Boron and Lithium in Calcium Sulfate Veins: Tracking Precipitation of Diagenetic Materials in Vera Rubin Ridge, Gale Crater

The NASA Curiosity rover’s ChemCam instrument suite has detected boron in calcium‐sulfate‐filled fractures throughout the sedimentary strata of Gale crater including Vera Rubin ridge (VRR). The presence of elevated B concentration provides insights into Martian subsurface aqueous processes. In this study we extend the dataset of B in Ca‐sulfate veins across Gale crater, comparing the detection frequency and relative abundances with Li. We report 33 new detections of B within veins analyzed between sols 1548 and 2311 where detections increase in Pettegrove Point and Jura members, which form VRR. The presence of B and Li in the Ca‐sulfate veins is possibly due to dissolution of pre‐existing B in clays of the bedrock by acids or neutral water and redistribution of the elements into the veins. Elevated frequency of B detection in veins of Gale crater correlate with presence of dehydration features such as desiccation cracks, altered clay minerals and detections of evaporites such as Mg‐sulfates, chloride salts in the host rocks. The increased observations of B also coincide with decreased Li concentration in the veins (average Li concentration of veins drops by ~15 ppm). Boron and Li have varying solubilities and Li does not form salts as readily upon dehydration as B, causing it to remain in the solution. So, the weak negative correlation between B and Li may reflect the crystallization sequence during dehydration on Vera Rubin ridge

Identification and characterization of Fe-rich smectites in the Çamlıca Region of western Turkey

Fe-rich dioctahedral smectites are the main constituent of clays in Camlica Region of Turkey. The structural, chemical and morphological characteristics of these smectites after washing are examined by X-ray diffraction, electron microscopy, inductively coupled plasma mass spectrometry and Fourier transform infrared spectroscopy. Smectite particles occur as individual flakes 0.2-2.0 mu m in size. These flakes are often aggregated into clusters up to 6.0 mu m in size

Monitoring possible light-time effect in the orbital period of some eclipsing binaries at the Ankara University Observatory

A significant number of close binaries are known to be members of physically bound triple or multiple star systems. The O - C analysis technique which is based on the minima times of an eclipsing binary can reveal the light-time effect due to the presence of gravitationally bound and generally unseen close component(s) in the system. In this study we present shortly the O - C analysis results based on the light-time effect possibilities for two of the eclipsing binaries observationally followed by our group; TZ Boo and CF Tau

Fluidity Characteristics of A201 and A206 Al-Cu Alloy

Al-4.5Cu alloys are widely used in aerospace industries due to their low weight and high mechanical properties. This group of aluminium alloys is known as 2xx series and exhibits the highest mechanical properties however this alloy is known to suffer from feedability and high tendency for hot tearing. Al-Si alloys (3xx) have improved fluidity and better feedability particularly by several modifications such as Ti, B or Sr. Eutectic temperature is decreased and mechanical properties can be enhanced. Yet, the strength values of this alloy group cannot reach the values of 2xx series. Therefore, in this study, the effect of Ag addition on the fluidity of Al-4.5Cu alloy has been investigated. Standard size spiral mould was used. The casting temperature was selected to be 770 degrees C. Five castings were made and Weibull statistical approach was used to evaluate the results. In addition, coating of the die with BN was also investigated. It was found that Ag addition and BN coating of the die revealed the most reproducible, reliable and high fluidity values

Activity diagrams of borates: implications on common deposits

Most of the world's borate minerals are found in Neogene deposits and Quaternary lake deposits. Only a few of the borates are common geologically and commercially. A series of equilibrium activity diagrams were calculated for the common as well as some rare borate minerals in the systems of (1) Na2O-B2O3-H2O, (2) CaO-B2O3-H2O +/- CO2, (3) MgO-B2O3-H2O +/- CO2, (4) CaO-Na2O-B2O3-H2O, and (5) CaO-MgO-B2O3-H2O. Stability diagrams constructed with respect to variables of log[a(Mbn+)/(a(H+))(n)] and log[a(Mbn+)/a(Mc(n-1))+(a(H+))] versus both log[aH(2)O] and log[a(B)(OH)(3)] showed that some rare borates are thermodynamically not stable (tertschite, inderborite) at all in these systems. Still some common phases are thermodynamically occurred as metastable phases (tincalconite, meyerhofferite) in some deposits. On the contrary, some thermodynamically stable phases can form kinetically slower than the others and not found as common phases (inyoite). Some common and uncommon minerals such as ulexite, aksaite, and gowerite have small stability fields indicating that they can form at very limited thermodynamic conditions. Some phases such as pandermite, ginorite, ascharite, and suanite being structurally complex phases, form after less complex precursor minerals at the end of diagenesis due to burial and/or increasing temperature. Concentrations of cations and boron, pH, evaporation rate are other controlling variables of diagenetic processes. Through these diagrams, observed paragenetic relations and geochemical conditions can be depicted and expectant paragenetic phases can be predicted in any deposits