Curiosity's Investigation of the Bagnold Dunes, Gale Crater: Overview of a Two-Phase Scientific Campaign

The Mars Science Laboratory (MSL) Curiosity rover landed at Gale crater in August 2012 with the goal of unravelling the climate and habitability history of ancient Mars. On its way to higher stratigraphic levels of Aeolis Mons, the crater's central mound, Curiosity crossed an active dune field informally named the Bagnold Dune Field. Curiosity's traverse through the Bagnold Dunes between December 2015 and April 2017 constituted the first in situ investigation of an active dune field on another planet. The scientific campaign at the dunes enabled a detailed study of martian eolian processes at scales that are unachievable from orbiter-based imagery, from the scale of compound bedforms down to those of individual sand grains. The eolian-science campaign was broadly divided into two main phases - a first-phase investigation near two barchan dunes along the northern trailing edge of the dune field, Namib and High Dunes, and a second-phase investigation farther south near a linear dune, the Nathan Bridges Dune, named after our beloved colleague and friend Nathan Bridges. In addition to these two phases, the Bagnold Dunes campaign included punctual investigations of isolated ripples and ripple fields further along the rover traverse away from the Bagnold Dune Field. The main goals of the scientific investigation at the Bagnold Dunes were two-fold: (I) developing a mechanistic understanding of martian eolian processes and rates from direct in situ observations of eolian structures and their dynamics, and (II) characterizing the physical properties and the chemical and mineral composition of eolian sands and dust on Mars. Significant advances in martian eolian science resulted from Curiosity's ground investigation of the active Bagnold Dunes. Altogether, results from the Bagnold Dunes campaign are key to understanding how the martian environment affects eolian processes, and will thus prove most useful to deciphering paleoenvironments from the martian eolian sedimentary record

Phyllosilicate Transitions in Ferromagnesian Soils: Short-Range Order Materials and Smectites Dominate Secondary Phases

Analyses of X-ray diffraction (XRD) patterns taken by the CheMin instrument on the Curiosity Rover in Gale crater have documented the presence of clay minerals interpreted as smectites and a suite of amorphous to short-range order materials termed X-ray amorphous materials. These X-ray amorphous materials are commonly ironrich and aluminum poor and likely some of them are weathering products rather than primary glasses due to the presence of volatiles. Outstanding questions remain regarding the chemical composition and mineral structure of these X-ray amorphous materials and the smectites present at Gale crater and what they indicate about environmental conditions during their formation. To gain a better understanding of the mineral transitions that occur within ferromagnesian parent materials, we have investigated the development of secondary clay minerals and shortrange order materials in two soil chronosequences with varying climates developing on ultramafic bedrock. Field Sites: We investigated soil weathering within two field locations, the Klamath Mountains of Northern California, and the Tablelands of Newfoundland, Canada. Both sites possess age dated or correlated recently deglaciated soils and undated but substantially older soils. In the Klamath mountains the Trinity Ultramafic Body was deglaciated roughly 15,000 years bp while in the Tablelands a moraine was dated to about 17,600 years bp. The Klamath Mountains feature a seasonally wet and dry climate while the Tablelands are wet year-round with saturated soil conditions observed during sampling and standing water observed within 3 of 4 soil pit sampling locations

Ekstraksi dan Identifikasi Komponen Utama Pasir Putih dari Desa Marinsow Kabupaten Minahasa Utara dengan Pengujian XRF dan XRD

North Sulawesi is one of the regions in Indonesia which has a wealth of natural resources which is quite abundant, one of the natural potential that can be utilized is White sand. White sand has a composition that is SiO2, CaO, Fe2O3, TiO2, MgO. This study aims to identify the composition of the main components of white sand through XRF testing and the results of extraction of white sand from Marinsow village using the alkaline fusion method, NaOH solution for extracting and crystallizing the formation of silica crystals and tested using XRD testing to determine the crystal characteristics. Extraction and testing processes have been carried out using XRF and XRD on white sand samples taken in Marinsow Village, North Minahasa Regency. The results of the identification of the components of the white sand constituents through XRF testing namely CaO is the largest main component of the white sand compilers in the village of Marinsow which is as much as 89.97%. The content of SiO2 compounds in white sand (Marinsow) is as much as 1.41%. Other components found in white sand from Marinsow village, North Minahasa Regency include MgO as much as 5.85%, SrO as much as 2.31%, Fe2O3 as much as 0.277 %, TiO2 is 0.079%, Cr2O3 is 0.032%, Nb2O5 is 0.0238%, MoO3 is 0.0159%, SnO2 is 0.0082%, Sb2O3 is 0.0079% and RuO4 is 0.0074%. The results of XRD testing on white sand taken in the village of Marinsow give results that white sand has a calcite crystal structure (CaO) and for the SiO2 silica component is quartz

Pengaruh Metode Problem Based Learning pada Materi Redoks di Kelas X SMA Negeri 1 Wori

The purpose of this study, to determine whether there are differences in student learning outcomes in using the Problem Based Learning method with the lecture method. During approximately 1 month different methods were applied in 2 classes, namely the Problem Based Learning class and the Lecture class with a total of 25 students each, then to see the learning outcomes a post-test was conducted. The results showed the value of t arithmetic = 2.92> t table 2.010, so that the conclusion Ha is accepted and H0 is rejected, it means there are differences in student learning outcomes using the Problem Based Learning method with those using the lecture method on redox material

Intensitas Serangan Akibat Hama Pemakan Daun Setelah Aplikasi Ekstrak Daun Babadotan (Ageratum Conyzoides L.) pada Tanaman Sawi (Brassica Juncea L.)

Telah dilakukan penelitian untuk mengevaluasi intensitas serangan akibat hama pemakan daun setelah aplikasi ekstrak daun Babadotan (Ageratum conyzoides L.), pada tanaman sawi (Brassica juncea L.). Penelitian bertempat di lahan percobaan Kelurahan Lansot, Kecamatan Tomohon Selatan, Kota Tomohon, Sulawesi Utara. Penelitian menggunakan metode eksperimen Rancangan Acak Lengkap (RAL) dengan tiga ulangan. Konsentrasi ekstrak daun babadotan dengan empat taraf perlakuan yaitu: P0=kontrol, P1=100 g/L, P2= 200 g/L dan P3= 300 g/L. Aplikasi ekstrak daun babadotan dilakukan pada 16 hari setelah tanam (HST), 26 HST dan 36 HST. Parameter yang diamati yaitu luas intensitas serangan. Data yang diperoleh dianalisis dengan ANAVA dan dilanjutkan dengan uji Beda Nyata Terkecil (BNT) pada p=0.05. Hasil penelitian menunjukkan bahwa aplikasi ekstrak daun babadotan menurunkan intensitas serangan hama pemakan daun pada tanaman sawi. Aplikasi ekstrak daun babadotan sebesar 300 gr/L dapat menekan serangan hama pemakan daun pada tanaman sawi.Kata kunci: Ekstrak daun babadotan (Ageratum conyzoides L.), Tanaman sawi (Brassica juncea L.), Intensitas serangan hama. INTENSITY OF ATTACK DUE TO LEAF EATER PESTS AFTER APPLICATION OF BABADOTAN LEAF EXTRACT (Ageratum conyzoides l.). IN MUSTARD PLANTS (Brassica juncea L.

Sediment Sorting and Rounding in a Basaltic Glacio-Fluvio-Aeolian Environment: hrisjkull Glacier, Iceland

Sediments and sedimentary rocks preserve a rich history of environment and climate. Identifying these signals requires an understanding of the physical and chemical processes that have affected sedimentary deposits [1]. Such processes include sorting and rounding during transport and chemical alteration through weathering and diagenesis. Although these processes have long been studied in quartz-dominated sedimentary systems [2], a lack of studies of basaltic sedimentary systems limits our interpretations of the environment and climate where mafic source rocks dominate, such as on Mars [3,4]. As part of the SAND-E: Semi-Autonomous Navigation for Detrital Environments project [5], which uses robotic operations to examine physical and chemical changes to sediments in basaltic glacio-fluvialaeolian environments, this research studies changes in sorting and rounding of fluvial-aeolian sediments along a glacier-proximal-to-glacier-distal transect in the outwash-plain of the risjkull glacier in SW Iceland (Fig. 1

Untangling Source-To-Sink Geochemical Signals in a ~3.5 Ga Martian Lake: Sedimentology and Geochemistry of the Murray Formation

Sedimentary rocks are historical archives of planetary surface processes; their grains, textures, and chemistry integrate the effects of source terrains, paleoclimatic conditions, weathering and transport processes, authigenic mineral precipitation, and diagenesis, which records groundwater chemistry through time. Source to Sink basin analysis seeks to constrain the influence of each of these different signals through sedimentary and geochemical analyses. Here, we use Mars Science Laboratory (MSL) Curiosity rover images and geochemical and mineralogical data from a traverse across a portion of the Murray formationthe lowermost unit exposed in the Gale crater central moundto begin to constrain the aspects of the source to sink system that formed this Martian mudstone between 3.7 and 3.2 Ga