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-rw-r--r-- | CosmicCalendarEvents.hs | 56 |
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 | |||
351 | 351 | ||
352 | CalendarEntry (2.7 & billionYearsAgo) Nothing | 352 | CalendarEntry (2.7 & billionYearsAgo) Nothing |
353 | "Oxygen from photosynthesis" | 353 | "Oxygen from photosynthesis" |
354 | "Cyanobacteria" | 354 | [text| |
355 | Cyanobacteria (blue-green algae) initiates "rusting of the Earth" | ||
356 | The resulting Ozone layer will make life possible on land | ||
357 | |] | ||
355 | [text| | 358 | [text| |
356 | These ubiquitous bacteria were the first oxygen producers. They absorb | 359 | These ubiquitous bacteria were the first oxygen producers. They absorb |
357 | visible light using a mix of pigments: phycobilins, carotenoids and several | 360 | visible light using a mix of pigments: phycobilins, carotenoids and several |
358 | forms of chlorophyll. | 361 | forms of chlorophyll. |
359 | |] | 362 | |
360 | "https://www.scientificamerican.com/article/timeline-of-photosynthesis-on-earth/", | 363 | The Great Oxidation Event (GOE), also called the Great Oxygenation Event, |
364 | the Oxygen Catastrophe, the Oxygen Revolution, and the Oxygen Crisis, was a | ||
365 | time interval when the Earth's atmosphere and the shallow ocean first | ||
366 | experienced a rise in the amount of oxygen. This occurred approximately | ||
367 | 2.4–2.0 Ga (billion years) ago, during the Paleoproterozoic era.[2] | ||
368 | Geological, isotopic, and chemical evidence suggests that | ||
369 | biologically-produced molecular oxygen (dioxygen, O2) started to accumulate | ||
370 | in Earth's atmosphere and changed it from a weakly reducing atmosphere | ||
371 | practically free of oxygen into an oxidizing atmosphere containing abundant | ||
372 | oxygen.[3] | ||
373 | |||
374 | The sudden injection of toxic oxygen into an anaerobic biosphere caused the | ||
375 | extinction of many existing anaerobic species on Earth.[4] Although the event is | ||
376 | inferred to have constituted a mass extinction,[5] due in part to the great | ||
377 | difficulty in surveying microscopic species' abundances, and in part to the | ||
378 | extreme age of fossil remains from that time, the Oxygen Catastrophe is | ||
379 | typically not counted among conventional lists of "great extinctions", which are | ||
380 | implicitly limited to the Phanerozoic eon. | ||
381 | |||
382 | The event is inferred to have been caused by cyanobacteria producing the | ||
383 | oxygen, which may have enabled the subsequent development of multicellular | ||
384 | life-forms.[6] | ||
385 | |||
386 | The current scientific understanding of when and how the Earth's atmosphere | ||
387 | changed from a weakly reducing to a strongly oxidizing atmosphere largely | ||
388 | began with the work of the American geologist Preston Cloud in the 1970s.[9] | ||
389 | Cloud observed that detrital sediments older than about 2 billion years ago | ||
390 | contained grains of pyrite, uraninite,[9] and siderite,[12] all minerals | ||
391 | containing reduced forms of iron or uranium that are not found in younger | ||
392 | sediments because they are rapidly oxidized in an oxidizing atmosphere. He | ||
393 | further observed that continental redbeds, which get their color from the | ||
394 | oxidized (ferric) mineral hematite, began to appear in the geological record | ||
395 | at about this time. Banded iron formation largely disappears from the | ||
396 | geological record at 1.85 billion years ago, after peaking at about 2.5 | ||
397 | billion years ago.[14] Banded iron formation can form only when abundant | ||
398 | dissolved ferrous iron is transported into depositional basins, and an | ||
399 | oxygenated ocean blocks such transport by oxidizing the iron to form | ||
400 | insoluble ferric iron compounds.[15] The end of the deposition of banded | ||
401 | iron formation at 1.85 billion years ago is therefore interpreted as marking | ||
402 | the oxygenation of the deep ocean.[9] Heinrich Holland further elaborated | ||
403 | these ideas through the 1980s, placing the main time interval of oxygenation | ||
404 | between 2.2 and 1.9 billion years ago, and they continue to shape the | ||
405 | current scientific understanding.[10] | ||
406 | |] | ||
407 | [text| | ||
408 | https://www.scientificamerican.com/article/timeline-of-photosynthesis-on-earth/ | ||
409 | https://en.wikipedia.org/wiki/Great_Oxidation_Event | ||
410 | |], | ||
361 | 411 | ||
362 | CalendarEntry (1.2 & billionYearsAgo) Nothing | 412 | CalendarEntry (1.2 & billionYearsAgo) Nothing |
363 | "Red and brown algae" | 413 | "Red and brown algae" |