“The forms can change only if the energy applied to the system changes.”

From Hack, J.T., 1960, Interpretation of erosional topography in humid temperate regions: American Journal of Science, v. 258A, p. 80-97.

The study of geomorphology may have seen some of its most profound and fundamental research published during the mid-twentieth century. John T. Hack (1913-1991) was a foremost geologist who, while working for the USGS, studied the evolution of the Earth’s surface. In this 1960 publication, Hack came up with a time-independent model for erosion and landscape change. He noted that the Earth’s surface is an open system upon which many processes could act simultaneously. Hack was also the first to propose that uplift could be slow enough to counteract erosion, thus leading to landforms that could remain in steady-state until a major energy input occurred, such as through an orogeny or climate change. Hack’s theory sparked the study of the various processes controlling landscape evolution, and how these processes interact with one another on a multitude of scales.

Many geologists and geomorphologists have built upon Hack’s theory, and I am continuing this work to further understand the processes governing the evolution of the Rio Grande fluvial system in northern New Mexico.

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Research Update!

I write this post with the hope of stumbling upon a mental strategy to narrow down my own research question for my Master’s thesis. This past weekend I completed my first round of field work in north-central New Mexico, focusing on finding evidence to elucidate the evolution of the Rio Grande and its tributaries. I couldn’t have asked for better winter weather, or better people to aid in my field efforts. I was able to collect samples of sand and gravel from river terraces and samples of basalt that overlie and underlie these terraces. I will use geochronologic techniques to obtain accurate ages of these samples with the hope of understanding the timing of river incision and aggradation of the Rio Grande. This data would allow me to tap into several different conundrums, which I will need to define more precisely.

Collecting basalt samples with help from Matt Heizler!
Collecting basalt samples with help from Matt Heizler!
Standing on the rim of the Rio Grande Gorge
Standing on the rim of the Rio Grande Gorge

Joining my advisor and me were several veteran geologists who have mapped all over the Rio Grande river basin in northern New Mexico, and shared with me their incredible wealth of knowledge on the area. If it weren’t for them, I would not have been able to differentiate river terrace gravels from alluvial fan or rift fill deposits, nor would I have been able to identify the provenance of the terrace gravels once they were found. If it weren’t for these guys I also wouldn’t be having such a difficult time narrowing down my thesis topic. After learning so much from them, I discovered how many questions about the Rio Grande’s evolution remain unanswered, and how much of the river valley needs to be remapped! Having so many possibilities it quite wondrous, however, for now I need to focus on one problem and try to solve that problem.

Strategy:

1. Make a list of all possible research problems that I could solve.

2. Find a way to encompass all listed problems into one cohesive question.

Easier said than done I suppose.

Wish me luck!

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Red River gorge with the Sangre de Cristo Mountains in the background