scholarly journals Deriving Surface Ages on Mars Using Automated Crater Counting

2020 ◽  
Vol 7 (3) ◽  
Author(s):  
G. K. Benedix ◽  
A. Lagain ◽  
K. Chai ◽  
S. Meka ◽  
S. Anderson ◽  
...  
Keyword(s):  
Crater Counting

An Automated Method for Crater Counting Using Rotational Pixel Swapping Method

2017 ◽  
Vol 55 (8) ◽  
pp. 4384-4397 ◽  
Author(s):  
Satoru Yamamoto ◽  
Tsuneo Matsunaga ◽  
Ryosuke Nakamura ◽  
Yasuhito Sekine ◽  
Naru Hirata ◽  
...  
Keyword(s):  
Automated Method ◽  
Crater Counting

scholarly journals AN INVESTIGATION OF THE HYPOTHESES FOR FORMATION OF THE PLATY-RIDGED-POLYGONIZED TERRAIN IN ELYSIUM PLANITIA, MARS

2017 ◽  
Vol XLII-3/W1 ◽  
pp. 205-211
Author(s):  
Z. Yue ◽  
S. Gou ◽  
G. Michael ◽  
K. Di ◽  
H. Xie ◽  
...  
Keyword(s):  
Martian Surface ◽  
Basalt Lava ◽  
Regional Environment ◽  
Low Viscosity ◽  
Quantitative Measurements ◽  
Scientific Exploration ◽  
Pack Ice ◽  
Crater Counting ◽  
Imaging Science ◽  
Resolution Imaging

The origin of the platy-ridged-polygonized (PRP) terrains on Martian surface has long been debated. The terrain has generally been classified as water, pack ice, or basalt lava related flow. The crater counting results of the PRP terrains suggest they are geologically very young; therefore, they are significant in understanding the recent evolution of Mars. This work evaluated the current hypotheses through detailed analysis of the distribution and microtopographies with the High Resolution Imaging Science Experiment (HiRISE) images for the PRP terrains in Elysium Planitia, Mars. Quantitative measurements and statistics of the typical features of the PRP terrains were also made. In addition, we also found an analog site in Tarim Basin in Xinjiang, China. Our results suggest that mud flow is responsible for the formation of the PRP terrains on the Mars surface, although the hypothesis of low-viscosity basalt lava floods cannot be completely excluded. This finding implies that a regional environment suitable for liquid water may have existed in recent geologic time, which has great importance for future Mars scientific exploration.

Lava flow ages in northeastern Oceanus Procellarum: The need for calibrating crater counting procedures

Icarus ◽  
2021 ◽  
pp. 114838
Author(s):  
Thomas A. Giguere ◽  
Joseph M. Boyce ◽  
Jeffrey J. Gillis-Davis ◽  
David Trang ◽  
Julie D. Stopar
Keyword(s):  
Lava Flow ◽  
Crater Counting

Testing models for the formation of the equatorial ridge on Iapetus via crater counting

Icarus ◽  
2018 ◽  
Vol 302 ◽  
pp. 134-144
Author(s):  
Amanda L. Damptz ◽  
Andrew J. Dombard ◽  
Michelle R. Kirchoff
Keyword(s):  
Crater Counting

scholarly journals NanoSIMS and EPMA dating of lunar zirconolite

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Nian Wang ◽  
Qian Mao ◽  
Ting Zhang ◽  
Jialong Hao ◽  
Yangting Lin
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Lunar Meteorite ◽  
Geochemical Study ◽  
Lunar Rocks ◽  
Crater Counting ◽  
Resolution Analysis ◽  
Lunar Mare ◽  
Mare Basalts ◽  
Non Destructive

Abstract Zirconolite is a common Zr-rich accessary mineral in mafic rocks. It is also an ideal U–Pb/Pb–Pb chronometer because it commonly contains high U content (mostly 0.1–10 wt%) and negligible initial Pb. However, zirconolite is usually very small (e.g., ~ 1 μm in width) in lunar rocks, requiring a high spatial resolution analysis. We analyzed a single, large (25 μm × 20 μm) grain of zirconolite in lunar meteorite NWA 4485 using Pb–Pb dating by NanoSIMS and U–Th–Pb dating by EPMA. The resultant U–Th–Pb age is 4540 ± 340 Ma (2σ) with a spatial resolution of 1.3 μm. The Pb–Pb age by NanoSIMS is 4348.5 ± 4.8 Ma (2σ) with a spatial resolution of ~ 2 μm, consistent with the age of 4352 ± 10 Ma and 4344 ± 14 Ma reported in the same meteorite and its paired meteorite NWA 4472. Although U–Th–Pb age is somewhat older, it still includes the NanoSIMS results within the analytical uncertainty. This work demonstrates the potential application of the combined EPMA dating and REE analysis of lunar zirconolite, with the benefits of high spatial resolution, non-destructive, and readily accessibility of the instrument. The precision of the EPMA dating (7.6%, 2σ) can be improved by increasing the counting time for Pb, U and Th. We expect to apply this EPMA technique for a quick and non-destructive age survey and geochemical study of zirconolite grains from the lunar mare basalts newly returned by Chang’E-5 mission which landed on a very young (1.2–2.0 Ga by crater-counting chronology) basalt unit in Procellarum KREEP Terrain.

scholarly journals Using Size and Composition to Assess the Quality of Lunar Impact Glass Ages

Geosciences ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 85 ◽  
Author(s):  
Pham Nguyen ◽  
Nicolle Zellner
Keyword(s):  
Planetary Science ◽  
Lunar Samples ◽  
Crater Counting ◽  
Lunar Impact ◽  
Impact Glass ◽  
Counting Statistics ◽  
The Impact ◽  
Proper Interpretation ◽  
Orbital Data

Determining the impact chronology of the Moon is an important yet challenging problem in planetary science even after decades of lunar samples and other analyses. In addition to crater counting statistics, orbital data, and dynamical models, well-constrained lunar sample ages are critical for proper interpretation of the Moon’s impact chronology. To understand which properties of lunar impact glasses yield well-constrained ages, we evaluated the compositions and sizes of 119 Apollo 14, 15, 16, and 17 impact glass samples whose compositions and 40Ar/39Ar ages have already been published, and we present new data on 43 others. These additional data support previous findings that the composition and size of the glass are good indicators of the quality of the age plateau derived for each sample. We have further constrained those findings: Glasses of ≥200 μm with a fraction of non-bridging oxygens (X(NBO)) of ≥0.23 and a K2O (wt%) of ≥0.07 are prime candidates for argon analyses and more likely to yield well-constrained 40Ar/39Ar ages. As a result, science resulting from impact glass analyses is maximized while analytical costs per glass are minimized. This has direct implications for future analyses of glass samples for both those in the current lunar collection and those that have yet to be collected.

scholarly journals Crater counting

2003 ◽  
Vol 44 (4) ◽  
pp. 4.21-4.21
Author(s):  
Phil Bland
Keyword(s):  
Crater Counting

The role of intrusive magmatism in shaping Venus’ present-day crust and its age distribution

2020 ◽  
Author(s):  
Sruthi Uppalapati ◽  
Tobias Rolf ◽  
Stephanie Werner
Keyword(s):  
Mantle Convection ◽  
Plate Tectonics ◽  
Numerical Models ◽  
Age Distribution ◽  
Crustal Thickness ◽  
Dominant Mode ◽  
Age Variations ◽  
Spherical Annulus ◽  
Crater Counting ◽  
History Of

<p>In its bulk properties, Venus appears similar to Earth, but both planets have developed substantially different geodynamic regimes. Earth has plate tectonics with a continuously renewed surface and its crustal distribution is very dichotomous in composition, thickness, and age. Venus, on the other hand, presently displays a period of a stagnant-lid regime, which may or may not was interrupted by catastrophic events of tectonic recycling during its history. Venus’ crustal thickness is not well constrained, but likely thicker than Earth’s oceanic crust; pronounced crustal dichotomy may be possible but evidence needs yet to be found. The age of the crust appears rather uniform, which traditionally has been taken as evidence that an episodic overturn must have taken place. However, recent arguments have challenged the episodic overturn hypothesis and favor a more continuous stagnant lid on Venus.</p><p> </p><p>To resolve the problem of Venus’ geodynamic regime understanding the generation of Venus’ crust in a dynamic context that also considers the underlying mantle is necessary. This can be achieved using numerical models of mantle convection tailored to Venus, which include the basic complexities of planetary mantle convection in terms of effective rheology, mineralogy and melting processes. Still, previous models have essentially failed to predict the thickness and age characteristics of Venus’ crust. One possible reason is that these models only considered extrusive volcanism, which renews the surface directly, while intrusive magmatism does not. Yet, intrusion seems the dominant mode of magmatism at least on Earth, so we investigate its influence in our model and evaluate whether this ingredient is key to predict Venus’ crustal characteristics.</p><p> </p><p>Using the code StagYY, we compute a suite of mantle convection models in 2D spherical annulus geometry that run through the entire solid-state history of Venus. We vary the partitioning of intrusive and extrusive volcanism from purely extrusive to dominantly intrusive and predict the present-day distributions of crustal thickness and surface age in the stagnant lid regime. With more intrusive magmatism, average crustal thickness is reduced by 20-25%, but mean crustal thickness still exceeds other independent estimates. The surface is on average much older, which is more consistent with mean age estimates from crater counting. However, lateral age variations also become stronger with dominantly intrusive volcanism, which indicates that volcanism keeps going on, but is more restricted spatially. Governing parameters like mantle reference viscosity and relative enrichment of heat-producing elements into the crust change the absolute values of mean crustal thickness and surface age, but do not improve surface age uniformity. This is somewhat at odds with Venus’ seemingly uniform surface age, so suitable conditions for this possibility are further evaluated in models featuring episodic overturn events.</p>

Minimum effective area for high resolution crater counting of martian terrains

Icarus ◽  
2015 ◽  
Vol 245 ◽  
pp. 198-240 ◽  
Author(s):  
Nicholas H. Warner ◽  
Sanjeev Gupta ◽  
Fred Calef ◽  
Peter Grindrod ◽  
Nathan Boll ◽  
...  
Keyword(s):  
High Resolution ◽  
Effective Area ◽  
Crater Counting
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