what was harry hesss theory

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What did Harry Hess's theory state?

As the ocean crust spread away from the higher ocean ridges, the guyots sank below sea level, becoming completely submerged. Hess also theorized that because the continental crust was lighter, it didn't sink back into the deep earth at trenches as did the oceanic crust.

What did Harry Hammond Hess discover?

Building on the work of English geologist Arthur Holmes in the 1930s, Hess' research ultimately resulted in a ground-breaking hypothesis that later would be called seafloor spreading. In 1959, he informally presented this hypothesis in a manuscript that was widely circulated.

What was Harry Hess known for?

Harry Hess was a geologist and Navy submarine commander during World War II. Part of his mission had been to study the deepest parts of the ocean floor. In 1946 he had discovered that hundreds of flat-topped mountains, perhaps sunken islands, shape the Pacific floor.

How did Harry Hess discover his theory?

During World War II, Hess was the captain of a Naval ship and used the ship's sonar to take depth readings of the Atlantic Ocean. He used this data to hypothesize on the way the seafloor was moving, which became known as his Seafloor Spreading Hypothesis.

What evidence supports Hess's theory of seafloor?

Sea floor continues to spread apart as new crust is added. Processes repeats like a conveyor belt, carrying continents along with them. Evidence supported Hess's theory of sea-floor spreading: eruptions of molten material, magnetic stripes in the rock of the ocean floor, and the ages of the rocks themselves.

Who proposed the theory of continental drift?

Alfred WegenerAlfred Wegener in Greenland. Plate tectonics is the theory that Earth's land masses are in constant motion. The realization that Earth's land masses move was first proposed by Alfred Wegener, which he called continental drift.

What is the importance of seafloor spreading theory?

Seafloor spreading proves that the ocean itself is a site of tectonic activity. Keeping Earth in Shape Seafloor spreading is just one part of plate tectonics. Subduction is another. Subduction happens where tectonic plates crash into each other instead of spreading apart.

What is sea floor spreading theory?

seafloor spreading, theory that oceanic crust forms along submarine mountain zones, known collectively as the mid-ocean ridge system, and spreads out laterally away from them.

What were Hess contributions to space research?

In 1962, President Kennedy appointed Hess to chair the Space Science Board, which advised NASA. Hess held the position until his death in 1969 and played a key role in the planning of the Apollo moon landings. One month prior to his death, Hess helped to analyze lunar rock samples from the Apollo 11 mission.

What is the continental drift theory *?

Continental drift was a revolutionary theory explaining that continents shift position on Earth's surface. The theory was proposed by geophysicist and meteorologist Alfred Wegener in 1912, but was rejected by mainstream science at the time.

Who was Hess in plate tectonics?

Harry Hammond HessHarry Hammond Hess (May 24, 1906 – August 25, 1969) was an American geologist and a United States Navy officer in World War II who is considered one of the "founding fathers" of the unifying theory of plate tectonics.

Who were the two scientist who proposed the theory of seafloor?

The idea that the seafloor itself moves and also carries the continents with it as it spreads from a central rift axis was proposed by Harold Hammond Hess from Princeton University and Robert Dietz of the U.S. Naval Electronics Laboratory in San Diego in the 1960s. The phenomenon is known today as plate tectonics.

When did Harry Hess discover seafloor spreading?

The seafloor spreading hypothesis was proposed by the American geophysicist Harry H. Hess in 1960.

Who discovered seafloor spreading?

The discovery of seafloor spreading is credited to Harry Hess, who first proposed the idea in the early 1960s.

Who mapped out the ocean floor in 1952?

Tharp and Heezen began mapping the individual ocean floors in 1952, but found obstacles in their way.

What were Hess contributions to space research?

In 1962, President Kennedy appointed Hess to chair the Space Science Board, which advised NASA. Hess held the position until his death in 1969 and played a key role in the planning of the Apollo moon landings. One month prior to his death, Hess helped to analyze lunar rock samples from the Apollo 11 mission.

What is a guyot volcano?

Hess theorized that these were once volcanic mountains that were moved and eroded over time. A guyot begins as a volcano on the ocean floor. As the oceanic plate moves the volcano moves as well. Without the magma from the plume to fuel the volcano it becomes dormant.

How did Hess explain the formation of the guyots?

This motion also explained the formation of the guyots that were found at the bottom of the ocean.

What did Harry Hess do for the Apollo 11 mission?

One month prior to his death, Hess helped to analyze lunar rock samples from the Apollo 11 mission. Another important contribution that Harry Hess made to science was the organization and direction of the Princeton Caribbean Research Project.

How did Harry Hess die?

from Princeton in 1932. Upon graduating, Hess taught for one year at Rutgers University and then spent a year as a research associate in the Geophysical Laboratory of the Carnegie Institution of Washington. In 1934, Hess became a professor at Princeton University, where he became the head of the Geology department in 1950 and in 1964 the sixth Blair Professor of Geology. Harry Hess died of a heart attack on August 26, 1969 in Massachusetts.

What would happen if magma cooled?

When the magma cooled, it would expand and push the tectonic plates apart. This theory addressed many unanswered questions in the field of geology. One such question was why no marine fossils found in the ocean were more than 180 million years old, but older marine fossils could be found on land.

What was Harry Hess' rank?

Beyond the world of geology Harry Hess was also an accomplished member of the Naval Reserves, where he earned the rank of Rear Admiral.

What was Hess's first class?

According to Hess, he failed his first class in mineralogy at Yale and was told that he had no future in the field. Over the course of his career, Hess was elected to several prestigious groups including the American Philosophical Society, the National Academy of Sciences, and the geological societies of London, South Africa, and Venezuela. Perhaps the most prestigious was the Academia Nationale dei Lincei of Rome, which is the oldest scientific group in the world. He was also the first geologist from the Western hemisphere to receive the Feltrinelli Prize from the ladder group.

What did Harry Hess do?

One of them, Harry Hess, was an instrumental figure in figuring out how plate tectonics worked. Hess possessed two valuable skills: careful attention to detail and the ability to form sweeping hypotheses. This unusual combination produced groundbreaking work on a number of subjects, including the origin of ocean basins and island arcs, ...

What did Hess discover?

Ever the scientist, while cruising from one battle to the next, Hess kept the transport’s sounding gear (which bounced sound waves off the sea-floor in order to determine the underwater relief or topography) running day and night. This led to his discovery of submerged and curiously flat-topped mountains that he named “guyots” in honor of the Swiss founder of the Princeton geology department. It also produced thousands of miles of echo-sounding surveys of the ocean floor.

How did Hess explain continental drift?

Supporting Wegener’s theory of continental drift, Hess explained how the once-joined continents had separated into the seven that exist today. The continents don’t change dramatically or move independently, but are transported by the shifting tectonic plates on which they rest. The theory also explained Hess’s puzzling guyots. They are believed to be once-active volcanoes that rose above the surface like modern-day island arcs and then were eroded to sea level. As the ocean crust spread away from the higher ocean ridges, the guyots sank below sea level, becoming completely submerged. Hess also theorized that because the continental crust was lighter, it didn’t sink back into the deep earth at trenches as did the oceanic crust. Instead, it scraped rock off the descending ocean crust and piled it into mountain rages at the trenches’ edge. Hess also incorporated the idea proposed by Swiss geologist Emile Argand in the 1920s that mountain belts are also created when two continents collide.

What rank did Hess go to after Pearl Harbor?

Already a lieutenant junior grade in the Naval Reserve, Hess was called to active duty after Pearl Harbor and was eventually to rise to the rank of Rear Admiral.

Who proposed the idea that mountain belts are also created when two continents collide?

Hess also incorporated the idea proposed by Swiss geologist Emile Argand in the 1920s that mountain belts are also created when two continents collide. Hess’s bold intuition was subsequently corroborated.

Did Hess' intuition confirm the oceanic crust?

Later studies showed that the age of the ocean floor increases with distance from the ridge crests, and seismic studies confirmed that the oceanic crust was indeed sinking into the trenches.

Who was Harry Hess?

Harry Hammond Hess (1906 - 1969) Harry Hess was a professor of geology at Princeton University (USA), and became interested in the geology of the oceans while serving in the US Navy in World War II. His time as a Navy officer was an opportunity to use sonar (also called echo sounding), then a new technology, to map the ocean floor across ...

How did Hess's theory of oceans work?

Hess envisaged that oceans grew from their centres, with molten material (basalt) oozing up from the Earth’s mantle along the mid ocean ridges. This created new seafloor which then spread away from the ridge in both directions. The ocean ridge was thermally expanded and consequently higher than the ocean floor further away. As spreading continued, the older ocean floor cooled and subsided to the level of the abyssal plain which is approximately 4 km deep.

What is the sea floor spreading theory?

Hess discovered that the oceans were shallower in the middle and identified the presence of Mid Ocean Ridges, raised above the surrounding generally flat sea floor ( abyssal plain) by as much as 1.5 km.

Did Hess know Wegener?

Although his theory made sense, Hess knew, like Wegener, that he still needed convincing geophysical evidence to support it. This was to come just a year after his 1962 publication...

What did Hess do in 1960?

In 1960, Hess made his single most important contribution, which is regarded as part of the major advance in geologic science of the 20th century. In a widely circulated report to the Office of Naval Research, he advanced the theory, now generally accepted, that the Earth's crust moved laterally away from long, volcanically active oceanic ridges. He only understood his ocean floor profiles across the North Pacific Ocean after Marie Tharp and Bruce Heezen (1953, Lamont Group) discovered the Great Global Rift, running along the Mid-Atlantic Ridge. Seafloor spreading, as the process was later named, helped establish Alfred Wegener 's earlier (but generally dismissed at the time) concept of continental drift as scientifically respectable. This triggered a revolution in the earth sciences. Hess's report was formally published in his History of Ocean Basins (1962), which for a time was the single most referenced work in solid-earth geophysics. Hess was also involved in many other scientific endeavours, including the Mohole project (1957–1966), an investigation onto the feasibility and techniques of deep sea drilling .

What was the purpose of the USS S-48?

Felix Vening Meinesz of Utrecht University on board the US Navy submarine USS S-48 to assist with the second U.S. expedition to obtain gravity measurements at sea. The expedition used a gravimeter, or gravity meter, designed by Meinesz. The submarine traveled a route from Guantanamo, Cuba, to Key West, Florida, and return to Guantanamo through the Bahamas and Turks and Caicos region from 5 February through 25 March 1932. The description of operations and results of the expedition were published by the U.S. Navy Hydrographic Office in The Navy-Princeton gravity expedition to the West Indies in 1932.

Where did Harry Hess teach?

Harry Hess taught for one year (1932–1933) at Rutgers University in New Jersey and spent a year as a research associate at the Geophysical Laboratory of Washington, D. C., before joining the faculty of Princeton University in 1934. Hess remained at Princeton for the rest of his career and served as Geology Department Chairman from 1950 to 1966.

Where did Hess travel?

Hess carefully tracked his travel routes to Pacific Ocean landings on the Marianas, Philippines, and Iwo Jima, continuously using his ship's echo sounder.

Where did Harry Hess go to high school?

Hess, a member of the New York Stock Exchange, and Elizabeth Engel Hess. He attended Asbury Park High School in Asbury Park, New Jersey. In 1923, he entered Yale University, where he intended to study electrical engineering but ended up graduating with a Bachelor ...

When was the Navy Princeton expedition published?

Navy Hydrographic Office in The Navy-Princeton gravity expedition to the West Indies in 1932.

Who was the president of the Geological Society of America in 1963?

Hess was president of The Geological Society of America in 1963 and received their Penrose Medal in 1966.

What did Hess show about the tectonic plates?

In his paper, Hess showed how magma could fill in areas tectonic plates pushed apart. Hot magma would bubble up from under the Earth’s crust and when the magma eventually cooled it created more land that filled in the gaps as the tectonic plates came apart. Hess referred to this process as “seafloor spreading”.

What did Hess show about ocean basins?

After years of extensive research and evaluation, Hess published the paper History of Ocean Basins in 1962. Hess’ paper explained how Wegener’s theory of continental drift could be possible. It showed that there was a mechanism that could actually shift the continents around over millions of years. In his paper, Hess showed how magma could fill in ...

What was Hess interested in?

Hess was deeply interested in how volcanic activity could impact the formation of island arcs and mountain ranges and was researching how crystallized magma could lead to the creation of island arcs when the second World War broke out.

What did Hess use his equipment for?

Hess used the equipment to conduct research and gathered a large amount of data on the floor of the Pacific Ocean.

What is Hess' theory?

Hess’ theory solved a few unanswered geological questions, such as how it was possible that fossils older than 180 million years could be found on land but not under the ocean.

When was the theory of continental drift introduced?

Wegener’s theory that the continents had once been whole and had drifted apart over millions of years was dismissed by many academics of his time, and it would not be until around 1953 when the theory of plate tectonics was introduced, thanks in large part to Hess, that continental drift would be taken seriously.

Did Hess have any resistance to his hypothesis?

Much like Wegener before him, Hess ran into considerable resistance to his hypothesis by other geologists. There was little data from the ocean floor that could support his current hypothesis. Knowing that he still needed more data to convince the scientific community, Hess continued to work on his research.

How does the seafloor spread?

In this classic paper, Hess outlined the basics of how seafloor spreading works: molten rock (magma) oozes up from the Earth's interior along the mid-oceanic ridges, creating new seafloor that spreads away from the active ridge crest and, eventually, sinks into the deep oceanic trenches.

What did Hess believe about continental drift?

He believed in many of the observations Wegener used in defending his theory of continental drift, but he had very different views about large-scale movements of the Earth. Even while serving in the U.S. Navy during World War II, Hess was keenly interested in the geology of the ocean basins. In between taking part in the fighting in ...

What was the mission of Hess in the Marianas?

In between taking part in the fighting in the Marianas, Leyte, Linguayan, and Iwo Jima, Hess -- with the cooperation of his crew -- was able to conduct echo-sounding surveys in the Pacific while cruising from one battle to the next.

How old are the oldest fossils on the seafloor?

This recycling of the seafloor also explained why the oldest fossils found on the seafloor are no more than about 180 million years old.

How long has sediment been accumulating?

Hess reasoned that the sediment has been accumulating for about 300 million years at most. This interval is approximately the time needed for the ocean floor to move from the ridge crest to the trenches, where oceanic crust descends into the trench and is destroyed.

Why did Hess run into resistance?

Hess, like Wegener, ran into resistance because little ocean-floor data existed for testing his ideas. In 1962, these ideas were published in a paper titled "History of Ocean Basins," which was one of the most important contributions in the development of plate tectonics.

Who was the head of Princeton's Geology Department?

Hess , who served for years as the head of Princeton's Geology Department, died in 1969. Unlike Wegener, he was able to see his seafloor-spreading hypothesis largely accepted and confirmed as knowledge of the ocean floor increased dramatically during his lifetime.

Biographical Information

Specific Contributions to Plate Tectonic Theory

• Dr. Hess' most significant contribution to the plate tectonic theory began in 1945 when he was the commander of the U.S.S. Cape Johnson. While traveling from one destination to another, Hess would leave the sounding equipment on that would take measurements of the sea floor. It was at this time that Dr. Hess discovered features on the floor of the ...

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