Pumice and volcanic samples were collected across southern Guatemala to correlate to the known st... more Pumice and volcanic samples were collected across southern Guatemala to correlate to the known stratigraphy. Unit correlation was required to constrain timing of faulting in these area. Samples were cleaned and sent to GeoAnalytical lab at Washington State University for XRF analysis.
Recent structural and geodetic data define the Guatemala City graben region as the continental tr... more Recent structural and geodetic data define the Guatemala City graben region as the continental triple junction between the North American plate, Caribbean plate, and the Central American Forearc sliver. We present minor fault analysis, geochronological and geochemical analyses, and newly updated GPS velocities in western Guatemala, west of the Guatemala City graben, to characterize the magnitude and timing of extensional deformation in this poorly understood area. Elongations estimated from fault data are parallel (∼east‐west) and perpendicular to the Polochic‐Motagua fault system to the north, similar to geodetically measured active deformation observed east of the Guatemala City graben. Four new 40Ar/39Ar dates and correlation of tephra deposits suggest that faulting was active during the Pliocene, but ceased eastward toward the Guatemala City graben over time. From west to east, fault cessation occurred before the deposition of the Los Chocoyos ash (75 ka) and E tephra (51 ka). Faulting just west of the Guatemala City graben appears to be active, where a major fault cuts the most recent Amatitlán tephras. Based on this data, we propose a time‐progressive strain model for deformation related to North America‐Caribbean plate interactions, whereby distributed elongation of the westernmost Caribbean plate occurred during the Pliocene but localized mostly within the Guatemala City graben and nearby faults during the Pleistocene. Our model supports that: (a) The Guatemala City graben is effectively the western limit of the Caribbean plate; and (b) Western Guatemala, which was the trailing edge of the Caribbean plate, has been transferred to the forearc region.
The Jalpatagua fault in Guatemala accommodates dextral movement of the Central America forearc. W... more The Jalpatagua fault in Guatemala accommodates dextral movement of the Central America forearc. We present new global positioning system (GPS) data, minor fault analysis, geochronological analyses, and analysis of lineaments to characterize deformation along the fault and near its terminations. Our data indicate that the Jalpatagua fault terminates at both ends into extensional regions. The western termination occurs near the Amatitlan caldera and the southern extension of the Guatemala City graben, as no through-going structures were observed to continue west into the active volcanic arc. Along the Jalpatagua fault, new and updated GPS site velocities are consistent with a slip rate of 7.1 ± 1.8 mm yr−1. Minor faulting along the central section of the fault includes: (1) N-S–striking normal faults accommodating E-W elongation; and (2) four sets of strike-slip faults (oriented 330°, 020°, 055°, and 295°, parallel to the Jalpatagua fault trace). Minor fault arrays support dextral mov...
Sketching is a valuable but underutilized tool for science education. Sketch worksheets were deve... more Sketching is a valuable but underutilized tool for science education. Sketch worksheets were developed to help change this, by using artificial intelligence technology to give students immediate feedback and to give instructors assistance in grading. Sketch worksheets use automatically computed visual representations combined with conceptual information to give feedback to students, by computing analogies between students’ sketches and an instructor’s solution sketch. This enables domain experts to develop sketch worksheets, to facilitate dissemination. We describe our experiences in deploying them in geoscience and artificial intelligence classes. The geoscience worksheets, authored by geoscientists at University of Wisconsin–Madison, were used at both Wisconsin and Northwestern University. The artificial intelligence worksheets were developed and used at Northwestern. Our experience indicates that sketch worksheets can provide helpful on-the-spot feedback to students, and signific...
Abstract Characterizing spatial thinking and the development of spatial expertise is essential to... more Abstract Characterizing spatial thinking and the development of spatial expertise is essential to understanding how to train geoscientists to succeed in both academia and industry. The Spatial Intelligence and Learning Center has supported an eight-year-long collaborative research program, which brings together disciplinary expertise in cognitive science and geology to characterize and develop spatial thinking in the geological sciences. To facilitate our understanding of science education and practice, we have characterized the spatial skills of geoscience discipline experts and the spatial thinking impediments experienced by students studying the geological sciences. In this chapter we review recent research on measuring and improving spatial thinking skills in the geosciences and on characterizing individual differences in spatial thinking, including the role of gender and age. We conclude with a discussion of important unanswered questions and some directions for future research. The research discussed here may help guide the development of best practices for spatial thinking training in both academic and industry settings.
Pumice and volcanic samples were collected across southern Guatemala to correlate to the known st... more Pumice and volcanic samples were collected across southern Guatemala to correlate to the known stratigraphy. Unit correlation was required to constrain timing of faulting in these area. Samples were cleaned and sent to GeoAnalytical lab at Washington State University for XRF analysis.
Recent structural and geodetic data define the Guatemala City graben region as the continental tr... more Recent structural and geodetic data define the Guatemala City graben region as the continental triple junction between the North American plate, Caribbean plate, and the Central American Forearc sliver. We present minor fault analysis, geochronological and geochemical analyses, and newly updated GPS velocities in western Guatemala, west of the Guatemala City graben, to characterize the magnitude and timing of extensional deformation in this poorly understood area. Elongations estimated from fault data are parallel (∼east‐west) and perpendicular to the Polochic‐Motagua fault system to the north, similar to geodetically measured active deformation observed east of the Guatemala City graben. Four new 40Ar/39Ar dates and correlation of tephra deposits suggest that faulting was active during the Pliocene, but ceased eastward toward the Guatemala City graben over time. From west to east, fault cessation occurred before the deposition of the Los Chocoyos ash (75 ka) and E tephra (51 ka). Faulting just west of the Guatemala City graben appears to be active, where a major fault cuts the most recent Amatitlán tephras. Based on this data, we propose a time‐progressive strain model for deformation related to North America‐Caribbean plate interactions, whereby distributed elongation of the westernmost Caribbean plate occurred during the Pliocene but localized mostly within the Guatemala City graben and nearby faults during the Pleistocene. Our model supports that: (a) The Guatemala City graben is effectively the western limit of the Caribbean plate; and (b) Western Guatemala, which was the trailing edge of the Caribbean plate, has been transferred to the forearc region.
The Jalpatagua fault in Guatemala accommodates dextral movement of the Central America forearc. W... more The Jalpatagua fault in Guatemala accommodates dextral movement of the Central America forearc. We present new global positioning system (GPS) data, minor fault analysis, geochronological analyses, and analysis of lineaments to characterize deformation along the fault and near its terminations. Our data indicate that the Jalpatagua fault terminates at both ends into extensional regions. The western termination occurs near the Amatitlan caldera and the southern extension of the Guatemala City graben, as no through-going structures were observed to continue west into the active volcanic arc. Along the Jalpatagua fault, new and updated GPS site velocities are consistent with a slip rate of 7.1 ± 1.8 mm yr−1. Minor faulting along the central section of the fault includes: (1) N-S–striking normal faults accommodating E-W elongation; and (2) four sets of strike-slip faults (oriented 330°, 020°, 055°, and 295°, parallel to the Jalpatagua fault trace). Minor fault arrays support dextral mov...
Sketching is a valuable but underutilized tool for science education. Sketch worksheets were deve... more Sketching is a valuable but underutilized tool for science education. Sketch worksheets were developed to help change this, by using artificial intelligence technology to give students immediate feedback and to give instructors assistance in grading. Sketch worksheets use automatically computed visual representations combined with conceptual information to give feedback to students, by computing analogies between students’ sketches and an instructor’s solution sketch. This enables domain experts to develop sketch worksheets, to facilitate dissemination. We describe our experiences in deploying them in geoscience and artificial intelligence classes. The geoscience worksheets, authored by geoscientists at University of Wisconsin–Madison, were used at both Wisconsin and Northwestern University. The artificial intelligence worksheets were developed and used at Northwestern. Our experience indicates that sketch worksheets can provide helpful on-the-spot feedback to students, and signific...
Abstract Characterizing spatial thinking and the development of spatial expertise is essential to... more Abstract Characterizing spatial thinking and the development of spatial expertise is essential to understanding how to train geoscientists to succeed in both academia and industry. The Spatial Intelligence and Learning Center has supported an eight-year-long collaborative research program, which brings together disciplinary expertise in cognitive science and geology to characterize and develop spatial thinking in the geological sciences. To facilitate our understanding of science education and practice, we have characterized the spatial skills of geoscience discipline experts and the spatial thinking impediments experienced by students studying the geological sciences. In this chapter we review recent research on measuring and improving spatial thinking skills in the geosciences and on characterizing individual differences in spatial thinking, including the role of gender and age. We conclude with a discussion of important unanswered questions and some directions for future research. The research discussed here may help guide the development of best practices for spatial thinking training in both academic and industry settings.
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