Posted: February 23, 2001. ... For instance, terrestrial helium is mostly helium-4 and contains only a small amount of helium-3, while extraterrestrial helium - the kind found in these fullerenes ...Web

Assuming reasonable end-member 3 He/ 4 He ratios of 0.03R A and 290 R A (19, 20) for the crustal and extraterrestrial components, the calculated [3 He] Et is >86% of the total 3 He. Helium-4 ([4 He]) is >99% terrestrial and may therefore be used as a tracer of the relative terrigenous flux .Web

Recent studies of some PTB sites indicate that the extinctions occurred very abruptly, consistent with a catastrophic, possibly extraterrestrial, cause. Fullerenes …Web

In 2001, Dr. Becker and her colleagues said they had found the calling card of a killer meteor: soccer- ball-shaped molecules known as buckyballs that contained helium with an extraterrestrial ...Web

Later work by Mukhopadhyay et al. (2001), covering the interval from 70 to 40 Myr ago, found a factor of 2-4 increase in the 3 He accretion rate about 55 Myr ago, but no evidence for variations of ...Web

Constant flux proxies, such as extraterrestrial helium-3 (³He_(ET)) and excess thorium-230 (²³⁰Th_(XS)), constrain vertical mass accumulation rates independent of the biases associated with ...Web

These studies build upon the discovery of extraterrestrial helium in deep-sea sediments in the early 1960s (Merrihue 1964). This signal is now ... 2001). Soon after the discovery of mantle helium in seawater, noble gases were applied to studies of hydrothermal systems. Originally, these studies were focused on the source ofWeb

Since the helium and argon found in PTB fullerenes were isotopically similar to that found in meteorites, Becker et al. (2001) suggested that the fullerenes must have come from a meteorite.Web

The accretion of extraterrestrial noble gases such as He and Ar was discussed by Becker et al. (2001), who reported high concentrations of extraterrestrial He ( 3 He ET ) in PTB rocks from Japan ...Web

Almost 40 years after the discovery of extraterrestrial helium in seafloor sediments, renewed attention is being focused on using helium as a proxy for the sedimentary abundance of extraterrestrial debris. Extraterrestrial He is carried to the seafloor by the finest fraction of interplanetary dust and is retained in at least some sediments for …Web

A.L. Myers and F. Siperstein, "Characterization of adsorbents by energy profile of adsorbed molecules", Colloids and Surfaces A 187-188, 73-81 (2001). Article [PDF] O. Talu and A.L. Myers, "Molecular simulation of adsorption: Gibbs dividing surface and comparison with experiment", AIChE J. 47, 1160-1168 (2001).Web

He in marine sediment is a two-component mixture of relatively light extraterrestrial and heavy terrestrial helium; to determine the fraction of 3 He attributable to an extraterrestrial source, we used 3 He/ 4 He ratios of 2.1 × 10 −8 and 4 × 10 −4 for the terrestrial and extraterrestrial endmembers of the mixing model, respectively (Eq.Web

February 22, 2001 . Filed under ... Terrestrial helium is mostly helium-4, while extraterrestrial helium is mostly helium-3. "These things form in carbon stars. That's what's excitingWeb

DOI: 10.1016/S0012-821X(98)00197-6 Corpus ID: 24720909; Preservation of extraterrestrial 3He in 480-Ma-old marine limestones. @article{Patterson1998PreservationOE, title={Preservation of extraterrestrial 3He in 480-Ma-old marine limestones.}, author={Desmond B. Patterson and Kenneth A. Farley and …Web

Extraterrestrial helium (He et) in ferromanganese crusts from the deep oceans is presumed to originate in micrometeorites. ... Pepin et al., 2000, 2001; Lal and Jull, 2005). These end member compositions largely overlap with those estimated here for HRPs and IDPs, inhibiting a quantitative estimate of these fractions in the currently discussed ...Web

Recent studies of some PTB sites indicate that the extinctions occurred very abruptly, consistent with a catastrophic, possibly extraterrestrial, cause. Fullerenes (C 60 to C …Web

Analyses of marine carbonates through the interval 63.9 to 65.4 million years ago indicate a near-constant flux of extraterrestrial helium-3, a tracer of the accretion …Web

Extraterrestrial helium (He et) in ferromanganese crusts from the deep oceans is presumed to originate in micrometeorites.The carrier phase of the He et has, so far, not been identified. To address this issue we have recovered and examined several metallic micrometeorites from crust 237KD from the deep Pacific Ocean, and have …Web

The Younger Dryas impact hypothesis (YDIH) consists of two essential parts, (1) an extraterrestrial impact occurring 12,820 ± 130 yrs ago that (2) resulted in continent-wide or worldwide wildfires, the YD cooling, megafaunal extinctions, and the disappearance of the Clovis culture. There is no evidence that there were continent-wide …Web

Extraterrestrial He is carried to the seafloor by the finest fraction of interplanetary dust and is retained in at least some sediments for hundreds of millions of years. Helium isotope …Web

Sediments contain interplanetary dust particles (IDPs) carrying extraterrestrial noble gases, such as 3 He, which have previously been used to estimate the IDP accretion flux over time and the duration of past environmental events. However, due to its high diffusivity, He can be lost by diffusion either due to frictional heating during …Web

Solar-type helium (He) and neon (Ne) in the Earth's mantle were suggested to be the result of solar-wind loaded extraterrestrial dust that accumulated in deep-sea sediments and was subducted into the Earth's mantle. To obtain additional constraints on this hypothesis, we analysed He, Ne and argon (Ar) in high pressure–low temperature …Web

The upper Farley K. A. (2001) Extraterrestrial helium in seafloor sediments: bound of this interval may record the effective end of the identification, characteristics, and accretion rate over geologic PETM perturbation to marine carbonate chemistry.Web

Step-heat experiments indicate rapid diffusion of extraterrestrial helium from sediments heated to temperatures above ∼ 70 °C. Given the likelihood of burial and associated heating in Permian–Triassic age rocks, the initially unexpected absence of IDP-hosted 3 He likely indicates thermally induced diffusive loss.Web

The helium we obtained from Bed 25 samples is reasonable for a 250-million-year-old volcanic ash bed. Large inter-aliquot variability in 4 He content and the survival of most 4 He through HF demineralization suggest that accessory zircons, known to exist in Bed 25 (), control the distribution of this isotope.The 3 He concentration and 3 …Web

To better understand the composition, characteristics of helium diffusion, and size distribution of interplanetary dust particles (IDPs) responsible for the long-term retention of extraterrestrial 3 He, we carried out leaching, stepped heating, and sieving experiments on pelagic clays that varied in age from 0.5 Ma to ∼90 Myr. The leaching experiments …Web

Helium in dust separated from kilogram-sized ice samples from the Vostok ice core site in East Antarctica has an isotopic composition consistent with an extraterrestrial origin. ... Higgins, S.M., 2001. Extraterrestrial tracer in the sea: evaluation and application of 3 He in interplanetary dust particles as a constant flux tracer in marine ...Web

Whereas the extraterrestrial IDP component is well constrained ( 3 He/ 4 He = 2.4×10-4,[ 3 He]= 1.9×10-5 cm 3 STP g-1,Nier and Schlutter 1992), the helium isotope composition of the ...Web

Previous reports of shocked quartz grains and extraterrestrial helium and argon trapped in fullerene molecules have not been substantiated (Farley and Mukhopadhyay, 2001; Farley et al., 2005 ...Web

The extraterrestrial 3 He concentrations in Shatsky Rise sediments vary by about an order of magnitude from 0.28 to 2.43 × 10 − 9 cm 3 STP g − 1 (Fig. 2).Such extraterrestrial helium concentrations are very similar to those found in late Quaternary and Holocene carbonate-rich sediments of the central equatorial Pacific (e.g., …Web

Washington - Feb. 22, 2001 - New findings provide evidence that Earth's most severe mass extinction -- an event 250 million years ago that wiped out 90 percent of the life on Earth …Web

It seems reasonable to suppose that, if Bekki's scenario is correct, the dark matter blob and/or the cloud may be linked to the temporary factor of ∼2 increase in the influx of extraterrestrial 3 He (helium-3) seen in the sedimentary record 36–34 × 10 6 y ago (Farley et al., 1998, Farley, 2001, Mukhopadhyay et al., 2001), as well as to ...Web

Recent studies of some PTB sites indicate that the extinction occurred very abruptly, consistent with a catastrophic, possibly extraterrestrial, cause. Fullerenes (C …Web