Dust, iron, and life


Share post:

Dust begets life, and Earth’s atmosphere 300 million years ago was perhaps the dustiest of all time, with large consequences for carbon cycling and the climate system. In a new paper for Geology, Sohini Sur and colleagues examine the bioavailability of iron in dust from Earth’s penultimate icehouse of the late Paleozoic. Dust links to carbon because of the iron — a key nutrient for nearly all life, so atmospheric dust acts as a fertilizer.

Dust, iron, and life
Late Paleozoic Pangaea, showing (boxed) region of interest 
in western tropical Pangaea [Credit: Sur et al.]

Vast volumes of dust deposits dating from the late Paleozoic, from both land areas and marine reefal deposits, record a remarkably dusty atmosphere. Moreover these dust deposits contain unusually high concentrations of reactive iron. This concomitance — dust with exceptionally high values of bioavailable iron — implies major ecosystem fertilization and an associated massive drawdown of atmospheric carbon.

The biogeochemical impacts of iron-rich dust to the oceans are known for Earth’s recent record but unexplored for deep time, despite recognition of large ancient dust fluxes, particularly during the late Paleozoic. Sur and colleagues report a unique iron relationship for Upper Pennsylvanian mudrock of eolian origin that records lowstand (glacial) conditions within a carbonate buildup of western equatorial Pangaea (now the western United States).

With iron fertilization proposed as a serious geoengineering scheme to control future atmospheric carbon and attendant climate change, authors Sur and colleagues write, “It behooves us to study the consequences of analogous events as archived in Earth’s deep-time record.”

Source: Geological Society of America [November 10, 2015]



Related articles

Explorers plan June mission to Andrea Doria shipwreck

Nearly six decades after 46 people died when the Andrea Doria sank to the sea floor following a...

1,400-year-old funeral chamber found in Mexico

A 1,400-year-old funeral chamber was found by chance in the southern Mexican state of Guerrero, authorities said.  The tomb...

Treasure hunter finds rare Roman coins

A hoard of 33 rare Roman coins has been found in a field near Hebden. Colne man Mick...

Amid Greek austerity, plunder of priceless treasures

The financial crisis in Greece has already had far-reaching consequences for many people, but now it is claiming...

Ancient cold period could provide clues about future climate change

Researchers at The University of Texas at Austin have found that a well-known period of abrupt climate change...

Climate change study reveals unappreciated impacts on biodiversity

Shrinking ice sheets and melting ice caps are well known consequences of climate change. But a new study...

Scarred child skulls were grisly gifts to Lake Gods?

Children's skulls found at the edges of Bronze Age settlements may have been a gruesome gift for the...

Mexican experts say original pyramid found at Chichen Itza

Archaeologists have discovered what may be the original structure built at the pyramid of Kukulkan at the Mayan...