Anne E. Egger

Rise and Fall of Late Pleistocene Pluvial Lakes in Response to Reduced Evaporation and Precipitation: Evidence from Lake Surprise, California

Widespread late Pleistocene lake systems of the Basin and Range Province indicate substantially greater moisture availability during glacial periods relative to modern times, but the climatic factors that drive changes in lake levels are poorly constrained. To better constrain these climatic forcing factors, we present a new lacustrine paleoclimate record and precipitation estimates for Lake Surprise, a closed basin lake in northeastern California. We combine a detailed analysis of lake hydrography and constitutive relationships describing the water balance to determine the influence of precipitation, evaporation, temperature, and seasonal insolation on past lake levels. At its maximum extent, during the last deglaciation, Lake Surprise covered 1366 km 2 (36%) of the terminally draining Surprise Valley watershed. Using paired radiocarbon and 230 Th-U analyses, we dated shoreline tufa deposits from wave-cut lake terraces in Surprise Valley, California, to determine the hydrography of the most recent lake cycle. This new lake hydrograph places the highest lake level 176 m above the present-day playa at 15.19 ± 0.18 calibrated ka ( 14 C age). This significantly postdates the Last Glacial Maximum (LGM), when Lake Surprise stood at only moderate levels, 65–99 m above modern playa, similar to nearby Lake Lahontan. To evaluate the climatic factors associated with lake-level changes, we use an oxygen isotope mass balance model combined with an analysis of predictions from the Paleoclimate Model Intercomparison Project 3 (PMIP3) climate model ensemble. Our isotope mass balance model predicts minimal precipitation increases of only 2%–18% during the LGM relative to modern, compared to an ∼75% increase in precipitation during the 15.19 ka highstand. LGM PMIP3 climate model simulations corroborate these findings, simulating an average precipitation increase of only 6.5% relative to modern, accompanied by a 28% decrease in total evaporation driven by a 7 °C decrease in mean annual temperature. LGM PMIP3 climate model simulations also suggest a seasonal decoupling of runoff and precipitation, with peak runoff shifting to the late spring–early summer from the late winter–early spring. Our coupled analyses suggest that moderate lake levels during the LGM were a result of reduced evaporation driven by reduced summer insolation and temperatures, not by increased precipitation. Reduced evaporation primed Basin and Range lake systems, particularly smaller, isolated basins such as Surprise Valley, to respond rapidly to increased precipitation during late-Heinrich Stadial 1 (HS1). Post-LGM highstands were potentially driven by increased rainfall during HS1 brought by latitudinally extensive and strengthened midlatitude westerly storm tracks, the effects of which are recorded in the region9s lacustrine and glacial records. These results suggest that seasonal insolation and reduced temperatures have been underinvestigated as long-term drivers of moisture availability in the western United States.

Hidden intrabasin extension: Evidence for dike-fault interaction from magnetic, gravity, and seismic reflection data in Surprise Valley, northeastern California

The relative contributions of tectonic and magmatic processes to continental rifting are highly variable. Magnetic, gravity, and seismic reflection data from Surprise Valley, California, in the northwest Basin and Range, reveal an intrabasin, fault-controlled, ∼10-m-thick dike at a depth of ∼150 m, providing an excellent example of the interplay between faulting and dike intrusion. The dike, likely a composite structure representing multiple successive intrusions, is inferred from modeling a positive magnetic anomaly that extends ∼35 km and parallels the basin-bounding Surprise Valley normal fault on the west side of the valley. A two-dimensional high-resolution seismic reflection profile acquired across the magnetic high images a normal fault dipping 56°E with ∼275 m of throw buried ∼60 m below the surface. Densely spaced gravity measurements reveal a

Engaging Students in Earthquakes via Real-Time Data and Decisions

Seismicity and Relative Risk, the IBI Prize–winning module, utilizes freely available earthquake data to help students apply their knowledge to risk-related decision-making. The topic of earthquakes appears in virtually all introductory undergraduate geoscience courses. Most students entering these courses already have some knowledge of earthquakes and why they occur, but that knowledge often derives from the most recent event in the news and can therefore be biased toward the most destructive earthquakes (1). In addition, students arrive at college with misconceptions (2, 3), perhaps picked up from erroneous or poorly presented media coverage. These misconceptions can go unchecked or even be reinforced by introductory textbooks, most of which contain errors and oversimplifications about earthquake processes (3, 4).

A Guided Inquiry Approach to Learning the Geology of the U.S.

A guided inquiry exercise has been developed to help teach the geology of the U.S. This exercise is intended for use early in the school term when undergraduate students have little background knowledge of geology. Before beginning, students should be introduced to rock types and have a basic understanding of geologic time. This exercise uses three maps: the U.S. Geological Surveys “A Tapestry of Time and Terrain” and “Landforms of the Conterminous United States” maps, and a geologic map of the United States. Using these maps, groups of 3 to 5 students are asked to identify between 8 and 12 geologic provinces based on topography, the age of rocks, and rock types. Each student is given a blank outline map of the contiguous U.S. and each group is given a set of the three maps and colored pencils; as a group, students work to define regions in the U.S. with similar geology. A goal of 8 to 12 geologic provinces is given to help establish the level of detail being asked of students. One member of each group is asked to present their groups findings to the class, describing their geologic provinces and the reasoning behind their choices.

New research and new opportunities within geoscience and across STEM

Like many scientists, educators, and researchers, I belong to several professional organizations and receive several publications and emails from these organizations. Often, they pile up on my desk until I have a spare hour, and then I skim through them and set aside articles I want to read in more detail. One of the journals that piles up quickly is Science— as a weekly, it is hard to stay on top of, but I often flip through it while I am eating lunch. The issues of Science that hang out the longest on my desk are those that include the Education Forum, an approximately monthly section that was first published in 2006 and highlights “the science of education” (Alberts, 2009). Although the consideration of education research as a science may be obvious to readers of an education research journal such as this one, it was a big step for a premier scientific research journal. Articles in the Education Forum often address topics that are of particular interest to research-intensive readers, such as the merits of training research mentors (Pfund, Maidl Pribbenow, Branchaw, Miller Lauffer, & Handelsman, 2006) and evidence for the effectiveness of active-learning pedagogies (Miller, Pfund, Pribbenow, & Handelsman, 2008). The March 30, 2018, Education Forum article has been open on my desk for over a month now, with the compelling title “Anatomy of STEM Teaching in North American Universities” (Stains et al., 2018). The authors reported on the results of their observations of teaching in more than 2000 classes across the STEM disciplines at 25 institutions. They used the Classroom Observation Protocol for Undergraduate STEM (COPUS; Smith, Jones, Gilbert, & Wieman, 2013), in which observers record every two minutes what the instructor is doing and what the students are doing, choosing from defined behaviors for each. COPUS is a useful tool for describing what is going on in the classroom for several reasons: It does not rely on self-reporting by instructors or evaluations from students, it is straightforward to train observers, and it has a high interrater reliability, which allows for the kinds of large-scale comparisons made in this study. From the results of their 2008 observations in 709 courses (each course was observed multiple times), the authors defined instructional profiles based on combinations of four instructor behaviors and four student behaviors. Didactic profiles consist of 80% or more class time devoted to instructors lecturing and students listening. Interactive lecture profiles still focus on instructors lecturing, but include more time spent in group activities. Student-centered profiles spend a majority of class time in group work strategies that have emerged as effective pedagogical practices from discipline-based educational research (National Research Council, 2012, 2015). The authors then used these profiles to explore their results further based on class size, the physical layout of the classroom, the course level, and the STEM discipline of the course. Figure 1 shows the results of their study broken down by discipline. Observations in geology courses comprise a relatively small proportion of the total observations (6%, or about 120 observations), but there are some distinct differences between geology and the other disciplines. About 30% of observations in geology were student-centered, which is higher by 10% to 20% than all the other STEM disciplines except math. Slightly more than 50% of observations in geology were didactic, which is similar to biology and computer science and significantly less than chemistry, engineering, and physics. What does this mean for our discipline? It would be easy to look at that figure and say we are doing pretty well as a discipline at promoting student-centered, evidence-based pedagogies in our courses. That quick observation takes away some of the power of this study, however, which has both strengths and limitations that provide opportunities for our community in geoscience education and education research. The primary strength of this research, as in most large-scale studies, is the scope of the work across disciplines, universities, and course levels. As the authors

Calling all peer reviewers! Why and how to review for JGE

It is easy to say that this journal—and the scientific process itself—relies on peer review. The editors rely on the thoughtful and careful comments of reviewers with diverse expertise to make decisions about what becomes part of the literature, our record of scientific knowledge. Writing a meaningful and substantial peer review takes time and effort; it is a skill that can be improved with practice. And in the same way that teaching can solidify your understanding of a concept or skill, reviewing others’ manuscripts can improve your own writing and help you anticipate what reviewers might be looking for when you submit your next manuscript. Serving as a peer reviewer is part of our commitment as scientists and researchers, yet peer review is something few of us learned how to do along the way to getting a degree. The goal of this editorial is to provide both guidance and encouragement to potential reviewers. It builds on the overview of JGE’s peer review process provided by Petcovic, Stokes, and St. John (2017), and the excellent strategy for writing a strong peer review provided by Nicholas and Gordon (2011). My focus here is at the intersection of those two perspectives: why and how to be a strong reviewer for JGE.

Sustainability, the Next Generation Science Standards, and the Education of Future Teachers

ABSTRACT The Next Generation Science Standards (NGSS) emphasize how human activities affect the Earth and how Earth processes impact humans, placing the concept of sustainability within the Earth and Space Sciences. We ask: how prepared are future teachers to address sustainability and systems thinking as encoded in the NGSS? And how can geoscientists support them? Most future teachers receive their Earth Science preparation in a single introductory geoscience course, but the content and delivery methods of these courses are not well matched to the NGSS knowledge and skills they will teach. We implemented a nationwide survey in undergraduate courses that addressed sustainability to some extent in order to assess career interests, behaviors, and motivations. Matched pre- and postdata (n = 1,125) respondents were divided into three groups: those very likely (22%), those somewhat likely (22%), and those not likely (56%) to become teachers. The very likely group resembles the current STEM teacher workforce in gender but is more diverse than the current workforce and the population currently enrolled in teacher preparation programs. The very likely group has higher rates of sustainable behaviors, is motivated by family and friends more than other groups, and is more likely to envision using their knowledge about sustainability in their careers. However, their understanding of key concepts, such as systems thinking, is limited. We suggest that curricular materials that address sustainability through concepts in introductory geoscience courses, such as those presented here, provide a means of reaching this group and better preparing future teachers to teach the NGSS.