add information about cyanobacteria (the rusting of earth)

1 files changed, 53 insertions, 3 deletions

diff --git a/CosmicCalendarEvents.hs b/CosmicCalendarEvents.hs
index d3461de..0973539 100644
--- a/CosmicCalendarEvents.hs
+++ b/CosmicCalendarEvents.hs
@@ -351,13 +351,63 @@ theCalendar = Map.fromList $ map (\x -> (calBeginTime x, x)) $ map unwrap
 
     CalendarEntry (2.7 & billionYearsAgo) Nothing
     "Oxygen from photosynthesis"
-    "Cyanobacteria"
+    [text|
+    Cyanobacteria (blue-green algae) initiates "rusting of the Earth"
+    The resulting Ozone layer will make life possible on land
+    |]
     [text|
     These ubiquitous bacteria were the first oxygen producers. They absorb
     visible light using a mix of pigments: phycobilins, carotenoids and several
     forms of chlorophyll.
-    |]
-    "https://www.scientificamerican.com/article/timeline-of-photosynthesis-on-earth/",
+
+    The Great Oxidation Event (GOE), also called the Great Oxygenation Event,
+    the Oxygen Catastrophe, the Oxygen Revolution, and the Oxygen Crisis, was a
+    time interval when the Earth's atmosphere and the shallow ocean first
+    experienced a rise in the amount of oxygen. This occurred approximately
+    2.4–2.0 Ga (billion years) ago, during the Paleoproterozoic era.[2]
+    Geological, isotopic, and chemical evidence suggests that
+    biologically-produced molecular oxygen (dioxygen, O2) started to accumulate
+    in Earth's atmosphere and changed it from a weakly reducing atmosphere
+    practically free of oxygen into an oxidizing atmosphere containing abundant
+    oxygen.[3]
+
+    The sudden injection of toxic oxygen into an anaerobic biosphere caused the
+    extinction of many existing anaerobic species on Earth.[4] Although the event is
+    inferred to have constituted a mass extinction,[5] due in part to the great
+    difficulty in surveying microscopic species' abundances, and in part to the
+    extreme age of fossil remains from that time, the Oxygen Catastrophe is
+    typically not counted among conventional lists of "great extinctions", which are
+    implicitly limited to the Phanerozoic eon.
+
+    The event is inferred to have been caused by cyanobacteria producing the
+    oxygen, which may have enabled the subsequent development of multicellular
+    life-forms.[6]
+
+    The current scientific understanding of when and how the Earth's atmosphere
+    changed from a weakly reducing to a strongly oxidizing atmosphere largely
+    began with the work of the American geologist Preston Cloud in the 1970s.[9]
+    Cloud observed that detrital sediments older than about 2 billion years ago
+    contained grains of pyrite, uraninite,[9] and siderite,[12] all minerals
+    containing reduced forms of iron or uranium that are not found in younger
+    sediments because they are rapidly oxidized in an oxidizing atmosphere. He
+    further observed that continental redbeds, which get their color from the
+    oxidized (ferric) mineral hematite, began to appear in the geological record
+    at about this time. Banded iron formation largely disappears from the
+    geological record at 1.85 billion years ago, after peaking at about 2.5
+    billion years ago.[14] Banded iron formation can form only when abundant
+    dissolved ferrous iron is transported into depositional basins, and an
+    oxygenated ocean blocks such transport by oxidizing the iron to form
+    insoluble ferric iron compounds.[15] The end of the deposition of banded
+    iron formation at 1.85 billion years ago is therefore interpreted as marking
+    the oxygenation of the deep ocean.[9] Heinrich Holland further elaborated
+    these ideas through the 1980s, placing the main time interval of oxygenation
+    between 2.2 and 1.9 billion years ago, and they continue to shape the
+    current scientific understanding.[10]
+    |]
+    [text|
+    https://www.scientificamerican.com/article/timeline-of-photosynthesis-on-earth/
+    https://en.wikipedia.org/wiki/Great_Oxidation_Event
+    |],
 
     CalendarEntry (1.2 & billionYearsAgo) Nothing
     "Red and brown algae"