Chapter 7 Post-obduction evolution of New Caledonia

Sevin, Brice; Maurizot, Pierre; Cluzel, Dominique; Tournadour, Elsa; Étienne, Samuel; Folcher, Nicolas; Jeanpert, Julie; Collot, Julien; Iseppi, Marion; Meffre, Sébastien; Patriat, M.

doi:10.1144/m51-2018-74

Cited by 19 publications

(13 citation statements)

References 124 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Chapter 7 considers the post-obduction evolution of New Caledonia (Sevin et al 2020). The post-obduction formations in New Caledonia comprise a variety of disparate and areally restricted Neogene geological units.…”

mentioning

confidence: 99%

Chapter 1 Introduction to New Caledonia: geology, geodynamic evolution and mineral resources

Maurizot

Robineau

Vendé‐Leclerc

et al. 2020

Memoirs

Self Cite

View full text Add to dashboard Cite

This Memoir summarizes our current knowledge of New Caledonia geology, geodynamics and mineral resources based on published and unpublished information. Except for a short paper timed for the 34th International Geological Congress (Cluzel et al. 2012b), there has been no review of the geology of New Caledonia since Paris (1981)that is, for more than 35 years. As such, it is timely that this Memoir is published.This Memoir comprises a collection of ten self-contained chapters written by 28 researchers from New Caledonia, France, New Zealand, Australia and Papua New Guinea. This work is not simply a summation of the factual material acquired since Paris (1981). The purpose of each chapter is to present: (1) a data synthesis from which the reader can make his or her own interpretations and (2) an interpretation by the authors incorporating contemporary datasets and geoscientific concepts. Onshore-offshore connections are emphasized, as are the geological relations with New Zealand, Australia and Papua New Guinea, although this Memoir certainly is not a synthesis of the geodynamics of the SW Pacific.This introductory chapter is a starting point for understanding how the current state of geoscientific knowledge of New Caledonia was reached. It includes a small-scale geological map and proposes a general stratigraphic scheme for New Caledonia. It reviews the advances in knowledge of the geology of the country since the last synthesis of Paris (1981). It also summarizes current problems and issues and the analyses strengths and weaknesses in the state of knowledge of the country's geology.Chapter 2 reviews the geodynamics of the SW Pacific and its relations with New Caledonian geology (Collot et al. 2020). The onshore geology of New Caledonia cannot be separated from its regional and offshore context. This chapter identifies the major geological structures of the SW Pacific from the eastern Australian coast to the Tonga-Kermadec Trench. This mostly submerged system of basins, ridges and seamounts of various ages is interpreted as oceanic and thinned continental crust, continental ridges, volcanic arcs, intra-plate volcanic chains and oceanic plateaus. Part of this region, including New Caledonia, is a submerged continent referred to as Zealandia (Mortimer et al. 2017). This chapter presents and compares tectonic models that attempt to explain the formation and development of this complex area.Chapter 3 considers the Pre-Late Cretaceous basement terranes of the Gondwana active margin (Maurizot et al. 2020a).

show abstract

mentioning

confidence: 99%

Chapter 1 Introduction to New Caledonia: geology, geodynamic evolution and mineral resources

Maurizot

Robineau

Vendé‐Leclerc

et al. 2020

Memoirs

Self Cite

View full text Add to dashboard Cite

show abstract

“…The Middle Miocene is also the time when the North-East dipping Vanuatu subduction zone initiated along the Vitiaz Lineament and rolled back to its present-day position [36,57]. The subduction of the Australian plate under the Vanuatu Arch induces a flexure of the downgoing lithosphere and hence uplift and extensional tectonics as far as southern Grande Terre [58,59].…”

Section: Regional Settingsmentioning

confidence: 99%

Origin and Composition of Ferromanganese Deposits of New Caledonia Exclusive Economic Zone

et al. 2022

Self Cite

View full text Add to dashboard Cite

Located in the South-West Pacific, at the northern extremity of the mostly submerged Zealandia continent, the New Caledonian Exclusive Economic Zone (EEZ) covers 1,470,000 km² and includes basins, ridges and seamounts where abundant ferromanganese crusts have been observed. Several investigations have been conducted since the 1970s on the nature and composition of ferromanganese crusts from New Caledonia’s seamounts and ridges, but none have covered the entire EEZ. We present data from 104 ferromanganese crusts collected in New Caledonia’s EEZ during twelve oceanographic cruises between 1974 and 2019. Samples were analysed for mineralogy, geochemical compositions, growth rates, and through a statistical approach using correlation coefficients and factor analysis. Crust thicknesses range from 1 mm to 115 mm, with growth rates between 0.45 mm/Ma and 102 mm/Ma. Based on textures, structures, discrimination plots, and growth rates, we distinguish a group of hydrogenetic crusts containing the highest mean contents of Co (0.42 wt%), Ni (0.31 wt%), and high contents of Mo, V, W, Pb, Zn, Nb, from a group of hydrothermal and/or diagenetic deposits showing high mean contents of Mn (38.17 wt%), Ba (0.56 wt%) and low contents of other trace metals. Several samples from this later group have exceptionally high content of Ni (0.7 wt%). The data shows that crusts from the southern part of the EEZ, notably seamounts of the Loyalty Ridge and the Lord Howe Rise, present high mineral potential for prospectivity owing to high contents of valuable metals, and constitute a great target for further investigation.

show abstract

“…Within the fluvio-lacustrine sediments, and later within the soils, concretionary ironstone horizons (duricrusts) formed in situ with the precipitation of hematite and goethite cements around existing grains, filling voids and greatly reducing the porosity and permeability of the horizon (Sevin et al 2011;Folcher et al 2015). Duricrusts commonly contain root casts and trunks preserved in growth position (Folcher et al 2015;Sevin et al 2020).…”

Section: Geological Settingmentioning

confidence: 99%

“…Many of these deposits are concealed beneath the recent regolith, but several have been eroded and provide good exposure (Folcher et al 2015). The timing of their deposition is unknown, as the iron-oxide dominated sediments are not suitable for radiogenic dating, lack index fossils, and paleomagnetic dating techniques reveal ages ranging from latest Oligocene to Holocene Folcher et al 2015;Maurizot et al 2020;Sevin et al 2020).…”

Section: Geological Settingmentioning

confidence: 99%

Leaves in Iron Oxide: Remarkable Preservation of a Neogene Flora From New Caledonia

Locatelli

Briggs

Leslie

et al. 2022

Palaios

View full text Add to dashboard Cite

A Neogene hematite-goethite concretionary ‘ironstone' horizon in laterized fluvial sediments in the Massif du Sud of New Caledonia yields abundant fossil dicotyledonous angiosperm leaves. The leaves are preserved in iron oxide, mainly goethite, which replicates the morphology and anatomy of the leaf tissues and comprises 73% of the matrix. Organic remains are minimal and associated with aluminosilicate clay. Leaf tissues are preserved three-dimensionally in multiple ways including casts/molds, permineralization/petrifaction, and replacement. Although the mesophyll is less well preserved, reflecting its greater susceptibility to decay, cellular details of vascular and epidermal tissues are commonly evident. Analyses of leaves from an analogous modern setting reveal the early encrustation and impregnation of tissues by amorphous iron-oxides and clays in association with a microbial biofilm. We propose a taphonomic model in which the fossil leaves, like their modern counterparts, were permeated by iron oxides due to the high availability of iron derived from weathering of ultramafic basement. In contrast to the iron-rich aluminosilicate coatings that form in relatively iron-poor settings, the unusually high concentration of dissolved iron oxides permitted rapid anatomical preservation.

show abstract

Chapter 7 Post-obduction evolution of New Caledonia

Cited by 19 publications

References 124 publications

Chapter 1 Introduction to New Caledonia: geology, geodynamic evolution and mineral resources

Chapter 1 Introduction to New Caledonia: geology, geodynamic evolution and mineral resources

Origin and Composition of Ferromanganese Deposits of New Caledonia Exclusive Economic Zone

Leaves in Iron Oxide: Remarkable Preservation of a Neogene Flora From New Caledonia

Contact Info

Product

Resources

About