Uranium isotopes distinguish two geochemically distinct stages during the later Cambrian SPICE event [0.03%]
铀同位素揭示晚期寒武纪SPICE事件包含两个地球化学阶段
Tais W Dahl,Richard A Boyle,Donald E Canfield et al.
Tais W Dahl et al.
Anoxic marine zones were common in early Paleozoic oceans (542-400 Ma), and present a potential link to atmospheric pO2 via feedbacks linking global marine phosphorous recycling, primary production and organic carbon burial. Uranium (U) iso...
Bomb fall-out 236U as a global oceanic tracer using an annually resolved coral core [0.03%]
利用年分辨率珊瑚年轮研究全球海洋的核试验示踪剂（即236Pu）
Stephan R Winkler,Peter Steier,Jessica Carilli
Stephan R Winkler
Anthropogenic 236U (t½=23.4 My) is an emerging isotopic ocean tracer with interesting oceanographic properties, but only with recent advances in accelerator mass spectrometry techniques is it now possible to detect the levels from global f...
Uranium-236 as a new oceanic tracer: A first depth profile in the Japan Sea and comparison with caesium-137 [0.03%]
海洋示踪剂的新成员——铀236同位素：以日本海的剖面为例及其与铯137的比较
Aya Sakaguchi,Akinobu Kadokura,Peter Steier et al.
Aya Sakaguchi et al.
We present a feasibility study for using 236U as an oceanic circulation tracer based on depth profiles of 236U and 137Cs in the Japan/East Sea. The concentration of the predominantly anthropogenic 236U, measured with Accelerator Mass Spectr...
P h Gillet,J A Barrat,T h Heulin et al.
P h Gillet et al.
We present a study of the textural signature of terrestrial weathering and related biological activity in the Tatahouine meteorite. Scanning and transmission electron microscopy images obtained on the weathered samples of the Tatahouine met...
L Becker,B Popp,T Rust et al.
L Becker et al.
Stable carbon isotope measurements of the organic matter associated with the carbonate globules and the bulk matrix material in the ALH84001 Martian meteorite indicate that two distinct sources are present in the sample. The delta 13C value...
D B Patterson,K A Farley,B Schmitz
D B Patterson
We have measured the helium abundance and isotopic composition of a suite of Lower Ordovician marine limestones and associated fossil meteorites from Kinnekulle, Sweden. Limestone 3He/4He ratios as high as 11.5 times the atmospheric value i...
Numerical simulations and the problem of periodicity in the cratering record [0.03%]
数值模拟与撞击坑记录的周期性问题
J S Trefil,D M Raup
J S Trefil
Ages of craters in the record of impacts on earth may be uniformly period, totally random, or a mixture of the two. These alternatives are studied through numerical simulation wherein time-series analysis is performed on real and simulated ...
Carbon abundance measurements in oceanic basalts: the need for a consensus [0.03%]
海洋玄武岩中碳丰度的测定：达成共识的必要性
D J Des Marais
D J Des Marais
Large systematic discrepancies currently exist among the carbon data reported for oceanic basalts by different laboratories. These discrepancies are likely attributable both to non-uniform criteria for the removal of carbon contamination fr...
Origin of magnetite in oxidized CV chondrites: in situ measurement of oxygen isotope compositions of Allende magnetite and olivine [0.03%]
氧化CV型碳质球粒陨石中磁铁矿的来源-原位测定艾伦德陨石磁铁矿和橄榄石的氧同位素组成
B G Choi,K D McKeegan,L A Leshin et al.
B G Choi et al.
Magnetite in the oxidized CV chondrite Allende mainly occurs as spherical nodules in porphyritic-olivine (PO) chondrules, where it is associated with Ni-rich metal and/or sulfides. To help constrain the origin of the magnetite, we measured ...
Impact winter and the Cretaceous/Tertiary extinctions: results of a Chicxulub asteroid impact model [0.03%]
撞击冬季以及白垩纪/第三纪灭绝事件：契克胥尤布小行星碰撞模型的结果
K O Pope,K H Baines,A C Ocampo et al.
K O Pope et al.
The Chicxulub impact crater in Mexico is the site of the impact purported to have caused mass extinctions at the Cretaceous/Tertiary (K/T) boundary. 2-D hydrocode modeling of the impact, coupled with studies of the impact site geology, indi...