ABSTRACTThis article describes an experimental six-month studythat was created to introduce first semester graduatestudents to geological research in fine-grained rocks. The study was conducted within a graduate-level Clastic

Diagenesis course where students examined themineralogical and chemical variability in shale samplesthat crop out in regions of different thermal maturityalong the Ouachita Mountain Fold Belt. A project-basedinstructional (PBL) approach was used with a drivingquestion of "what happens to shales during burial

diagenesis?" This approach was intended to give studentsan opportunity early in their graduate studies toparticipate in authentic geologic research. Each samplewas analyzed for the clay-mineralogy using XRD,whole-rock chemistry using XRF, mineralogy of heavyseparates, character of the silt-sized quartz and feldspar,and grain size of the non-clay fraction.

Qualitative data analyses from student interviewtranscriptions revealed that based on their experiencewith the Ouachita project students were able to approach their own thesis topics, regardless of the subject areawith a more holistic and experienced scientificperspective. The depth and quality of the researchquestions they asked in their own subsequent researchwas influenced by their exposure to the clastic diagenesis problem-based project. Developing competency in theanalyses techniques was not the goal of this project butrather developing an overarching understanding of theprocess used when studying the diagenesis offine-grained rocks. Evidence that this was achieved isdemonstrated in the student's final presentation of theClastic Diagenesis project at a regional geologic meeting.

INTRODUCTIONAn experimental six-month study was conducted at theUniversity of New Orleans to introduce first semestergeology graduate students to research in sedimentarypetrology. Five students enrolled in a graduate ClasticDiagenesis course completed a study on the Mineralogical

Variations in Ouachita Shales using a project-basedlearning (PBL) instructional approach. The studyinvolved examining the mineralogical variation in shales that were known to occur in areas of differing thermalmaturity along the Ouachita Mountain Fold Belt insouthwest Arkansas and southeast Oklahoma. Thisapproach was intended to give students an opportunityearly on in their graduate studies to participate inauthentic scientific inquiry and therefore set the stage forhow to approach a thesis research problem.

The concept of "authentic" geologic research impliesthat the cognitive demands (the thinking required)placed on the student, are consistent with the cognitivedemands that are expected in the geologic communityfor which we are preparing the student (Honebein, etal.,1993). Thus, we do not want the student to learn solely

about the historical, textbook background on the clasticdiagenesis of fine-grained rocks but rather to engage inscientific discourse and problem solving that researchersuse to construct interpretations in this field.

A PROBLEM-BASED LEARNINGAPPROACHThe problem based-learning instructional approach used in the clastic diagenesis course is grounded in aconstructivist theoretical framework. Constructivism is a cognitive theory on how we come to understand orknow. The body of literature on constructivism isvoluminous and extensive and therefore a summary ofthe constructivist view is presented via the followingthree central concepts: 1) our understanding is directlyconnected to our interactions with the environment, 2)social negotiation is critical to the evolution ofknowledge and 3) cognitive conflict created by multipleperspectives is the stimulus for learning and howknowledge is organized (Savory and Duffy, 1995).

Constructivism focuses on the idea that learningnever occurs in isolation and the elements of thesurrounding environment such as the context, theactivity of the learner, and the goals of the learner allcontribute to how the learner constructs meaning andknowledge. The perspectives of collaborators thereforeprofoundly affect individual understanding, and this iswhy working in groups is encouraged in PBL for itallows the testing of individual ideas and the ideas ofothers. This testing serves as a mechanism forinterweaving perspectives, which results in a greaterunderstanding of particular phenomena. The socialnegotiation of alternative perspectives within a groupalso implies that all views are not equally viable and thatsocial negotiation is driven by the goal of obtaining thecollectively most viable understanding (vonGlaserfeld,1989).

The constructivist core concepts summarized abovecan guide instruction and the design of optimal learningenvironments. These concepts can be expanded into thesix following problem-based instructional principles(Lebow, 1993), all of which were used as a guide in theClastic Diagenesis project: 1) Anchor all the learningactivities to an overall problem. Learning must have apurpose and relevance other than the acquisition of agrade. This is an important transition fromundergraduate to graduate studies. 2) Facilitate studentownership for the overall task. Challenging students tovalidate or disprove research by introducing their newdata to an area with an already published scientificinterpretation is a successful strategy for developingownership. 3) Create an "authentic" task whereauthenticity comes from working on a research problemthat is a genuine, viable question in the scientificcommunity. 4) Do not simplify the environment butrather allow the natural complexity to exist. This ideareflects the importance of context in determining theunderstanding that a researcher develops of any

Project Based Learning Approach to Shale Diagenesis: A BetterAvenue to the Big PictureIris M. Totten Department of Geology, Kansas State University, Manhattan, KS 66506,

itotten@ksu.eduMatthew W. Totten, Sr. Department of Geology, Kansas State University, Manhattan, KS 66506

particular concept. 5) Encourage the testing of ideasagainst multiple perspectives. Because knowledge issocially negotiated, encourage discourse betweenstudents, and other experts in the area of study. 6)Support student reflection on both the content and thelearning process. Interviewing students at theculmination of a PBL project can accomplish this. All ofthese principles can serve as a guide for incorporatingproblem-based learning. Table 1 presents a modifiedoutline from Arends (2004) that offers a five phaseinstructional PBL approach that can be implemented inany project driven course.

The project-based learning approach had its start inthe 1960s at McMaster Medical School where facultywere frustrated with the quality of the studentpreparation they were providing (Schmidt et al., 1987;deVolder and deGrave, 1989; Barrows and Tamblyn,1980; Bok, 1989, Boud and Feletti, 1991). It was preferredover traditional didactic teaching (TDT) because itrecognized that students retained minimal informationand had difficulty transferring knowledge to newexperiences with TDT (Schmidt, 1983). One of the majorcriticisms of traditional lecture-based education was theencouragement of "a passive, static attitude towardlearning that emphasized memorization instead of theactive, inquiring approach that the mind required tokeep up in a rapidly changing field," (Bok, 1989). Coles(1990) describes that much of medical education ismemorization of facts and data, often composed ofabstract information, which is to be applied clinically at alater time. He explains how, "the students experienceoverload, they lose their motivation, find it difficult tosee the relevance of what they are being taught, and lateron experience difficulty in retrieving and applying in aclinical setting the information they learned early on."Boshuizen and Schmidt (1990) suggest that this type ofeducation results in a professional that possesses aknowledge that he or she may be unable to access duringapplication, especially in actual field or clinical settings.The 1998 Boyer Report, Reinventing undergraduate

education: A blueprint for America's research universities,articulates the need for students who can think critically,solve problems, and work in teams and recommendsproblem-based learning as a vehicle for improvement(The Boyer Commission, 1998). Coles (1985) and Newbleand Clark (1986) report that students were more likely touse versatile and meaningful approaches to studyingthan non-PBL students, who were likely to usereproduction. Blumberg and Michael (1992) found thatPBL students were more likely to use textbooks andother books and informal discussion with peers than didnon-PBL students, who were more likely to rely onlecture notes.

This instructional approach can be extracted fromthe medical field and used in other areas of science. In the 1990's the use of problem-based learning expanded intoother fields including, management, education, law,engineering, and architecture. We have incorporatedPBL into a project for first semester geology graduatestudents who are expected to make the transition intotheir thesis work often with limited research experiencesand problem solving skills. Geoscience undergraduateprograms typically focus on concept mastery andprepare students for success in traditional coursework.Some students participate in undergraduate researchopportunities such as senior theses but many do not andconsequently complete their baccalaureate programswith little if any research experience. Therefore, researchareas where first-year graduate students struggleinclude: project management, problem solving,collaboration, and presentation of ideas. Using the PBLapproach as shown in Table 1 instead of learningpredominantly from textbooks and lecture in graduatecourses has the following benefits: improved researchand problem-solving skills, a deeper contextualizedknowledge of the subject, increased self-direction, andgreater information retention levels across time (Curtis,2001; Bok, 1989).

Phase General Behavior Clay-Diagenesis Project

Phase 1Professor goes over the objectives of the project,describes important logistical requirements, andmotivates students to engage in self-selectedproblem-solving activity.

Presented the Ouachita project and its currentscientific interpretation. Introduced the new portion of the project that students would be working onand how it related to the preexisting work.

Phase 2 Help students define and organize study tasksrelated to the problem.

The professor offered a couple weeks of lecture andstudents further defined their individual roles in the project. Each student picked a portion of the project to assume ownership of.

Phase 3 Encourage students to gather background literatureon the problem and identify experts in the field.

Background research was conducted and a fieldexcursion was planned collaboratively with sitelocations and all the planning done by the students.

Phase 4 Analyze the dataAfter rocks were collected students preparedsamples and conducted analyses with the help oflocal experts and the professor.

Phase 5 Interpret the dataStudents worked together to interpret their dataresults and how they fit into the already existingbody of research on this project.

Phase 6 Present artifacts and exhibits Students prepared a poster for a regional conference and presented their data and findings.

Phase7 Reflect on the problem solving process used in thePBL project

Students were interviewed on their experience withthe PBL project.

Table 1: Phases of the problem-based learning cycle (modified from Arends, 2004).

COURSE DESCRIPTIONClastic Diagenesis is a graduate level class designed tointroduce students to the mineralogical changes clasticrocks typically undergo during burial diagenesis. Thecourse has been taught multiple times by the researcher,usually in a standard lecture-lab format. Both sandstones and finer-grained rocks are covered, but as the researchof the co-author has concentrated on mudrocks, theircorresponding coverage in the course has increased.

Students bring many preconceptions regardingmudrocks to this class. This is primarily due to thelimited coverage they receive in the typicalundergraduate curriculum. Perhaps the biggestmisconception is that mudrocks are composed entirely of clay minerals. A significant body of literature to thecontrary exists (Blatt, 1992), but has not beenincorporated into very many undergraduate texts.Active investigation into the actual mineral make-up ofshales is an ideal way to address student misconceptions.The course during the semester covered in this paperwas approached from this point of view. A researchquestion was posed to the class, "What happens to a shale during burial diagenesis"? The formation to be studiedwas provided by the professor, the background researchbecame the responsibility of the class. This was vital tothe success of the project. The formation to be studiedshould be well known to the instructor, and robustenough to facilitate multiple research thrusts by thestudents. The research question became the theme of theclass, the search for the answer the major goal. Theinstructor had a general expectation of the answer to theresearch question from the results of previous work,even though the actual answers would be answered bythe research conducted by the class.

In this case, the Stanley shale of the OuachitaMountains of southwest Arkansas and southeastOklahoma was chosen for study because it met thefollowing conditions. The Stanley outcrops over a widearea, it exhibits variable thermal maturity, and it hasbeen extensively mapped with identified outcroplocations. Figure 1 illustrates the variation of thermalmaturity across the Ouachita Mountains, and theavailability of outcrop locations based upon sample sitesfrom previous studies.

The class had three weeks to research the geologicalbackground, collect the maps, and plan a samplecollection field trip. Class meetings during this periodwere spent discussing the Stanley formation and therelevant previous literature. Measures of thermalmaturity, including vitrinite reflectance wereintroduced. Using published maps with vitrinite andillite-crystallinity contours (Houseknecht and Matthews, 1985; Guthrie et al., 1986) the students planned thesampling trip, including all stops, camping areas, andother logistical information. Every student at each stopcollected samples. We returned with more than enoughrock for multiple analyses.

Upon return from the field, each student becameresponsible for a separate laboratory method ofinvestigating fine-grained rocks. This step is also vital tothe success of the PBL experience. The choice ofanalytical procedures is dependent on many factors, notthe least of which is availability. We were particularlyinterested in collecting information about mineralfractions that could be compared to other mineralfractions across a range in diagenetic grade. In addition,the choice of which student would be responsible forwhich specific set of analyses is important to the successof the class. The students were intimately involved inthese decisions; however, a certain amount oforchestration by the instructor is beneficial. Thepreceding three weeks of class, combined with the morepersonal interaction of the five-day sampling trip, aidsthe instructor in facilitating these decisions. Ultimately, it is important for the students to take ownership of thesedecisions.

After several alternative analytical procedures werediscussed and rejected, five procedures were chosen forthe class study. These included:

1. Whole-rock geochemical analyses by XRF2. Clay-mineral identification by XRD, including

determination of illite crystallinity3. Heavy mineral separations using LMT (Hanan and

Totten, 1996), followed by SEM mineralidentification

4. Quartz and feldspar separations by Na-bisulfatefusions (Totten and Blatt, 1993), followed by SEMidentification

5. Grain size analyses of the non-clay fraction (Blatt and Totten, 1981)

Figure 1.

Students were encouraged to help one another with anyportion of the lab work that they were not specificallyresponsible for. All five procedures had a technician orfaculty expert available to assist the class.Demonstrations of sample preparation, followed bysupervised practice by the students, were shown beforeactual data were collected. Additional sample aliquots,appropriate to each analytical technique, were analyzedfor sample precision and accuracy determinations. In afew cases, poor technique led to questionable data. These samples were reprocessed with the assistance of thetechnician.

The students are certainly not "experts" in any ofthese procedures at the end of the course, and requireddifferent amounts of help to collect their contribution tothe course dataset. They were very enthusiastic about the process, and conscientious about the quality of theirparticular data. As the data were collected, classmeetings were held to discuss preliminary results, and to incorporate any additional measurements that seemedappropriate.

An important component of the class was thesynthesis of all of the data collected. Relationshipsbetween different mineral components wereinvestigated. The class collectively submitted an abstract

to the south-central sectional GSA meeting, andcollaborated on the preparation and presentation of aposter at that meeting. This final presentation was anindicator of the success of the PBL project in that itdemonstrated that students understood the process, thecontext, and the relevancy of the research that theygenerated.

QUALITATIVE EVALUATION OF THECOURSEPBL presents some unique challenges for assessment.Because the focus of this pedagogy is primarily onlearning to learn and less on mastery of a particular bodyof knowledge, traditional methods of course assessmentsuch as examinations are not very effective (Major, 1999). Structured student interviews, a final projectpresentation, and feedback from experts associated withthe project were the assessments used to evaluate theimpact of the PBL approach in the clastic diagenesiscourse. Six interview questions were administered at theend of the course. The interview questions are shown inTable 2 and were done with a population of five, firstyear geology graduate students at the University of NewOrleans. Responses were collected during 30-40 minute

1) Explain the overall Clastic Diagenesis course project and what your role was. How was the project conceived? What elsewas included in the course?2) How many graduate classes have you taken so far that follow this style of teaching? How are your other graduate coursestaught?3)What did you like or dislike about the project-based approach to learning clastic diagenesis? Be specific.4) Do you think you learned as much about clastic diagenesis using this approach than you would have if it had been taughtlike a traditional graduate course?5) How did students with such differing backgrounds work together on the project?6) What would you do differently to improve this approach to learning clastic diagenesis?

Table 2. Clastic diagenesis interview questions.

Graduate Student Question 2: How many classes have you taken so far that follow this style?

Student 1

This is the only graduate class where I have actually done science. In my undergraduate degree insedimentology I did a project where we did the same work that has been well documented so weknew what to expect. That wasn't the same thing. Here we were doing real science withoutknowing what the answer would be. Most graduate classes are lecture, reading, and some tests. There were readings in the Clastic Diagenesis class. I think Matt lectured a total of 2 times and hegave us a series of pertinent papers and sent us off to find more in the literature. One thing thatreally set the tone early on in the course and made a huge difference to me is when Matt said you allare colleagues and scientists, you have degrees in geology and this is your project. This got us out ofthe student mode and I really felt like I was a scientists and doing real science and not just a studentlearning info that one day would be used to do science.

Student 2

This is one course that wholly uses this style. Metamorphic petrology class did the analysis ofeclogite and Chris had the samples, did SEM probe work, Fe and Mg garnets and pyroxenes tocalculate pressure temperatures (1 month) wrote paper for Chris. We got into groups of 4 andassigned us our region for the eclogite piece. Looked for previously published papers on our areas. Other graduate courses are set up like undergraduate courses, seminars, lecture, some lab, and thentests and some home works. No possibility to publish.

Student 3I have not had a graduate - or undergraduate - class experience quite like this one. All of my othergrad classes were taught in the 'traditional style'; that is, they leaned heavily on lecture and readingassignments to educate students, augmented in varying degrees by in-class participation.

Student 4None. I have had classes that have involved mainly lectures and paper projects such as reports,poster projects, and tests. There have been a few classes that involved field trips that were verybeneficial to understand the material.

Student 5 This was the first and only course I have taken in this style of teaching. My other graduate courseswere the traditional lecture and exam style.

Table 3. Sample interview transcription.

interviews and analyzed in a matrix for patternrecognition (Table 3).

Based on the interview responses, the PBL approachis not a widely used instructional strategy. We asked thefollowing question, "How many classes have you takenthat follow this style?" during the student's firstsemester, and then we revisited this question after thefive graduate students had finished their program ofstudy in Geology at UNO. None of the five students hada graduate course structured completely around the PBLstrategy. One student worked on a project that had beenpreviously completed and published where the expected results were defined and their role was to learn theprocedure on how to duplicate this type of researchstudy rather than explore a newly interpreted researchquestion. The other four students reported this beingtheir first and only course that followed the PBL model.

Students overwhelmingly expressed a positiveexperience with this approach. They liked being the onesto make decisions and felt that this was a part of sciencethat is often left out in the classroom, "We had to decidewhich samples were good and which ones were not. Inreality you need to know how to do this when you aredoing your own research." Another common theme wasfeeling a sense of ownership with the project becausethey were immersed in every aspect from the planning to the presentation of the work, "I can participate in theentire process, contribute to making decisions that guidethe research, take part in discussions with classmates,and present results to a peer group." Students were alsoexcited by the prospect of publishing an abstract from the work they did, "Other graduate courses are set up likeundergraduate courses, seminars, lecture, some lab, andthen tests and some homework, all with no possibility ofpublishing." This was the first time that any of thesestudents had presented at a regional meeting and thisprofessional experience initiated a comfort level withpublic speaking, which resulted in all five studentspresenting later in their graduate degrees at thefollowing national conferences: Geological Society ofAmerica, Society of Vertebrate Paleontology, and GulfCoast Association of Geological Societies.

Exposure to lab techniques and equipment wasnoted in the interviews as something that students likedand learned a lot from. One student described the benefitof having time alone in the lab as well as with the group.This allowed for individual decision-making andconfidence building as well as collaborative group work.A couple of the students used some of the equipmentagain in their own thesis research, and felt moreconfident and prepared because they had used thetechniques previously in this course, "The experience inthis project allowed for vision of our own individualtheses and how to manage the difficulties that could crop up in our own projects."

One of the questions that we were interested inexploring is whether students perceived their learning tobe as great with the PBL approach compared totraditional didactic instructional approach. Responses tothis question were mixed. Student responses revealed aneed to define what type of student learning we werelooking to enhance. Some commented that you do notlearn as much textbook facts as a traditional class but you learn the basics and a contextualized application as towhen and how diagenetic factors affect mineralogicalvariations in shales. A few students commented that they retained a lot of what they learned in the course becauseit was done in a hands-on application approach, "Aworking knowledge also stays with you much longerthan a memorizing for the exam only approach tolearning." The hands-on approach gave the students a

better understanding of the science techniques that theyread about in scientific journal articles, " I can read apaper and get info from it, but I don't have the depth ofunderstanding of what the paper is talking about like Ido with my own project."

Some of the aspects of the PBL approach were alsoviewed as difficult. A few students commented that theproject needed more structure at different places. Onestudent wanted more of a structured lecture, " I'veadapted well to the lecture environment and have cometo expect the dissemination of information in thatmanner. The informal lecture style used put me at adisadvantage because I didn't have notes to go to." Astructured timeline was also suggested for thecompletion of different stages of the project. The need formore of a structured group organization was alsoexpressed. Meetings were scheduled and not all fivestudents could be present and some group dynamicsformed as a result.

Overall, the PBL approach provided a base for thesefive graduate students to start their own thesis work,"Your graduate work is suppose to focus on your thesis,but classes like these really help you get into the researchand writing mode." Having a central, "defining question" required everyone to cooperate and workcollaboratively, "Just trying to get an "A" isolates you,working to put a poster together for a conference seemsto make everyone meet somewhere in the middle. Thesampling field trip also helped us to bond early on." Themixture of having collaboration with students of varyingbackgrounds proved to bring strengths and insights tothe project, the diversity served the class well, "Somemembers had very little experience with the microscope,some had done chemical separations before, thesediffering strengths complimented each other.

In the semester following the course students puttheir conclusions together and created a posterpresentation. This required the students to revisit andsynthesize all of the pieces of data that they hadindividually generated. Constructing the posterprovided an opportunity for a lot of discussion andinterpretation of the data, as well as, learning skills ofworking with media such as Adobe Illustrator. Studentspresented their work at a sectional geologic conferenceand received feedback from other professionals.

As a result of their work students showed thatincreased illite crystalinity corresponds to increasedthermal maturity. Illite crystallinity was different thanpredicted from the previously published thermalmaturity map at several sample locations. Based uponthis new data the thermal maturity map was slightlymodified. No correlation (R2= .129) was determined toexist between illite crystalinity and heavy mineralpercentages. Quartz grains showed an increase inpolycrystallinity versus monocrystalline grains astemperature increased, in agreement with previouswork. No relationship was evident between whole rocksilica percentages and illite crystalinity.

CONCLUSIONSFindings suggest that the PBL approach was successfulas evaluated by the five graduate students in a ClasticDiagenesis course at the University of New Orleans. Theresults demonstrate that a student-centered strategy canbe a successful alternative to the traditional didacticteaching approach that is prevalent in graduategeoscience courses. Based on student responses, the PBLapproach promoted better long-term knowledgeretention and helped to structure information so thatacquisition and recall were optimized. As a result of the

PBL approach, students could read the literature in thisarea and understand the research in a more meaningfulway than if they learned about clastic diagenesis withlecture-based instruction.

There are some limitations with this study thatinclude a small sample size and the evaluation processfor PBL projects. Typically projects that involve graduate students will always have small sample sizes comparedto those that utilize the introductory service courses. Thebest approach to reveal rich, deeper contextualizedinformation is via the interview process where studentsdiscuss their perspectives in detail and at length. Thetrade off is, it is difficult to find and interpret validacceptable measure of outcomes of PBL curricula.Testing with multiple choice instruments do not revealproblem-solving abilities and are not readily adapted tomeasuring process skills needed for critical thinking.

Another barrier to PBL is the effectiveimplementation of the "professor as facilitator" process.Professors must adopt new roles that are frequently verydifferent from those of their past. The professor acts as amodel, thinking aloud with students, prompting them totake on responsibilities, encouraging independence, andthen fading into the background to become anothercolleague on the team. Successful implementation is noteasy and it takes practice with this style of instruction.

Project based learning experiences help studentsbecome more self-directed learners and promoteintegrated education. Few problems facing society thatinvolve the geosciences are aligned within disciplines.Subsequently, students need to be able to solve problems that require them to make connections and userelationships between concepts and content. Studentsthat learn information via the PBL approach are betterable to do this. This is perhaps the most important goal in graduate school is for a student to be able to recognizehow their knowledge and expertise relates to the bigpicture.

ACKNOWLEDGEMENTSThe authors would like to thank Eric Day, DanaHensley, Casey Mobley, Chandra Dreher, and LizPetro for their efforts, feedback, and contributions tothe Project-Based Clastic Diagenesis course andmanuscript.

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