Calcareous nannofossil from the hemipelagic lower Ypresian Arnakatxa section (Basque-Cantabrian basin, western Pyrenees)
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| Format: | Dataset Open Access |
| Langue: | en |
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PANGAEA
2022
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| _version_ | 1867168215575035904 |
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| author | Martínez-Braceras, Naroa Franceschetti, Gloria Payros, Aitor Monechi, Simonetta Dinarès-Turell, Jaume |
| author_facet | Martínez-Braceras, Naroa Franceschetti, Gloria Payros, Aitor Monechi, Simonetta Dinarès-Turell, Jaume |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Here we present calcareus nannofossil and colour datasets from the hemipelagic lower Ypresian Arnakatxa section (Basque-Cantabrian basin, western Pyrenees). The Arnakatxa coastal cliffs, which constitute the present study area, are located approximately 15 km northwest of Bilbao (43°23'34.4N, 2°59'24.2W, altitude 0 m). The expanded hemiplegic succession offered a potentially valuable orbitally paced geological record. Sampling was carried out in 2015. For the study of calcareous nannofossils 65 hand samples were collected (average spacing of about 50 cm). For colour analysis, 635 rock-powder samples were collected (average resolution of ~5 cm) using a standard cordless drill with an 8 mm bit. Slides for nannofloral analysis were prepared according to Flores and Sierro (1997), avoiding any mechanical or physical disturbance of the samples that could modify the original fossil assemblages. A Zeiss Axioplan2 petrographic microscope at 1250× magnification was used to analyze the samples. Quantitative analysis was performed by counting at least 300 specimens per sample. Additionally, three random traverses (~9 mm2) were analyzed on each slide in order to detect rare but biostratigraphically significant species. The rock powder samples were stored in transparent antiglare prismatic plastic vials (3 ml) and scanned at high-resolution (600 dpi) using a desktop office scanner in a dark room. The average colour value of a homogeneous rectangular area covering 10-20% of the scanned image of each vial was measured using ImageJ software version 1.50i. Average colour value represents to the mean pixel RGB value of the selected area, which is equivalent to the brightness value. In order to perform a cyclostratigraphic analysis, the colour data series was linearly interpolated and the LOESS regression trend subtracted. The Astrochron code commands used to perform that spectral analysis are herein available. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_943590 |
| institution | PANGAEA |
| language | en |
| publishDate | 2022 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Calcareous nannofossil from the hemipelagic lower Ypresian Arnakatxa section (Basque-Cantabrian basin, western Pyrenees) Martínez-Braceras, Naroa Franceschetti, Gloria Payros, Aitor Monechi, Simonetta Dinarès-Turell, Jaume Arnakatxa_coastal_cliffs; astronomical tuning; Basque-Cantabria basin; Biantholithus spp.; Biscutum spp.; Braarudosphaera spp.; Calcareous nannofossils; Chiasmolithus bidens; Chiasmolithus consuetus; Chiasmolithus solitus; Chiasmolithus spp.; Coccolithus pelagicus; colour; Cruciplacolithus spp.; Cyclostratigraphy; Discoaster barbadiensis; Discoaster diastypus; Discoaster mohleri; Discoaster multiradiatus; Discoaster nobilis; Discoaster salisburgensis; Discoaster spp.; Ellipsolithus spp.; Ericsonia spp.; Fasciculithus tympaniformis; Individuals; Light microscope; Markalius spp.; Rhomboaster bramlettei; Rhomboaster contortus; Sample code/label; SECTION, height; Sphenolithus anarrhopus; Sphenolithus moriformis; Sphenolithus radians; Thoracosphaera spp.; Toweius eminens; Toweius pertusus; Tribrachiatus orthostylus; Ypresian; Zygrhablithus bijugatus Here we present calcareus nannofossil and colour datasets from the hemipelagic lower Ypresian Arnakatxa section (Basque-Cantabrian basin, western Pyrenees). The Arnakatxa coastal cliffs, which constitute the present study area, are located approximately 15 km northwest of Bilbao (43°23'34.4N, 2°59'24.2W, altitude 0 m). The expanded hemiplegic succession offered a potentially valuable orbitally paced geological record. Sampling was carried out in 2015. For the study of calcareous nannofossils 65 hand samples were collected (average spacing of about 50 cm). For colour analysis, 635 rock-powder samples were collected (average resolution of ~5 cm) using a standard cordless drill with an 8 mm bit. Slides for nannofloral analysis were prepared according to Flores and Sierro (1997), avoiding any mechanical or physical disturbance of the samples that could modify the original fossil assemblages. A Zeiss Axioplan2 petrographic microscope at 1250× magnification was used to analyze the samples. Quantitative analysis was performed by counting at least 300 specimens per sample. Additionally, three random traverses (~9 mm2) were analyzed on each slide in order to detect rare but biostratigraphically significant species. The rock powder samples were stored in transparent antiglare prismatic plastic vials (3 ml) and scanned at high-resolution (600 dpi) using a desktop office scanner in a dark room. The average colour value of a homogeneous rectangular area covering 10-20% of the scanned image of each vial was measured using ImageJ software version 1.50i. Average colour value represents to the mean pixel RGB value of the selected area, which is equivalent to the brightness value. In order to perform a cyclostratigraphic analysis, the colour data series was linearly interpolated and the LOESS regression trend subtracted. The Astrochron code commands used to perform that spectral analysis are herein available. |
| title | Calcareous nannofossil from the hemipelagic lower Ypresian Arnakatxa section (Basque-Cantabrian basin, western Pyrenees) |
| topic | Arnakatxa_coastal_cliffs; astronomical tuning; Basque-Cantabria basin; Biantholithus spp.; Biscutum spp.; Braarudosphaera spp.; Calcareous nannofossils; Chiasmolithus bidens; Chiasmolithus consuetus; Chiasmolithus solitus; Chiasmolithus spp.; Coccolithus pelagicus; colour; Cruciplacolithus spp.; Cyclostratigraphy; Discoaster barbadiensis; Discoaster diastypus; Discoaster mohleri; Discoaster multiradiatus; Discoaster nobilis; Discoaster salisburgensis; Discoaster spp.; Ellipsolithus spp.; Ericsonia spp.; Fasciculithus tympaniformis; Individuals; Light microscope; Markalius spp.; Rhomboaster bramlettei; Rhomboaster contortus; Sample code/label; SECTION, height; Sphenolithus anarrhopus; Sphenolithus moriformis; Sphenolithus radians; Thoracosphaera spp.; Toweius eminens; Toweius pertusus; Tribrachiatus orthostylus; Ypresian; Zygrhablithus bijugatus |
| url | https://doi.org/10.1594/PANGAEA.943590 |