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Hesperian
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The Hesperian is a geologic system and time period on the planet Mars characterized by widespread volcanic activity and catastrophic flooding that carved immense outflow channels across the surface. The Hesperian is an intermediate and transitional period of Martian history. During the Hesperian, Mars changed from the wetter and perhaps warmer world of the Noachian to the dry, cold, and dusty planet seen today. The absolute age of the Hesperian Period is uncertain. The beginning of the period followed the end of the Late Heavy Bombardment and probably corresponds to the start of the lunar Late

Key facts

Geologic timespan.name
Hesperian
Geologic timespan.manual_color
rgb(255.0, 51.0, 51.0)
Geologic timespan.top_bar
mars
Geologic timespan.time_start
3700
Geologic timespan.time_end
3000
Geologic timespan.latest
2000
Geologic timespan.top_bar_ps
(upper bound uncertain – between about 3200 and 2000 million years ago)
Geologic timespan.image_outcrop
Hesperia Planum.jpg
Geologic timespan.caption_outcrop
MOLA colorized relief map of Hesperia Planum, the type area for the Hesperian System. Note that Hesperia Planum has fewer large impact craters than the surrounding Noachian terrain, indicating a younger age. Colors indicate elevation, with red highest, yellow intermediate, and green/blue lowest.
Geologic timespan.subdivisions
Early Heperian Late Hesperian
Geologic timespan.celestial_body
mars
Geologic timespan.timescales_used
Martian Geologic Timescale
Geologic timespan.chrono_unit
Period
Geologic timespan.strat_unit
System
Geologic timespan.type_section
Hesperia Planum

via Wikipedia infobox

~14 min read

Encyclopedic overview

8 sections
Contents
  • Description and name origin
  • Hesperian chronology and stratigraphy
  • System vs. period
  • Boundaries and subdivisions
  • Mars during the Hesperian Period
  • Impact cratering
  • Notes and references
  • Bibliography and recommended reading

The Hesperian is a geologic system and time period on the planet Mars characterized by widespread volcanic activity and catastrophic flooding that carved immense outflow channels across the surface. The Hesperian is an intermediate and transitional period of Martian history. During the Hesperian, Mars changed from the wetter and perhaps warmer world of the Noachian to the dry, cold, and dusty planet seen today. The absolute age of the Hesperian Period is uncertain. The beginning of the period followed the end of the Late Heavy Bombardment and probably corresponds to the start of the lunar Late Imbrian period, around 3700 million years ago (Mya). The end of the Hesperian Period is much more uncertain and could range anywhere from 3200 to 2000 Mya, with 3000 Mya being frequently cited. The Hesperian Period is roughly coincident with the Earth's early Archean Eon.

With the decline of heavy impacts at the end of the Noachian, volcanism became the primary geologic process on Mars, producing vast plains of flood basalts and broad volcanic constructs (highland paterae). By Hesperian times, all of the large shield volcanoes on Mars, including Olympus Mons, had begun to form. Volcanic outgassing released large amounts of sulfur dioxide (SO2) and hydrogen sulfide (H2S) into the atmosphere, causing a transition in the style of weathering from dominantly phyllosilicate (clay) to sulfate mineralogy. Liquid water became more localized in extent and turned more acidic as it interacted with SO2 and H2S to form sulfuric acid.

Excerpted from Wikipedia’s “Hesperian” article, available under the CC BY-SA 4.0 licence.

Gallery (5)

On the map

2 mapped locations