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Fan studying Mexican mountain range’s effect on major weather pattern

Majie Fan
Majie Fan

An earth and environmental sciences researcher at The University of Texas at Arlington is studying a mountain range in Mexico and its role in the formation of a major weather pattern that affects North America.

Majie Fan, associate professor of earth and environmental sciences, received a 2019 ConTex Collaborative Research Grant Proposal Award for $48,759 for a project titled “Rise of the Sierra Madre Occidental, Mexico, and its impact on the North American Monsoon.”

ConTex is a joint initiative between the UT System and Mexico’s CONACYT (National Council for Science and Technology). The goal of the joint initiative is to enhance academic and research collaborations between Texas and Mexico.

Fan is collaborating with Aaron Martin, a researcher at the Institute of Scientific Research and Technology (IPICYT) in San Luis Potosí, Mexico. One of Fan’s master’s students, Jordan Foote, is working on the project as well.

The North American Monsoon is a regional-scale weather pattern that develops over the southwest portion of North America during the months of July, August, and September. It affects a large part of western and northwestern Mexico and the southwestern United States, and it brings more than half the annual rainfall to the drylands of Chihuahua, West Texas, and many neighboring states in both countries.

The North American Monsoon centers over the Sierra Madre Occidental, a mountain range that stretches along the west coast of northern mainland Mexico. Since high inland topography is an essential element for a monsoon climate, the origin of the North American Monsoon is closely related to the rise of the Sierra Madre Occidental.

“In this project we are investigating the central part of the range to understand the timing of its rise and its role in forming the monsoon,” Fan said. “The birth and development of the North American Monsoon have received little modern research attention despite the millions of people in the southwestern United States and western Mexico who rely on its rains for agriculture, domestic use, and industry.”

Fan said she and her colleagues will measure stable isotope compositions in modern river water and in ancient water archived in hydrated volcanic glass that erupted millions of years ago. They will also date the volcanic glass samples using single sanidine crystal 40Ar/39Ar geochronology. Foote is heading to the central Sierra Madre Occidental later this month to collect the first batch of modern river water samples.

 “Investigation of modern river water will quantify the seasonal (wet vs. dry) variations of stable isotope composition across modern topographic relief,” Fan said. “Reconstructed ancient water stable isotope compositions will be compared to modern counterparts to reveal the topographic history and assess paleoelevation uncertainty and the evolution of the monsoon.

“Understanding gained from our pilot study has implications for mountain-building processes in Mexico as well as the response of the monsoon to climate change. The latter is particularly important for future water management because numerical simulations suggest changes to the timing of monsoon rains in a future warmer world.”

The pilot study will demonstrate the feasibility of paleoaltimetry – the quantitative estimate of the past elevation of the land surface – in the Sierra Madre Occidental, Fan said. That will enable her and her collaborators to seek future federal funding to expand their reconstruction to all parts of the range and to a longer time scale.

Arne Winguth, professor and chair of the UTA Department of Earth and Environmental Sciences, said the project could provide important advances in the area of global environmental impact, one of the four main themes of UTA’s Strategic Plan 2020.

“Dr. Fan’s work could lead to a better understanding of how the North American Monsoon is being affected by climate change,” Winguth said. “As weather patterns change and weather phenomena become more severe due to climate change, it will be critical to understand the processes that lead to the intensification of these patterns so that we can better adapt to their environmental impacts.”

Fan received a B.S. in Geology in 2000 and an M.S. in Geology in 2003, both from Lanzhou University in Lanzhou, China. She then came to the University of Arizona, where she earned an M.S. in Geosciences in 2005 and a Ph.D. in Geosciences in 2009. In 2010-11 she worked as a postdoctoral researcher in the Department of Geology and Geophysics at the University of Wyoming. She joined the UTA Department of Earth and Environmental Sciences in fall 2011.