We propose a new model for the Fe-oxide concretion formation on Earth and that can also explain the early martian history.

The 320 Ma Ghareh Bagh mica mine is the only active mica mine in northwest Iran, and hosts Mg-bearing biotite (phlogopite) with apatite, epidote, and calcite. Chemical investigation of apatite infers the high abundances of the rare earth elements (REEs up to 5619 ppm), higher ratios of the LREE/HREE ((La/Yb)_N = 28.5–36.7)) and high content of Y (236–497 ppm). REE pattern in the apatite and host A-type granite is almost the same. Ghareh Bagh apatite formed from the early magmatic-hydrothermal exsolved fluids at the high temperature from the Ghushchi alkali feldspar granite. The apatite crystals came up as suspension grains and precipitated in the brecciated zone. The early magmatic-hydrothermal fluids settle phlogopite, epidote, chlorite, K-feldspar and albite down in the brecciation zone. Due to the precipitation of these minerals, the late-stage fluids with low contents of Na⁺, Ca²⁺ and REE affected the early stage of alteration minerals. The high ratios of ⁸⁷Sr/⁸⁶Sr (0.70917 to 0.70950) are more consistent with crustal sources for the apatite large crystals. The same ages (320 Ma) for both brecciated mica veins and host alkali feldspar granites infer the apatite and paragenesis minerals were related to host granite A-type granite in the Ghareh Bagh area.

During Heinrich Stadial 1 (HS1, 18.0–14.7 kyr ago), the Bering and Okhotsk Seas in the western Subarctic Pacific (SAP) exhibited boundary conditions that enhanced intermediate water convection. However, little is known about the quantitative contribution of the intermediate waters from the Bering and Okhotsk Sea (BSIW and OSIW) to ventilation in the open SAP intermediate–deep layers. In this study, we analyzed the neodymium (Nd) isotopes of fish debris (ε_Nd‐FD) from sediment cores in the Northwestern Pacific, and observed a reduction in ε_Nd (up to −2.6) from the Last Glacial Maximum to HS1 at Sites MD01‐2420 (2,101 m) and KH99‐3 ES (2,388 m). The relevance of reduced HS1 ε_Nd‐FD shifts across the cores cannot be explained by the porewater influence, which generally changes authigenic ε_Nd in opposite ways. Instead, as the ε_Nd‐FD shifts concurred with a reduction in the ¹⁴C ventilation age, HS1 ε_Nd‐FD shifts suggest the entrainment of younger and distinct ε_Nd water mass sinking in the Okhotsk and/or Bering Seas. A mixing model applying Nd isotopes, their concentrations, and ¹⁴C ventilation ages of BSIW, OSIW, and the Lower Circumpolar Deep Water showed that during HS1, BSIW (36%–41%) was more conducive to the water mass at Site MD01‐2420, compared to OSIW (4%–8%). We argue that the Bering Sea has wider and deeper connections (Kamchatka and Near Straits, ∼4,400–2,200 m) with the western SAP, and the deep conduit would enable BSIW to more effectively flow out into the open Northwestern Pacific deep layer.

Ebrahim-Attar granitic pegmatite, which is distributed in southwest Ghorveh, western Iran, is strongly peraluminous and contains minor beryl crystals. Pale-green to white beryl grains are crystallized in the rim and central parts of the granite body. The beryl grains are characterized by low contents of alkali oxides (Na₂O = 0.24–0.41 wt.%, K₂O = 0.05–0.17 wt.%, Li₂O = 0.03–0.04 wt.%, and Cs₂O = 0.01–0.03 wt.%) and high contents of Be₂O oxide (10.0 to 11.9 wt.%). The low contents of alkali elements (oxides), low Na/Li (apfu) ratios (2.94 to 5.75), and variations in iron oxide (FeO= 0.28–1.18 wt.%) reveal a poorly evolved magmatic source of the beryl grains. Low abundances of rare earth elements (ΣREE = 0.8–4.9 ppm) with high ⁸⁷Sr^/86Sr_(i) ratios of 0.739 ±0.036 for the beryl grains and 0.7081 for the host granites infer that the primary magma was directly produced by partial melting of the upper continental crust (UCC). The crystallization temperature of the Ebrahim-Attar granitic pegmatite changes from 586 to 755 °C (average = 629 °C), as calculated based on the zircon saturation index. Furthermore, the quartz geobarometer calculation shows that crystallization occurred at pressures of approximately 233–246 MPa. This pressure range is a promising condition for saturation of Be in magma. During granitic magma crystallization, the melt was gradually saturated with Be, and then beryl crystallized in the assemblage of the main minerals such as quartz and feldspar. Likewise, the host granite is characterized by high ratios of Nb/Ta (4.79–16.3) and Zr/Hf (12.2–19.1), and peraluminous signatures are compatible with Be-bearing LCT (Li-Ce and Ta) pegmatites.