Catastrophes and Prehistory

Duncan Steel hypothesizes that the "... giant impact in Mexico apparently induced seismic waves which were focused on western India, causing fracturing which then led to the widespread Deccan eruptions. ...". Since India was then south of its present position, the Deccan basalt traps of India were then roughly antipodal to the Chicxlub Yucatan crater.

According to an islandone.org web article released by Don Savage, and Diane Ainsworth of JPL, dated 28 December 1994:

"... it was the sulfur-rich atmosphere created in the aftermath of an immense asteroid collision with Earth 65 million years ago that brought about a global freeze and the demise of the dinosaurs. The impact of this large asteroid hit a geologically unique, sulfur-rich region of the Yucatan Peninsula in Mexico ... the impact kicked up billions of tons of sulfur and other materials and was between 10,000 to 50,000 times more powerful than the comet Shoemaker-Levy 9 impact on Jupiter last July. ... this asteroid was between 10 to 20 kilometers (6 to 12 miles) in diameter and its collision on Earth brought about total darkness around the world for about half a year ... But more importantly, persistent clouds generated by the impact on this geologically distinct region of sulfur-rich materials caused temperatures to plunge globally to near freezing. ... These environmental changes lasted for a decade and subjected organisms all over the world to long-term stresses to which they could not adapt in such a brief time span ... Half of the species on Earth became extinct as a result. ...
... it was the specific geological location of the impact in a region that is rich in sulfur materials that created catastrophic climate changes and led to the downfall of the dinosaurs. If this asteroid had struck almost any other place on Earth, it wouldn't have generated the tremendous amount of sulfur ... On impact, the asteroid hurled some 35 billion to 770 billion tons of sulfur high into the atmosphere, along with other materials.

The NASA team ... recently discovered rocks in Belize -- some the size of a small car -- that were blown out of the crater and landed south of the Chicxulub site. The boulder deposit in Belize also contained fragments of glass ... known as "tektites," ... The tektites have been found in other regions near the crater, such as Haiti, Mexico, Texas and Alabama, but never in association with large boulders. Another important find at the Belize rock quarry was limestone with fossils dating to the early part of the Cretaceous. ... Early Cretaceous fossils have been found deep below the surface near the crater during drilling by the Mexican Petroleum Company. We think the limestone found in Belize was excavated by the impact, which probably blew a hole more than 15 kilometers (nine miles) deep in the Yucatan Peninsula. ...

... The researchers used sophisticated atmospheric models of the sulfur-rich atmosphere of Venus to model their impact scenario. ... Initially, thick sulfur clouds, combined with soot and dust generated by this impact, would have spread worldwide and blocked out the Sun ... Night-like conditions probably existed all over Earth for at least six months essentially bringing photosynthesis to a halt.

Unlike the aftermath of typical impacts, the skies remained murky for at least a decade, due to chemically generated clouds of sulfuric acid high in the stratosphere. ... The reflection of sunlight back into space from these high-altitude clouds caused surface temperatures to drop to nearly freezing for many years all over the planet. ... These atmospheric conditions occur in Venus' perpetually cloudy atmosphere ... where ultraviolet sunlight and water in the high atmosphere can convert sulfur dioxide into sulfuric acid clouds. Sulfuric acid clouds like those that cover Venus may have continued to blanket the Earth for more than a decade after the initial impact of the asteroid, causing a secondary and more long-lasting effect which killed much of life on Earth. ...".