Workshop for Scientific Drilling in the Indian Ocean Crust & Mantle. May 13th to 16th, 2015 Woods Hole MA, USA
Notice bibliographique
Résumé
The Workshop for Scientific Drilling in the Indian Ocean Crust and Mantle was held May 13-‐16, 2015 at the Woods Hole Oceanographic Institution, bringing together 60 scientists from Australia, Canada, China, France, Germany, Great Britain, Italy, Japan, the Netherlands, Poland, Portugal and the United States. The meeting was co-‐sponsored by IODP China and the United States Scientific Support Program. Forty-‐four half hour talks were given, with an extensive overview of the tectonics, geophysics, geochemistry, and biogeochemistry of the principal regional interest, the SW Indian Ridge (SWIR). Two new and one scheduled drilling proposal were presented and reviewed. Twelve 30-‐minute discussion sessions provided time for audience input, resulting in specific workshop recommendations as outlined below. The SW Indian Ridge (~14) mm/yr is the best-‐studied ultra slow end-‐member for seafloor spreading. In addition to the unique tectonics of ultra slow spreading, the crust ranges from near zero to some of the thickest ocean crust measured far from a mantle hotspot. Thus, it is a unique laboratory for the study of lithospheric accretion. Unlike faster spreading ridges, the mantle is directly exposed over approximately a quarter of the seafloor formed along it. Mantle peridotite is a highly reactive substrate for water -‐ rock interaction compared to the basaltic crust at faster spreading ridges. This may have significant implications for the global carbon budget. The workshop was particularly timely as it coincided with planning for the 2016 to 2020 2nd International Indian Ocean Expedition. The meeting reviewed plans for the first leg of the SloMo Project (Slow Spreading Ridge Moho). This allowed an exchange between the expedition science party and the community on operation plans and objectives for drilling there, and for forming collaborations between ship and shore-‐based scientists. A review of existing Atlantis Bank surveys identified needed site survey data, including new surveys based on recent state-‐of-‐the-‐art seismic experiments to characterize the internal structure of the crust, as well as constrain the nature and variability of Moho. Near-‐bottom high-‐resolution bathymetric surveys are also needed to constrain the tectonic evolution of the Atlantis Bank Core Complex are needed. Presentations of seismic, bathymetric, submersible, biologic, and geochemical data were made for the Dragon Flag hydrothermal area (49°40’E) and the Dragon Bone Amagmatic Segment (53°E). The former represents the early stages of seafloor massive sulphide (SMS) formation, where shallow drill holes can establish the basic pattern of hydrothermal circulation during SMS formation, which is obscured by long episodic cycles of hydrothermal circulation at older deposits such as TAG. Local exposure of mantle peridotite at Dragon Flag adjacent to the thick crust of the volcanic segment to the east and the non-‐transform discontinuity to the west is an opportunity to explore the nature of the transition from basaltic to ultramafic outcrops along axis. Drilling mantle peridotite at the Dragon Bone Segment would compare mantle from two adjacent extreme melting environments. It was agreed, though, that additional survey data; particularly near-‐seafloor bathymetric mapping, is needed for both sites prior to a preliminary drilling proposal. A proposal was presented for drilling ‘smooth seafloor’ at 64°30'E on the SW Indian Ridge, which represents the magma-‐starved end-‐member of ultra-‐slow spreading ridges. This region lacks the characteristic roughness of most slow spread ocean crust, and crustal rock is virtually absent over large regions with the mantle directly exposed to the seafloor. Moreover, this represents another extreme mantle environment whose geochemistry should contrast sharply to the Dragon Flag and Dragon Bone areas. Based on the existing iii magnetic, seismic, geologic and bathymetric surveys, the consensus was that this was an important objective for lithosphere drilling, and that it is ready for a pre-‐proposal to IODP.\n
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,002 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,001 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,003 | 0,001 |
| Science ouverte | 0,001 | 0,004 |
| Intégrité de la recherche | 0,001 | 0,002 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,159 | 0,064 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».