为什么西伯利亚甲烷陨石坑有光滑的垂直壁?-地江南体育网页版球科学堆栈交换江南电子竞技平台 最近30个来自www.hoelymoley.com 2023 - 03 - 30 - t05:25:04z //www.hoelymoley.com/feeds/question/2355 https://creativecommons.org/licenses/by-sa/4.0/rdf //www.hoelymoley.com/q/2355 37 为什么西伯利亚甲烷陨石坑有光滑的垂直壁? spraff //www.hoelymoley.com/users/770 2014 - 08 - 10 - t20:16:33z 2016 - 12 - 26 - t18:03:29z 我希望你们大多数人都听说过this。< / p >

enter image description here

All the news is about whether or not they were formed by the release of methane, but it is also mysterious to me why this crater has jagged edges but smooth vertical walls. It almost looks like it has been drilled.

I'm not a geologist but I would expect it to be rough all the way down. Can someone explain why it isn't?

//www.hoelymoley.com/questions/2355/-/2362#2362 4 为什么西伯利亚甲烷陨石坑有光滑的垂直壁? 德米特里• //www.hoelymoley.com/users/775 2014 - 08 - 12 - t13:48:11z 2014 - 12 - 11 - t07:56:08z 我的一个朋友在莫斯科的永久冻土研究所工作,他和他的同事普遍支持这个想法。我认为边缘是由掉落的土壤碎片形成的垂直墙是由巨大的甲烷气泡冲出更深的地层形成的。< / p > //www.hoelymoley.com/questions/2355/-/4267#4267 6 为什么西伯利亚甲烷陨石坑有光滑的垂直壁? user889 //www.hoelymoley.com/users/0 2015 - 01 - 15 - t03:38:01z 2015 - 01 - 15 - t03:45:20z 这个答案可能有点推测性,但看看这些陨石坑发生的地区的“冰石学”,特别是考虑到最近对这些陨石坑进行科学探索的图像,正如新闻来源报道的那样,如澳大利亚每日邮报文章下降到西伯利亚神秘陨石坑的深处:专家们探索了98英尺宽的洞,以了解更多关于它的起源。有一种说法认为,这一形成可能是由于a pingo的形成,而不是甲烷喷发。不管原因是什么,很明显,有什么东西从地下“喷发”出来,形成了陨石坑。这个答案将不关注原因,而是回答是什么导致了光滑的墙壁。< / p >

Clues to how the craters have smooth walls and rugged crater surface features come from both the cryolithology of the Yamal Peninsula (where these craters are, according to the article linked in the question) and from the observations in the articles themselves. The Yamal Peninsula possesses an extensive permafrost.

As the Yamal Peninsula is an area rich in hydrocarbon deposits that are being extracted, one of the best insights to the cryolithology of the region is from exploration observations. According to the article Genesis of Methane Entrapped in Ground Ice, Yamal Peninsula, WS Russia (Streletskaya, 2013), the sediments contain ground ice bodies and icy sediments with between 50-95% volumetric ice content.

According to the Smithsonian webpage about a Yamal expedition, these sediments consist of clay, silt, sand and mud - and very rarely are there any rocks greater than the size of pebbles. Effectively frozen and depending on the ambient air temperature, semi-frozen-mud-slush.

So, the sediments would behave like mud, and the ice content would have held the sediments together to make the smooth walls, particularly in the absence of rocks to scour the walls. The ice in the sediments in the exposed areas, particularly on the surface would have melted, forming the drainage rivulets in the picture in the question. The article does mention that there were trickles of water down the sides, suggesting that the crater wall were also beginning to melt.

The articles also suggest this by stating that attempts to descent into the crater were successfully performed in winter, as the ground is hard (= frozen).

//www.hoelymoley.com/questions/2355/-/4286#4286 18 为什么西伯利亚甲烷陨石坑有光滑的垂直壁? marsisalie //www.hoelymoley.com/users/1411 2015 - 01 - 17 t13:48:08z 2016 - 12 - 26 - t14:18:27z 永久冻土的定义是至少连续两年年平均温度低于0°C的地面或介质(包括岩石、土壤和有机物)。

墙壁光滑的外观可以通过理解永久冻土的工作原理来解释。永久冻土的特征是一个活动层,这是一个通常在表面的层,每年冬天冻结,夏天解冻——亚马尔的这一层可能有1-2米深,这取决于当地的地面特征(雪深、反照率、坡度、空气温度、热导率、径流等)。这个地区的地面富含冰。< / p >

Then let's assume this crater was caused by a methane bubble escaping/exploding and walls could be rough immediately following the event. By deduction, there should not be an active layer found on the walls following the explosion, as it is the first time this ground (walls) were exposed to air. During the middle of the summer, above 0°C air enters the hole due to convection. The ground is ice-rich (can be porous or invisible ice but still ice-rich) and active-layer start to form on the wall.

Due to the near vertical orientation of the walls, saturated soil (or active layer in formation) cannot stand because as soon as it thaw to a depth exceeding its equilibrium limit, it fall at the bottom of the crater due to gravitational forces, exposing a new frozen surface (and the cycle continue until equilibrium can take a few years). Thawing sediments in ice-rich soils can reach saturation quickly, further adding to the weight and accelerating the time of the fall. Rugged and unequal surface are typically the first elements to thaw and fall.

I took this picture about an hundred km from the featured crater. enter image description here

This display a very ice-rich section of the Yamal Peninsula littoral in the course of erosion. This coastal section has been eroding for decades at least. At the top the active layer is light brown, and look dry (1 m deep). Just under this top-layer, the ice is poly-genetic: ice wedge ice-rich soil and massive ice can be seen as well. The active layer cannot stand on the side for the reasons I exposed in the previous paragraph (gravity).

Side-note, the jagged edges were not initiated by anything related to a pingo. It takes decades, up to many centuries for a pingo to develop until its natural collapse. When it happen, a depression can form at its center - which could lead to a lake, but these are not overnight processes. Also, contours of the pingo mound would not appear as jagged edges if this was a pingo - the remains would appear pretty old and vegetated, alike the surrounding countryside.

//www.hoelymoley.com/questions/2355/-/9345#9345 -2 为什么西伯利亚甲烷陨石坑有光滑的垂直壁? 达里克 //www.hoelymoley.com/users/7195 2016 - 12 - 26 - t04:38:53z 2016 - 12 - 26 - t18:03:29z

最古怪的答案:

它具有等离子体放电的所有特征。锯齿边的灼烧痕迹类似于电火花加工的疤痕。< / p >

EDM machining scars

crater walls show characteristic scalloping of electrical discharge

vertical walls cut by plasma, saw tooth edge results from hypersonic blast

large crater in Mexico showing same triangular shapes around rim

diagram of electrical discharge event, shock wave blast creates triangular shaped wave which superimposes on the surface

There are some excellent videos on youtube about electric geology if you are interested in more detailed info.

Video about electric geology, explains arc blasted earth features

Speculation on the cause could go wild. Some natural phenomena might account for such an event, but likely would have been easily noticed by locals, even at a great distance.

There has been much chatter lately about hypersonic reentry vehicles as weapons.

http://www.nationaldefensemagazine.org/archive/2015/August/Pages/HypersonicWeaponsRaceGathersSpeed.aspx

http://rbth.com/defence/2016/09/27/russia-could-get-hypersonic-weapons-by-early-2020s_633689

Such a device creates very different conditions in the atmosphere around it as it forms a plasma from the high speeds involved. It is likely that such weapons are being tested, far from man, but somewhere accessible. A hole that size would only require a test sized vehicle, a scale model maybe. And with such obvious success, you might want to leak pics to notify the enemy of your capability, because the best defense is a good offence.

/kook

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