It was one of the great mysteries of the climate history of the last millennium:Which volcano caused the catastrophic cold spell in the years after 1257? The Samalas volcano in Indonesia, researchers now write in PNAS.
In the year 1258 there was no summer. It was especially cold in the northern hemisphere. It rained a lot, the world was ravaged by floods, many crops failed and famine reigned. These are typical phenomena that occur after a huge volcanic eruption. The ash particles that are emitted during this process block the sunlight, resulting in darkening and cooling.
Tiny shards of glass, originating from volcanic ash, confirmed 30 years ago that a large volcano had indeed erupted just before 1258:The splinters were found in drilled-out ice sheets from that time. But which volcano was it? The answer to that question only came this week.
Mega Outburst
The Samalas volcano on Lombok was to blame, a team of earth scientists wrote in PNAS. this week. This monster volcano erupted between May and October in 1257. All that remains today is a crater lake, flanked by the Rinjani volcano that is active there today.
The eruption must have been huge. Larger than the well-known eruption of Mount Tambora on Sumbawa in 1815. The ash cloud reached a height of between 34 and 52 kilometers – the ash particles eventually whirled down to both the north and south poles. At least thirty times more lava was emitted than the eruption of Vesuvius in 79, when Pompeii disappeared under the lava. The eruption of the Samalas is therefore one of the five most violent volcanic eruptions of the past 7,000 years, the researchers write.
Evidence
The conviction of the Samalas as guilty of the short-lived climate disaster was preceded by extensive evidence. The main clue that led the researchers to this volcano was a historical document, a poem in ancient Javanese, Babad Lombok, noted on palm fronds. It tells of lava flows that engulf an entire city (Pamatan).
The evidence then consisted of studying the volcanic rocks (tephra) around the Samalas, dating the volcanic ashes with the 14 C method, and comparing the chemical composition of the Samalas lovage with the glass particles in the ice. Quite a difficult job, writes volcano expert Erik Klemetti, who himself did not participate in the study, in his blog.
“It's like taking fingerprints. Only in this case you only have small pieces of the print, and then also from several fingers,” he explains. Still, the similarity between the Samalas lavas and the particles from the ice was great enough to serve as convincing evidence.
Pamatan
The city of Pamatan was never heard from again. For archaeologists, therefore, a nice follow-up study is waiting:The subsoil of Lombok may contain an equivalent of the buried city of Pompeii.
More about volcanoes on Kennislink
Volcanoes and climate on Science 24
Nature as CO2 source (Elmar Veerman, August 2013)