1. The Moon’s Eastern Seas
Part 1: Formation & Evolution of the Moon
Part 2: Lunar Libration
Part 3: The Eastern Seas

2. Geologic timeline of Earth
4570 Earth Formation
1800 First Complex single-cell life
380 First Vertebrate Land Animals
Dinosaurs
80-55 Rocky Mts. Uplift
Glaciers Retreat

3. Geologic timeline of Moon & Earth
4570 Earth Forms
4533 Moon Forms from Giant Impact

4. Formation & Evolution of the Moon
Nectarian
Nectaris, Humboldtianum, Humorum, Crisium, Serenitatis
Pre-Nectarian
Procellarum
Insularum
Marginis
Fecunditatis
Australe
Tranquillitatis
Nubium
Smythii
Grimaldi
NECTARIS
IMBRIUM
Imbrian
Eratosthenian
Copernican
ERATOSTHENES
COPERNICUS
NOW
Pythagoras, Theophilus, Langrenus, Hercules
Tycho, Aristarchus, Kepler
ORIENTALE
Lava Flows
Surface Hardens
Late Heavy Bombardment

5. Timeline for Lunar Lava Flows
NECTARIS
IMBRIUM
COPERNICUS
Nectarian
ERATOSTHENES
Pre-Nectarian
ORIENTALE 50 40
NOW
Lunar Volcanic Activity
Basalt Units 30 20 10

6. Beginning of the Late Imbrian Period
Drawing by
Don Davis

7. End of the Late Imbrian Period
Drawing by
Don Davis

8. Present Day Moon
Drawing by
Don Davis

9. Lunar Libration

10. Lunar Directions N W E S

11. The Eastern Seas N E
In early February the 6-day-old Moon was Librated so that more of the eastern area was visible than usual.

12. Mare Humboldtianum

13. Mare Humboldtianum Located in the Moon’s NE Corner
Outer Basin is 600 Km in Diameter
Formed during the Nectarian Period
Inner Basin & Mare are 300 Km in Diameter
The Basin formed during the Nectarian Period, and filled with lava during the Late Imbrian
Named for Alexander von Humboldt by
Johann H. Mädler
Lunar Periods
Late Heavy Bombardment

14. Alexander von Humboldt
Johann Heinrich von Mädler
(May 29, 1794 – March 14, 1874) one of the great and eminent astronomers of the 19th century. Has a crater on the Moon and one on Mars named for him.
(September 14, 1769 – May 6, 1859) was a Prussian geographer, naturalist and explorer. Humboldt's quantitative work on botanical geography laid the foundation for the field of biogeography.

15. Mare Smythii,

16. Mare Smythii
One of the lowest Maria, 4 – 4.5 Km below the avg. Lunar Surface
Impact basin is Pre Nectarin, Km in diameter
Southern floor is late Imbrian basalt. Northern floor is from the Eratosthenian period & may be only 1 – 2 billion years old.
Named for Admiral William Henry Smyth (21 Jan – 8 Sep.1865), English naval officer & astronomer. President Royal Astronomical Society. Published Bedford Catalogue with observations of 1604 double stars and nebulae (with a 5.9-inch refractor).

17. Mare Marginis

18. Mare Marginis (The Sea of the Edge)
Thought to be one of the oldest Maria on the Moon. About 200 Km north-to-south.
Apparently not area with a major impact basin. Appears to be a low-lying area where lava filled several cratered areas where the lunar crust was relatively thin. The lava flows are also thin, being only an estimated 1000 to 1700 feet thick.
The highland area is Pre-Nectarian and lava flows are probably Late - Imbrian

19. Mare Anguis, Undarum & Spumans

20. Mare Anguis Mare Undarum Mare Spumans
(Serpent Sea)
(150 Km long)
(Sea of Waves)
(240 Km dia.)
(Foaming Sea)
(140 Km dia.)
All three Maria are of Nectarin origin, with lava filling them during the Late Imbrian Period.

21. Mare Australe (The Southern Sea)
This 600 Km heavily-cratered basin was formed during the pre-Nectarin period, and filled with lava during the late Imbrian period.
The basin is located in the Southeast area of the moon, and half of the basin is on the far side, but can be seen (barely) during favorable librations.

22. References The Modern Moon – a personal view
By Charles A. Wood
The Geologic History of the Moon
(US Geological Survey Professional Paper 1348) –By Don E. Wilhelms
Wikipedia
“Eastern Seas” photo taken with 6” f/8 Refractor at prime focus, Canon Rebel DSLR, ISO 100, 1/250th second

23. The End!
Questions?