scholarly journals Drilling into deep-seated hard rocks of the oceanic plate formed at the Mid-Ocean Ridge: results and future perspectives: Deep-seated Hard Rock Drilling

2017 ◽  
Vol 123 (4) ◽  
pp. 185-205
Author(s):  
Tomoaki Morishita
Keyword(s):  
Hard Rock ◽  
Oceanic Plate ◽  
Future Perspectives ◽  
Rock Drilling ◽  
Hard Rocks ◽  
Mid Ocean Ridge ◽  
Ocean Ridge

PETROGENESIS OF GABBRO FROM ARCTIC GAKKEL MID-OCEAN RIDGE

2019 ◽  
Author(s):  
Yung Ping Lee ◽  
◽  
Jonathan E. Snow ◽  
Yongjun Gao
Keyword(s):  
Mid Ocean Ridge ◽  
Ocean Ridge

scholarly journals Melt addition to mid-ocean ridge peridotites increases spinel Cr# with no significant effect on recorded oxygen fugacity

2021 ◽  
Vol 566 ◽  
pp. 116951
Author(s):  
Suzanne K. Birner ◽  
Elizabeth Cottrell ◽  
Jessica M. Warren ◽  
Katherine A. Kelley ◽  
Fred A. Davis
Keyword(s):  
Oxygen Fugacity ◽  
Mid Ocean Ridge ◽  
Ocean Ridge

scholarly journals Sunda arc mantle source δ18O value revealed by intracrystal isotope analysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Frances M. Deegan ◽  
Martin J. Whitehouse ◽  
Valentin R. Troll ◽  
Harri Geiger ◽  
Heejin Jeon ◽  
...  
Keyword(s):  
Mantle Source ◽  
Secondary Ion Mass Spectrometry ◽  
Isotope Composition ◽  
Isotope Analysis ◽  
Sunda Arc ◽  
Mid Ocean Ridge ◽  
Plumbing Systems ◽  
Ocean Ridge ◽  
Secondary Ion ◽  
Magma Plumbing

AbstractMagma plumbing systems underlying subduction zone volcanoes extend from the mantle through the overlying crust and facilitate protracted fractional crystallisation, assimilation, and mixing, which frequently obscures a clear view of mantle source compositions. In order to see through this crustal noise, we present intracrystal Secondary Ion Mass Spectrometry (SIMS) δ18O values in clinopyroxene from Merapi, Kelut, Batur, and Agung volcanoes in the Sunda arc, Indonesia, under which the thickness of the crust decreases from ca. 30 km at Merapi to ≤20 km at Agung. Here we show that mean clinopyroxene δ18O values decrease concomitantly with crustal thickness and that lavas from Agung possess mantle-like He-Sr-Nd-Pb isotope ratios and clinopyroxene mean equilibrium melt δ18O values of 5.7 ‰ (±0.2 1 SD) indistinguishable from the δ18O range for Mid Ocean Ridge Basalt (MORB). The oxygen isotope composition of the mantle underlying the East Sunda Arc is therefore largely unaffected by subduction-driven metasomatism and may thus represent a sediment-poor arc end-member.

scholarly journals Rockslides on limestone cliffs with subhorizontal bedding in the southwestern calcareous area of China

2014 ◽  
Vol 14 (9) ◽  
pp. 2627-2635 ◽  
Author(s):  
Z. Feng ◽  
B. Li ◽  
Y. P. Yin ◽  
K. He
Keyword(s):  
Numerical Modeling ◽  
Rock Mass ◽  
Hard Rock ◽  
Compression Fracture ◽  
Field Observations ◽  
Mountainous Areas ◽  
Hard Rocks ◽  
Rupture Plane ◽  
Rock Collapse ◽  
Cliff Retreat

Abstract. Calcareous mountainous areas are highly prone to geohazards, and rockslides play an important role in cliff retreat. This study presents three examples of failures of limestone cliffs with subhorizontal bedding in the southwestern calcareous area of China. Field observations and numerical modeling of Yudong Escarpment, Zengzi Cliff, and Wangxia Cliff showed that pre-existing vertical joints passing through thick limestone and the alternation of competent and incompetent layers are the most significant features for rockslides. A "hard-on-soft" cliff made of hard rocks superimposed on soft rocks is prone to rock slump, characterized by shearing through the underlying weak strata along a curved surface and backward tilting. When a slope contains weak interlayers rather than a soft basal, a rock collapse could occur from the compression fracture and tensile split of the rock mass near the interfaces. A rockslide might shear through a hard rock mass if no discontinuities are exposed in the cliff slope, and sliding may occur along a moderately inclined rupture plane. The "toe breakout" mechanism mainly depends on the strength characteristics of the rock mass.

Mid-ocean-ridge seismicity reveals extreme types of ocean lithosphere

Nature ◽  
2016 ◽  
Vol 535 (7611) ◽  
pp. 276-279 ◽  
Author(s):  
Vera Schlindwein ◽  
Florian Schmid
Keyword(s):  
Mid Ocean Ridge ◽  
Ocean Lithosphere ◽  
Ocean Ridge
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