First Map Of The Ocean Floor

Topographic maps of the sea floor produced at a 1 100 000 scale that contain loran c rates bottom sediment types and known bottom obstructions.
First map of the ocean floor. We ve come a long way in ocean exploration since the days of the hms challenger launched in 1858. Today we know more about the topography of the moon and mars than we do about our own planet s sea floor. Typically finely wrought ocean maps have been the result of extensive sonar. These early maps based on hundreds of thousands of hand picked depths provided the context for the plate tectonics revolution.
Each consist of three sheets a base bathymetric map. But in the 1950s and 60s when this feat of cartography was being assembled by us cartographers marie tharp and bruce heezen we knew almost nothing. This is expensive and time consuming so sonar maps are mostly only made of places where ships spend the most time. This product is intended to aid fishermen and those needing seafloor features and potential fishing grounds.
This graphic shows several ocean floor features on a scale from 0 35 000 feet below sea level. Revealed to the world in 1977 this is the first map of the earth s ocean floor. The following features are shown at example depths to scale though each feature has a considerable range at which it may occur.