AR Solá

BM Eglington

D. Davis

KN Sircombe

M Chichorro

M. F. Pereira

S. A. Bowring

Lopes, C.

Ferreira, A.

Chichorro, Martim

Pereira, Manuel Francisco Costa

Almeida, J. A.

Solá, A. Rita

Repositório do LNEG

CHRONIBERIA : ongoing development of a geochronological GIS database of Iberia

Chichorro, Martím A.

Solá, Ana Rita

Laboratório Nacional de Energia e Geologia Repository

Pereira, M. Francisco

Chroniberia: The Ongoing Developmentof a Geochronological GIS Databaseof IberiaC. Lopes, A. Ferreira, M. Chichorro, M. F. Pereira, J. A. Almeidaand A. R SoláAbstract Geochronological comparisons of large datasets are facilitated by theuse of structured databases. This paper reports the ongoing development ofCHRONIBERIA, a geochronological GIS database that will provide access tozircon U–Pb age datasets from Iberia. The database will also integrate relevantdistinct datasets from other correlative regions around the world to construct aframework based on stratigraphic, sedimentological, and palaeogeographical data.Keywords Geochronology  Zircon U–Th–Pb  Database  GIS  IberiaA detailed and precise temporal framework is essential for exploring the richnessof the geological record (Bowring and Schmitz 2003). Zircon U–Th–Pb geo-chronology has been widely used to provide an exact measure of time (Davis et al.2003), which has give rise to large geochronological datasets. Geochronologicalcomparisons of such large datasets are facilitated by the use of structured dat-abases. Several distinct geochronological databases and database systems havebeen developed in the last decade, including: CHRONOBANK, a GIS-basedgeochronological database (Brazil, Silva et al. 2003); NGDB, the National Geo-chronological Database (USA, Silva et al. 2003); and OZCHRON (Australia,Sircombe 2006). DateView (a freeware desktop database system; Eglington 2004),the StratDB/IGCP509 initiative (a database system and web interface with links tothe geochronology database DateView; Eglington et al. 2009), and the EarthCheminitiative (http://www.earthchem.org/earthchemWeb/index.jsp) are all part of theC. Lopes  A. Ferreira  M. Chichorro (&)  J. A. AlmeidaCICEGe, Departamento de Ciências da Terra, Faculdade de Ciências e Tecnologia,Universidade Nova de Lisboa, 2829-516 Caparica, Portugale-mail: ma.chichorro@fct.unl.ptM. F. PereiraIDL, Departamento de Geociências, ECT, Universidade de Évora, Évora, PortugalA. R SoláUnidade de Geologia, Hidrogeologia e Geologia Costeira, LNEG, Lisbon, PortugalR. Rocha et al. (eds.), STRATI 2013, Springer Geology,DOI: 10.1007/978-3-319-04364-7_138,  Springer International Publishing Switzerland 2014733ma.chichorro@fct.unl.ptmost recent developments to construct an international database system. Thesedatabases use GIS tools to improve spatial analysis, to generate maps, and tointegrate distinct data set (Silva et al. 2003; Eglington 2004). To understand thegeological history of the Gondwana supercontinent and related peripheral mag-matic arcs (the Avalonia and Cadomian terranes), a geochronological GIS data-base of Iberia (CHRONIBERIA), based on the zircon contents of rocks fromIberia, has been created.Design of the Geochronological DatabaseIn the conception of the database, the following main issues were considered: thenature of the data; the types of queries expected; and the workflow and main goalsof the GONDWANA project (a research project that focuses on obtaining new U–Pb zircon ages in southwestern Iberia and which intends to analyse them togetherwith data already published on Iberia). Some technical considerations were alsoaddressed: the number of users and usage pattern; the type of database (relational);the usage of the database (for editing/read-only); the degree of demand (high/low);the type of software; the connection/transaction to the web; and the administrationof the database.Based on a set of typical queries normally applied to isotope data (see Eglington2004), the nature, detail, and amount of information to be used in the CHRONI-BERIA were, on a first level, defined as follows: Which samples are associatedwith some specified age? Which samples from a specific formation are associatedwith some specified age? What is the age of a specified geological unit or of anevent? How do dates from one area or geological entity compare with those fromother areas? What is the geographical distribution of dates in some area relative totheir geological interpretation? How do initial ratios vary with time in some areas?It is clear that spatial information is required in addition to chronological.Based on a synthetic workflow related to isotope data acquisition, the majorentities and relations of the database were defined (Fig. 1).The schematic design ofthe database was subsequently defined based on a diagram of entities andrelationships.Some technical considerations were then addressed, regarding the type ofsoftware. Databases using Microsoft Access offer, for example, better and moreuser-friendly manipulation of alphanumerical data and easier generation of dataforms and queries involving several tables, whereas ArcGIS databases (geodata-bases) provide the possibility of making spatial queries of and spatial operations onthe data. Original datafile formats for ArcGIS geodatabases can be stored andmanaged in Microsoft Access data files, which offers a hybrid solution as a startingpoint.734 C. Lopes et al.ma.chichorro@fct.unl.ptImplementation of the Database and Data LoadingThe database was first implemented in Microsoft Access. The information is storedin 18 tables, interlinked by key-data columns, and centralized in the sample tablewhere the geographical information is stored. In several tables, multiple valueswere stored to form a list of predefined values to improve the precision and speedof the feeding process (data loading). In the present phase, the database has beenloaded with data acquired from the GONDWANA project. Not all these data areyet completely loaded in the database; in some cases, there are still data andinformation missing, such as some geographical coordinates, auxiliary informa-tion, and even analytical data.Follow-upIn the follow-up, more data from the project and from the literature will be addedto the database. The geodatabase, already implemented in ArcGIS, will beFig. 1 Synthetic workflow and correspondence with the main tables of the database. Some dataimages are shown from Solá et al. (2008); Chichorro et al. (2008); and Pereira et al. (2012)illustrating the type of data stored in each tableChroniberia: The Ongoing Development 735ma.chichorro@fct.unl.ptdeveloped and tested. Moreover, a WebGIS (Geographic Information System forthe World Wide Web) will be implemented.Acknowledgments C. Lopes acknowledges a research grant of 12 months duration that wassponsored by project GONDWANA-PTDC/CTE-GIX/110426/2009 funded by Fundação para aCiência e Tecnologia (Portugal). It is a contribution to project PEst-OE/CTE/UI4073/2014.ReferencesBowring, S. A., & Schmitz, M. D. (2003). High-precision U-Pb zircon geochronology and thestratigraphic record. Reviews in Mineralogy and Geochemistry, 53, 305–326.Chichorro, M., Pereira, M. F., Díaz-Azpiroz, M., Williams, I. S., Fernández, C., Pin, C., et al.(2008). Cambrian ensialic rift-related magmatism in the Ossa-Morena Zone (Évora–Aracenametamorphic belt, SW Iberian Massif): Sm–Nd isotopes and SHRIMP zircon U–Th–Pbgeochronology. Tectonophysics, 461, 91–113.Davis, D., Williams, I. S., & Krogh, T. E. (2003). Historical development of zircongeochronology. Reviews in Mineralogy and Geochemistry, 53, 145–182.Eglington, B. M. (2004). DateView: a windows geochronology database. Computers &Geosciences, 30, 847–858.Eglington, B. M., Reddy, S. M., & Evans, D. A. D. (2009). The IGCP 509 database system;design and application of a tool to capture and illustrate litho- and chrono-stratigraphicinformation for Palaeoproterozoic tectonic domains, large igneous provinces and ore deposits;with examples from Southern Africa (in Palaeoproterozoic supercontinents and globalevolution). Geological Society Special Publications, 323, 27–47.Pereira, M. F., Solá, A. R., Chichorro, M., Lopes, L., Gerde, A., & Silva, J. B. (2012). North-Gondwana assembly, break up and paleogeography: U–Pb isotope evidence from detrital andigneous zircons of Ediacaran and Cambrian rocks of SW Iberia. Gondwana Research 22(3-4),866–881. http://dx.doi.org/10.1016/j.gr.2012.02.010Silva, L. C., Rodrigues, J. B., Silveira, L. M. C., & Pimentel, M. M. (2003). The BrazilianNational Geochronological Database: Chronobank, IV South American Symposium on IsotopeGeology, Salvador.Sircombe, K. N. (2006). Standardising geochronological data. Geochimica et CosmochimicaActa, 70, A594.Solá, A. R., Pereira, M. F., Williams, I. S., Ribeiro, M. L., Neiva, A. M. R., Montero, P., et al.(2008). New insights from U–Pb zircon dating of Early Ordovician magmatism on thenorthern Gondwana margin: The Urra Formation (SW Iberian Massif, Portugal). Tectono-physics, 461, 114–129.736 C. Lopes et al.ma.chichorro@fct.unl.pt