Percentage of meteors containing iridium?

Hello. I am new here and am not sure this is the NG to ask this
question to. If it is not, could you kindly point me in the right
direction?


Approximately what percentage of meteors contain iridium and of what
percentage by volume and/or mass?

The reason I ask is because this is put forth as a primary reason for
the posit that the inter-KT clay layer was generated by an iridium
meteor. So how valid is this claim in terms of relative rarity of
iridium meteors? (As opposed to non-iridium containing meteors)

Thanks!

"mearvk" wrote in message
ups.com...
Hello. I am new here and am not sure this is the NG to ask this
question to. If it is not, could you kindly point me in the right
direction?


Approximately what percentage of meteors contain iridium and of what
percentage by volume and/or mass?

The reason I ask is because this is put forth as a primary reason for
the posit that the inter-KT clay layer was generated by an iridium
meteor. So how valid is this claim in terms of relative rarity of
iridium meteors? (As opposed to non-iridium containing meteors)

Thanks!


It appears that all "chondritic" meteorites contain amounts of iridium.
These meteorites were formed at approximately the same time the solar system
formed. They also contain molten glass spherules as well as iron and a host
of other heavy elements. Since all other constituent meteorite elements,
with the exception of iridium, of are also found on earth in similar
proportions, iridium traces stick out like a sore thumb, after an impact,
indicating that it was indeed a meteorite impact. The iridium also
chronicles how widely the debris of the meteorite scattered after the
impact, thus giving scientists a clue as to the size and impact speed of the
critter.
A Google search for "Chondritic Meteorites" will reveal a plethora of links
to answer your question in depth.

On 25 Oct 2006 01:39:19 -0700, "mearvk" wrote:

Hello. I am new here and am not sure this is the NG to ask this
question to. If it is not, could you kindly point me in the right
direction?


Approximately what percentage of meteors contain iridium and of what
percentage by volume and/or mass?

The reason I ask is because this is put forth as a primary reason for
the posit that the inter-KT clay layer was generated by an iridium
meteor. So how valid is this claim in terms of relative rarity of
iridium meteors? (As opposed to non-iridium containing meteors)

Thanks!


Hagar is right.

the easy observation to make is that most of earth's Ir is in the
core. there is only a hint of Ir in the crust.

chondritic meteors are closer to our own core's metal values.

this is ne reason why mining Ni Fe asteroids should be so
fantastically valuable. things like Au, Pt, Rh, Ir exist in much
higher concentrations than found here on (in) the earth's crust.