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Polar ice core records attest to a colossal volcanic eruption that took place ca. A.D. 1257 or 1258, most probably in the tropics. Estimates based on sulfate deposition in these records suggest that it yielded the largest volcanic sulfur release to the stratosphere of the past 7,000 y. Tree rings, medieval chronicles, and computational models corroborate the expected worldwide atmospheric and climatic effects of this eruption. However, until now there has been no convincing candidate for the mid-13th century “mystery eruption.” Drawing upon compelling evidence from stratigraphic and geomorphic data, physical volcanology, radiocarbon dating, tephra geochemistry, and chronicles, we argue the source of this long-sought eruption is the Samalas volcano, adjacent to Mount Rinjani on Lombok Island, Indonesia. At least 40 km ³ (dense-rock equivalent) of tephra were deposited and the eruption column reached an altitude of up to 43 km. Three principal pumice fallout deposits mantle the region and thick pyroclastic flow deposits are found at the coast, 25 km from source. With an estimated magnitude of 7, this event ranks among the largest Holocene explosive eruptions. Radiocarbon dates on charcoal are consistent with a mid-13th century eruption. In addition, glass geochemistry of the associated pumice deposits matches that of shards found in both Arctic and Antarctic ice cores, providing compelling evidence to link the prominent A.D. 1258/1259 ice core sulfate spike to Samalas. We further constrain the timing of the mystery eruption based on tephra dispersal and historical records, suggesting it occurred between May and October A.D. 1257.

During Earth’s history, geosphere-biosphere interactions were often determined by momentary, catastrophic changes such as large explosive volcanic eruptions. The Miocene ignimbrite flare-up in the Pannonian Basin, which is located along a complex convergent plate boundary between Europe and Africa, provides a superb example of this interaction. In North Hungary, the famous Ipolytarnóc Fossil Site, often referred to as “ancient Pompeii”, records a snapshot of rich Early Miocene life buried under thick ignimbrite cover. Here, we use a multi-technique approach to constrain the successive phases of a catastrophic silicic eruption (VEI ≥ 7) dated at 17.2 Ma. An event-scale reconstruction shows that the initial PDC phase was phreatomagmatic, affecting ≥ 1500 km 2 and causing the destruction of an interfingering terrestrial–intertidal environment at Ipolytarnóc. This was followed by pumice fall, and finally the emplacement of up to 40 m-thick ignimbrite that completely buried the site. However, unlike the seemingly similar AD 79 Vesuvius eruption that buried Pompeii by hot pyroclastic density currents, the presence of fallen but uncharred tree trunks, branches, and intact leaves in the basal pyroclastic deposits at Ipolytarnóc as well as rock paleomagnetic properties indicate a low-temperature pyroclastic event, that superbly preserved the coastal habitat, including unique fossil tracks.

Voluminous Miocene silicic volcanism sourced mainly from the extensional Pannonian Basin played a major role in the evolution of the Central Paratethys. Here, we identify a widely distributed (> 3150 km 2 ) member of the Upper Rhyolite Tuff in Hungary, called the Dobi Ignimbrite, with a precise sanidine/plagioclase 40 Ar/ 39 Ar age of 13.064 ± 0.065 Ma (~ Badenian/Sarmatian boundary in Central Paratethys chronology). It has distinctive glass geochemistry with wide compositional variations, which conforms with large-scale silicic explosive eruptions. In line with this, the calculated minimum volume (~ 200 km 3 ) of the Dobi Ignimbrite is consistent with a high-end VEI 7 eruption, with possible ultradistal transport distance of over 300 km. Most of the pyroclastic succession, which erupted in two phases, was emplaced on land, as it contains leaves and tree trunks in the basal layer that we correlate with the Badenian/Sarmatian ‘volcanic floras’ of northern Hungary. At the same time, the ignimbrite has a strongly phreatomagmatic character, and, together with the presence of free-floating foraminifera, this suggest that the source vent was located in coastal waters of the Central Paratethys. These findings indicate either a late Badenian marine incursion prior to the eruption, or the shift of the eruption center toward the sea.

We propose a vast area in the middle of Lombok, Indonesia, dominated by hummock hills, is a debris avalanche deposit (DAD). We define this > 500 km 2 area as Kalibabak DAD that may originate from Samalas volcano. No descriptions of the morphology, stratigraphy, mechanism, and age of this DAD have yet been reported; this contribution bridges this research gap. Here we present morphological and internal architecture analysis, radiocarbon dating, paleotopographic modeling, and numerical simulation of the DAD. We also present geospatial data e.g., topographical and geological maps, digital elevation models (DEMs), satellite imagery – in combination with stratigraphic data constructed from field surveys, archived data, and electrical resistivity data. Results show that the DAD was formed by a sector-collapse of Samalas volcano and covers an area of 535 km 2 , with a deposit width of 41 km and a runout distance up to 39 km from the source. The average deposit thickness is 28 m, reaching a measured local maximum of 58 m and a calculated volume of ~ 15 km 3 . Andesitic breccia boulders and a sandy matrix dominate the deposit. Using ShapeVolc, we reconstructed the pre-DAD paleotopography and then used the reconstructed DEM to model the debris avalanche using VolcFlow. The model provides an estimate of the flow characteristics, but the extent of the modelled deposit does not match the present-day deposit, for at least two reasons: (i) the lack of information on the previous edifice topography that collapsed, and (ii) limited understanding of how DADs translate across the landscape. Fourteen radiocarbon dating samples indicate that the DAD was emplaced between 7,000–2,600 BCE. The DAD's enormous volume, vast extent and poorly weathered facies strongly suggest that it was not triggered by a Bandai-type debris avalanche (solely phreatic eruption), but more likely by a Bezymianny-type (magmatic eruption). This event was potentially triggered by a sub-Plinian or Plinian eruption (high eruption column with umbrella-like cloud) dated ~ 3,500 BCE, which produced the Propok pumice fall deposits.

Twenty-six new and seven previous K–Ar ages obtained on groundmass separates for samples from the Axial Chain massif (Guadeloupe, F.W.I.), associated with geomorphological investigations, allow us to propose a new model of the volcanic evolution of the central part of Basse-Terre Island. The Axial Chain is composed of four edifices, Moustique, Matéliane, Capesterre, and Icaque mounts, showing coeval activity from 681 ± 12 to 509 ± 10 ka, which contradicts a previous hypothesis that flank collapse affected them successively. Our geomorphological reconstruction shows that the Axial Chain can be considered as a single large volcano, named the Southern Axial Chain volcano (SCA), rather than a succession of several smaller volcanoes. It raises questions regarding the formation of a large depression within the SCA volcano, prior to the construction of the Sans-Toucher volcano between 451 ± 13 and 412 ± 8 ka. Given presently available evidence, a slump affecting the western part of the SCA volcano is the most probable scenario to reconcile the complete age dataset and the present-day morphology of central Basse-Terre. Finally, our study shows that the SCA volcano had a post-activity volume of 90 km 3 , implying a construction rate of 0.5 km 3 /kyr. This value strongly constrains interpretations of magma generation processes throughout the Lesser Antilles arc.

Detailed analyses of mineral composition and whole-rock geochemical data helped to unravel the volcanic plumbing system beneath the rhyolitic Šumovit Greben lava dome, the westernmost member of the Kožuf-Voras volcanic system (N. Macedonia). It is characterized by high SiO2 content (> 70 wt%) coupled with low MgO (< 1 wt%) and Sr (< 500 ppm) suggesting fractionation of clinopyroxene and plagioclase at depth forming a crystal mush and a crystal-poor rhyolitic lens by fractional crystallization and melt extraction on top of it. The crystal mush is composed of mainly clinopyroxene, biotite and plagioclase, whereas sanidine and plagioclase are the most abundant phenocrysts of the rhyolitic lens. The main dome forming event occurred at ca. 2.9 Ma, which sampled the crystal-poor rhyolitic lens. After a short quiescence time, an explosive eruption occurred depositing a massive lapilli tuff layer northwest of the lava dome, and an extrusion of a small-volume lava flow on the northern side of the lava dome at ca. 2.8 Ma. This latter sampled also the crystal mush, as it contains abundant glomeroporphyritic clots of clinopyroxene ± plagioclase ± biotite. The clinopyroxene phenocrysts are chemically homogeneous, their crystallization temperature is ca. 900 °C representing the crystal mush, whereas the plagioclase and the sanidine crystallized at a lower temperature (ca. 790 °C) representing the rhyolitic lens. Noble gas isotopic composition of the clinopyroxene indicate no mantle-derived fluids (< 0.5%) having an R/Ra of ca. 0.04 Ra. The rejuvenation of the system probably occurred due to implementation of mafic magma at depth leading to a heat transfer and partial melting of the cumulate. This led to crystallization of Ba-rich rims of the sanidine and An- and Sr-rich rims of the plagioclase. The crystal mush zone beneath Šumovit Greben might be connected to the nearby, more mafic volcanic centers, and the eruption of Šumovit Greben could have been the start of the last cycle in the lifetime of the Kožuf-Voras volcanic system.

The erosional state of a landscape is often assessed through a series of metrics that quantify the morphology of drainage basins and divides. Such metrics have been well explored in tectonically active environments to evaluate the role of different processes in sculpting topography, yet relatively few works have applied these analyses to radial landforms such as volcanoes. We quantify drainage basin geometries on volcanic edifices of varying ages using common metrics (e.g., Hack's law, drainage density, and number of basins that reach the edifice summit, as well as basin hypsometry integral, length, width, relief, and average topographic slope). Relating these measurements to the log-mean age of activity for each edifice, we find that drainage density, basin hypsometry, basin length, and basin width quantify the degree of erosional maturity for these landforms. We also explore edifice drainage basin growth and competition by conducting a divide mobility analysis on the volcanoes, finding that young volcanoes are characterized by nearly uniform fluvial basins within unstable configurations that are more prone to divide migration. As basins on young volcanoes erode, they become less uniform but adapt to a more stable configuration with less divide migration. Finally, we analyze basin spatial geometries and outlet spacing on edifices, discovering an evolution in radial basin configurations that differ from typical linear mountain ranges. From these, we present a novel conceptual model for edifice degradation that allows new interpretations of composite volcano histories and provides predictive quantities for edifice morphologic evolution.