Scientists trace source of massive Iron age volcanic eruption that triggered global cooling

Scientists trace source of massive Iron age volcanic eruption that triggered global cooling

Scientists have discovered that Lake Ilopango, the caldera of Ilopango volcanic complex, El Salvador was the source of the strongest volcanic eruption in the last 7 000 years that resulted in global cooling, affecting crops worldwide.

According to National Geographic (NatGeo), the eruption ravaged the local Maya community and caused harvest failures around 540 A.D.

The gigantic explosion killed thousands and was recorded as one of the worst eras of global cooling in the last 2 000 years.

Ilopango, now an inactive volcano, is located in El Salvador. Scientists revealed that the volcano spewed out 44 km3 (10 mi3) of dense rock which made it one of the most massive volcanic eruptions on the planet in the last 7 000 years.

Read more: Detailed stratigraphy of massive Tierra Blanca Joven eruption, one the worst volcanic catastrophes in Central America

The Ilopango explosion was over a hundred times larger than the Mount St. Helens eruption in 1980 and was also worse than Mount Pinatubo eruption in 1991.

Robert Dull, California Lutheran University geologist, stated that 'this is the largest eruption in Central America that human beings have ever witnessed.'

Historical accounts dating around 536 A.D. showed that dark fogs caused a wave of crop failures. Modern information confirmed that this event was caused by two volcanoes erupting up to four years apart.

Sulfur gases from the gigantic explosions covered the Sun that triggered extreme global cooling.

Geological summary

The scenic 8 x 11 km (5 x 6.8 miles)Ilopango caldera, filled by one of El Salvador's largest lakes, has a scalloped 150 - 500 m (490 - 1 640 feet) high rim. The caldera, which lies immediately east of the capital city of San Salvador, is strongly controlled by regional faults of the central Salvador graben.

Four major dacitic-rhyolitic explosive eruptions during the late Pleistocene and Holocene produced extensive pyroclastic-flow and pyroclastic-fall deposits that blanket much of El Salvador. The latest collapse resulted from the massive 5th century CE Tierra Blanca Joven (TBJ) eruption, which produced widespread pyroclastic flows and devastated early Mayan cities. Post-caldera eruptions formed a series of glassy dacitic and andesitic lava domes within the lake and near its shore.

The Islas Quemadas, a group of low islets in the center of the lake that mark the summit of a largely submerged lava dome, were formed in 1879-80 during the only historical eruption of Ilopango.

Reference

"Radiocarbon and geologic evidence reveal Ilopango volcano as source of the colossal ‘mystery’ eruption of 539/40 CE" - Robert A. Dull et al. - Quaternary Science Reviews - https://doi.org/10.1016/j.quascirev.2019.07.037

Abstract

Ilopango volcano (El Salvador) erupted violently during the Maya Classic Period (250–900 CE) in a densely-populated and intensively-cultivated region of the southern Maya realm, causing regional abandonment of an area covering more than 20,000 km2. However, neither the regional nor global impacts of the Tierra Blanca Joven (TBJ) eruption in Mesoamerica have been well appraised due to limitations in available volcanological, chronological, and archaeological observations. Here we present new evidence of the age, magnitude and sulfur release of the TBJ eruption, establishing it as one of the two hitherto unidentified volcanic triggers of a period of stratospheric aerosol loading that profoundly impacted Northern Hemisphere climate and society between circa 536 and 550 CE. Our chronology is derived from 100 new radiocarbon measurements performed on three subfossil tree trunks enveloped in proximal TBJ pyroclastic deposits. We also reassess the eruption magnitude using terrestrial (El Salvador, Guatemala, Honduras) and near-shore marine TBJ tephra deposit thickness measurements. Together, our new constraints on the age, eruption size (43.6 km3 Dense Rock Equivalent of magma, magnitude = 7.0) and sulfur yield (∼9–90 Tg), along with Ilopango's latitude (13.7° N), squarely frame the TBJ as the major climate-forcing eruption of 539 or 540 CE identified in bipolar ice cores and sourced to the tropics. In addition to deepening appreciation of the TBJ eruption's impacts in Mesoamerica, linking it to the major Northern Hemisphere climatic downturn of the mid-6th century CE offers another piece in the puzzle of understanding Eurasian history of the period.

Featured image: Renembg

Comments

No comments yet. Why don't you post the first comment?

Post a comment

Your name: *

Your email address: *

Comment text: *

The image that appears on your comment is your Gravatar