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Collection Description

The Department of Geological Sciences has a long-standing Senior Thesis research option for the B.S. Degree which involves a written thesis, and a public oral presentation done under the supervision of a faculty member. These independent research projects typically involve field work and laboratory analyses of samples, but can also include laboratory-based experimental projects, numerical modeling of geologic phenomena and literature reviews. Senior theses are kept in the permanent collection of the Malcolm A. Love Library on the SDSU campus.

Authors hold full copyright ownership of their original works. Please contact the repository manager at digital@sdsu.edu for any further questions.

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A microseismic approach to hurricane monitoring
Contemporary seismological studies are finding new applications of ground motion data. Tracking the location of tropical storms along the coast of seismic networks has been of particular interest to many scientists throughout the world. Using Earthscope (USArray), it is possible to gather a seismic array over the duration of a storm in order to draw conclusions about the magnitude and direction of a hurricane. Also, by studying the ground motion over the period of the storm, we can better understand the relationship between oceans, atmosphere and land. In 2014, Chen et al. found that microseisms generated by Hurricane Sandy exhibit coherent energy within 1 h time windows in the frequency band of 0.1 – 0.25 Hz, with correlated signals among seismic stations aligned with the hurricane center. We used the same method of cross-correlation among seismic stations in Southern California in order to track the more recent, category 5, Hurricane Patricia that affected Central Mexico in October 2015. The correlated signals we gathered are attributed to two seismic sources along separate azimuth, with one being the hurricane center and the other from the coastal region. The seismic sources from the coastal region are expected to move eastward, while we seek to find a second source from the hurricane center coming from the southeast. By limiting the correlated stations to meet various parameters of Hurricane Patricia’s magnitude and direction, the focus of this study was to confirm whether or not it is possible to track the hurricane center along its time-dependent path. Although many correlated station pairs satisfied the parameters we set based on the magnitude and location of the hurricane, our findings present alternative results in comparison to the paper we have replicated., San Diego State University
A note on the distribution of selected groups of upper cretaceous forminiferida and their value as environmental indicators
A comparison of the faunal characteristics of two foraminiferal assemblages from the Rosario Formation in Baja California suggests the following general criteria which may prove to be useful in the interpretation of Upper Cretaceous paleoenvironments: 1) specific groups of arenaceous foraminifers characterize relatively deep-water assemblages, 2) arenaceous foraminifers constitute the greatest percentage of tests in relatively deep-water as­semblages, 3) specimens of Bulimina are not abundant in relatively shallow-water assemblages, and 4) attached foraminifers are most abundant in relatively shallow-water faunas. Sixty species and subspecies of benthonic forminifera are recorded from the two faunules; only six were common to both faunules., San Diego State University
A paleomagnetic study of tertiary intrusives in western San Diego County, California
In western San Diego county there are three igneous bodies that had no previous paleomagnetic work done on them. Two intrude Eocene, flat-lying sediments, and all are assumed to be Tertiary. Between seven and eight oriented cores were collected from each body. Lithologies range from basaltic to dacitic. The samples were measured for their natural remanent magnetization and then magnetically cleaned and re-measured. The direction of magnetization at two of the sites yielded good groupings. One site yielded poor results, not grouping at all and had weak intensities. All displayed more easterly declinations (N30E) than expected and steeper inclinations than expected. A magnetic survey was also conducted over one of the sites- Scripps Dike just north of La Jolla. Modeling of the magnetic anomaly from this survey suggests the dike is nearly vertical and thickens with depth., San Diego State University
A petrographic study of quartzite conglomerate clasts found in cretaceous fore-arc basin sediments of the Vizcaino Peninsula, Baja California, Mexico
Turbidite deposits located in the Vizcaino Peninsula of Baja California Sur, Mexico, contain several conglomerate units of Mid Cretaceous to Early Paleocene age. They contain the detrital history of material eroded from, presumably, the Peninsular Ranges batholith and its supra-crustal cover to the east. Petrographic analysis of quartz-rich metasedimentary clasts collected from these conglomerates reveals that these cobbles are true quartz arenites (contain > 95% quartz grains) and meta-quartzites. The quartz grains are mostly silica cemented, but hematite and carbonate cements are abundant in some clasts. Individual contacts between framework grains vary between different cobbles ranging from tangential and concavoconvex to highly sutured near-triple-point contacts. Undeformed quartz arenite cobbles have preserved original well-rounded grain outlines typical of multi-cylce reworked sandstone with clearly visible quartz overgrowths. More deformed clasts exhibit various strain fabrics including highly tectonized shear-induced foliation. The main accessory minerals in the quartz arenites are rounded zircon and tourmaline grains. The texturally and compositionally supermature quartz arenite sandstone and meta-sandstones clasts must have been derived from a continental source. Potential sources for quartz-rich sediments occur in prebatholithic sedimentary rocks and farther east on the Mexican mainland. Some of the sedimentary clasts examined are arkosic sandstone with feldspar and lithic clasts in addition to quartz and appear to be more locally derived first cycle sediments. These clasts contain include biotite, chlorite, carbonate, epidote, clay, hematite, as well as zircon and tourmaline grains. Some clasts also contain reworked schist and chert lithics., San Diego State University
A river runs through it: GPR interpretations of the Silver Strand
The Silver Strand was examined using Ground Penetrating Radar (GPR) and satellite imagery, to locate paleochannels and correlate the channels with rivers discharging into San Diego Bay. The area is active tectonically, and several faults pass nearby and, if active recently, could result in a stratigraphic signature detectable by the GPR. The GPR survey was conducted using a MALA GX with 450 and 160 MHz antennas. The survey extended along the Silver Strand Bikeway for 1.9 km between Fiddler’s Cove Marina and Naval Amphibious Base Coronado. Several features were identified in the subsurface and interpreted paleochannels, with the southern-most system exhibiting signs of reactivation. While these paleochannels stretch across the Silver Strand, no clear connection can be drawn between these channels and the Otay River, the Sweetwater River, or Chollas Creek. Therefore, the paleochannels could have been formed by any of the rivers, or by tidal inlets, as the Silver Stand is a barrier system. Stratigraphic offsets and disturbances indicative of faults were not identified in the GPR data, suggesting that either the survey did not cross an active fault, or the fault did not rupture in the upper 4 m. Future work should include direct subsurface sampling and dating of paleochannel features., San Diego State University
A study investigating the understanding of earthquakes by primary teachers
Concept maps are a self-constructed, pictorial representation of an individual's or group's understanding of major concepts and relationships to important sub-concepts. This study was conducted with San Diego City School (SOCS) K-6 teachers and was designed to test their understanding of earthquakes through the use of concept maps. 60 teachers were asked to break up into mixed-grade level groups of their own choosing. 19 mixed grade level groups were formed ranging from 2 participants up to 6 per group. Groups were then provided instructions which directed them to construct concept maps using the major concept of Earthquakes and a specified list of key sub-concepts of sufficient range to provide a measure of the understanding of Earthquakes held by each group. The completed concept maps were analyzed for overall understanding and continuity, proper linkages between the major concept and the sub-concepts, multiple links between the major concept and sub-concepts, cross links between sub-concepts, and overall construction. The focus of this analysis was on correctness, patterns, and trends observed in the development of the concept maps. The results show that most groups possess an adequate, basic understanding of earthquake processes, but with several identifiable areas where additional focused professional development could help primary teachers reach a more sophisticated level of understanding. More technical sub-concepts such as strain and fault slip tended to be poorly understood by the teachers, demonstrated by the poor and discontinuous development of correctness in those links. Also, a vast majority of the groups were unable to develop multiple links and cross links, both of which demonstrate a deeper understanding of the relationship between the major and sub-concepts. Our results also show that concepts maps are a useful tool to assess the understanding of primary teachers of major geological concepts, and can be used to refine the direction and content of professional development institutes., San Diego State University
A study on the fire agate of coon hollow in the Mule Mountains, Riverside County, California
The first documented discovery of fire agate took place by C.E. Squires in 1945 or 1946 at Coon Hollow, California in the Oligocene volcanics of the Mule Mountains. The fire agate is found in veins and pockets of a porphyritic andesitic basalt and in an indurated unwelded tuff. The fire agate formed hydrothermally from hot waters saturated with colloidal silica and goethite which invaded cavitites in the volcanics and began to cool. As the solution lost silica through growth, it was periodically adjusted and restabilized when goethite pre-cipitated out of suspension. These solutions were replenished periodically and the cycle repeated, forming Schiller layers of goethite within chalcedony. These iridedescent layers of goethite cause the brililiant interefence colors seen as "fire". The patterns and color combinations are endless and 3 fire agate mines lie in. A series of X-ray diffraction tests were run to determine the iron oxide mineral species and an atomic absorption test to determine total iron oxide content. A petrographic analysis determined the iron oxide to be goethite., San Diego State University
A test of provenance linkage between volcanic clasts of the Upper Miocene Punchbowl Formation and the Jurassic Sidewinder volcanics
The Punchbowl Formation comprises upper Miocene strata outcropping at the Devil's Punchbowl County Park located in the northern San Gabriel Mountains just west of the San Andreas Fault. The Punchbowl Formation is approximately 1500 m thick and interpreted as a nonmarine fluvial deposit of conglomerate, sandstone and mudstone that accumulated in a pull apart basin that originated during an early phase of San Andreas motion (Coffee, 2015). The formation is divided into two members based on conglomerate clast composition. The lower member is dominated by plutonic and gneissic basement clasts, while the upper member contains a distinct component of volcanic clasts. The volcanic clasts include rhyolite, dacite, andesite, latite and trachyte (Barrows et al., 1985). Volcanic clasts in the upper member of the Punchbowl Formation are believed to have been derived entirely from the Jurassic age Sidewinder Volcanics in the Mojave Desert on the opposite side of the San Andreas Fault (Robinson and Woodburn, 1971; Stone et al., 2013). These areas have now been separated by ~100 km by right lateral displacement along the fault. The purpose of this project was to test the hypothesis that Punchbowl Formation volcanic clasts were derived from the Sidewinder Volcanics. Volcanic clasts from the upper member of the formation were collected for chemical analysis to compare with published data from the Sidewinder Volcanics. Sixteen representative samples of volcanic clasts were collected from the Punchbowl Formation and pressed pellets and fused disks prepared for X-ray fluorescence analysis. The results when plotted on a standard SiO2 versus total alkali diagram show that the Punchbowl clasts range in composition from rhyolites to dacites with a few trachydacites present as well. The major element chemistry of the Punchbowl clasts match pretty well with previously published data for the Sidewinder Volcanics supporting the provenance linkage suggested by prior workers. However, comparison of trace element data tells a different story suggesting significant differences between these two groups of rocks. Yttrium concentrations in particular are significantly higher in the Sidewinder Volcanics and there appear to be systematic differences in lanthanum and cerium as well. Since these trace elements are relatively immobile during rock alteration, this result calls into question the provenance linkage between the two groups of rocks. Additional work is required to resolve this question., San Diego State University
An educational website on the nature of volcanic eruptions
The website located at http://crew.sdsu.edu/aviNiolent.html/Introduction.html is an educational resource for high-school students grades 9-12. The website conforms to the theme-related pedagogy established by the California Science Framework for Public Schools. The "framework" stresses that science should be taught through the integration of concepts rather than through rote memorization of seemingly unrelated facts. Our website is to be used as a educational guide to the nature of volcanic eruptions. Concepts within the website are connected through the general theme of"explosivity". The chemical controls on the explosive potential of eruptions are briefly described in the introductory home page. The website is then subdivided into two parallel topics based on the explosive potential of volcanism: "Violent Eruptions" and ''Non-Violent Eruptions". We describe each of these eruption types in a parallel fashion with links to the same subcategories: (1) eruptive styles, (2) magma types, (3) volcano morphology, and (4) the effects on humans. Within this context, the contrasting features and processes associated with each eruption type can be easily recognized. The website concludes with a link for the reader to test his/her knowledge on violent and non-violent volcanism. The website uses integrated concepts to provide the reader with an educational environment conducive to learning at the high school level. One of our goals was to make the website interactive and fun, as well as educational. Testing of the website demonstrates that our overall goals were met. The individuals tested found the site to be interesting, fun, and educational. They were also able to follow the general theme of the website and recall the basic ideas and concepts., San Diego State University
Analysis and comparison of Cold Water Springs - Cuyamaca Rancho State Park
Cuyamaca Rancho State Park, located roughly forty miles East of San Diego, houses a multitude of different springs and different springs systems contributing to the San Diego Watershed, which offers the opportunity for study on groundwater recharge and discharge. With the availability of past research done in the area supplied by past Geology students of SDSU, there is then the ability to do spring analysis comparisons in order to asses how groundwater chemistry, recharge, discharge, rock- water interactions, and path lengths have changed over time. The scope of this study covers six springs, one culvert, and one sample of snow melt, with five of the six springs and the culvert having been researched in a previous thesis. The samples were collected during mid February 2013 until March 2013, in which temperature, conductivity, and discharge were all taken on site and geochemical data was accumulated in a lab setting at USGS at a later time. Water quality comparisons were then made, aided by pH, alkalinity, and knowledge of mineral weathering, as well as comparisons between the current spring samples and those of the past thesis [Higley, 1976], in which trends were examined between the current samples and also with those of the past. This was a joint research project, with the coauthor focusing on the analysis of the major ion concentrations of the water samples., San Diego State University
Analysis of anionic contribution to total dissolved solids in the lower San Diego River
The Lower San Diego River has been severely impacted by several anthropogenic sources. Specific water quality objectives are set in the San Diego Basin Plan for this reach of the river and many of these objectives are not being met. Research included in this report will test 17 sites in the Lower San Diego River Watershed for sulfate, bicarbonate, carbonate, and chloride ion concentrations and analyze their relationship to the observed specific conductivity values over a nine-month period. It was found that chloride is the dominant ion in the region and exceeds the water quality objectives set by the water quality control board at most sites over the study period. This report provides details not previously known on the contribution of anions to the high conductivity observed in the river. Spatial and temporal trends are identified. Correlation equations are obtained to estimate chloride, sulfate, or bicarbonate from specific conductance. The data in this report also lends insight into potentially natural occurring background levels of ions and locations of possible concentrated inputs into the river., San Diego State University