Sedimentary rocks provide records of past surface and subsurface processes and environments. The first step in the study of the sedimentary rock record of another world is to learn to recognize their occurrences in images from instruments aboard orbiting, flyby, or aerial platforms. For two decades, Mars has been known to have sedimentary rocks; however, planet-wide identification is incomplete. Global coverage at 0.25–6 m/pixel, and observations from the Curiosity rover in Gale crater, expand the ability to recognize Martian sedimentary rocks. No longer limited to cases that are light-toned, lightly cratered, and stratified—or mimic original depositional setting (e.g., lithified deltas)—Martian sedimentary rocks include dark-toned examples, as well as rocks that are erosion-resistant enough to retain small craters as well as do lava flows. Breakdown of conglomerates, breccias, and even some mudstones, can produce a pebbly regolith that imparts a “smooth” appearance in satellite and aerial images. Context is important; sedimentary rocks remain challenging to distinguish from primary igneous rocks in some cases. Detection of ultramafic, mafic, or andesitic compositions do not dictate that a rock is igneous, and clast genesis should be considered separately from the depositional record. Mars likely has much more sedimentary rock than previously recognized.

Ceres is a partially differentiated dwarf planet, as confirmed by NASA’s Dawn mission. The Urvara basin (diameter ~170 km) is its third-largest impact feature, enabling insights into the cerean crust. Urvara’s geology and mineralogy suggest a potential brine layer at the crust-mantle transition. Here we report new findings that help in understanding the structure and composition of the cerean crust. These results were derived by using the highest-resolution Framing Camera images acquired by Dawn at Ceres. Unexpectedly, we found meter-scale concentrated exposures of bright material (salts) along the crater’s upper central ridge, which originate from an enormous depth, possibly from a deep-seated brine or salt reservoir. An extended resurfacing modified the southern floor ~100 Myr after crater formation (~250 Myr), long after the dissipation of the impact-generated heat. In this resurfaced area, one floor scarp shows a granular flow pattern of bright material, showing spectra consistent with the presence of organic material, the first such finding on Ceres beyond the vast Ernutet area. Our results strengthen the hypothesis that Ceres is and has been a geologically active world even in recent epochs, with salts and organic-rich material playing a major role in its evolution.

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BackgroundFine needle aspiration cytology (FNAC) assisted with scrotal ultrasonography is the best preoperative diagnostic modality for palpable epididymal nodules. It also aids in their successive remedial approach as well as serves semi‐therapeutically in cystic lesions. The objectives of this study are to recognize the spectrum of pathological conditions giving rise to epididymal nodules, then to compare them with corresponding ultrasound images, and to evaluate the histological features wherever practicable.MethodsTotal 62 patients underwent FNAC as well as sonographic evaluation for their epididymal nodules. Histopathology was performed in only 20 cases.ResultsEpididymitis either caused by tuberculosis (30.6%), or in its acute (11.3%) and chronic (8.1%) forms remained the commonest cytological diagnosis. Neoplastic lesions included mostly adenomatoid tumors (8.1%), and another case of seminomatous spread from ipsilateral testicular primary. Nineteen of the excised masses corroborated with their respective cytodiagnoses. The discrepant lesion was actually a papillary cystadenoma, which was cytologically misinterpreted as adenomatoid tumor.ConclusionsFNAC becomes the first‐hand investigative measure for epididymal nodules, by virtue of its early, easy and highly accurate diagnostic implications. It segregates the patients into proper therapeutic protocol and thereby estranges those who really need operative management. When deployed together with ultrasound, the diagnostic accuracy of FNAC improves further.

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