1458 mystery eruption
There are two large sulfate spikes caused by mystery volcanic eruptions in the mid-1400s: the 1452/1453 mystery eruption and 1458 mystery eruption. Before 2012, the date of 1458 sulfate spike was incorrectly assigned to be 1452 because previous ice core work had poor time resolution. The exact location of this eruption is uncertain, but possible candidates include the submerged caldera of Kuwae in the Coral Sea, Mount Reclus and Tofua caldera. The eruption is believed to have been VEI-7.
Date of sulfate spike
This sulfate spike was first discovered in Antarctica ice cores and is one of largest sulfur events along with that of Samalas and Tambora. Initial efforts to constrain the date of the event concluded that 1452/53 is the year of eruption with uncertainty up to a few years. Since 2012, highly accurate ice core chronology has re-dated this massive sulfur spike to 1458 and has matched with its corresponding Greenland sulfur spike though the latter is significantly smaller.Ice-core and tree-ring records
The sulfate deposition of this event is the largest recorded in ice cores in the last 700 years. The deposition however is asymmetric with much larger sulfate flux in the Antarctic ice cores compared to that of Greenland ice cores, indicating that the eruption probably occurred in the low latitudes of the Southern Hemisphere. Sulfur isotope composition of the 1458 sulfate indicates that the eruption emitted volcanic gases directly into the stratosphere, with significant impact on atmospheric chemistry and potential consequence for global climate. The reconstructed volcanic stratospheric sulfur injection of the 1458 event estimates that about 37.5 trillion grams of sulfur was injected into stratosphere, roughly equivalent to that of Tambora but three times more massive than the earlier 1452/53 eruption, based on the same set of sulfate records. In South Pole ice core, tephra was discovered in the sulfate layer, allowing geochemical matching to identify the source volcano of the sulfate spike if the tephra source was responsible for the sulfate spike.In the year following the eruption, tree-rings formed in the Northern Hemisphere during the summer of 1459 registered a strong cooling of followed by a cooling of in 1460.
Kuwae caldera
In Tongoan folklore, the Kuwae caldera resulted from the catastrophic mid-fifteenth century volcanic eruption and disappearance of the Kuwae landmass. Its exact location, however, is debated. Two candidates are:- a submarine caldera between the Epi and Tongoa islands
- south of Tongoa, the exposed part of the western rim marked by the islands of Tongoa, Ewose, Buninga and Tongariki
Németh et. al., however, questioned the proposed large magnitude and intensity of the eruption, noting that pyroclastic flow deposits on the surrounding islands are small-volume and lacking widespread fall deposits. Further evidence is needed to establish the relation between formation of large submarine caldera and the apparently small mid-fifteenth century eruption preserved on land. Furthermore, geochemistry of Kuwae magma does not match with that of the tephra discovered in 1458 sulfate layer.
As of early 2023, a new investigation led by volcanologists and anthropologists was ongoing to resolve the debate around the nature of Kuwae eruption and its climate consequence.