Discovering anything from 115 million years is a challenge. But the awareness that the tsunami happened is more prominent.
The discovery was almost by chance. The researchers examined the rocks from a quarry on the Japanese island of Hokkaido when they found evidence of an ancient catastrophe: a family of amber buried deeply in the deposits of what was previously at the sea floor. Unlike the typical amber deposits found in the forests or shallow coastal environments, these fossilized trees are found more than 150 km from the old coast. It was included in the deep marine sandstone. This is where the story begins.
The study concludes that the amber was originally formed in the coastal forests. During huge tsunami events, complete sections of these forests – including trees, resin, vegetable and soil – were violent and transmitted directly to the deep sea.
Ratang in depths
Tsunami is some of the most destructive natural forces on Earth. The result of earthquakes below the surface of the sea or landslides, they throw the walls of huge water across ocean ponds and can flatten the entire coasts in minutes. But while it is well documented in the modern era, it is far in deeper geological history.
Coastal tsunami, such as sand layers or dandruff family, is often erased due to the disturbances they record. In Old rock recordIt may be difficult to know this about other high -energy events such as hurricanes or floods.
But the amber introduces a new type of evidence.
The team focused on a 150-meter sequence of early chalk deposits (dated to approximately 116-114 million years). The lower layers were originally volcanic. He sits on top of them, a thick pile of marine sediments was deposited when tectonic paintings collided and new landscapes were pushed. Somewhere in this transition, the amber split its way to this mixture. It should not be, but she did.
Thirty distinct beds are found in the marine sandstone. In five of them, amber represents up to 80 % of the open surface. One layer rich in resin was to the point that it formed a blanket of amber up to seven centimeters through a ten -meter mattress. This alone will be unusual. But what amazing researchers is what the amber seemed to.
“Fire” that indicates water
The researchers used a technique called “fluorine tomography” to cut and photograph amber in wonderful layers under the ultraviolet light. However, they found that the amber leaves had folded, flowing and even moved up to form flame -like structures. This is usually seen when it distorts the wet sand under pressure.
This indicates that the amber was not embodied and was still a soft and sticky resin when it flows under the water, mixes with mud, and settled on the deep floor.
Using a new technique called optical grinding-chopping and photographing amber mainly in wonderful layers under the UV light-they revealed that the fossil resinning structures bear the soft deformation structures. The flat amber leaves were folded and flowing and even the “flame tongues” formed ascending, and shapes are usually seen when wet sand abnormalities under pressure.
These were not dry parts, stiffness of ejaculation by waves. The soft, sticky rivers were from the resin that were flowing under the water, mixed with mud, and settled on the bottom of the deep sea before they had time to harden.
The team wrote, citing previous studies: “Modern resin stars in about one week after secretion,” citing previous studies. “In contrast, the resin that flows into the water remains soft unless it is exposed to air.”
But it was still unclear how the amber reached the sea floor in the first place. To solve this, the team looked at the surrounding geology. In particular, they looked at what was about amber.
Trees at the bottom of the ocean
The family of amber was not alone. They came with the wreckage of the plant, large pieces of tip wood (some are more than a meter in length), and “torn peels”-huge fragments of the bottom of the sea floor filled with sediments. All of these were intertwined with turbide, gradient sandstone deposited by the underwater ice collapses of the sediments.
Together, the signs referred to the same perpetrator: tsunami.
Researchers propose a series of events. First, send a huge earthquake – it is likely to be the result of drawing a tectonic plate – a tsunami race towards the ground. It was shattered by coastal forests, tearing trees and raining the ocean with the resin. At the same time, a vast carbonate platform collapsed abroad, and sent limestone blocks in the depths.
From both the land and the shallow sea, the torrents were wiped from the debris in the pelagic basin. Some of this debris, such as sand and clay, sank quickly. The other debris – like tip wood and resin – floating longer, then settled slowly over time. The repeated nature of the amber layers – 30 separate beds on several meters of rocks – indicates that such events occurred more than once during this active tectonic break.
Amber is really useful
The amber has long been fossil scientists because of its preservation of ancient life. Previously, geologists found insects, pollen and even microscopic creatures preserved in prehistoric amber. But here, in the depths of the sea, the amber becomes completely else: the tragedy recorded. It is a window in moments in which the Earth shakes hands and shattered ecosystems in minutes.
What makes this discovery scientifically important is that tsunami deposits are difficult to determine in the rock record. Their signatures are often shattered in storms or floods. However, in the Pelagic environment, away from rivers or hurricanes, such events are highlighted.
This research adds a powerful new tool to search for an old tsunami – especially in the places where the coast has long disappeared. It also reformulates amber more than just the remains of the forest. In the words of the authors, “the new resin perspective as a soft doctor reveals the entire sedimentary process from corrosion to burial, a view that has been neglected through previous sedimentary studies.”
the study Deployed in Nature scientific reports.
