Chapter 810: Starting From Continental Drift

Chapter 810: Starting from the continental drift.

Five o'clock in the afternoon.

This is the time when the temperature is the highest in the day. Bifang and the camel hid under a rock wall to cool off.

"The best time to travel in a day is from 4 to 11 in the morning, and then from 4 to 7 in the afternoon. It is also possible to travel overnight, but I said that it is the peak period of animal activity, so the danger is relatively high, and in the dark environment, it is easier for people to bear greater mental pressure."

"And people always need to rest. We are not camels. It is impossible to go without food and water for several days. The nights in the Sahara are very cold. In a cold environment, sleep as much as possible. The heat you lose due to excessive activity will not be recycled."

"Don't worry that you will fall asleep in your sleep. Unless you are exhausted, you will be awakened by the cold before you are frozen."

Bifang sipped his water, his forearms drooped naturally, placed on his knees, squinting at the scorching sun outside the shadow, with heat waves and deserts everywhere.

If you are traveling with a large group and camel team, you will naturally see the magnificent natural scenery, which will broaden your horizons and your body and mind. But if you are alone, your heart will probably be filled with despair, right?

Bifang turned on the kettle and pointed to the vast desert in front of him: "Can you imagine that the Sahara, which is now full of sand dunes, used to be a dense forest."

[I can imagine, I thought of it]

[Give me some face, Fang Shen doesn't want to see your reaction]

[Pasta should be mixed with No. 42 concrete]

[Although I can't believe it, I'm not stupid. When Lao Fang said this, I knew that it was true no matter how outrageous it was (dog head)]

[Reason tells me to accept it]

The barrage is always weird, and Bifang, who has long been accustomed to it, did not interrupt his narration.

"Under the northeast trade winds, hundreds of millions of tons of dust are carried away from the Sahara every year, most of which will be deposited in the Atlantic Ocean,"

"Through the study of ancient sediments, scientists have found that over the past hundreds of thousands of years, the climate of the Sahara has been switching regularly between dry and wet, with a time period of more than 20,000 years."

"The ancient murals found in the Sahara Desert also confirm this phenomenon from another perspective. In these murals, there are many horses, buffaloes, elephants, giraffes and other animals, and we all know that these animals cannot survive in the desert, especially horses."

"About 40,000 to 20,000 years ago, the Sahara region was still a humid climate period, when vegetation was lush, rivers were crisscrossed, lakes were in groups, and floods often occurred."

"And in the period from 20,000 to 10,000 years ago, the climate here became Dry, plants became scarce, rivers dried up and became dry valleys. "

"After this dry period, the climate turned humid again. Around 3500 BC, rainfall was abundant, vegetation flourished, lakes and rivers were full, and the water area reached its maximum. "

"But after that, strong winds returned to this land, and the lush forests turned into grasslands, becoming a paradise for cattle, sheep, antelopes, and giraffes. Animals such as hippos and buffaloes became extinct, and fishing no longer existed. "

"After 2000 BC, the climate became increasingly dry, and grassland animals also withdrew from the stage. Rivers dried up, lakes became smaller, dried up or disappeared, vegetation withered and degraded, and grasslands completely turned into deserts. Many grassland animals were forced to withdraw from the historical stage of the Sahara. "

"Until now, the Sahara has completely become the world's largest and most typical tropical dry area. "

"Why did it become like this? Is it simply due to climate reasons, or something else? 】

"Environmental damage? 】

【Not necessarily, the Sahara seems to have been like this a long time ago】

"It's not environmental damage, but the climate. If you want to talk about the fundamental reason, it should be the contraction of the Tethys Sea."

【What what what】

【Another thing I haven't heard of】

【Is there such a sea on the earth? 】

"There used to be."

Bifang grabbed a handful of sand and slid down slowly.

"Due to the movement of the earth's plates, the land on the earth has actually been moving slowly. 40 million years ago, the plate where Africa is located was not located where we see it now. There was a wide ocean to the north, which was the Tethys Sea."

"Under the nourishment of a large amount of humid air from the ocean, there was no Sahara Desert in northern Africa at that time, but a large oasis.

"However, starting from 40 million years ago, the plate where Africa is located began to move northward continuously. As time went on, it eventually collided with the plate where Europe is located, which caused the closure of the Tethys Sea, and the northern part of the plate where Africa is located was also lifted due to compression, and more land was exposed to the sea. ”

“The contraction of the Tethys Sea not only led to changes in the average climate state of North Africa, but also strengthened the response of the African summer monsoon to orbital changes, and subsequently became the main factor controlling the changes in the range of the Sahara Desert.”

[Something strange flew into my head]

[I seem to have glimpsed the truth of the world]

[Oh no, my brain is about to grow out]

“If the contraction of the Tethys Sea is the root cause, then the precession of the earth is the direct cause of the regular switching of the Sahara climate.”

“The so-called precession of the earth refers to the fact that the earth's rotation axis will rotate around the earth's revolution axis under the influence of the gravity of the sun and the moon. The trajectory of this rotation in space is a cone surface with a period of about 25,700 years.”

"We know that the solar energy obtained is the highest at the location where the sun shines directly on the earth, and as the inclination of the sun increases, the solar energy obtained will also decrease accordingly."

"The precession of the earth will change the inclination of the sun in the same season on the earth, thereby affecting the distribution of solar energy between seasons on the earth."

"In other words, the precession of the earth will cause the sunlight energy in the same area of ​​the earth in the same season to fluctuate in a regular manner, from less to more, and from more to less. For the area where the Sahara is located, this will directly affect the strength of the summer monsoon."

"In fact, it is the sea breeze and the land breeze. If the summer monsoon is not enough, the sea breeze will be weak, and there will not be enough ocean moist air entering the land, and slowly, it will become dry."

"Perhaps thousands of years later, this place will become a moist forest and a paradise for animals."

[Fuck, I have never learned these things.]

[Be more confident, high school geography does not teach this]

[If I were still a high school student, this topic, sorry, even if I were a high school student, I would not be able to say a few words about this topic. ]

[That's not right. The sea shrank 40 million years ago. Why did it become a desert 40,000 years ago? 】

"Because contraction is just the beginning, continental movement is a slow process. It was not until the late Miocene Tortonian, about 7 million to 11 million years ago, that this sea shrank almost completely, completely cutting off the source of water vapor."

"The reason why the cycle began 40,000 years ago involves the meteorological history of the earth. In fact, the annual summer monsoon or prevailing wind belts that you see now are all formed in the past tens of thousands of years."

"40,000 years ago, the earth was still in the Ice Age, and it had lasted for millions of years before. There was no so-called summer monsoon at all."

The audience fell into dementia.

From the beginning of continental drift to climate change, and then to the history of the earth, it is not necessarily clear without professional research.

"How does this guy know so much?"

In the Egyptian camel team, Mugalen was riding on a camel and looking at his mobile phone, with a constipated face.

Is this something people should know?

Bifang flipped through the backpack and counted the supplies.

The water resources are still sufficient, and there are also a few desert gourds hanging on the camel as a supplement, which can last at least five days, but the food is not enough, and there are a few pieces of dried fish.

The previous food was basically the leftover fish caught in the second half of crossing Point Nemo, and it was almost eaten up after a few days.

Looking up and looking around, the Gobi Desert has completely turned into a vast desert.

Taking out a piece of dried fish, Bifang stuffed it into his mouth and chewed it dry, watching the sun gradually setting in the west.

"We need to build a shelter, and tomorrow we need to find some food."