Marte: sedimentos ou impactitos?

Um ponto altamente relevante foi levantado por Frank Guardia, um experiente geólogo de exploração, fundador de várias junior companies no Brasil e Canadá,  que, nas horas vagas, é um pesquisador voraz sobre meteoritos, cometas e outros corpos estelares.

Frank tem algumas idéias bastante interessantes sobre os impactos de meteoritos na Terra.

Neste caso ele entrou de sola e falou o que muitos geólogos também perceberam mas não falaram: será que os "sedimentos" descritos pelas sondas enviadas à  Marte como a Curiosity são realmente sedimentos? Ou serão ejecta, impactitos  gerados após os impactos de meteoritos como  tufos, brechas e aglomerados  transportados ou não pela água.

Não há como negar o ponto levantado pelo Frank, que copiou neste email que me enviou, o Jonathan Amos, o principal  correspondente científico da BBC News. É só olhar para a superfície de Marte que veremos a marca de milhões de impactos de meteoritos que, com certeza, geraram  milhões de toneladas de ejecta que se acumularam em todos os rincões do planeta.  A chance de encontrarmos esses impactitos na superfície pode ser bem maior do que os afloramentos de sedimentos antigos.

A NASA, por não ter falado sobre essa hipótese, foi pega de calça curta pelo Frank. Realmente os geólogos dela pisaram na bola pois só falam de sedimentos e  de água. A NASA está tão preocupada em provar a existência de vida em Marte que está se tornando parcial, vendo somente as evidências que reforçam essa teoria em uma  geologia que deve ser imparcial.

Acredito que Marte teve, muito tempo atrás uma atmosfera mais densa e, também, mares internos e rios, que naturalmente formaram rochas sedimentares e, possivelmente, vida. No entanto o planeta sofreu um evento catastrófico que  acabou quase que totalmente com a água e com a atmosfera. Esse foi um impacto  gigantesco, que segundo geólogos colocou uma boa parte de Marte no espaço. Daí  os meteoritos marcianos que são frequentemente descritos aqui na Terra.

Ponto para o Frank!

 (veja abaixo)

Hello once more, Pedro:

First, congratulations on your article of yesterday, Bandidos e Mocinhos: a  mineração e o meio ambiente; a superb and detailed piece of work, written while  all the time I was bugging you with my own ideas.

I address this to you primarily, as from your writings from time to time in  your O Portal do Geológo, you give some important new insights to your readers  on current space technology.  For example, recently you reported on the  news given out by NASA regarding early results coming in from the Curiosity  Rover operating, still very tentatively, on the surface of Mars; the sort of  important news most of your readers would otherwise miss entirely.

So I thought that you would enjoy some very current news, written by Jonathan  Amos, the principal Science correspondent for BBC News, on the latest activities  of that marvelous machine Curiosity:

http://www.bbc.co.uk/news/science-environment-22832673

 Jonathan Amos, on reporting news from Mars, always writes the  engineering part with great reverence and detail and it is a pleasure to read  his stuff on what is another fantastic achievement by NASA engineers, not only  in the design of the rover, but being able to have placed it on the Martian  surface with pinpoint accuracy and delicacy.

 However, we must question why Jonathan places such unquestioning  trust in the very youthful team of “geological” types that are responsible for  the manoeuvring of the science lab vehicle to selected spots, conducting  physical and chemical tests and reporting the results and their conclusions as  the work progresses.

 It is quite clear from their reporting that they have been  pre-programmed, as indeed those responsible for previous rover missions to Mars  have been, to report only on any phenomenon that they believe indicates past  flowing or standing water on the Martian surface that might or might not  indicate the possibility of past life forms.

 So far they have reported on some loose rocks that are reasonably  believed to be volcanic, but mostly they have reported on some conglomeratic,  pebbly formations, some mudstones and some clayey material, all three of which  they state to be sedimentary and therefore proof of flowing water. They  also are quoted as believing that the presence of clay minerals to be  unequivocal proof of the past presence of flowing or standing water.

 Come on!  Anyone familiar with the products of terrestrial  impacting of meteoritic bodies, as very many older NASA scientists are, knows  that products of that impacting are ballistically distributed over great  distances (see image of our Moon’s Tycho Crater, attached) and include loosely  dispersed or reasonably well aggregated impactites, varying from clay-sized  particles up to huge boulders, or more often than not, mixtures of all grain  sizes together in great profusion.  Conglomerate-like diamictites, mildly  lithified pebble beds and platy clay strata of the type demonstrated in images  coming from Curiosity, are extremely frequent in such terrestrial  impact-generated deposits.

 I suggest careful perusal of my old friend Kord Ernstson’s site www.impact-structures.com, to  familiarize yourselves with the bewildering varieties of textures and  lithologies involved in the impacting process.

 What I find so unbelievable and incomprehensible is that NASA,  having selected a relatively tiny impact crater on a planet bearing millions of  impact craters (see attached image), varying from hundreds of kilometres across  to mere pinpricks, as the target for landing the rover, and where impactites  would inevitably constitute all of the present day covering material, could to  date not even mention the possibility of the existence of impact-generated  material.

 As illustrations of NASA’s incredible habit of employing  geological neophytes, hopelessly ill-trained to handle such vital and colossally  expensive missions, I would like you to take the time to read a chapter from my  unpublished book, written in October 2003, when the spectacular engineering side  of the Pathfinder Lander and the Sojourner Rover missions had recently  terminated and the Opportunity and Spirit twin rover mission had already  commenced in June of 2003.  The chapter (attached) is entitled CHAPTER 9 -  NASA’S WATER WISH – SUPERB ENGINEERING, DISMAL SCIENCE.  (Go on!   Reading the entire chapter is only going to take you 35-45 minutes, despite the  irritatingly poor editing!)

Personally, I have not the slightest doubt that water was once plentiful on  Mars and played a very significant role in shaping its topography, but what I am  complaining about is the flamboyant, sensational reporting of facts and proofs,  based on false premises.

Don’t think for one minute that I denigrate the sterling reporting of  Jonathan Amos, I certainly do not.  It is that I think that all scientists,  such as you and I, and even those of the incomparable NASA, require periodic  reorientation of their ideas and objectives, by just coming back down to Earth  for a while.

Respectfully

Frank Guardia