Saturday, November 3, 2012

Ocean of Storms, Oceans of Argument

Oceanus Procellarum, the "Ocean of Storms," is easily the largest feature of the Moon's complex topography visible, even to the naked eye, from Earth. But is it a true remnant of a basin-forming impact, merely a low remnant of early lunar morphology or perhaps the largest remnant of a hemisphere-sized impact some have labeled "Gargantua? Thumbnail of a 48-image mosaic captured by Yuri Goryachko, Mikhail Abgarian and Konstantin Morozov (ASTRONOMINSK) of Belarus, August 3, 2010.
Paul D. Spudis
The Once & Future Moon
Smithsonian Air & Space

Once upon a time, back in the Dark ages when I was a young student of lunar science, an idea was advanced that Oceanus Procellarum (the largest dark maria on the near side of the Moon) was the site of an ancient, almost obliterated impact basin.  This “Procellarum basin” (then called the “Gargantuan” basin – superlatives fail us sometimes) has been invoked to explain any and every observed aspect of lunar geology, from the distribution of the dark mare lavas, the near/far side dichotomy, the thickness of the crust, the composition of highland rocks, and the relative amounts of radioactively generated heat flow in the Moon.  Such a useful concept to explain so much!

The acceptance by lunar scientists of a Procellarum basin has waxed and waned over the years.  Originally proposed by Peter Cadogan in 1974, the presence of a large, ancient impact basin covering most of the western near side of this part of the Moon, was advanced to explain the unusually high concentration of the chemical component called KREEP – (K) potassium, (REE) rare earth elements, and (P) phosphorus.  Subsequently, Ewen Whitaker (noted cartographer of the Moon) carefully mapped landforms, such as ridges and massifs (mountains) over this area, which purportedly showed that the patterns were best explained by a three-ring basin – 3200 km across, centered on the western near side.  Whitaker named this feature the “Procellarum basin” after the largest mare region that filled it.  Lunar geologist Don Wilhelms fully embraced this interpretation in his classic book The Geologic History of the Moon, making the Procellarum basin the prime cause for the distribution of geologic units on the Moon.

LRO topographic map of the Moon, showing the approximate outline of the "Procellarum" basin on the near side (left) and the South Pole-Aitken basin on the far side (right). One's real, the other isn't.
Yet doubts persisted.  In 1985, Peter Schultz and I suggested that the quasi-concentric arrangements mapped by Whitaker, were related to the Imbrium basin (not to an earlier, underlying mega-basin) on the basis of the ring pattern of this putative feature.  We also pointed out that the patterns of rock compositions supposedly explained by a Procellarum basin were not consistent everywhere, at least casting doubt on the predictive power of the basin’s presence.  The 1994 Clementine mission gave us our first global topographic map of the Moon.  Interestingly, that map dramatically revealed the presence of a circular mega-basin on the far side of the Moon – the enormous 2600 km-diameter South Pole-Aitken basin.  The Procellarum region was also shown to be a low region, but it is not circular (more horseshoe-shaped) and is not as clearly defined as Whitaker’s ring structure suggested.  The stock in the existence of Procellarum basin declined.

But some ideas in lunar science never really go away.  Since that time, several attempts have been made to resurrect the basin.  The latest effort, just published in Nature Geoscience, comes from mineralogical mapping data obtained from the Japanese Kaguya (SELENE) mission.  The authors of this study claim that orthopyroxene (a magnesium-silicate mineral) is distributed on the Moon in association with its largest basins – South Pole-Aitken and Imbrium.  However, in addition to those occurrences, additional outcrops occur in the highlands adjacent to Oceanus Procellarum.  Therefore, these rocks were made during the slow cooling of an enormous impact melt sheet created by the impact which formed the Procellarum basin.

The logic here seems weak.  It has not been established that orthopyroxene only forms from the slow cooling of an impact melt sheet.  When this mineral occurs with the most abundant mineral of the lunar highlands (plagioclase), it makes up a rock type called norite.  Norite is very abundant on the Moon.  It is the dominant rock type at the Apollo 14, 15 and 17 landing sites and occurs elsewhere on the Moon in quantity.  It is particularly prevalent around the edges of the Imbrium basin and one could argue that norite is a characteristic of that basin and the presence of Procellarum basin to explain its occurrence is unnecessary.  Likewise, the existence here of a large differentiated impact melt sheet is inferred from analogy to a terrestrial example, the Sudbury igneous complex, but even in this case, the impact origin of the terrestrial igneous body is not universally accepted.

Evidence for the existence of Procellarum basin must be sought in its topography.  The clarity and preservation of the far side’s South Pole-Aitken basin in the topographic data is surprising.  This feature is one of the oldest on the Moon, yet it preserves relief of over 12 km (the depth one would expect of a fresh feature).  One might expect such an old feature to be indistinct at best, making the discovery of its large relief one of the surprises of the Clementine mission.  At the same time, Procellarum is a vast irregular depression averaging less than 3-4 km deep; its lack of topographic expression is more in line with what one might expect for the oldest basin on the Moon.  However, unlike all other lunar basins, a topographic bulge 2-3 km high occurs near the center of this feature (near the crater Copernicus).  No other basin on the Moon (or on any other planet) contains interior topography higher than the elevation of its topographic rim; at SPA, all of the terrain within the 2600 km diameter rim crest is lower than its rim.  The unusual relation of a bulge within Procellarum does not support the concept that it is an impact basin.  It seems more likely that it is either a feature of internal origin (possibly related to early melting episodes) or a coalescence of several overlapping impact craters and basins.

The elliptical South Pole-Aitken (SPA) basin, mostly on the Moon's farside though it's mountainous outer ring encompasses the the nearside's polar south and the Moon's lowest elevations. The oldest and largest of the Moon's definitively identified impact basins, recent studies appear to have pushed it's formation back beyond 4.1 billion years ago, within less than 500 million years after the formation of Earth and Moon [NASA/GSFC/LOLA].
As we search for the truth, Procellarum basin may well crop up again.  But for today and contrary to the current space press, the new results do not uniquely point to the existence of a large basin here.  In fact, the observations tend to support previous ideas that it is the smaller, overlying Imbrium basin that is associated with a large regional ejecta blanket of roughly noritic composition.

Originally published at his Smithsonian Air & Space blog The Once and Future Moon, Dr. Spudis is a senior staff scientist at the Lunar and Planetary Institute. The opinions expressed are those of the author and are better informed than average.

32 comments:

Unknown said...


A great article indeed and a very detailed, realistic and superb analysis of the current
and past scenarios.

Real Estate Publicity
Multimedia Presentation
epoxy coatings
glue removal

Unknown said...

Top Wellness Guru is a health-related website, with continuous use of this you will find important tips to make your health even better, we have created this site with the help of some other helpers, all those helpful and especially faithful. We are able to share the solution of the health problems with the help of them, which is faced by you on daily basis; this site is completely honestly created. And the articles shared by us are also written in the correct manner, no errors have been found in these articles from us, and every knowledge shared with you have been prepared our special health experts. http://topwellnessguru.com

Unknown said...

Hello, I am Prithvika malhotra thank you for this informative post. That is a great job. Wish you more success.Thank you so much and for you all the best. Takes Down
123movies

Anonymous said...

HealRun is a health news blog we provide the latest news about health, Drugs and latest Diseases and conditions. We update our users with health tips and health products reviews. If you want to know any information about health or health product (Side Effects & Benefits) Feel Free To ask HealRun Support Team.

qoao pakis said...

Supplements For Fitness suitable for use as a medicine". Apparently, most supplements are not labeled with any of these 2 grades. Some say that the pharmaceutical grade claim used by some supplement sellers is simply a marketing tactic. Others say it is an important consideration.

Supplements Book said...

Keto Slim : A weight loss works one day may not work the next. We'll make hay while the sun shines. On the other hand, have a top drawer month. There's no mistake dealing with weight loss. I should tell punks how it actually is. If they bring a weight loss to the fight, we might want to bring a weight loss. It's certainly paramount to have that. Weight loss is too attached to the old stratagem to make the change to a new one.

Visit Us : www.supplementsbook.org/ketoslim

Olivia Jakeman said...

Are you looking for a natural and effective way to enlarge your penis? You may have tried several techniques, and all your efforts might have gone in vain. Let me give you an introduction to the PE Bible PDF

Legends Keto said...


Legends Keto Okay, so exercise is great; staying fit and active keeps you slim, trim, and in shape. But how does it make you a more successful person? Daily exercise will give you the confidence to do more with your life. Daily exercise gets you moving and gets you energized, and soon you will find exercise is simply not enough. You'll want to channel this new energy into something else, something productive. That's why activity is a "key" to opening the door to fulfillment.
https://t.im/c5s4

Unknown said...

Opti Farms Keto supports healthy immunity and drives to reduce overweight size
of the body by eliminating bad cholesterol level. It improves ketosis that restricts
fat accumulation inside the body and makes best utilized as energy boost. The supplement
is one of the best selling product over the internet that makes you slim and stylish
Opti Farms Keto

Dexter Johnson said...

Abundance Manifestor eBook is an online program aimed at those who want to change their lives. It is one of the latest guides that revolves around the law of attraction.

tophealthychat said...

Constantly CBD - If we're thinking along the same lines that means you should realize this I could not simply evade this ASAP. I wish that was available then. I am sure you have heard of Wellness, but, just in the event you haven't, this column is for you. Here's how to decrease problems with your Wellness.

https://www.tophealthychat.com/constantly-cbd-oil/

Shark Tank Diet said...

Alka Tone Keto - In this essay, I shall to show you an example of what I'm talking about germane to Weight Loss Shark tank. Where can mere mortals seize attractive Ketosis webinars? Weight Loss Shark tank is impractical. Yikes! I can sound holier than thou. You can redeem it at your local Ketosis store. There are only a few guesses in that sphere. Take a look at the matter of fact thoughts in reference to Keto.

http://www.sharktankdiets.com/alka-tone-keto/

Unknown said...

Most ideal Way to peruse surveys and purchase online Health and Beauty Prodcuts at "Fitdiettrendss".

https://www.fitdiettrends.com/

Health said...

Erectile Dysfunction is commonly characterized as the failure to accomplish an erection for enough time to have intercourse. These standard meds are not intended to improve richness, increment want, semen volume or penis size.

male extra pills

Damian said...

Are you the kind of person who suffers from obesity? Do you want to tackle your problem with excess weight? Here is the perfect solution for you. You can check the latest Weight loss Supplement reviews to know more about this and you can choose the best from this according to your body type and weight.

Bale said...

Path of Exile has undergone several revolutions since 2013. It is the year of the PC and Xbox One release, with only fixed-featured free games. Recently, the Path of Exile 3.8.0 has released. At present, the evaluation of players is excellent, and the demand for POE Currency is getting higher and higher. But I think most old players' suggestions are to buy on the website, and I believe they choose that too.

The best place to buy POE Currency is IGGM. First of all, the price of their website's POE Exalted Orb is very reasonable. Although it may not be the lowest, the comprehensive data is the best. IGGM's security system protects sensitive data from phishing attacks, while service systems ensure their services are optimal. It provides a place for feedback to ensure the quality of service. With these two systems, you can assure of trading. In addition, their live chat is available 24/7.

Mark Ling said...

Check out Kibo Code Review , to understand in detail about how to make money online using this 8-week e-commerce based The Kibo code training program by Aidan Booth

Adam Waterman said...

If you know the courses that help you make money, Kibo Code is one of them. I mean the Kibo code is a very profitable course for e-commerce companies. It is unique and highly predictable due to the business strategies presented in the course. Read this Kibo Code Review carefully so that you can make an easy decision of whether to register in the Kibo Code System or not

Medical Council said...

Over 30 Hormone support Ingredients are natural and proven ingredients which helps to improve your metabolism to reduce body fat.

taniya dsouza said...

Hellio Fat Flusher Diet It is an excellent job, I really like your articles and wish you all the very best. And I hope you continue doing this work well.
https://apnews.com/afb2359c4f60fc9320923be0907dbc62

parthistha jose said...

Hellio fillmyzilla It is an excellent job, I really like your articles and wish you all the very best. And I hope you continue doing this work well.
https://www.smore.com/9k3ds-fillmyzilla-in-watch-online-movies

Helanbenna said...

Here in this GlucoFlow Review, you will learn whether the GlucoFlow supplement can help you balance your blood sugar and improve your overall health naturally.

alisha said...

Hellio 2movierulz It is a great job, I love your posts and wish you all the very best. And I hope you continue doing this job well.
https://www.smore.com/ety8u-2movierulz-2020

peakbioboost said...


Peak BioBoost is an additive that can be included in something as simple as your morning coffee or oatmeal. This product Peak Bioboost , who claims that they help people improve their lives by focusing on people’s guts. The product, Peak BioBoost is meant to give you “perfect poops,” lose weight, and live a happier life.

Peak BioBoost supplements promote healthy digestion. Digestive health, in turn, determines the state of your general health and well-being. Unfortunately, most people take their digestive health for granted believing that digestive problems are not as important as other health problems.

https://www.peakbioboostreview.com/

peakbioboost said...

Peak BioBoost is an additive that can be included in something as simple as your morning coffee or oatmeal. This product Peak Bioboost , who claims that they help people improve their lives by focusing on people’s guts. The product, Peak BioBoost is meant to give you “perfect poops,” lose weight, and live a happier life.


[url=https://www.peakbioboostreview.com/]Peak bioboost review[/url]

Manifestation Sigil said...

[url=https://www.politigenomics.com/manifestation-sigil-review/]Manifestation Sigil[/url]

[url=http://zenwriting.net/ok51duzwk2]http://zenwriting.net/ok51duzwk2[/url]

Manifestation Sigil said...

http://zenwriting.net/ok51duzwk2
http://postheaven.net/an3ztwdi4u
http://blogfreely.net/manifestation-sigil-review/reveal-your-dream-with-these-accessories

Manifestation Sigil said...

http://5f574ff9d4271.site123.me/
http://www.godry.co.uk/profiles/blogs/reveal-money-5-ways-to-become-a-channel-for-money-flowing-in-yo-4
http://dualsite789.wixsite.com/manifestation4546

Manifestation Sigil said...



http://rivendell.faithwebsites.com/community/messageboard.cfm?posts=1&threadid=1776#detailid_352614

dermavixskin said...

Look at it this method when it draws a parallel to muscle building because you opt to try and do one thing about it. This can be how to develop working memory of muscle building. What are we have a tendency to fascinated by? What concerning them? You will would like to require this into thought. Granting all that, how do you do it? Although I may provide blessing to that mediocre opinion. Muscle building may be a passion of mine.


https://dermavixskin.com/are-steroids-price-the-risk/

global Things said...

Although I don't usually comment on blogs, Maasalong your article is convincing enough that I can't help but to write something. Keep up the great work, Man.

Maasalong Review said...

At the point when you really want energy and endurance quick, there's nothing better compared to Maasalong. Maasalong expands the bloodstream and oxygen to your muscles and the penile organs, assisting you with accomplishing your maximized execution. Maasalong Review