Geology Reference
In-Depth Information
rapidly rotating neutron stars. (For a time, some astronomers thought these radio signals
must originate from distant alien technologies, hence the astronomical designation for all
pulsars is LGM—short for “Little Green Men.”)
ThoughGoldventuredintomanyotherspheresofscience—fromthephysiologyofhear-
ing to the consistency of the powdery lunar surface—his most notable contribution outside
astrophysics was to champion the abiotic origins of petroleum and natural gas. Petroleum
looks biological, he argued, simply because a thriving community of microbes—the “deep
hotbiosphere”—usestheabiotichydrocarbonsasfood.Microbesthusoverprintabiotichy-
drocarbons with their distinctive biochemical markers—hopanes, lipids, and more. Based
on this hypothesis, Gold advocated hydrocarbon exploration in unconventional places like
igneous and metamorphic rocks. He even persuaded a Swedish company to drill an explor-
atorywellintosuchhardrocks—aprojectthatyieldedintriguing,ifambiguousresults(and
lost a lot of unhappy investors a lot of money).
If you listen closely to both sides of this argument, it's clear that the answer to the ques-
tion of hydrocarbon origins is not yet resolved. Tommy Gold was endlessly inquisitive and
eager for answers. Shortly before his unexpected death, he came to my lab to lecture on
the deep hot biosphere and to discuss a possible collaboration—experiments that might
have helped to resolve the matter. The critical question of methane's origins remains un-
answered, but it is not unanswerable. What we need is a new, international effort to under-
stand deep carbon.
The Deep Carbon Observatory
Carbon is arguably Earth's most important element. Carbon is the key to understanding
Earth's variable climate and environment. Carbon has long been, and continues to be, the
centralelementinourquestforenergy.Carbonisalsothecrucialelementoflifeand,byex-
tension,thecoreelementinthedesignofnewdrugsandmyriadotherproducts.Weneedto
understand carbon, not just in its well-studied surface cycles of oceans, atmosphere, rocks,
and life, but from crust to core.
So it was that in the summer of 2009, the Alfred P. Sloan Foundation and the Geophys-
ical Laboratory launched the Deep Carbon Observatory (DCO), an ambitious ten-year pro-
gram to study carbon in our planet, especially its chemical and biological roles in Earth's
deepinterior.Whereisthecarbon?Howmuchisdownthere?Howdoesitmove,especially
toandfromthesurface?Howextensiveisthedeepbiosphere?Thisinterdisciplinary,inter-
national effort has already attracted hundreds of researchers from dozens of countries. We
have many objectives, from completing a global census of deep microbial life to monitor-
ing the carbon dioxide emissions from every active volcano on Earth. But discovering the
origins of Earth's hydrocarbons, from methane to petroleum, is a centerpiece of the DCO's
