‘Terrestrial lava tubes as analogues for Mars – a review of the mineralogy and biosignatures of lava tubes from Iceland and the Terceira islands.’

2021 ◽  
Author(s):  
Mahid Ahmed ◽  
Nina Kopacz ◽  
Inge Loes ten Kate
Keyword(s):  
Regions Of Interest ◽  
Lava Tube ◽  
Lava Tubes ◽  
Thin Sections ◽  
The North ◽  
Point Analysis ◽  
Alteration Processes ◽  
Specific Alteration ◽  
Imagej Software ◽  
Areas Of Interest

<p>Lava tubes have been detected on Mars and because of their subsurface nature are shielded from the harsh conditions at the surface. If water intersects with the Martian lava tubes, a life nurturing environment may exist locally in these tubes. Lava tubes on Iceland and the Azores may support similar conditions as lava tubes on Mars and have been shown to contain a wide variety of microbes. [Planetary Analogues and Lava Tube ] (PELE) field expeditions have been setup to understand the relationship between microbes and susbtrate and the preservation of microbes in deeptime within these systems. Within such systems biogenic and hydrothermal alteration processes are not necessarily mutually exclusive and a good understanding of the mineralogy helps distinguish one from the other. Here, I have performed an analytical study analysing basalt mineralogy from recent lava flows from Iceland and Azores islands, attempting to distinguish between biogenic and hydrothermal signatures. I used a workflow of semi quantitative analysis using viewing thin sections under a light microscope to understand textural information. This was supplemented by  ImageJ software and using SEM+EDX for point analysis of regions of interest to shed light on our areas of interest. My results showed some ambiguous features linked to alteration in a sample in the north of Iceland related to clays or spherulites, in the Azores vesicle infill of clays or devitrified glass were seen with potential bio signatures including carbon,calcum and phosphorous. These results may indicate environmental factors leading to location specific alteration or related to lava rock mineralogy. Contamination effects cannot be ignored and must be taken into consideration when reviewing these results. Overall these analyses will contribute to the larger PELE outcome by providing a complimentary workflow that can be used to assess biosignatures and specific regions of interest within lava tube rocks.</p><p> </p>

Machine Learning applied to Lunar Data to Characterize Potential Sites for Future Science, Mobile Exploration, Utilization, lunar Bases and Moon Villages.

2021 ◽  
Author(s):  
Daniël den Heijer ◽  
Bernard Foing
Keyword(s):  
Machine Learning ◽  
Regions Of Interest ◽  
Machine Learning Techniques ◽  
Identification Algorithm ◽  
South Pole ◽  
Lava Tubes ◽  
Crater Detection ◽  
Lunar South Pole ◽  
Areas Of Interest ◽  
Human Exploration

<p>The lunar south pole is of particular interest to researchers because of its unique geographical features. It contains craters where the near-constant sunlight does not reach the interior. These craters are of enormous importance in the process of human exploration of the moon.This research aims to develop an identification algorithm applied to LROC data to characterize and identify potential regions of interest on the lunar south pole. Such areas of interest include (surroundings of) lava tubes, skylights, crater detection for age estimation, and planning traverses for the Artemis successive missions.Identifying these regions will be done using machine learning techniques such as a deep convolutional neural network that will be trained on labeled data and are then used to identify and characterize new regions of interest.</p>

Building a Low-Manned Production Installation: Considerations for Rotating Equipment, Electrical & Automation Systems, and Digitalization

2021 ◽  
Author(s):  
Elgonda LaGrange
Keyword(s):  
Oil And Gas ◽  
Cost Savings ◽  
Decision Makers ◽  
The North ◽  
Automation Systems ◽  
The North Sea ◽  
Rotating Equipment ◽  
Using Data ◽  
Areas Of Interest ◽  
Insight Into

Abstract Nearly all oil and gas operators and engineering companies in the offshore sector today are engaged in programs to advance concepts for low-manned and/or normally unattended production installations (NUIs). When it comes to the design of these facilities, topsides rotating equipment and electrical, instrumentation, control, and telecommunications (EICT) packages represent key areas of interest for decision-makers, owing to the significant impact they can have on required manning levels. Over the past decade, the author's company has worked closely with major Operators in the U.S. and the North Sea to look at how existing technologies can be applied in these areas to safely facilitate de-manning of both brownfields and greenfields. This paper provides insight into these efforts. It also presents projected manpower and cost savings from de-manning, using data derived from both studies and real-world projects.

Banded sphalerite from the North Pennine Orefield

1991 ◽  
Vol 55 (380) ◽  
pp. 409-416 ◽  
Author(s):  
A. P. More ◽  
D. J. Vaughan ◽  
J. R. Ashworth
Keyword(s):  
Electron Microscopy ◽  
Ultra Violet ◽  
Crystal Defects ◽  
Growth Band ◽  
Thin Sections ◽  
The North ◽  
Slip Planes ◽  
High Concentrations ◽  
Growth Zoning

AbstractOptical microscopy of doubly polished thin sections of North Pennine sphalerite has revealed a range of previously unrecognised textures for the Alston Block mineralisation. Delicate growth zoning, interrupted by numerous solution disconformities, was seen in transmitted light. Two principal varieties of growth-banded sphalerite are recognised; the earlier (Type 1) is characterised by the development of thin opaque bands. Type 2 has colour bands between yellow and brown, correlated with iron content. In Type 1, iron levels (up to 3 wt.%) are not sufficient to account for the observed opacity. Ultra-violet and infra-red techniques failed to detect any organic inclusions. Electron microscopy revealed locally high concentrations of sub-micrometre inclusions, both beam-stable and beam-unstable, and a variety of growth-related crystal defects.Fluid inclusion thermometry in both sphalerite varieties and the accompanying quartz gangue implies a saline mineralising fluid (20–25 wt.% equiv. NaCl) at a relatively low temperature (100° to 140°C). Tubular inclusions are conspicuous. A deformation-induced lamelliform optical anisotropy is superimposed on a growth-related grid-iron anisotropy. Growth band offset is apparent where the deformation fabric cross-cuts the growth banding. Deformation on {111} twin and slip planes was indicated by electron microscopy.

scholarly journals Change-Point Analysis of Precipitation and Drought Extremes in China over the Past 50 Years

Atmosphere ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Min Liu ◽  
Pengfei Liu ◽  
Ying Guo ◽  
Yanfang Wang ◽  
Xinxin Geng ◽  
...  
Keyword(s):  
Change Point ◽  
Climate Extremes ◽  
Northwest China ◽  
Change Point Analysis ◽  
Human Society ◽  
The North ◽  
Point Analysis ◽  
Yangzi River ◽  
Increasing Trends ◽  
Cumulative Deviation

Increases in climate extremes and their impacts have attracted global attention recently. In this study, the change-point years of precipitation extremes (PEs) and drought extremes (DEs) were investigated by Moving t-Test at 500 stations across the six regions in China. The detailed temporal change processes of them were demonstrated by the cumulative deviation method based on the data from nine typical stations. The results showed that: 1) DEs were more significantly and widely increased than PEs, the stations with increasing trends of PEs and DEs accounted for greater than 52.6% and 61.6% of the total, respectively; 2) increasing trends of DEs were mainly distributed in the east of Hu Huanyong Line. In this area, the increasing change-point years of DEs often occurred in the early 1980s in the south of the Yangzi River, while occurred in the 1990s in the north of the Yangzi River; 3) increasing trends of PEs were mainly distributed in Qing-Tibet Platen, Northwest China, and the southeastern area of Hu Huanyong Line. In these areas, the increasing change-point years of PEs often occurred around 1990 in the southeast of Hu Huanyong Line, while often occurred in the early 1980s in Qing-Tibet Platen. The results indicated that the area in the southeast of Hu Huanyong Line was under the threats of both PEs and DEs, this may produce severe impacts on agriculture, environment, water resources management, human society, etc.

Characteristics and Sequences of Fractures in the Tight Conglomerate Reservoirs of Jiulongshan Structure

2014 ◽  
Vol 900 ◽  
pp. 689-692
Author(s):  
Lei Gong ◽  
Shuai Gao ◽  
Shu Ju Guo ◽  
Jian Guo Huang ◽  
Xian Xian Tao
Keyword(s):  
Fractal Dimension ◽  
Fractal Dimensions ◽  
Areal Density ◽  
Lower Jurassic ◽  
Fracture Origin ◽  
Thin Sections ◽  
Western Sichuan ◽  
The North ◽  
Western Sichuan Basin ◽  
Natural Gas Reservoirs

Fracture is an important controlling factor for the distribution of natural gas reservoirs in the tight conglomerate reservoirs in the Lower Jurassic Zhenzhuchong Formation at the north of Western Sichuan basin. Using the data of outcrops, cores, image logs and thin sections, combined with experimental analysis, we analyze the fracture origin types, distribution characteristics and formation sequences. There are three types of fractures, i.e. tectonic fractures, diagenetic fractures and original fractures in the tight conglomerate reservoirs. Among them, tectonic fractures are dominant, which can be classified into four sets, i.e. E-W, nearly S-W, NWW-SEE, NEE-SWW orientations. According to the statistics of areal density and fractal dimension, the average fracture areal density is 0.31cm/cm2, with the bulk in the range of 0.15-0.60cm/cm2. The fracture fractal dimensions are distributed at 0.95-1.70. There is a well positive correlation between fracture areal density and fractal dimension. Micro-fractures are important channels that connect matrix intergranular pores and intragranular dissolved pores, which improve the connectivity among pores. The tectonic fractures in the study area were formed in two periods, i.e. the end of Cretaceous and the end of Neogene.

Microdiamonds, their classification and tectonic implications for the host eclogites from the Dabie and Su-Lu regions in central eastern China

2005 ◽  
Vol 69 (4) ◽  
pp. 509-520 ◽  
Author(s):  
Shutong Xu ◽  
Yican Liu ◽  
Guanbao Chen ◽  
Shouyuan Ji ◽  
Pei Ni ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Eastern China ◽  
Dabie Mountains ◽  
Thin Sections ◽  
The North ◽  
First Occurrence ◽  
Metamorphic Terrane ◽  
Central Eastern ◽  
Mixed Types

AbstractWe have found >10 in situ microdiamonds in thin sections of eclogites from the Dabie and Su-Lu regions of central eastern China since the first occurrence of microdiamond in eclogites from the Dabie Mountains (DMT) reported in 1992. The microdiamonds are found not only in the central part but also in the northern part of the DMT. Several free crystals have been recovered from the crushed eclogites from the central DMT. Most in situ microdiamonds are inclusions in garnets but a few larger ones are intergranular. Most of the diamondiferous eclogites in the central part of the DMT are associated with coesite. Most importantly, the observation of microdiamonds in northern Dabie lead us to question the supposition that this is a low-P metamorphic terrane. All the diamondiferous eclogites from both the north and central DMT are of continental affinity as demonstrated by their negative εNd values. Therefore, both the north and central eclogite belts in the DMT are considered to be from the deep subducted terrane. Five in situ microdiamonds and two free crystals are first reported in this paper. The dimensions of the in situ microdiamonds are 30–180 µm and the free crystals are up to 400–700 mm across. All the microdiamonds are confirmed as such by Raman spectroscopy. The results of an infrared spectroscopic investigation on two larger free crystals and two in situ microdiamonds show that all the microdiamonds from both the Dabie and Su-Lu regions are mixed types IaA and IaB diamonds and there is no indication of any synthetic microdiamonds in our samples because such synthetic microdiamonds are always rich in type Ib.

scholarly journals Development of Improved Characteristic Equations for Lake Rukwa in Tanzania

2019 ◽  
Vol 38 (1) ◽  
pp. 83-96
Author(s):  
Patric C. Valimba
Keyword(s):  
Change Point Analysis ◽  
Lake Area ◽  
Characteristic Equations ◽  
Surface Areas ◽  
Boundary Change ◽  
The North ◽  
Point Analysis ◽  
Contour Boundary ◽  
North And South ◽  
Topographical Maps

Often Lake Rukwa characteristics have been misreported in literature giving different volumes and surface areas at similar water surface elevations. This study aimed at establishing reliable lake characteristics elevation-area-storage equations for Lake Rukwa by utilising all available data and information to define the bathymetry and derive characteristic equations. A procedure was developed that combines historical lake extents, spot heights from topographical maps and surveyed lake bathymetry to define refined bathymetry to levels it has never reached. It combined spot heights around the lake and selected 13,934 surveyed points (from 107,938 available) within the lake confined by the 820 m land contour boundary and define topographical raster image, which was used to extract lake volumes and surface areas between the lowest point (778 m) and 820 m boundary. Change-point analysis was used to detect segmentation of the elevation-area and elevation-volume relationships, which were fitted to a shifted power model. Contours generated from a refined bathymetry raster indicated Lake Rukwa to comprise two north and south lake basins, which are separated by a ridge lying at an altitude of 794.3 m. The north and south lakes consist respectively of five (5) and three (3) deeper depressions (pools) paralleling the northwest- southeast Konongo Scarp, which are disconnected below altitudes 792 m (north) and 789.4 m (south). Characteristic elevation-area and elevation-volume equations are segmented for lake below ridge altitude (794.3 m) whereas single relationships prevail for a single Lake Rukwa. Comparison of lake volumes estimated by refined and old equations indicated underestimation of lake stored volumes between 782.2 m and 805.65 m altitudes and overestimation thereafter by the old equations although the under/over-estimation remained within 10% between 801 m and 812 m. Old elevation-area equations underestimate lake surface area of up to 796.8 m, thereafter overestimate the lake area up to an altitude of 804.85 m and above this altitude underestimation re-appear. The old equations under/over-estimation, however, remains within 11% for altitudes between 794.3 m and 810 m. The refined equations indicate surface areas of north and south lakes at ridge altitude to be 2,554.4 and 837.1 km2 , respectively forming a 3,391.5 km2 lake while at its highest recorded historical elevation of 804.69 m, Lake Rukwa is 183 km long and 17-51 km wide occupying an area of 5,614.7 km2 (north: 4,409.8 km2; south: 1,204.9 km2) and containing 58.243 km3 of water (north: 44.318 km3; south: 13.925 km3). The developed characteristic equations can be used for water management studies of Lake Rukwa.

scholarly journals GLOBAL EVOLUTION AND PALEOGEOGRAPHIC DISTRIBUTION OF MID - CRETACEOUS ORBITOLINIDS

2019 ◽  
Author(s):  
Marcelle Boudagher-Fadel ◽  
G. David Price
Keyword(s):  
Sea Level ◽  
Morphological Changes ◽  
Western Pacific ◽  
Northwest Pacific ◽  
Thin Sections ◽  
The North ◽  
Southern Tibetan Plateau ◽  
Stratigraphic Ranges ◽  
Tectonic Forces ◽  
The Western Pacific

Members of the Larger Benthic Foraminiferal (LBF) family Orbitolinidae occured from the Cretaceous to the Paleogene, however, they were most diverse during the mid-Cretaceous, and dominated the agglutinated LBF assemblages described from limestones of that period. Various orbitolinid species have been used to zone and date lithologies formed in the shallow, warm waters of the Aptian to the Early Cenomanian, and many, sometimes inaccurate, generic and sub-generic nomenclatures have been proposed to differentiate the often subtle morphological changes that orbitolinids exhibit over time. Until now, it has not been possible to develop an effective global overview of their evolution and environmental development because descriptions of specimens from Asia have been relatively rare. Following our recent study of over 1800 orbitolinid-rich thin sections of material from 13 outcrops of the Langshan Limestone, from the Southern Tibetan Plateau, and from the Barito Basin, South Kalimantan, Indonesia, it has been possible to compare the stratigraphic ranges of these orbitolinids with previously described Tethyan and American forms, based on the use of a planktonic zonal (PZ) scheme, itself tied to the most recent chronostratigraphic scale. This has allowed the reconstruction of the phylogenetic and paleogeographic evolution of the orbitolinids from their Valanginian origin in the Tethys. Although Tethys remained the paleogeographic focus for the orbitolinids, it is inferred here for the first time that a bi-directional paleogeographic migration of some orbitolinid genera occurred from Tethys to the Americas and also to the Western Pacific region. Our observations and dating confirm that global marine regressions in the Aptian were coincident with, and may well have facilitated, these orbitolinid transoceanic migrations. However, migration stopped after rising sea-level in the Early Albian appears to have again isolated these provinces from each other. Tectonic forces associated with the subduction of the Farallon Plate and further sea-level raises led to the opening of the Western Interior Seaway in the North America, which correlates with, and may have been the cause of, the Middle Albian (top of PZ Albian 2) extinction of the American orbitolinids. The extinction of the orbitolinids revealed that the Western Pacific province was split into two sub-provinces, with extinction occurring at the end of the Early Albian (top of PZ Albian 1) in the Northwest Pacific sub-province, and at the end of the Albian (top of PZ Albian 4) in the sub-province that is today South East Asia (on the margins and west of the Wallace Line). The final virtual extinction of the orbitolinids occurred at the end of the Cenomanian in the Tethyan province, which coincides with, and may have been caused by, global anoxic oceanic events that correlate with a near-peak Mesozoic eustatic sea-level high-stand that led to the overall global collapse of the paleotropical reef ecosystem at that time.

scholarly journals Strategies for Deploying a Sensor Network to Explore Planetary Lava Tubes

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6203
Author(s):  
Himangshu Kalita ◽  
Jekan Thangavelautham
Keyword(s):  
Low Cost ◽  
Line Of Sight ◽  
Communication Link ◽  
Wireless Power ◽  
Lava Tube ◽  
Long Distance ◽  
Lava Tubes ◽  
Distance Communication ◽  
High Resolution Images ◽  
Exploration Mission

Recently discovered pits on the surface of the Moon and Mars are theorized to be remnants of lava tubes, and their interior may be in pristine condition. Current landers and rovers are unable to access these areas of high interest. However, multiple small, low-cost robots that can utilize unconventional mobility through ballistic hopping can work as a team to explore these environments. In this work, we propose strategies for exploring these newly discovered Lunar and Martian pits with the help of a mother-daughter architecture for exploration. In this architecture, a highly capable rover or lander would tactically deploy several spherical robots (SphereX) that would hop into the rugged pit environments without risking the rover or lander. The SphereX robots would operate autonomously and perform science tasks, such as getting inside the pit entrance, obtaining high-resolution images, and generating 3D maps of the environment. The SphereX robot utilizes the rover or lander’s resources, including the power to recharge and a long-distance communication link to Earth. Multiple SphereX robots would be placed along the theorized caves/lava tube to maintain a direct line-of-sight connection link from the rover/lander to the team of robots inside. This direct line-of-sight connection link can be used for multi-hop communication and wireless power transfer to sustain the exploration mission for longer durations and even lay a foundation for future high-risk missions.

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