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of a collaborative effort between France
and Australia (the Pilbara Drilling Project)
during August 2004, including the
3481 Ma Dresser Formation (Warrawoona
Group) and 2724 Ma Tumbiana
Formation (Fortescue Group). A new
diamond drill hole was cored in August
2008 through part of the 3250 Ma Fig
Tree Group in the Barberton Greenstone
Belt as part of a joint project between
France and South Africa. These pristine
diamond drill cores present a unique opportunity
to constrain the chemistry of
the earliest ocean, the composition of the
atmosphere, and the settings and types
of microbial ecosystems spanning the
Archean Eon. These drill core samples
can also provide new clues on the earliest
metabolic pathways
2010010010
在 地 面 模 拟 环 境 中 天 体 生 物 学 技 术 和
仪 器 操 作 的 有 效 性 = Validation of
astrobiology technologies and instrument
operations in terrestrial analogue
environments. ( 英 文 ). Léveillé R.
Comptes Rendus Palevol, 2009, 8(7):
637-648
Terrestrial analogue environments are
places on Earth that present geological
or environmental conditions that are
similar to those found on an extraterrestrial
body. Analogue environments serve
four functions: (1) learn about planetary
processes on Earth and elsewhere; (2)
test technologies, methodologies, and
protocols; (3) train highly-qualified personnel,
as well as science and operations
teams; (4) engage the public, space
agencies, media, and educators. Analogue
studies also enable the development
and validation of biosignatures and
detection techniques. Analogue programs
include the Canadian Space
Agency's Canadian Analogue Research
Network, NASA's Astrobiology Science
and Technology for Exploring Planets,
and NASA's Analog Missions. Examples
of technology and instrument testing
and validation in analogue environments
include the Haughton-Mars Project
Research Station, the Arctic Mars
Analog Svalbard Expedition (AMASE),
the Rio Tinto basin, and NASA's Field
Integrated Design and Operations
(FIDO).
2010010011
生 物 活 性 和 地 球 表 面 的 演 化 : 从 岩 石
记 录 中 观 察 碳 , 硫 , 氮 和 铁 的 稳 定 同
位 素 的 变 化 = Biologi-cal activity and
the Earth's surface evolution: Insights
from carbon, sulfur, nitro-gen and iron
stable isotopes in the rock record. ( 英 文 ).
Thomazo C; Pinti D L; Busigny V; Ader
M; Hashizume K; Philippot P. Comptes
Ren-dus Palevol, 2009, 8(7): 665-678
The search for early Earth biological
activity is hindered by the scarcity of the
rock record. The very few exposed
sedimentary rocks have all been affected
by secondary processes such as metamorphism
and weathering, which might
have distorted morphological microfossils
and biogenic minerals beyond recognition
and have altered organic matter
to kerogen. The search for biological
activity in such rocks therefore relies
entirely on chemical, molecular or isotopic
indicators. A powerful tool used
for this purpose is the stable isotope signature
of elements related to life (C, N,
S, Fe). It provides key informations not
only on the metabolic pathways operating
at the time of the sediment deposition,
but more globally on the biogeochemical
cycling of these elements and
thus on the Earth's surface evolution.
Here, we review the basis of stable isotope
biogeochemistry for these isotopic
systems. Rather than an exhaustive approach,
we address some examples to
illustrate how they can be used as
biosignatures of early life and as proxies
for its environment, while keeping in
mind what their limitations are. We then
focus on the covariations among these
isotopic systems during the Archean
time period to show that they convey
important information both on the evolu-
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