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This study analyzed quantitative and qualitative data from classroom observations combined with instructor survey results to characterize the application of reformed teaching practices in undergraduate geoscience classes in the United States. Trained observers used the Reformed Teaching Observation Protocol (RTOP) to score 204 geoscience classes. Observed faculty represent a diversity of institutions, teaching rank, and years of experience. Classrooms observed included introductory and upper-level undergraduate courses that ranged in size from 6 to 275 students. Total RTOP scores do not correlate with class size, class level, institution type, instructor gender, instructor rank, or years of teaching experience. Classroom instruction was separated into three categories based on total RTOP scores: Teacher Centered (≤30), Transitional (31-49), or Student Centered (≥50). Statistical analyses of RTOP subscales and individual item scores are used to identify the instructional practices that are characteristic of each category. Instructor survey responses and qualitative classroom observations provide additional details about instructional practices common within each instructional category. Results of these analyses provide a coherent picture of instructional strategies used in geoscience classrooms. Instruction in the most Student Centered classrooms differs from that in Transitional and Teacher Centered classrooms in at least one of three ways. Student Centered classes are more likely to include (1) students engaged in class activities with one another; (2) activities in which instructors assess student learning and adjust lessons accordingly; and (3) opportunities for students to answer and pose questions that determine the focus of a lesson.

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We compared 236 geoscience instructors' histories of professional development (PD) participation with classroom observations using the Reformed Teaching Observation Protocol (RTOP) that describe undergraduate classes as Student-Centered (score ≥ 50), Transitional (score 31-49) or Teacher-Centered (score ≤ 30). Instructors who attended PD (n = 111) have higher average RTOP scores (44.5 vs. 34.2) and are more frequently observed teaching Student-Centered classes (33% vs. 13%) than instructors with no PD (p < 0.001). Instructors who attended PD that is topically-aligned with content taught during the classroom observation are likely to have RTOP scores that are higher by 13.5 points (p < 0.0001), and are 5.6 times more likely to teach a Student-Centered class than instructors without topically-aligned PD. Comparable odds of teaching Student-Centered classes (5.8x) occur for instructors who attended two topical PD events but were observed teaching a different topic. Models suggest that instructors with at least 24 h of PD are significantly more likely to teach a Student-Centered class than instructors with fewer hours. Our results highlight the effectiveness of disciplinespecific PD in impacting teaching practices, and the importance of attending more than one such PD event to aid transfer of learning.

The 1998 eruption of Volcµn Cerro Azul in the Galµpagos Islands produced two intra-caldera vents and a flank vent that erupted more than 1.010 8 m 3 of lava. Lava compositions changed notably during the 5-week eruption, and contemporaneous eruptions in the caldera and on the flank produced different compositions. Lavas erupted from the flank vent range from 6.3 to 14.1% MgO, nearly the entire range of MgO contents previously reported from the volcano. On-site monitoring of eruptive activity is linked with petrogenetic processes such that geochemical variations are evaluated in a temporal context. Lavas from the 1998 eruption record two petrogenetic stages characterized by progressively more mafic lavas as the eruption proceeded. Crystal compositions, whole rock major and trace element compositions, and isotope ratios indicate that early lavas are the product of mixing between 1998 magma and remnant magma of the 1979 eruption. Intra-caldera lavas and later lavas have no 1979 signature, but were produced by the 1998 magma incorporating olivine and clinopyroxene xenocrysts. Thus, early magma petrogenesis is characterized by mixing with the 1979 magma, followed by the magma progressively entraining wehrlite cumulate mush.