PRELIMINARY GEOCHEMICAL AND MINERALOGICAL ASSESSMENT OF THE BEACH SAND, VIEQUES, PUERTO RICO
Bibliographic record
Abstract
PRELIMINARY GEOCHEMICAL AND MINERALOGICAL ASSESSMENT OF THE BEACH SAND, VIEQUES, PUERTO RICO ROBBINS, Kathy H., KHANDAKER, Nazrul, SINGH, Andrew, and MUNRO, Toralv, Geological Society of America Abstracts with Programs, Vol 54, No. 5, https://doi.org/10.1130/abs/2022AM-379886 ROBBINS, Kathy H., Bronx Early College Academy for Teaching and Learning, 250E 164 STREET, Bronx, NY 10456, KHANDAKER, Nazrul, Geology Discipline, York College of CUNY, 9420 Guy R Brewer Blvd, AC-2F09, Jamaica, NY 11451-0001, SINGH, Andrew, Earth and Physical Sciences, York College of CUNY, 9420 Guy R Brewer Blvd, AC-2F09, Jamaica, NY 11451-0001 and MUNRO, Toralv, 10911 164th St Apt 1, Jamaica, NY 11433-2921 Representative beach sand samples were collected from Vieques (18.095901948142554, -65.49229758368986; Puerto Rico) and chemically analyzed for provenance interpretation. Puerto Rico is the eastern-most island of the Greater Antilles, which is a group of islands in the Caribbean Sea that includes the countries of Cuba, Hispaniola (Haiti and the Dominican Republic), Jamaica, and the U.S. territory – the Commonwealth of Puerto Rico. Puerto Rico (and its outlying islands of Culebra and Vieques), along with the U.S and British Virgin Islands are the subaerial form of a microplate that exists at a seismically active plate boundary between the North American plate and the northeast margin of the Caribbean plate (United States Geological Survey Bulletin #1042-1, 1957). The Black Sand Beach is a short drive from the town of La Esperanza and it’s about a quarter of a mile long. Samples were collected from low-and high tide dominated areas. The most abundant heavy mineral in the beach sands of Puerto Rico is magnetite. It occurs on all shores of the island. Ilmenite is present, associated with the magnetite. The beach sands also contain minor amounts of chromite. The west and southwest shores, from Punta Guanajiba to Ponce, are composed of weathered rocks, mangrove swamps, and beaches composed of shell fragments. Heavy minerals are a major constituent of the beach sand in many places on the south coast and magnetite often constitutes more than 15 percent of the sand. The east coast, from the Rio Grande de Patillas to Naguabo, consists of outcropping volcanic and intrusive rocks of Cretaceous and early Tertiary age and sandy beaches. Rich concentrations of heavy minerals occur locally. Both bulk oxide (silica, alumina, soda, potash, magnesia, both ferrous and ferric oxide, calcium oxide, etc.) and trace elements (Ti, Zr, Y, Cr, Sr, Rb, Ce, La, etc.) analyses were performed on collected sands by using both X-ray Fluorescence (XRF) and Inductively coupled plasma mass spectrometry (ICP-MS). Based on geochemical discriminating factor, there seemed to be an affinity of most of the black sands with volcanic-sourced derivation. Ceaseless shoreline processes ultimately fractionated heavy mineral concentrations in black sands due to hydraulic sorting. Keywords: Beach Sand, Heavy Minerals, Geochemical Investigation, Provenance, Black Sand, Puerto Rico, Vieques Sunday, 9 October 2022: 9:00 AM-1:00 PM Exhibit Hall F (Colorado Convention Center)
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".