Chronology - Topics

The Permian-Triassic clay layer that marks 96 percent of marine species gone The iridium anomaly at the K-Pg boundary: how the Alvarez team found an asteroid Egyptian king lists and the Sothic cycle dated pharaohs before radiocarbon existed Why the Quaternary was redefined and the Holocene start moved to 11700 years ago The Anthropocene was voted down in 2024: why geologists refused to end the Holocene Geological periods are defined by rock layers and their absolute dates are a separate layer of work Carbon-14 runs out at about 50000 years and deeper time needs other isotopes Radiocarbon dating is useless without the calibration curve and the curve rewrote Egyptian chronology Why is 776 BC the start of Greek history when the Olympics were not the only thing happening? Sealing a capsule with stainless steel and silica gel under inert gas Dendrochronology and radiocarbon dating do not always agree — what do you do then? Tree rings pinned the Norse settlement at L'Anse aux Meadows to a single year Paleography: deciding whether a charter is a tenth-century original or a twelfth-century copy Crawford Lake in Canada was proposed as the Anthropocene's golden spike What is the difference between a relative sequence and an absolute date? Century labels like the 1900s are ambiguous: 1900 to 1909 or the whole hundred years? BC and AD vs BCE and CE: the notation fight is about more than two letters The Crypt of Civilization stays sealed until 8113 1582 lost ten days and nobody who went to bed on the fourth of October woke up on the fifth Radiocarbon dates come with a range and a calibration curve rather than a year Archives file by provenance first and by date second and the order matters Why calibrated radiocarbon ranges are lopsided rather than symmetric Retrospective inevitability: why a linear narrative makes every accident look planned Westinghouse buried a capsule in 1939 with instructions for the year 6939 Siccar Point in 1788: the unconformity that made deep time thinkable A parish register's entries are not in the order the volume was written The Dark Ages survives in popular use long after historians dropped it What actually survives a century underground and what turns to mush Julian and Gregorian calendars disagree and the gap keeps growing Tree rings can date a Viking timber to the exact felling year When two chronicles contradict each other the first move is to compare their dates of composition not their facts An Assyrian record of a solar eclipse fixed the reign of an entire dynasty