Thursday, April 27, 2023

Chicxulub Crater — History Mystery

Chicxulub Crater — History Mystery

The Chicxulub crater, also called an impact crater, is near the community of Chicxulub and buried underneath the Yucatán Peninsula in Mexico. It's named according to its position. This crater was formed more than 66 million years ago when a big asteroid struck Earth. The diameter of that asteroid was about ten kilometres (six miles). Its diameter is assumed to be 180 kilometres (110 miles), while its depth is 20 kilometres (12 miles). This one is the 2nd biggest impact structure on Earth. It is the only crater whose peak ring is intact; people can access it for scientific research.

The culprit that is behind the end of the dinosaurs is accepted as an extraterrestrial collision of epic proportions. It has left behind the gargantuan crater of Chicxulub in Mexico. However, the evidence behind this theory increased over time.

Antonio Camargo and Glen Penfield were geophysicists by profession. They found the crater. During the late 1970s, they had been finding petroleum in the Yucatán Peninsula. Penfield could not prove that the geological feature was a crater. So, he stopped his search. Later, he contacted Alan R. Hildebrand in 1990 and collected samples, according to which it can be concluded that the feature was impacted. Proof for its impact origin contains shocked quartz, a gravity anomaly, and tektites in these areas.

The impact date coincides with the Cretaceous–Paleogene boundary. We can also call this the K–Pg or K–T boundary. People now accept that the Cretaceous–Paleogene extinction event was caused due to the result of devastation and climate disruption.

Thick Impact Ejecta Deposit at the K-T Boundary in Haiti:

The event took place in Haiti, on the southern peninsula of the island of Hispaniola. In the year 1990, Alan Hildebrand and David Kring measured the thick deposits of impact melt spherules, capped with a layer of iridium-rich and shocked quartz-bearing sediment. Around 46 centimetres is the impact ejecta deposit's primary thickness adjacent to Beloc, Haiti. In other places, impact ejected materials seem like seafloor bottom currents have been reworked, generating deposits up to 125 centimetres thick. The thickness of impact debris in Haiti was more than it was at other locations known at that time.

Impact Melt Spherules at the Cretaceous-Tertiary (K-T) Boundary:

Impact melt is a vital product of an impact cratering event. The melt fraction is ejected from the crater. As soon as the melt is ejected, it will separate into molten droplets. These quench the glass before landing. Due to the glassy beads, a layer of ejecta can be formed on land or a seafloor. The discovery of impact melt spherules means that the source crater was in the region. Besides, you should know about the composition of the impact melt spherules. The reason is that it refers to the impact occurring in a place where continental crust exists, not oceanic crust.

Shocked and Unshocked Quartz at the Cretaceous-Tertiary (K-T) Boundary:

One of the most common minerals present in Earth’s continental crust is Quartz. Once the comet hits, a huge shock pressure is produced. Therefore, the pressures can produce shock lamellae or planar deformation features via quartz crystals. It has finished the planes and the crystal structure. No geologic process except that can cause damage. Therefore, it can be concluded that the features are diagnostic proof of an impact event. A shocked quartz crystal was ejected from the Chicxulub impact crater while placed in its sediments in Haiti. The length of a quartz crystal is 0.45 millimetres. D. A. Kring, A. R. Hildebrand, and W.V. Boynton described the crystal.

Chicxulub Impact Breccia:

As per the discovery of shocked quartz, shocked feldspar, and impact melts in the Yucatán-6 exploration borehole from the interior of the Chicxulub structure, it was proved that the impact crater generated at the Cretaceous-Tertiary (K-T) boundary. There is a melted rock sample under the polymictic breccia. In this regard, you should know that the sample of melt rook was found deep from the ground, around 1.3 kilometres. David A. Kring, Alan R. Hildebrand, and William V. Boynton were the founders at the 1991 Lunar and Planetary Science Conference.

Chicxulub Gravity Map and Boreholes

You can see its subsurface structure in a gravity map of the northwestern margin of the Yucatán Peninsula, where the crater is outlined by a black Circle. Its diameter is around 180 kilometres. The crater was more than enough to ensure that it had an impact source. Near the Haciende Yaxcopoil (Yax-1) in 2001-2002, a scientific borehole was drilled.

Radar Tomography Map of Chicxulub

Shuttle Radar Tomography Mission made the shaded relief map on Space Shuttle Endeavor in 2000. There exists a deep semicircular trough of 3-5 meter in depth, and you can call this a darker green arcing line. The Chicxulub-1, Sacapuc-1, Yucatán-6, and Yaxcopoil-1 boreholes exist within the crater's rim. The dotted line outlines its ~170 to 180 km central area. Several investigators find it as the rim of the crater.

Chicxulub Zone of Cenotes:

It was discovered in the mid-20th Century and found on topographic maps of the Yucatán Peninsula. Until this crater was found, we did not know the cause of the ring. Groundwater that flows north encounters the buried rim of the crater. The direction of water flow changes around the crater & flows (visibly) into the Gulf of Mexico, whereas the crater rim overlaid the northern coastline of the peninsula. A chain of cenotes surrounds the crater like a blue pearl necklace. Jake Bailey and David Kring crafted a version of this diagram. LPI was recently modified for its collection of classroom illustrations.


On Earth, it is the only well-preserved peak ring crater connected to the K-Pg mass extinction of several plant and animal species. Geologists drilled an 83-millimetre borehole in 1990 into the peak ring of Chicxulub crater as part of the International Ocean Discovery Program and International Continental Scientific Drilling Program (IODP-ICDP) Expedition 364.

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