Hard rock cosmic ray archaeology

Lal, D.

doi:10.1007/bf00227810

Cited by 88 publications

(32 citation statements)

References 58 publications

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“…Calculation of Production Rate SEP production rates of the di †erent short-lived nuclides are estimated as a function of shielding depth within a target of given size and with chondritic composition using equation (1). The energy-degraded SEP spectrum at a shielding depth x within the target, is obtained by (dN/dE) x , considering only ionization energy loss, following the approach of Lal (1972) :…”

Section: Nuclear Reaction Cross Sectionsmentioning

confidence: 99%

Did Solar Energetic Particles Produce the Short‐lived Nuclides Present in the Early Solar System?

Goswami

Marhas

Sahijpal

2001

ApJ

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Production of the short-lived nuclides 41Ca, 36Cl, 26Al, and 53Mn by solar energetic particles (SEP) interacting with dust grains of chondritic (\solar) composition is estimated considering a broad range of spectral parameters for the SEP and appropriate nuclear reaction cross sections. The dust grains are assumed to follow a power-law size distribution and to range in size from 10 km to 1 cm. The possibility that an enhanced Ñux of SEP from an active early (T Tauri) Sun could have been responsible for the production of these short-lived nuclides in the early solar system is investigated. SEP production of 41Ca and 36Cl will match their abundances in the early solar system inferred from meteorite data if the SEP irradiation duration was D 5 ] 105È106 yr and the SEP Ñux was higher by a factor of more than 5 ] 103 than the contemporary long-term averaged value of (E [ 10 MeV) D 100 cm~2 s~1. N proton However, corresponding production of 26Al will be much below the level needed to match its inferred abundance in the early solar system. SEP production, therefore, fails to explain the observed correlated presence of 41Ca and 26Al with canonical initial abundances in early solar system solids. The abundance of 53Mn in the early solar system is not tightly constrained by the meteorite data, and the various estimates di †er by a factor of 5. Coproduction of 41Ca, 36Cl, and 53Mn that will match the meteorite data for the higher initial abundance of 53Mn is possible if the SEP irradiation persisted for about a million years or more with a Ñux enhancement factor of D 5000È10,000. On the other hand, the lower initial value of 53Mn can also be matched by a Ñux enhancement factor of D1000 and an irradiation duration of a few million years ; the corresponding production of the other nuclides will be ¹10% of the level needed to match their abundances in the early solar system. Target abundance consideration rules out the possibility of SEP production of 60Fe, another short-lived nuclide present in the early solar system. Thus, SEP production as the primary source of the short-lived nuclides in the early solar system appears to be unlikely. However, the possibility that SEP production could be an important source of 53Mn as well as of the short-lived nuclide 10Be, whose presence in the early solar system solids has been recently reported, makes it difficult to completely rule out any contribution from this source to the inventory of these nuclides in the early solar system.

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Section: Nuclear Reaction Cross Sectionsmentioning

confidence: 99%

Did Solar Energetic Particles Produce the Short‐lived Nuclides Present in the Early Solar System?

Goswami

Marhas

Sahijpal

2001

ApJ

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“…The production of 14C by solar flare protons is estimated by the equation 4 in T, or the corresponding expression in R. The time averaged solar flare cosmic ray spectra are well represented over a wide range of energies by a single exponentional rigidity spectrum of the type; dN = const e-R/ItodR (5) where Ro is the characteristic slope (Lal and Venkatavaradan, 1967;Lal, 1972;Reedy, 1977). Pomerantz and Duggal (1974), Lanzerotti (1977), and Duggal (1979) have recently reviewed observations of solar cosmic rays during solar cycles 18 through 20.…”

Section: Natural 14c Variationsmentioning

confidence: 99%

“…Such slow changes for which the attenuation factor is small, < 5, might also be caused partly by slow time variations (of unknown causes) in the cosmic ray flux. Our present knowledge of long-term secular variations in the cosmic ray flux (Arnold, Honda, and Lal, 1961;Lal, 1972Lal, , 1974Schaeffer, 1975;Forman, Schaeffer, and Schaeffer, 1978) is not precise enough to exclude this possibility. We can only conclude the 10,000 year variation seems principally attributable to changes in the geomagnetic field.…”

Section: Introductionmentioning

confidence: 95%

“…Additional data comes from meteorites and moon samples that have preserved records of galactic and cosmic irradiation (Arnold, Honda, and Lal, 1961;Lal, 1974;Schaeffer, 1975;Reedy, 1977). These data, although accurately recorded by advanced prehistoric methods, generally lack details on, eg, isotopic composition, fluxes of nuclei Solar modulation effects in terrestrial production of heavier than helium and lighter than iron, and time variations in the past, during 10?-108 years BP.…”

Section: Introductionmentioning

confidence: 99%

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Solar Modulation Effects in Terrestrial Production of Carbon-14

Castagnoli¹,

1980

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ABSTRACT. This paper is concerned with the expected deviations in the production rate of natural 14C on the earth due to changes in solar activity. We review the published estimates of the global production rates of 14C due to galactic and solar cosmic ray particles, and present new estimates of the expected secular variations in 14C production, taking into account the latest information available on galactic cosmic ray modulation and long-term variations in solar activity.Estimated secular variations are related to data on atmospheric 14Cf 12C ratios based on tree rings. It is concluded that the observed higher frequency wiggles in atmospheric "C/12C ratios occurring with time scales of about two hundred years and of 1 to 2 percent in magnitude (de Vries, 1958; Suess, 1970a,b;1979;Damon, Lerman, and Long, 1978), are largely due to solar activity dependent modulation of the galactic cosmic ray flux by solar plasma. These variations override a slowly varying sinusoidal change of about 10 percent in magnitude during the last approximately 8000 years, which is believed to be primarily due to changes in the geomagnetic field. The high frequency modulation effect in 14C production is substantial, about 20 percent, which, considering the response function of the atmosphere (cf Houtermans, Suess, and Oeschger, 1973), is adequate to explain the observed 14C wiggles (also named Suess wiggles or de Vries oscillations) if in the past, periods of large modulation effects and also periods of weak modulation persisted, ie, the sun remained both active and inactive over long periods of time, of the order of several decades to centuries. The pioneering investigations of Eddy (1976; 1977) of the ancient records of solar activity make it plausible that the 14C wiggles in the ancient 14C/12C ratios are primarily due to modulation of galactic cosmic ray flux by a varying sun. Thus, the 14C wiggles are good indicators of solar activity in the past.We also present revised estimates of the production rates of 14C on the earth due to solar flare accelerated cosmic rays and limits of direct accretion of 14C on the earth.

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“…However, to obtain information about their nature and characteristics at more distant epochs, we have to rely on indirect approaches. Our present understanding of the past intensity and composition of energetic particles present in the interplanetary space is mainly based on studies of interaction records of these particles with lunar samples and meteorites (see, e.g., Lal, 1972;Reedy et al, 1983;Goswami et al, 1984;Caffee et al, , 1991. Similarly, studies of micrometeoroid impact induced records in lunar samples and meteorites also provide useful information about the nature of the dust grains present in the interplanetary space at different epochs in the past (see, e.g., Gault et al, 1972Gault et al, , 1974Brownlee and Rajan, 1973;Zinner, 1976, 1977;Goswami et al, 1976Goswami et al, , 1984Ashworth, 1978;McDonnell, 1978;Grun et al, 1985).…”

Section: Introductionmentioning

confidence: 99%

Interaction of energetic particles and dust grains with asteroidal surfaces

Goswami

2014

Earth Planet Sp

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Low energy solar wind (SW) and solar energetic particles (SEP) interact with material exposed on the surface of planetary objects devoid of an atmosphere and a global magnetic field such as the Moon and the asteroids. Micrometeoroid impacts will produce microcraters on samples exposed on the surfaces of these bodies and also cause microscale erosion and at times catastrophic rupture of the target rocks and soil grains. The impacting flux of meteoroids thus controls the effective SW and SEP exposure durations of samples on the lunar and asteroidal surfaces. The lunar samples contain abundant records of energetic particle interactions and micrometeoroid impacts while such records found in gas-rich meteorites can be considered to be representative of asteroidal samples. These records allow us to infer the composition and intensity of SW and SEP in the past as well as surface dynamical processes operating on the Moon and asteroids at different epochs. However, unlike the lunar records that span the time interval from the present to several billion years in the past, the asteroidal (gas-rich meteorite) records provide information only for some distant epochs in the past. We do not have much information about the contemporary energetic particle and dust grain environment in the asteroidal region. The Muses-C mission, that will bring back near surface samples from an asteroid, will be extremely important in this regard.

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Hard rock cosmic ray archaeology

Cited by 88 publications

References 58 publications

Did Solar Energetic Particles Produce the Short‐lived Nuclides Present in the Early Solar System?

Did Solar Energetic Particles Produce the Short‐lived Nuclides Present in the Early Solar System?

Solar Modulation Effects in Terrestrial Production of Carbon-14

Interaction of energetic particles and dust grains with asteroidal surfaces

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