tharp drew sketches, using data that Heezen
collected, aboard the ship. The woman, who unlocked the
crucial mysteries of the ocean floor, could not set foot on
ships, owing to the sexism that did not ‘allow’ women to do
After marking the locations the ship had traveled to, Tharp
read the depth at each location using the sonar technique.
Sonar uses sound waves to detect objects on or under the
surface of water. It helped her to plot the ocean floor
depths against the distance traveled.. Tharp’s observations
across the North Atlantic brought up something unexpected.
Her calculations indicated a huge cleft in the center of the
ocean. She suggested that it was a
a linear lowland between highlands created by pulling the
earth’s outermost layer apart. Until then, it was something
known to exist only on land. Heezen accepted her hypothesis
as justified only after confirming that the location of
earthquake epicenters (points where earthquakes originate),
as mapped by another researcher, aligned with her ‘proposed’
rift valley. This revolutionary discovery was crucial
for major developments in the geological sciences. For
example, the theory of plate tectonics, which states that
the earth’s outermost layer (crust) is separated into plates
that move over the molten upper-mantle layer, or the theory
of continental drift, stating that the planet’s continents
have moved across the ocean bed over time, gained momentum
within the scientific community with this discovery.
Seeing is Believing
In order to present their findings credibly before a much
wider audience, Tharp and Heezen decided to draw
physiographic maps of the ocean floor.
These showed the terrain as it would look from a low-flying
plane, capturing the varied features of the ocean floor.
These maps helped to publish their work too, as the U.S.
Navy’s contour maps were classified. With time, Tharp used
information obtained from 30 cruises to establish that the
rift valley extended into the South Atlantic as well. The
Indian Ocean, Red Sea, Arabian Sea, and the Gulf of Aden
disclosed similar features, proving that the
mid-ocean rift system extended throughout the earth!
We can understand
this rift system
as a range of underwater volcanoes wrapping around the globe
like seams on a baseball.
Meanwhile, scientist and explorer Jacques Cousteau, doubtful
of their claims, set sail into the Atlantic Ocean with an
underwater camera, aiming to prove Tharp and Heezen wrong.
But, his photos and videos clearly captured the rift valley,
proving its existence. Cousteau displayed his photographs at
the First International Oceanographic Congress in 1959,
thereby convincing many people of Tharp’s hypothesis. The
North Atlantic physiographic map was first published in
1956, revealing that the ocean floor consists of features
like valleys and mountains. In 1959, The Geological Society
of America reprinted it. Then followed the publishing of the
South Atlantic diagram in 1961. Tharp, Heezen, and Heinrich
Berann (an Austrian painter and mapmaker) sketched the
Indian Ocean map in 1967, published by National Geographic.
They also made a map of the Antarctic Ocean floor in 1975.
Next, Heezen and Tharp proceeded to draw the entire world’s
ocean floor. Their previous work, new updates, several
collaborations, and tireless efforts
gave us the first map of the earth’s ocean floor in
The Queen Prevails
Managing to carve a place for herself in the male-dominated
world, Marie Tharp was finally able to board a ship for
research data collection in 1968. She and Heezen (after his
death) were awarded the Hubbard Medal in 1978. It
is the National Geographic Society’s highest honor. Tharp
was a faculty member at Columbia University until 1983. In
1997, the Library of Congress named her
one of the four greatest mapmakers of the 20th century.
Woods Hole Oceanographic Institution
recognized her with the
Mary Sears Woman Pioneer in Oceanography Award.
She received the
first annual Lamont-Doherty Heritage Award
as a pioneer in oceanography in 2001. At the age of 86, she
died of cancer in New York on 23rd August 2006. The
International Astronomical Union, in 2015, named a crater on
the moon as “Tharp” in her honor. Craters are depressions
produced by the impact of volcanic activity, meteorite, or
In the words of Vicki Ferrini
, a senior research scientist in marine geology and
geophysics at Lamont-Doherty Earth Observatory, Columbia
University, “Marie Tharp’s maps were building blocks for
discoveries that transformed our understanding of the
planet.” Even though her accomplishments were exceptional,
Tharp’s work was often undervalued in a world dominated by
men. For most of her career as a scientist, she worked in
the background. In 1956, Heezen received credit for the rift
valley discovery. Tharp’s name was also absent from major
papers on plate tectonics for a long time. Nonetheless, she
overcame the barriers that limited the progress of women
during her time. She never looked for glory, loved her work
above everything else, and used the opportunities coming her
way whenever she could. Above all, she never gave up,
contributing significantly to marine mapmaking and science.
She is an incredible example of “girl-power,” not just for
women of her generation, but for many other generations to
come. Marie Tharp truly is the queen who rose to rule and
showed us the backbone of our planet, unfolding the
beautiful yet powerful story of the seas and oceans!
Bettie Matheson Higgs. Understanding the Earth: the
contribution of Marie Tharp. Geological Society, London,
Special Publications, 506, 231-243, 12 October 2020.
Earth Institute. Marie Tharp’s Adventures in Mapping the
Seafloor, In Her Own Words. State of the Planet,
Columbia Climate School. 24 July 2020.
Cathy Barton. Marie Tharp, oceanographic cartographer,
and her contributions to the revolution in the Earth
sciences. Geological Society, London, Special
Publications, 192, 215-228, 1 January 2002.
Apeksha Srivastava completed her MTech in Biological Engineering
from the Indian Institute of Technology Gandhinagar, Gujarat,
India. She is currently an aspiring science writer and a PhD
candidate at this institute. Her research area lies at the
intersection of science communication, and psychology. Aniruddha
Mukherjee completed his BS-MS with a major in Biological
Sciences from IISER Kolkata. He will be joining University of
Alabama at Birmingham, U.S.A for his graduate studies in
Biomedical Sciences in the coming fall. Apart from being a movie
buff he enjoys cooking and playing chess.