1967 US NAVY FILM

[Music] throughout all history most nations have found the Seas to be barriers to military operations but those few nations that have developed naval power consider them to be an asset today of the United States Navy is the most powerful naval force in the world to maintain that superiority requires constant effort along a broad front of activity basic to that effort is a continuous expansion of our knowledge of the oceans such knowledge is difficult to obtain but fortunately it pays double dividends eventually it will enable man to exploit the vast resources that are locked within these waters and the land Vanita for within its almost limitless domain scientists see an expanding supply of food for the teeming populations of tomorrow and a virtually inexhaustible supply of minerals and metals to be exploited when advancement in technology makes it commercially feasible a major element of the Navy's research program is focused upon the land that lies beneath the sea [Music] no one knows how or when it all began but many believe there was a time in a distant past when the molten earth froze into the form similar to that which exists today rain spell for millions of years filling the low places that are the great potion bases no one knows what the continents look like them but there's one thing that's known for certain they differed greatly from what they are today for the ensuing billions of years forces of nature of the network changing the shape and features of the lab most of the water that falls upon the land eventually flows into the sea carrying part of the land with glaciers pick up part of the lab carry it to see in icebergs and drop it where the ice melts [Music] winds pick up dust and sand and drop them into the sea waves beating against shorelines eat them away water movement caused by storms tides and currents move solitary particles from place to place [Music] as the earth cooled all the millions of years enormous pressures upon its crust of God's faulting folding buckling distortion of the land often slowly but sometimes suddenly molten lava from thousands of volcanoes of a geologic time have formed gills and Peaks even mountains under the seas these changes are as extensive and are of the same type as online [Music] this hidden land has always been difficult to measure to sample to observe the accumulation of knowledge has been slow in recent years improvements and instruments and techniques have made marine geological studies more rapid and precise the precision depth recorder plots a continuous record of depth as your ship moves at normal speed the deep-sea camera brings back photographs of the ocean floor from depths of nearly 36,000 feet the deep-sea coral obtains cores more than a hundred feet long from the ocean floor and most dramatic new deep submersibles carry men to the deepest parts of the oceans to observe and to photograph a knowledge of this land even though it is incomplete is essential for greater economic exploitation of the Seas and for national defense the portion of the oceans adjacent to the continents are better known than any other no other part of the ocean attracts as many people here a man can establish close communion with the forces of nature no other part is as hazardous to shipping it's the portion that's most subject to clean so it's rocks reefs Shoals tides and currents have been the most accurately charted buoys and lighthouses warned of dangerous and health navigators died their ships along safe channels great fish populations seem to prefer to live in these shallow waters here are caught millions of tons of fish annually for thousands a livelihood for millions an important source of protein to some nations ocean fishing is so important in industry that they have claimed exclusive fishing rights far out to sea sometimes for hundreds of miles to others undersea oil reserves and mineral deposits are of similar importance for example in 1948 the United States claimed oil and mineral rights out from our shores to a water depth of six hundred feet outward from the shores of the continents the land slopes gently downward usually several miles to a point where there is a marked increase in slope to greater depths worldwide this break in slope comes at an average depth of about 430 feet deposited on these continental shelves is sedimentary material that has been eroded from the land ancient riverbeds meander across the shelves and ancient features have been found at the edge of the show evidence that they were once part of the land during periods of low sea level the continental shelf varies greatly in width as can be seen along our East Coast 275 miles in Massachusetts 90 miles at new jersey becomes narrower at cape hatteras then widens to 60 miles at northern Florida and disappears at the east coast of southern Florida where rivers flow into quiet areas of the ocean deltas are built up in some cases on the shelf in others they form the shell these shelves vary greatly in profile from Boston there's a downward slope for about 35 miles a Sand Ridge at Stellwagen bank a series of basins and crops for the next 160 miles and another rise at George's Bank which itself is about a hundred miles wide that New Jersey the bottom is rough but the slope is consistent and gradual at Jacksonville Florida it smooths out the shelf area is of great significance to naval planets because it is here that two major operations of naval warfare take place mine warfare which includes both mine laying and mine sweeping and amphibious operation [Music] or transporting men and equipment from ship to shore landing craft must have an unobstructed passage right up to the beach and the beach sand must be sufficiently compacted to hold the weight of the heavy equipment tentative operational climbs can be prepared from charts that show depths autumn conditions and tides based upon the best information available but waves frequently build destroy and ship sandbars and beaches so before finalizing plans up-to-date intelligence must be obtained of the beach and the sea approaches one major element in planning minefields is predicting the effectiveness of individual minds upon impact they may penetrate into the bottom or gradually sink over a period of time the degree of burial depends upon the type of bottom sediment and the strength of surf or cover for most mines a moderately firm slightly rough surface is best such as coarse Sam or a mixture of sand and gravel [Music] in a soft mud bottom bottom I may become so deeply buried that most of their effectiveness is lost buried mines are extremely difficult to sweep if the bottom is hard and smooth the mine may roll become displaced and possibly damaged but the Lord mines the anchor holes more friendly if it does sink so here a soft bottom is better in sheltered harbors bays and estuaries most of the bottomless mud outside the bays most of the bottom sediment is sand but large areas of gravel and mud are found rocks and rock bottom are frequently found or brother portions of the coast this information is furnished to the naval planner in the form of bottom sediment charts at the outer edge of the continental shelf the land plunges downward two to three miles to the ocean bottom forming the walls of the great ocean basins the slopes are frequently cut by ravines and canyons sometimes 2,000 to 4,000 feet deep some canyons are continuations of existing rivers that once flowed across the shelf when it was above sea level others may have been formed by Trinity currents whose movements were triggered by earthquakes or by various combinations of causes continental slopes are usually unbroken in their descent or almost so with perhaps only an occasional slight interruption but a few slopes have terraces like the Bleak plateau east of Cape Kennedy Florida the slope is interrupted at about 3,000 feet by this plateau which extends some 150 miles before the final plunge to the bottom other slopes are interrupted by mountain ridges and Peaks for example west of Los Angeles are the islands of Santa Catalina San Clemente and Santa Cruz all Peaks some 8,000 feet above the ocean floor if the sea level were lowered by about 3500 feet the mountain ridges would contain several lakes as deepest 4000 feet up to 20 miles wide and 80 miles long the sediments deposited upon continental slopes vary greatly but worldwide they average about 60% mud 25% sand 10% rock and gravel and 5% shells and ooze these photographs were taken in 8,000 feet of water along the Atlantic slope east of Massachusetts here in 1963 the submarine pressure went down in searching for her remains hundreds of bottom photographs were taken and this became the most intensively photographed slope area in the world the deep ocean floor begins at the foot of the continental slope some 12,000 feet down [Music] here the landscape is as varied as on land in this domain of Perpetual darkness topographic features formed millions of years ago have changed very slowly here there is no wind rain or frost to erode them in the Atlantic the most prominent feature is the greatest mountain range on earth the mid-atlantic ridge rising near Iceland it extends southward for 10,000 miles at a height of 5,000 to 10,000 feet above the ocean floor it lies almost exactly midway between South America and Africa leading some geologists to suggest that at some time in the distant past the two continents would join and that they broke apart leaving a crack where the ridge was formed while the continents drifted to their present positions occasionally Pentacles poke above sea level as Islands the Azores Ascension and Tristan da Cunha at about 50 degrees south latitude the ridge turn sharply eastward around the tip of Africa and continues toward the Indian Ocean a mighty riff up to 30 miles wide slits the ridges crest along its entire length it is along this Ridge that most of the earthquakes in the Atlantic occur at the base of the ridge are bumpy stretches called the Bissell Hills which level off and to flat smooth abyssal Plains some three miles below sea level throughout the Atlantic are hundreds of peaks called sea mounts that rise thousands of feet above the ocean floor many are of volcanic origin Underland the Earth's crust is 25 to 35 miles thick and is primarily granite but under the sea it pins down to some three to eight miles and is primarily basalt a dark fine-grained igneous rock denser than granite on top of this basaltic crust lies several thousand feet of sediment materials that have remained undisturbed for millions of years a record of geological history most of it is debris that has rained down all the ian's of time imperishable remains of marine life [Music] the Pacific Ocean is the biggest single feature of the Earth's surface bigger than all six continents half of all the water on Earth is here it is almost completely surrounded by lands that are volcanic Li active in fact the volcanoes along its rim are so numerous that they are sometimes referred to collectively as a ring of fire its numerous islands are but visible evidence of volcanic eruptions that have occurred in numerable times over geologic history beneath its deep waters the Hawaiian Islands are all volcanic peaks along a ridge formed by volcanic material being forced upward through a break in the Earth's crust the Aleutian Islands are Peaks along a curved mountain ridge that extends some 1,800 miles from the Alaskan mainland however this ridge was formed by an upward buckling of the Earth's crust and the volcanic Peaks were formed after the ridge was built scattered throughout the entire Pacific Ocean are many mountain ridges and hundreds of sea mounts round-topped volcanic Peaks some of these Peaks are flat top and are called Yeo's why flattop nobody knows one explanation is that once their rounded peaks extended above the surface as Islands while thus exposed they were flattened by erosion then over ian's of time the ocean floor site possibly during this time the sea level rose now most of these platforms are found at depths of 3,000 to 5,000 feet a few are scattered at random but most of the air along three lines one extending south of the Kamchatka Peninsula another and the Markus neck arise west of Hawaii and the third in a zone between the Marianas and Marshall Islands one particularly interesting feature of the Pacific is it does honest old deep trenches the greatest depths on earth all over 25,000 feet deep they appear intermittently almost around the entire rim of the ocean they are all alongside curved mountain ridges on the side away from the nearest land numerous volcanoes appear along these ridges there are more earthquakes near them than in any other equal area in the world indicating that false lie underneath these almost always have argues at a shallow depth toward the shore earthquakes have origins at increasing depth indicating that the fault line gets deeper possibly these trenches were all formed by a folding or distortion of the Earth's crust here are photographs of the deepest place under the floor of the Marianas Trench at its deepest point thirty five thousand seven hundred feet these would take in the 1960 by dr. Jacques Piccard and Navy lieutenant Don Wolfe and the Baths escape creates another interesting feature in the Pacific is the hundreds of coral reefs and atolls found in the tropical areas most coral reefs are built up by the skeletal remains of small animals that grow in vast colonies for maximum growth they need plenty of light so they are usually found in clear warm water and a shallow depth fringing reefs grow out directly from the coasts of many islands with scarcely a break sometimes for many miles Barrier Reef's are separated from a coastline by a lagoon channel a typical one lies off papa ET Harbor two heating atolls are reached that extend above sea level and enclose a circular Lagoon an amazing feature of atolls is the thickness of the coral on any we talk for example it is over 4,000 feet thick below that is lava evidence that the coral grew on top of the volcanic peak since coral can only grow in shallow water it seems highly probable that the top of the volcanic peak was at one time near the surface and that it's sank at the same rate that the coral grew any we talk Carl started growing some 60 million years ago and sank at the rate of two millimeters a century until recent years few people could see how any real benefit could dumb from a study of the floor under the ocean basins but already applications are beginning to appear enable operations this knowledge is of primary interest to the Submariner and to his adversary the ADI submarine forces at present submarine operations are limited to the upper few hundred feet of ocean debt future submarines will almost certainly be able to go much deeper they may be able to escape detection in rough terrain by lying quietly behind a peak or in a depression or Canyon finding a submarine in these areas will require special sonar skills and meticulous interpretation of sound echoes so no range can sometimes be extended by bouncing the sound from a hard smooth bottom the range that can be attained depends in part upon the slope so both slope and bottom type must be known a major objective of Navy geologists is to provide charts of the entire ocean bottom showing details of depths contours bottom types and slopes before that can be accomplished much work must be done the vast areas great depth tremendous pressures all contribute toward the difficulties and cost of accumulating scientific data in advancing the frontiers of any basic science no one can predict the nature or scope of its practical applications but from the information now available there are few areas of research that show as much potential as marine geology the study of the land beneath the sea [Music]