[meteorite-list] Antartic Meteories - Was Dry Lake Stewnfields??
From: Lars Pedersen <lbp_at_meteoritecentral.com>
Date: Thu Apr 22 10:17:48 2004 Message-ID: <004c01c3c3f1$379fa590$365ea150_at_star> This is a multi-part message in MIME format. ------=_NextPart_000_0049_01C3C3F9.990FFA20 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Frederic The reasons there is found so many meteorites in Antartica, are many. I = will try to give e few here: 1- The climat is extremely dry, so even old ones are well=20 preserved. 2- The meteorites that fall far far inland are transported=20 toward the shores with the movement of the ice. When snow keeps faling - meter after meter and covering the meteorites - and there is very litle evaporation - the layer should just get thicher and thicker. It cant.=20 The pressure builds up and the snow turns to ice. The pressure builds up even more, and the whole thing start to sink as the lower layers - under high pressure - turns plastic. So so the icecap is moving all the time, from the center=20 and out, and eventualy falls into the ocean as icebergs. BUT, in some places (the famous locations like Allan=20 Hills etc.) the ice is forced up to the surface by rock=20 formations beneath. Here the ice is worn down by=20 ablation, and you see the famouse "blueice fields". Over time meteorites will just keep comming up on these locations. The eception is the meteorites that are very heavy. They just sink to the bottom of the ice, and will only be seen when all the ice is melted. Can you see the picture ? Else I can make a drawing, and send you, it is not easy to explane in = words alone :-) Best wishes Lars Pedersen ----- Original Message -----=20 From: meteoriteshow=20 To: MexicoDoug_at_aol.com=20 Cc: meteorite-list_at_meteoritecentral.com=20 Sent: Tuesday, December 16, 2003 10:02 AM Subject: Re: [meteorite-list] Dry Lake Stewnfields?? Hi Doug and List, I also wonder about another point on meteorite falls... Since I = started hunting them, I thought that they can fall anywhere, the = location of their landing place depending on their orbit around the sun = and the angle they meet the Earth with. Is that right or are there any = areas on our planet where they get more "attracted" ? There have been more finds in Antarctic than anywhere else, but I = guess that it's simply because people have been searching for them there = for a longer time, but can it be for another reason ? Has the magnetic = field linking the poles any effect (like for boreal auroras) ? ... I'm not a scientist and maybe my question sounds strange, but should = anybody have a clear and easy to understand explanation, thanks in = advance for sending it, just for my knowledge. Kind regards Frederic Beroud www.meteoriteshow.com IMCA #2491 ----- Original Message -----=20 From: MexicoDoug_at_aol.com=20 To: j.divelbiss_at_att.net=20 Cc: meteorite-list_at_meteoritecentral.com=20 Sent: Tuesday, December 16, 2003 5:49 AM Subject: Re: [meteorite-list] Dry Lake Stewnfields?? Hi John, I think if we get back to basic definitions, a strewn field = is an ellipsoid shape caused by a mid air explosion raining down = material, as far as I understand. What happens afterwards to the = material is irrelevant. And the strewn field is a geometric = representation fitted to the fall in practice, not the actual individual = stones. If some gets moved, picked clean, the boundaries of the strewn = field can't change, from their original definition. Perhaps some of the hunters among us will not see it that way...as = strewn tends to bring a connotation of waltzing in and cleaning up. And = an empty strewn field sounds odd... So I would think that the technical "set one straight answer" you = want is that: Mathematically it takes at least four border points to = make an ellipse, but to actually be able to fit one with any confidence = in an area, you need plenty more, to fill in the area. A neat = statistical definition seems impractical, so it will come down top the = field researcher's opinion. If the one who did the research wants to = call it a strewn field and their is evidence for a mid air = explosion...then we should have one. And if there are a few rocks...in = the desert, or in Chicago, and the principal investigator(s) don't feel = there is enough for an ellipse, then its not, because they say so. An = it is a good assumption if we happen upon an old scattered field, we can = say...this might be a strewn field, but lacking a good cause-effect = ellipse explanation there can't be a right answer for lack of data. In = the end one can probably collect opinions on this until blue in the = face...and who calls what a what...but for what? Strewn fields are simply human categories so we can make sense out = of natural events that don't have to conform to our neat, ways of = nomenclature. Just like the concept of a species or a race in biology. = You know an obvious one when you see it...but when you start taking it = as gospel and look at the limits of the definition, the whole think = breaks down, and mass consensus isn't reached...plus air resistance = already distorts a strewn field to a researcher. So there has got to be = a little eyeballing going on since tiny particles don't fall nicely. If = it looks like a strewn field, (tastes like one), ... Sipping my hot chocolate...Saludos Doug Dawn Mexico En un mensaje con fecha 12/15/2003 10:17:15 PM Mexico Standard Time, = j.divelbiss_at_att.net escribe: To Rob, Bob, Adam, and others: Recent finds from the Nevada dry lakes were grouped in a small = area within a=20 dry lake. The finding of three apparent pieces from same fall = created a=20 description by Adam that these finds might constitute a new = strewnfield.=20 Questions/observations in regards to desert strewnfields. 1. Obvious groupings of fallen masses would make the likelihood of = the area=20 being a meteorite stewnfield. Do multiple finds in desert locale = usually get=20 described as a stewnfield? 2. Does the fact that many rocks get moved around in these = environments take=20 the strewnfield idea down a notch with rocks being scattered?...or = does their=20 proximity within the bounds of normal surface movements qualify = them to be=20 still within the original strewnfield?=20 3. Is the idea of stating a location has a new strewnfield more = about this=20 location being a new place to find more than one meteorite of the = same=20 apparent fall?...and not so much about the actual fall = characteristics? I guess I'm just curious about the use of word strewnfield in this = case? Yearning to be set straight, John ------=_NextPart_000_0049_01C3C3F9.990FFA20 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=3DContent-Type content=3D"text/html; = charset=3Diso-8859-1"> <META content=3D"MSHTML 6.00.2600.0" name=3DGENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff> <DIV><FONT face=3DArial size=3D2>Hi Frederic</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>The reasons there is found so many = meteorites in=20 Antartica, are many. I will try to give e few here:</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>1- The climat is extremely dry, so even = old ones=20 are well </FONT></DIV> <DIV><FONT face=3DArial size=3D2> = preserved.</FONT></DIV> <DIV><FONT face=3DArial size=3D2>2- The meteorites that fall far far = inland are=20 transported </FONT></DIV> <DIV><FONT face=3DArial size=3D2> toward the shores = with the=20 movement of the ice.</FONT></DIV> <DIV><FONT face=3DArial size=3D2> When snow keeps = faling -=20 meter after meter and covering</FONT></DIV> <DIV><FONT face=3DArial size=3D2> the = meteorites - and there=20 is </FONT><FONT face=3DArial size=3D2>very litle evaporation - = the</FONT></DIV> <DIV><FONT face=3DArial size=3D2> layer should just = get thicher=20 </FONT><FONT face=3DArial size=3D2>and thicker. It cant. </FONT></DIV> <DIV><FONT face=3DArial size=3D2> The pressure builds = up and the=20 snow turns to ice.</FONT></DIV> <DIV><FONT face=3DArial size=3D2> The pressure = builds up even=20 more, and the whole thing</FONT></DIV> <DIV><FONT face=3DArial size=3D2> start to sink as the = lower=20 layers - under high pressure -</FONT></DIV> <DIV><FONT face=3DArial size=3D2> turns=20 plastic.</FONT></DIV> <DIV><FONT face=3DArial size=3D2> So so the = icecap is moving=20 all the time, from the center </FONT></DIV> <DIV><FONT face=3DArial size=3D2> and out, and = eventualy=20 falls into the ocean as icebergs.</FONT></DIV> <DIV><FONT face=3DArial size=3D2> BUT, in some = places (the=20 famous locations like Allan</FONT><FONT face=3DArial = size=3D2> </FONT></DIV> <DIV><FONT face=3DArial size=3D2> Hills etc.) = the ice is=20 forced up to the surface by rock </FONT></DIV> <DIV><FONT face=3DArial size=3D2> formations = beneath. Here=20 the ice is worn down by </FONT></DIV> <DIV><FONT face=3DArial size=3D2> ablation, and = you see the=20 famouse "blueice fields".</FONT></DIV> <DIV><FONT face=3DArial size=3D2> Over time = meteorites will=20 just keep comming up on these</FONT></DIV> <DIV><FONT face=3DArial size=3D2> =20 locations.</FONT></DIV> <DIV><FONT face=3DArial size=3D2> The = eception is the=20 meteorites that are very heavy.</FONT></DIV> <DIV><FONT face=3DArial size=3D2> They = just sink to=20 the bottom of the ice, and will only be</FONT></DIV> <DIV><FONT face=3DArial size=3D2> = seen when all=20 the ice is melted.</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>Can you see the picture ?</FONT></DIV> <DIV><FONT face=3DArial size=3D2>Else I can make a drawing, and send = you, it is not=20 easy to explane in words alone :-)</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>Best wishes</FONT></DIV> <DIV><FONT face=3DArial size=3D2>Lars Pedersen</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <BLOCKQUOTE dir=3Dltr=20 style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; = BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV> <DIV=20 style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: = black"><B>From:</B>=20 <A title=3Dmeteoriteshow_at_free.fr=20 href=3D"mailto:meteoriteshow_at_free.fr">meteoriteshow</A> </DIV> <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A = title=3DMexicoDoug_at_aol.com=20 href=3D"mailto:MexicoDoug_at_aol.com">MexicoDoug@aol.com</A> </DIV> <DIV style=3D"FONT: 10pt arial"><B>Cc:</B> <A=20 title=3Dmeteorite-list_at_meteoritecentral.com=20 = href=3D"mailto:meteorite-list_at_meteoritecentral.com">meteorite-list@meteor= itecentral.com</A>=20 </DIV> <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Tuesday, December 16, = 2003 10:02=20 AM</DIV> <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: [meteorite-list] = Dry Lake=20 Stewnfields??</DIV> <DIV><BR></DIV> <DIV><FONT face=3DArial size=3D2>Hi Doug and List,</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>I also wonder about another = point on=20 meteorite falls... Since I started hunting them, I thought that they = can fall=20 anywhere, the location of their landing place depending on their orbit = around=20 the sun and the angle they meet the Earth with. Is that right or are = there any=20 areas on our planet where they get more "attracted" ?</FONT></DIV> <DIV><FONT face=3DArial size=3D2>There have been more finds in = Antarctic than=20 anywhere else, but I guess that it's simply because people have been = searching=20 for them there for a longer time, but can it be for another reason ? = Has the=20 magnetic field linking the poles any effect (like for boreal auroras) = ?=20 ...</FONT></DIV> <DIV><FONT face=3DArial size=3D2>I'm not a scientist and maybe my = question sounds=20 strange, but should anybody have a clear and easy to understand = explanation,=20 thanks in advance for sending it, just for my = knowledge.</FONT></DIV> <DIV><FONT face=3DArial size=3D2>Kind regards</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>Frederic Beroud<BR><A=20 = href=3D"http://www.meteoriteshow.com">www.meteoriteshow.com</A><BR>IMCA=20 #2491</FONT></DIV> <BLOCKQUOTE=20 style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; = BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV> <DIV=20 style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: = black"><B>From:</B>=20 <A title=3DMexicoDoug_at_aol.com=20 href=3D"mailto:MexicoDoug_at_aol.com">MexicoDoug@aol.com</A> </DIV> <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A = title=3Dj.divelbiss_at_att.net=20 href=3D"mailto:j.divelbiss_at_att.net">j.divelbiss@att.net</A> </DIV> <DIV style=3D"FONT: 10pt arial"><B>Cc:</B> <A=20 title=3Dmeteorite-list_at_meteoritecentral.com=20 = href=3D"mailto:meteorite-list_at_meteoritecentral.com">meteorite-list@meteor= itecentral.com</A>=20 </DIV> <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Tuesday, December 16, = 2003 5:49=20 AM</DIV> <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: [meteorite-list] = Dry Lake=20 Stewnfields??</DIV> <DIV><BR></DIV><FONT face=3Darial,helvetica><FONT lang=3D0 = face=3DArial size=3D2=20 PTSIZE=3D"10" FAMILY=3D"SANSSERIF">Hi John, I think if we get back = to basic=20 definitions, a strewn field is an ellipsoid shape caused by a mid = air=20 explosion raining down material, as far as I understand. What = happens=20 afterwards to the material is irrelevant. And the strewn field = is a=20 geometric representation fitted to the fall in practice, not the = actual=20 individual stones. If some gets moved, picked clean, the = boundaries of=20 the strewn field can't change, from their original=20 definition.<BR><BR>Perhaps some of the hunters among us will not see = it that=20 way...as strewn tends to bring a connotation of waltzing in and = cleaning=20 up. And an empty strewn field sounds odd...<BR><BR>So I would = think=20 that the technical "set one straight answer" you want is that: = Mathematically it takes at least four border points to make an = ellipse, but=20 to actually be able to fit one with any confidence in an area, you = need=20 plenty more, to fill in the area. A neat statistical = definition seems=20 impractical, so it will come down top the field researcher's = opinion. =20 If the one who did the research wants to call it a strewn field and = their is=20 evidence for a mid air explosion...then we should have one. = And if=20 there are a few rocks...in the desert, or in Chicago, and the = principal=20 investigator(s) don't feel there is enough for an ellipse, then its = not,=20 because they say so. An it is a good assumption if we happen = upon an=20 old scattered field, we can say...this might be a strewn field, but = lacking=20 a good cause-effect ellipse explanation there can't be a right = answer for=20 lack of data. In the end one can probably collect opinions on = this=20 until blue in the face...and who calls what a what...but for=20 what?<BR><BR>Strewn fields are simply human categories so we can = make sense=20 out of natural events that don't have to conform to our neat, ways = of=20 nomenclature. Just like the concept of a species or a race in=20 biology. You know an obvious one when you see it...but when = you start=20 taking it as gospel and look at the limits of the definition, the = whole=20 think breaks down, and mass consensus isn't reached...plus air = resistance=20 already distorts a strewn field to a researcher. So there has = got to=20 be a little eyeballing going on since tiny particles don't fall=20 nicely. If it looks like a strewn field, (tastes like one),=20 ...<BR><BR>Sipping my hot chocolate...Saludos<BR>Doug=20 Dawn<BR>Mexico<BR><BR>En un mensaje con fecha 12/15/2003 10:17:15 PM = Mexico=20 Standard Time, j.divelbiss_at_att.net escribe:<BR><BR> <BLOCKQUOTE=20 style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff = 2px solid; MARGIN-RIGHT: 0px"=20 TYPE=3D"CITE"><BR><BR>To Rob, Bob, Adam, and others:<BR><BR>Recent = finds=20 from the Nevada dry lakes were grouped in a small area within a = <BR>dry=20 lake. The finding of three apparent pieces from same fall created = a=20 <BR>description by Adam that these finds might constitute a new=20 strewnfield. <BR><BR>Questions/observations in regards to desert=20 strewnfields.<BR><BR>1. Obvious groupings of fallen masses would = make the=20 likelihood of the area <BR>being a meteorite stewnfield. Do = multiple finds=20 in desert locale usually get <BR>described as a = stewnfield?<BR><BR>2. Does=20 the fact that many rocks get moved around in these environments = take=20 <BR>the strewnfield idea down a notch with rocks being = scattered?...or=20 does their <BR>proximity within the bounds of normal surface = movements=20 qualify them to be <BR>still within the original strewnfield? = <BR><BR>3.=20 Is the idea of stating a location has a new strewnfield more about = this=20 <BR>location being a new place to find more than one meteorite of = the same=20 <BR>apparent fall?...and not so much about the actual fall=20 characteristics?<BR><BR>I guess I'm just curious about the use of = word=20 strewnfield in this case?<BR><BR>Yearning to be set=20 = straight,<BR><BR>John<BR><BR><BR></BLOCKQUOTE><BR><BR></BLOCKQUOTE></BLOC= KQUOTE></FONT></FONT></BODY></HTML> ------=_NextPart_000_0049_01C3C3F9.990FFA20-- Received on Tue 16 Dec 2003 11:25:27 AM PST |
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