1957 CE–1977 CE
Tharp and Heezen make seafloor relief visible
Oceans, navigation & cartography · Hydrography & bathymetry · Oceanography
The 1957 physiographic map of the Atlantic and later syntheses by Marie Tharp and Bruce Heezen turned scattered profiles into a continuous picture of ridges, valleys, and abyssal plains. The mapping helped interpret plate tectonics and culminated in a 1977 world ocean-floor map.
Precision, calendar, and review
- Start
- year · no uncertainty qualifier in this record
- End
- year · no uncertainty qualifier in this record
- Calendar and convention
- Historical-era years; the source calendar is not identified. No conversion of days is assumed.
- Year zero
- The scale goes from 1 BCE to 1 CE without year zero. Changing era names changes labels only.
- Documentary review
- Date not recorded
Reading the date: duration of a process.
Sources
- 1. www.lib.uchicago.edu (opens in a new tab)
Source provenance and scope
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- 2026-09-23
The correspondence between this reference and individual claims has not yet been itemized.
- 2. www.loc.gov (opens in a new tab)
Source provenance and scope
- Publication date
- Pending verification: the source could not be accessed
- Bibliographic date checked
- 2026-09-23
The correspondence between this reference and individual claims has not yet been itemized.
This record is an editorial synthesis. Consult the sources to check claims and their limits. Chronological relationships alone do not establish causation.