Lisa Tauxe

and 4 more

Twenty-two sites, subjected to an IZZI-modified Thellier-Thellier experiment and strict selection criteria, recover a paleomagnetic axial dipole moment (PADM) of 62.24$\pm$ 30.6 ZAm$^2$ in Northern Israel over the Pleistocene (0.012 - 2.58 Ma). Pleistocene data from comparable studies from Antarctica, Iceland, and Hawaii, re-analyzed using the same criteria and age range, show that the Northern Israeli data are on average slightly higher than those from Iceland (PADM = 53.8 $\pm$ 23 ZAm$^2$, n = 51 sites) and even higher than the Antarctica average %\cite{asefaw21} (PADM = 40.3 $\pm$ 17.3 ZAm$^2$, n = 42 sites). Also, the data from the Hawaiian drill core, HSDP2, spanning the last half million years (PADM = 76.7 $\pm$ 21.3 ZAm$^2$, n = 59 sites) are higher than those from Northern Israel. These results, when compared to Pleistocene results filtered from the PINT database (www.pintdb.org) suggest that data from the Northern hemisphere mid-latitudes are on average higher than those from the southern hemisphere and than those from latitudes higher than 60$^{\circ}$N. The weaker intensities found at high (northern and southern) latitudes therefore, cannot be attributed to inadequate spatio-temporal sampling of a time-varying dipole moment or low quality data. The high fields in mid-latitude Northern hemisphere could result from long-lived non-axial dipole terms in the geomagnetic field with episodes of high field intensities occurring at different times in different longitudes. This hypothesis is supported by an asymmetry predicted from the Holocene, 100 kyr, and five million year time-averaged geomagnetic field models.

Nicholas Jarboe

and 5 more

MagIC (earthref.org/MagIC (https://www2.earthref.org/MagIC)) is an organization dedicated to improving research capacity in the Earth and Ocean sciences by maintaining an open community digital data archive for rock and paleomagnetic data with portals that allow scientists and others to access to archive, search, visualize, download, and combine versioned datasets. A recent focus of MagIC has been to make our data more accessible, discoverable, and interoperable to further this goal. In collaboration with the GeoCodes/P418 group, we have continued to add more schema.org metadata fields to our data sets which allows for more detailed and deep automated searches. We are involved with the Earth Science Information Partners (ESIP) schema.org cluster which is working on extending the schema.org schema to the sciences. MagIC has been focusing on geo- science issues such as standards for describing deep time. We are also collaborating with the European Plate Observing System (EPOS)’s Thematic Core Service Multi-scale laboratories (TCS MSL). MagIC is sending its contributions’ metadata to TCS MSL via DataCite records for representation in the EPOS system. This collaboration should allow European scientists to use MagIC as an official repository for European rock and paleomagnetic data and help prevent the fragmenting of the global paleomagnetic and rock data into many separate data repositories. By having our data well described by an EarthCube supported standard (schema.org/JSON-LD), we will be able to more easily share data with other EarthCube projects in the future.

Peter Davidson

and 3 more

Expedition NBP1808 on the R/V Nathan B. Palmer completed 32 dredges between October and December, 2018 from locations across the Rio Grande Rise (RGR)—a largely unstudied oceanic plateau on the South American plate—and several seamounts located between RGR and the Mid-Atlantic Ridge (MAR). Eighteen samples from 10 dredge locations on RGR were dated to better understand the geochronological history of this large igneous province and to provide clues to its relationship with the Walvis Ridge and Tristan-Gough hotspot(s) on the conjugate African plate. 40Ar/39Ar results from plagioclase separates (and one biotite) show a prolonged emplacement history throughout RGR ranging from ~84 to 48 Ma. Ages in general decrease towards the MAR in accord with plate motions showing that RGR as a whole was emplaced over at least several Ma and not as a single pulse like some other oceanic plateaus. Using the recently published tectonic reconstruction of Sager et al., most volcanism in the NW and NE sectors on RGR was emplaced off-axis while that in the SE sector was erupted on-axis. This suggests that the plume source for RGR changed from more intraplate to more ridge-centered as the system evolved through time. There is evidence of a possible reversed age progression in the NE RGR which could provide evidence for micro-plate activity that has been suggested in this region, though more ages are needed to confirm this trend. Geochemistry studies are ongoing and will be used in the future to better understand the eruptive processes. Additional age analyses are also ongoing and will focus on the other dredge locations throughout RGR as well as the seamounts to complete the geochronological picture of the emplacement of RGR.

Lisa Tauxe

and 6 more

The Magnetics Information Consortium (MagIC), hosted at http://earthref.org/MagIC is a database that serves as a Findable, Accessible, Interoperable, Reusable (FAIR) archive for paleomagnetic and rock magnetic data. It has a flexible, comprehensive data model that can accomodate most kinds of paleomagnetic data. The **PmagPy** software package is a cross-platform and open-source set of tools written in Python for the analysis of paleomagnetic data that serves as one interface to MagIC, accommodating various levels of user expertise. It is available through github.com/PmagPy. Because PmagPy requires installation of Python, several non-standard Python modules, and the PmagPy software package, there is a speed bump for many practitioners on beginning to use the software. In order to make the software and MagIC more accessible to the broad spectrum of scientists interested in paleo and rock magnetism, we have prepared a set of Jupyter notebooks, hosted on [jupyterhub.earthref.org](https://jupyterhub.earthref.org) which serve a set of purposes. 1) There is a complete course in Python for Earth Scientists, 2) a set of notebooks that introduce PmagPy (pulling the software package from the github repository) and illustrate how it can be used to create data products and figures for typical papers, and 3) show how to prepare data from the laboratory to upload into the MagIC database. The latter will satisfy expectations from NSF for data archiving and for example the AGU publication data archiving requirements.