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Dr. John Holbrook

John Holbrook
Professor of Geology Direct: 817.257.6275
B.S. University of Kentucky, 1985 Geology M.S. University of New Mexico, 1988 Geology Ph.D. Indiana University, 1992 Geology with a Minor in Geophysics

Teaching Philosophy and Approach

Surely the most lasting and rewarding contribution I will ever make to my profession will be shown in the students I have taught. I treasure the idea that I have that rare opportunity to further the success of others and that my role in the preparation of my students will one day be my lasting legacy. As such, I take my role as the teacher/scholar very seriously. In my 19 years of teaching experience as a professor, I have always strived to improve my craft by exploring new and varied educational techniques. In doing so, I have distilled a few basic principles that have consistently proven true for me. These tenets thread through my courses at every level, and have integrated into what I now call my teaching philosophy. My courses and my extramural teaching are designed around these tenets. First, understanding process is the key to functional and retained learning. Students are easily overwhelmed in a malange of details that may now come to them through a multitude of instantaneous media venues. In science, understanding the fundamentals of process and then applying the root logic of cause and effect becomes the key to contextualizing, filtering, and developing a functional use of this vast well of information. Coupled with a willingness and ability to prudently distil and retest one’s own base assumptions, this ability soon distinguishes those as problem solvers who can critically think from those who can merely repeat procedures. My primary goal in teaching is to give each student a firm foundation upon which to build a career of functional knowledge and thought by imparting a working understanding and a lasting appreciation of the processes that govern Earth systems. This exposure opens a door that invites life-long excitement and motivation for learning. As well, this process understanding helps the student to better distil the specifics of any new conundrum that may arise. I teach process by presentation and expectation. Process is emphasized and discussed in all my classes during teaching, as well as in any field or lab or other informal student interaction. My tests ask the student to address the same problems that I as the professional would be asked to solve. Problem solving begins at the introductory level. At the mid-undergraduate level all tests are problem-solving essay questions. At the advanced undergraduate and graduate level testing of skills is mostly by completion of projects. Second, all students within a class will typically learn in differing ways. Students may be tactile, visual, audio, combination, or other types of learners, and all types will typically be in my class simultaneously. To accommodate this, I always teach with a combination of field trips, labs, visual aids, stories, examples, quirky associations, comedy, classical lecture, in what balance appears to be working. I have also adapted a more personal approach. In order to aid in the difficult task of ascertaining whether a classroom student is learning and to assess how I must quickly adapt my approach, I must get close. I have adjusted my teaching style to remove as many barriers as possible between the student and myself. I constantly gage feedback from the class through conversation and questioning as I teach in rooms laid out to accommodate close direct contact. I also take students to the field and lab to place geology within their hands so that, to them, I can make what once were words now tangible. There I can also shed the constraints of the classroom and engage students directly one-to-one. There I learn more directly about their learning needs. Third, some things just defy simple explanations and must be learned by doing. Research projects constantly challenge students with complex problems that have no pat solution or even standard approach. Facing and surmounting such problems hones the adaptive versatility and confidence that a student will need in order to survive in a very fluid job market. This also teaches students the nuances of science in ways that the classroom cannot. For this reason, I regularly bring my research directly to the classroom through student projects that directly augment active research projects. For example, I established the “Big Muddy Expedition”. This project teaches undergraduates (12 per summer; roughly half from TCC) research skills as they decode the processes that shape the Missouri River through collection and analysis of field data. This project is funded by the NSF and the USGS through their respective educational initiatives. Finally, I attempt to always teach from the student’s prospective. Teaching a familiar subject is much like giving directions to your own home to a first-time visitor. Omission of a turn that has become automatic to you will leave your guest wandering for hours in hopeless frustration. No matter what the course, I always put myself in the student’s position and try to anticipate the full framework of knowledge and explanation the student will need in order to keep on track and digest the entire scope of the material. This is a matter of eternal vigilance.

Research Philosophy and Interests

Research Philosophy   I imagine I am not alone in saying that I chose the study of sediments as my professional emphasis largely because I liked too many of the varied fields of geoscience to choose only one. Sedimentology and stratigraphy utilize a diverse collection of sister disciplines. My study of sediments has not only allowed but demanded past and current sojourns into tectonics, paleontology, oceanography, climatology, structural geology, geochemistry, Earth-system modeling, geophysics, geomorphology, and a host of other widely varied disciplines. My research interests are, thus, quite varied and, in many respects reflect both the generalist and specialist. Evolutionary theory does teach widely applicable lessons to this effect. The generalist can thrive in a wider range of environments and is better poised to exploit a newly emerging ecospace. The specialist, however, emerges quickly thereafter, and is better equipped to compete for limited resources within their niche. This means, in practical terms, that the researcher that is strictly a generalist will face difficulty building a reputation that will make them competitive for limited resources in well-established arenas. But by the same token, no research niche is likely to last forever, leaving the true academic specialist with few research options once the frenzy for their niche inevitably dwindles or resources become generally scarce. I have tailored my research interests to balance these competing factors in an effort to insure my continued research relevance. I retain my broad interests and skills in the geosciences, but have focused these broad interests into a short list of related specialties that demand such breadth. In these specialties I have focused on building a reputation. I have also positioned myself as quickly adaptable to new and appealing opportunities by fostering the ability to emphasize existing specialties preferentially and/or develop new specialties rapidly in emerging related fields. This is my strategy for remaining solvent as resource and opportunity bases continually morph and the research and professional needs of society rapidly change. My research history reflects this adaptability of specialties, and a common thread of retained research focus. My initial works were in general sequence stratigraphy during the latter boom-days of this field (e.g., Holbrook and Wright Dunbar, 1992). I also sowed the seeds of a lasting interest in tectonics and sedimentation at this time. As the field of sequence stratigraphy matured, I began focusing specifically on a niche within this now large and highly competitive subdiscipline. Namely, I concentrated my research on factors controlling formation and morphology of sequence-stratigraphic geosurfaces (e.g., Holbrook, 1996; 2010). This requires not only a literacy in the tenants of sequence stratigraphy, oceanography, paleoecology, and other diverse facets of transgressive/regressive cycles, but also a strong background in fluvial sedimentation. I continue to hone and use sequence stratigraphy as a primary tool in my ongoing and active forensic study of sedimentary deposits (e.g., Holbrook, 2001; Holbrook, et al., 2006). As my opportunities in sedimentology evolved, however, I began expounding upon my existing foundation in fluvial research. I dovetailed my interests in fluvial sedimentology with the growing movement toward surficial processes and environmental applications by expanding into a new specialty, modern fluvial systems. I integrated my early interests in subtle tectonic controls on sedimentation with my expanding interests in fluvial systems in order to address millennial-scale neotectonic interaction between modern rivers and active faults (e.g., Holbrook and Schumm, 1999; Holbrook, et al., 2006). This move was spawned by a notable addition to my resource base when I moved to a faculty position on the banks of the Mississippi River just north of the New Madrid seismic zone. Recently, I have expanded my interests in modern fluvial systems and am engaged in the study of Quaternary climatic control on alluvial fill of the Missouri Valley and coupling rates for sediment flux within large river trunks (e.g., Holbrook, et al., 2006; Holbrook, et al., in review). These days I would characterize myself as a specialist in modern and ancient fluvial-to-coastal depositional systems, with a strong propensity to draw upon many related fields. My current research interests and products address two main areas: 1) Stratigraphic architectural patterns and mechanics of deposition/discontinuity development within fluvial-to-nearshore-dominated stratigraphic sequences, and, 2) Fundamental forcing mechanisms (e.g., tectonics, climate, base-level, etc.) and process response rates for modern surficial fluvial systems.

Current Research Emphasis   Stratigraphic architectural patterns and mechanics of deposition/discontinuity development within fluvial-to-nearshore-dominated stratigraphic sequences Understanding the porosity structure of subsurface units is fundamental to petroleum, hydro-environmental, geothermal, CO2 sequestration, and flush-uranium industries. As these industries evolve toward more complex applications (e.g., gas extraction and disposal, DNAPLE transport pathways, high-pressure injection fields, etc.), their need to understand reservoir architecture becomes more complex as well. Prior concerns of general net-to-gross reservoir and aquifer volume yield to more modern issues such as fine-scale connectivity and capillary migration pathways. Our next generation of energy and environmental technologies requires a considerable ramp up in understanding of the subsurface”plumbing” of sedimentary rocks.   Meeting practical societal needs requires a bold new understanding of the fundamental controls on sedimentary processes, and the stratal patterns these processes generate, that are applicable at the finest resolution. This pursuit requires much basic research into the depositional processes that ultimately transition surficial deposits into sedimentary deposits. My students and I are vigorously addressing these issues. Some selected examples of research on this topic currently in process within our working group include:

  1. Evaluating the statistics and predictive controls on connectivity between stacked channel-belt reservoirs at progressively greater vertical spacing;
  2. Broadly applicable differential equations to assess fill rate and type for ox-bow lakes as a means of predicting fluid communication within channel-belt reservoirs
  3. Techniques for correlating sand-rich horizons over long distances;
  4. Processes generating regional fluvial scour surfaces;
  5. Iterative construction processes and sources of heterogeneity for “uniform” sand bodies; and
  6. Buffer and buttress models as a means for better relating base-level control and distribution/density patterns for permeable stratigraphic units. Each of these studies relies heavily on field observational science, coupled with conceptual, mathematical, and experimental modeling.

Fundamental forcing mechanisms (e.g., tectonics, climate, base-level, etc.) and process response rates for modern surficial fluvial systems. The fundamentals of surficial fluvial processes are immensely fascinating and touch so many facets of modern life. Understanding river processes impacts such diverse areas as river restoration and management, water resources and hazards, landscape evolution and stability, architecture of fluvial reservoir and aquifer units, and terraforming/landscape engineering of new or degrading land surface. As pressure increases on land surface resources in a rapidly developing world, so must our understanding of surface process in order to reach a point of sustainable development. Land loss, like that of the Mississippi Delta, may only be mitigated by targeted manipulation of sediment input.   Natural channel design initiatives balance financial and ascetic value of a native channel against a perceived certainty of safety rendered from hard channel engineering. These and other growing trends require levels of predictability in natural and induced river response that well exceed prior requirements. All actions on rivers must also satisfy a complex mix of intensive social and economic concerns. Likewise, river strata are the archives of recent events. Just as rivers are sensitive to man-induced changes, they also record natural changes that were imposed in the recent past. As such they are a wealth of banked information on recent tectonic and climatic changes.

Advancing our understanding of river system response builds upon gaining a better understanding of the feedbacks between shifts in allogenic forces and natural river processes. My students and I are heavily engaged in such research. Examples of research projects into which we are currently invested include:

  1. Use of forensic river reconstruction as a paleoseismic and a paleoclimate proxy;
  2. Rates, vectors, and processes for response of large rivers to changes in landscape sediment and water supply;
  3. Fundamental processes of splay-delta propagation into lakes, triangular deltas vs. propagating channels;
  4. Reasons for variations in meander process and morphology;
  5. Scour migration trend in large rivers; and
  6. River tectonic response rates.


Click here to download an entire CV Holbrook_Vita_TCU