Steven Semken

The formation of the intra-Carpathian basins as determined from subsidence data

The Carpathian arc is the result of continental collision during subduction of the European plate beneath a Pannonian continental block. In the Early/Middle Miocene, during and after the last stages of thrusting in the Outer Carpathians, several “back-arc” basins started to form within the Carpathian loop. These basins are of two types: (1) those lying in the peripheral regions of the intra-Carpathian lowlands (Vienna, West Danube, Transcarpathian and Transylvanian), and (2) those lying in the central intra-Carpathian region (East Danube, Little Hungarian and Great Hungarian (Pannonian)). Though both groups of basins have thin crust, the subsidence history and the present heat flow are different. The peripheral basins exhibit a rapid initial subsidence followed by a much slower general increase in depth. Their heat flow is close to the average for continental areas. In contrast the central basins have no initial subsidence but do show a fast linear increase in depth which has continued until the present. The heat flow is nearly twice the average for continents. We believe that the basins are thermal in origin and are the direct result of the continental collision which formed the Carpathian arc. The peripheral basins appear to be the result of uniform stretching of the lithosphere by about a factor of two. The rapid initial subsidence is an immediate isostatic adjustment to the stretching, the slower linear subsidence is due to conductive cooling of the thinned lithosphere. In the central basins, uniform stretching by about a factor of 3 could explain the thermal subsidence and the high heat flow. Unfortunately such a simple explanation is not supported by either the geology or the absence of a clearly defined initial subsidence. Alternative explanation involve crustal stretching with additional subcrustal thinning or, alternatively, attenuation of the whole subcrustal lithosphere and part of the crust by melting and erosion. Both explanations create a very thin lithosphere, reduce the initial subsidence to a minimum but still give a rapid thermal subsidence and high heat flow. The subsidence history gives quantitative information concerning the evolution of the inter-Carpathian basins. In other areas, it may place equally important constraints on the development of intercontinental basins and continental shelves.

Sense of Place and Place-Based Introductory Geoscience Teaching for American Indian and Alaska Native Undergraduates

Places are localities given meaning by human experiences in them. Sense of place refers to a set of meanings of and attachments to places that are held by individuals or by groups. The cultures and educational philosophies of American Indian and Alaska Native peoples reflect rich senses of the places that make up their traditional homelands. However, sense of place does not manifest itself in proportionate enrollments in undergraduate geoscience by American Indians and Alaska Natives. This is because mainstream geoscience teaching emphasizes global syntheses over exploration and in-depth understanding of places that have prior meaning for Indigenous students, and may even depict such places in culturally-inappropriate ways. Many teachers and researchers with experience in Native educational systems recommend a greater emphasis on the study of local places, synthesis of local cultural knowledge, and community-directed activities in science education. Such a “place-based” approach is used by a small number of school systems, nearly all outside of Native communities. Place-based geoscience teaching could potentially enhance science literacy among American Indian, Alaska Native, and other underrepresented minority students, and bring more of them into the geoscience profession. However, this hypothesis has not yet been rigorously tested. Empirical and descriptive studies of place attachment and meaning among different student populations, and clearer definition of place-based teaching, are prerequisite to more authentic place-based geoscience courses and programs. Five characteristics of place-based geoscience teaching are identified here and illustrated with suggestions for implementation in diverse educational settings.

Navajo pedagogy and earth systems

The Navajo interpretation of nature attributes geological change and equilibrium, and the sustainability of life in the surface environment, to dynamic processes of renewal driven by interactions b...

Implications of Sense of Place and Place-Based Education for Ecological Integrity and Cultural Sustainability in Diverse Places

Emotional and intellectual estrangement – or even the outright eviction – of people from places personally and culturally important to them is rampant in this time of anthropic sprawl, economic globalization, and cultural homogenization. Placelessness (Relph 1976) unmoors individuals, often with detrimental effects to self-identity and well-being. Mass displacement, typically to suit the economic or political purposes of others, removes aboriginal or historically resident populations, each of which possesses a diachronic collective memory of local environmental processes and cycles, hard-won expertise in how to dwell sustainably in a place, and usually the most vested interest in preserving that place. Contested places are the loci of past, ongoing, and potential future conflicts and displacements, which threaten ecological integrity (Nabhan 1997) and cultural sustainability (Cernea 2000) around the globe.

Informal geoscience education on a grand scale: the Trail of Time exhibition at Grand Canyon

The Trail of Time exhibition under construction at Grand Canyon National Park is the worlds largest geoscience exhibition at one of the worlds grandest geologic landscapes. It is a 2-km-long interpretive walking timeline trail that leverages Grand Canyon vistas and rocks to guide visitors to ponder, explore, and understand the magnitude of geologic time and the stories encoded by Grand Canyon rock layers and landscapes. As one of a new generation of geoscience education exhibits, the Trail of Time targets multiple cognitive and affective levels with accurate content, active geoscience inquiry and interpretation, and place-based cultural integration. It developed as an outgrowth of sustained geoscience research funded by the National Science Foundation, with scientists as the conceivers and coordinators of the project. It benefits from a high level of synergy with the National Park Service interpretation division, as well as extensive on-site and off-site evaluation of pedagogic effectiveness in the outdoor informal science environment. The Trail of Time will impact many of the five million annual visitors to the National Park. Associated cognitive research on public understanding of “deep time” offers opportunities to inform more effective geoscience pedagogy for informal and formal educational settings.

Teaching Geoscience in the Context of Culture and Place

[Our world] is highly diverse in almost all senses—physical, biological, and cultural—and although this produces problems for society and even conflicts and war, would we really want a less diverse and interesting home?...The broad diversity of places, materials, living things, experiences and peoples not only makes the world a more useful and interesting place, but probably also stimulates creativity and progress in a wide range of ways. (Gray, 2013, p. 4–5).

Integrating undergraduate education and scientific discovery through field research in igneous petrology

We recast a standard igneous petrology course at Fort Lewis College into a field-based, inquiry-driven research course focused on a specific field area, in this case the Tertiary volcanic complex at Ship Rock, Navajo Nation, New Mexico. The main goal was to allow undergraduate students an opportunity to use field work to investigate advanced topics in igneous petrology while engaging in scientific research and developing important skills that are needed for all careers in science. Constructing research projects around this class enabled students to learn science by doing it, and to carry enthusiasm for research into further studies. This also better served the needs of the Geoscience program at Fort Lewis College by further developing skills for critical analysis and inquiry, and building on content taught in the introductory petrology course.

Hands-On Geology for Navajo Nation Teachers

The Navajo Nation comprises the largest land area and the largest population of any Native American community in the United States, and it hosts some of Earths most spectacular geology. Geologic resources and environmental concerns have figured prominently in the Navajo Nations recent history and economy. Despite the traditional cultural ties of the Dine (Navajo) people to their land, and the natural curiosity of most K-12 students about the earth, geoscience courses are virtually absent from curricula in Navajo Nation public schools. Many native-born teachers are familiar with the landscape and its cultural geography, but few have received formal training in geology and are not comfortable introducing it into their classrooms. A collaborative project between the U.S. Geological Survey and Navajo Community College has addressed this issue on a local scale by developing a classroom and field- intensive one-week summer course for Navajo Nation teachers with no previous geologic experience. The course intr...

The Design of Place-Based, Culturally Informed Geoscience Assessment

ABSTRACT We present a mixed-methods approach to community-based assessment design that engages tribal college and university faculty, students, and science educators, as well as experts in cultural knowledge from the Blackfeet and Diné (Navajo) nations. Information from cultural experts, gathered through a combination of sequential surveys and focus group sessions, was analyzed to identify important themes with regard to assessment and geoscience content within the context of these communities. While experts use a variety of assessment approaches in their classrooms, only pre- and posttesting and portfolios were found to be most valuable. Experts indicated that the primary role of assessment was to monitor student progress, steer instruction, and prepare students for success; thus, assessment should be tied to the course goals. Experts differed on their views regarding sources of bias in testing, but overall they agreed that test language and content were both strong sources of bias. They indicated that input on assessment would help to incorporate local context and provide a mechanism for combating bias. Surveys completed by tribal college faculty and Native American students from Blackfeet Community College (BCC) and Arizona State University (ASU) provided information on the themes of geoscience, native science, place, and culture. Participants provided a variety of examples of important geoscience concepts that focused on (1) traditional geoscience concepts (e.g., the composition of Earth materials), (2) Earth system concepts (e.g., the environment and ecosystems), and (3) interactions between native culture and geoscience (e.g., incorporation of native language in science curriculum). Combined, these data offer the basis for developing place-based and culturally informed geoscience assessments by revealing geoscience content that is important to the local community. To aid in assessment design, one-on-one interviews with tribal college faculty and science educators, as well as students from BCC and ASU, provided specific feedback on the question validity of select items from an existing instrument: the Geoscience Concept Inventory (GCI). Emergent themes from the interview transcripts address assessment content, language, and format and reference school science, cultural knowledge, physical places, and connections to the local landscape (e.g., sense of place). Together, these data (1) address the validity of the GCI as a standardized assessment measure in these student populations and (2) provide the basis for developing open-ended assessment questions and concept inventory–like questions that incorporate this feedback.

Place-Based Education in Geoscience: Theory, Research, Practice, and Assessment

ABSTRACT Place-based education (PBE) is a situated, context-rich, transdisciplinary teaching and learning modality distinguished by its unequivocal relationship to place, which is any locality that people have imbued with meanings and personal attachments through actual or vicarious experiences. As an observational and historical science, geoscience is highly dependent on place, and place-based curricula and instructional methods apply to geoscience education. The sense of place operationalizes the human connection to place and functions as a definable and measurable learning outcome for PBE. Although PBE is rooted in historic and indigenous teaching philosophies, it has gained particular notice and traction in concert with more recent interest in environmental education, sustainability, and diversity in geoscience. This paper presents a current review of theory and research methods that have directly informed development of curriculum and instruction in, authentic assessment of, and implementation of PBE in geoscience sensu lato (Earth-system and environmental sciences); a survey of place-based teaching in geoscience currently or recently practiced across different grade levels and situated in different places, regions, and cultures; information about teaching and assessment methods for those who may be interested in adopting the place-based modality; and suggested future directions for research, practice, and assessment in PBE in geoscience.