Alan Russell Hildebrand is a geologist born in Calgary, Canada in 1955. He is relatively young for all the contributions that he has done for the field of geology. Geology, as you may know, is the study of the structure, formation, and composition of our planet.
As a geologist, Russell primarily studies meteorites and the impact site. As you know, meteorites tell myriads of information about our essential elements and building blocks. Impact sites are important to track because they may help predict future landings, and perhaps even prevent damage from meteorite showers. He currently teaches and continues to research on this field for the University of Calgary, in Canada.
Perhaps you have heard that theory about a huge meteor impacting Earth millions of years ago, extinguishing the dinosaurs and all life on the planet. You may have also heard about the Yucatan Peninsula, and how it obtained its concave shape because it is presumed that this was the impact site of such event. It was Russell who first proposed the location of the impact, which is now almost universally accepted as a scientific and factual event that is thought to have occurred 65 million years ago. It is known in the scientific community as the "Cretaceous Tertiary Mass Extinction", for this was the time period attributed to the time of the incident. You may also hear or read it being referred to as the KT event.
When Russell proposed the impact site in he conducted further investigations, and an in-depth look into the area resulted in the 1991 discovery of a crater in that area, whose diameter is wide enough (over 100 miles in diameter) to presume that something massive and at a tremendous speed crashed against the core of the earth, becoming pulverized on impact. This crater is called the Chicxulub.
As previously stated, Russell still works as a researcher and faculty at the University of Calgary's Geology department and his primary job is to continue to track minor meteorite impact sites, and the recruitment of farmers and other countryside volunteers that would collect pieces and samples of meteorites as they are detected on site.