Laschamp Event ==> Language?

I  recently ran across a couple of articles (copies of these appended below) concerning a geological event that happened 40,000 years ago:  the Laschamp Event, an unusual short (300 year) reversal and temporary reduction in the strength of the Earth’s magnetic field. Coincidentally, also 40,000 years ago, the Neanderthals began to die out and humans entered a period of rapid growth in population that extends to today. Could it be that the effects of the Laschamp Event triggered the dawn to humankind's domination of the planet?

The Earth's magnetic fields normally shield us from cosmic and solar radiation. The Laschamp Event's big reduction in the strength of the Earth's magnetic field resulted in surface radiation levels approximately 100 times higher than normal. Levels that would have surely stimulated high genetic mutation rates. Perhaps this was how and when humans gained the capability for language.

Language changes everything. Without it humans would likely still be living in caves.  With it, nearly endless possibilities for advancements in society and technology are opened. (See Thoughts on Language.)

Had humans become language capable and Neanderthals not, humans would have gained a huge advantage - one that would have given them the power to crush their competitors into extinction. The sharing and passing on of knowledge and technology - enabled via language - surely led to mankind greatly growing his population at the time

This from Wikipedia on the origin of language:

The origin of language in the human species has been the topic of scholarly discussions for several centuries. In spite of this, there is no consensus on its ultimate origin or age. One problem that makes the topic difficult to study is the lack of direct evidence. Consequently, scholars wishing to study the origins of language must draw inferences from other kinds of evidence such as the fossil record or from archaeological evidence, from contemporary language diversity, from studies of language acquisition, and from comparisons between human language and systems of communication existing among other animals, particularly other primates. It is generally agreed that the origins of language are closely tied to the origins of modern human behavior, but there is little agreement about the implications and directionality of this connection.

I would suggest that when human language did appear it created such a gigantic leap in mankind's capabilities that the signs of this leap are all we have to look for in order to identify the date.  And I suggest that two of those signs were the extinction of the Neanderthals and the explosion in the growth of the human population at the time of the LasChamp Event.  Read this July, 2011 news article that speaks to these changes 40,000 years ago.
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cosmic rays explained

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article from: http://phys.org/news/2012-11-cosmic-rays-reveal-event-earth.html#jCp:

Cosmic rays reveal event in Earth's magnetic field history

Nov 29, 2012

41 000 years ago, the Earth's magnetic field faded and practically disappeared, leaving our planet unprotected from the bombardment of cosmic rays. Evidence for this event has been found in ocean sediment cores by a team from the Centre de Recherche et d'Enseignement de Géosciences de l'Environnement (CEREGE, CNRS/Aix-Marseille Université/IRD/Collège de France). In the cores, the researchers measured variations in concentrations of beryllium-10, a radioactive isotope produced by the action of cosmic rays on oxygen and nitrogen atoms in the atmosphere. The work, published in the Journal of Geophysical Research, is an important step towards developing a new method for studying the history of Earth's magnetic field, which should shed light on why its strength has been declining over the past three thousand years.

The Earth's magnetic field forms an efficient shield  that deflects charged particles of cosmic origin headed for Earth.  Far from being constant, the magnetic field has undergone many reversals, with the North magnetic pole shifting to the South geographic pole. Such reversals are always accompanied by a disappearance of the magnetic field. The last such reversal took place 780 000 years ago. The magnetic field can also undergo excursions, periods when the field suddenly drops as if it was going to reverse, before recovering its normal polarity. The most recent event of this kind, known as the Laschamp excursion, took place 41 000 years ago. 

Evidence for the event was uncovered by the researchers in sediment cores collected off the coasts of Portugal and Papua New Guinea. In the samples, they found an excess of beryllium-10, an isotope produced solely by collisions between particles of cosmic origin and atoms of nitrogen and oxygen. The beryllium-10 (¹⁰Be) produced in the atmosphere then falls to the Earth's surface where it is incorporated into ice and sediments. In sedimentary beds dating from the age of the Laschamp excursion, the researchers found up to twice as much ¹⁰Be as normal, evidence of the intense cosmic ray bombardment that the Earth underwent for several thousand years.

Traditionally, the presence of various iron oxides, especially magnetite, in volcanic lavas, sediments and ancient pottery provides information on the history of the magnetic field by indicating its direction and strength at the time when these materials solidified. This so-called paleomagnetic approach does not always allow global variations in the magnetic field to be quantified accurately. The researchers combined this method with the measurement of beryllium-10 concentrations in the same sedimentary records. This enabled them to demonstrate that peak concentrations of this isotope are synchronous and have the same dynamics and amplitude in Atlantic and Pacific sediments as in the previously analyzed Greenland ice cores. The method based on beryllium-10, which has been developed over the past 10 years at CEREGE, therefore makes it possible to obtain a continuous reconstruction of variations in the strength of the Earth's global magnetic field. 

It is also known that over the past 3000 years the magnetic field has lost 30% of its strength. This trend suggests that in the coming centuries, the Earth might undergo an excursion similar to the one that took place 41 000 years ago. Since high energy cosmic rays can cause mutations and cell damage, such an event would have a significant impact on biodiversity, and in particular on humans. This is why the researchers are seeking to find out the precise rates of the magnetic field's reversal and excursion sequences, in order to identify potential regularities in its behavior and thus shed light on the cause of these phenomena, which originate in the Earth's core. This is the objective of the MAGORB project, launched in 2009, funded by the French National Research Agency ANR and run by CEREGE, the Institut de Physique du Globe de Paris (IPGP) and the Laboratoire des Sciences du Climat et de l'Environnement (LSCE, CNRS/CEA/UVSQ).

More information: L. Ménabréaz, D. L. Bourlès, N. Thouveny, in press. Amplitude and timing of the Laschamp geomagnetic dipole low from the global atmospheric 10Be overproduction: contribution of authigenic 10Be/9Be ratios in West Equatorial Pacific sediments. Journal of Geophysical Research. 8 November 2012.  Abstract:

Journal of Geophysical Research: Solid Earth (1978–2012)
Volume 117, Issue B11,November 2012

• Laschamp excursion;
• cosmogenic ¹⁰Be;
• geomagnetic dipole moment;
• production rate

[1] Authigenic ¹⁰Be/⁹Be ratios were measured along a sediment core collected in the west equatorial Pacific in order to reconstruct cosmogenic ¹⁰Be production variations near the equator, where the geomagnetic modulation is maximum. From 60 to 20 ka, the single significant ¹⁰Be production impulse recorded at 41 ka results from the geomagnetic dipole low that triggered the Laschamp excursion. No significant ¹⁰Be overproduction signature is recorded at the age of the Mono Lake excursion (∼34 ka). A compilation of authigenic¹⁰Be/⁹Be records obtained from sediments was averaged over a 1 kyr window and compared with the 1 kyr averaged ¹⁰Be flux record of Greenland ice cores. Their remarkable similarity demonstrates that ¹⁰Be production is globally modulated by geomagnetic dipole variations and redistributed by atmosphere dynamics. After calibration using absolute values of the virtual dipole moment drawn from paleomagnetic database, the authigenic ¹⁰Be/⁹Be stack allows reconstructing the geomagnetic dipole moment variations over the 20–50 ka time interval. Between 48 and 41 ka, the dipole moment collapsed at a rate of −1.5 × 10²² A m² kyr⁻¹, which will be an interesting criterion for the assessment of the loss rate of the historical field and the comparison of dipole moment loss prior to excursions and reversals. After a 2 kyr duration of the minimum dipole moment (∼1 × 10²² A m²), a slow increase started at 39 ka, progressively reaching 5 × 10²² A m² at 20 ka. The absence of a significant dipole moment drop at 34 ka, the age of the Mono lake excursion, suggests that the duration and amplitude of the dipole weakening cannot be compared with that of the Laschamp. This study provides a reliable basis to model the production of radiocarbon and in situ cosmogenic nuclides and to improve the calibration of these dating methods.

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article from: http://phys.org/news/2012-10-extremely-reversal-geomagnetic-field-climate.html#jCp

An extremely brief reversal of the geomagnetic field, climate variability and a super volcano

Oct 16, 2012

The polarity reversal was a global event. © Dr. habil. Norbert R. Nowaczyk / GFZ

41,000 years ago, a complete and rapid reversal of the geomagnetic field occured. Magnetic studies of the GFZ German Research Centre for Geosciences on sediment cores from the Black Sea show that during this period, during the last ice age, a compass at the Black Sea would have pointed to the south instead of north. Moreover, data obtained by the research team formed around GFZ researchers Dr. Norbert Nowaczyk and Prof. Helge Arz, together with additional data from other studies in the North Atlantic, the South Pacific and Hawaii, prove that this polarity reversal was a global event. Their results are published in the latest issue of the scientific journal Earth and Planetary Science Letters.

What is remarkable is the speed of the reversal: "The field geometry of reversed polarity, with field lines pointing into the opposite direction when compared to today's configuration, lasted for only about 440 years, and it was associated with a field strength that was only one quarter of today's field," explains Norbert Nowaczyk. "The actual polarity changes lasted only 250 years. In terms of geological time scales, that is very fast." During this period, the field was even weaker, with only 5% of today's field strength. As a consequence, the Earth nearly completely lost its protection shield against hard cosmic rays, leading to a significantly increased radiation exposure. 

This is documented by peaks of radioactive beryllium (10Be) in ice cores from this time, recovered from the Greenland ice sheet. 10Be as well as radioactive carbon (14C) is caused by the collision of high-energy protons from space with atoms of the atmosphere.

The Laschamp event

The polarity reversal now found with the magnetisation of Black Sea sediments has already been known for 45 years. It was first discovered after the analysis of the magnetisation of several lava flows near the village Laschamp near Clermont-Ferrand in the Massif Central, which differed significantly from today's direction of the geomagnetic field. Since then, this geomagnetic feature is known as the 'Laschamp event'. However, the data of the Massif Central represent only some point readings of the geomagnetic field during the last ice age, whereas the new data from the Black Sea give a complete image of geomagnetic field variability at a high temporal resolution.

Abrupt climate changes and a super volcano

Besides giving evidence for a geomagnetic field reversal 41,000 years ago, the geoscientists from Potsdam discovered numerous abrupt climate changes during the last ice age in the analysed cores from the Black Sea, as it was already known from the Greenland ice cores. This ultimately allowed a high precision synchronisation of the two data records from the Black Sea and Greenland. The largest volcanic eruption on the Northern hemisphere in the past 100 000 years, namely the eruption of the super volcano 39400 years ago in the area of today's Phlegraean Fields near Naples, Italy, is also documented within the studied sediments from the Black Sea. The ashes of this eruption, during which about 350 cubic kilometers of rock and lava were ejected, were distributed over the entire eastern Mediterranean and up to central Russia. These three extreme scenarios, a short and fast reversal of the Earth's magnetic field, short-term climate variability of the last ice age and the volcanic eruption in Italy, have been investigated for the first time in a single geological archive and placed in precise chronological order.

More information: Nowaczyk, N. R.; Arz, H. W.; Frank, U.; Kind, J.; Plessen, B. (2012): "Dynamics of the Laschamp geomagnetic excursion from Black Sea sediments" Earth and Planetary Science Letters, 351-352, 54-69. doi:10.1016/j.epsl.2012.06.050