Remote sensing studies of the Orientale Region of the Moon: A pre‐Galileo view

Hawke, B. R.; Lucey, P. G.; Taylor, G. J.; Bell, J. F.; Peterson, C. A.; Blewett, D. T.; Horton, Kyle G.; Smith, G. A.; Spudis, P. D.

doi:10.1029/91gl02667

Cited by 43 publications

(38 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The anorthosites that occur in the inner ring may have been derived firom a layer of pure anorthosite that existed at depth beneath a more pyroxene rich unit in the Humorum basin target site. Pure anorthosites have now been identified on the inner rings of Orientale, Nectaris, Grimaldi, and Humorum basins [Spudis et al, 1984[Spudis et al, , 1989Hawke et al, 1991aHawke et al, ,b, 1992a. Luceyeífl/.…”

Section: Resultsmentioning

confidence: 99%

Remote sensing studies of the terrain northwest of Humorum Basin

Hawke

Peterson

Lucey

et al. 1993

Geophysical Research Letters

View full text Add to dashboard Cite

Abstract. We have used near-inftarcd reflectance spectra and Earth-based radar data to investigate the composition and origin of the various geologic units northwest of Humorum basin as well as the stratigraphy of the Humorum pre-Ímpact target site. The results of our spectral analysis indicate that at least a portion of the inner, m are-bounding ring is composed of pure anorthosite. Other highlands units in the region are dominated by noritic anorthosite.

show abstract

Section: Resultsmentioning

confidence: 99%

Remote sensing studies of the terrain northwest of Humorum Basin

Hawke

Peterson

Lucey

et al. 1993

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…In previous analyses [Li et al, 1996], an image-based spectral mixture modeling was used in the investigation of the southern edge of the Grimaldi basin. Critical evaluation of results from both linear and nonlinear mixture modeling methods maldi have mafic assemblages dominated by high-Ca pyroxenes and exhibit TiO 2 abundances of 2-3%, while the primary ejecta deposits of the Grimaldi basin are dominated by noritic anorthosite and anorthositic norite [Hawke et al, 1991;Greeley et al, 1993;Peterson et al, 1995]. While the mare age varies across the Grimaldi basin , Williams et al, 1995, the age for the region of our study is estimated to be 3.25 Ga by Greeley et al [1993] and 3.12 Ga by Williams et al [ 1995].…”

Section: Introductionmentioning

confidence: 99%

Compositional gradients across mare‐highland contacts: Importance and geological implication of lateral transport

Li¹,

Mustard²

2000

J. Geophys. Res.

View full text Add to dashboard Cite

Observations of mixing across mare-highland contacts using high-resolution Clementine data allow a new assessment of the relative importance of vertical versus lateral mass transport on the Moon at least at mare-highland contact. We analyze mare-highland contacts in the Grimaldi, Orientale, and Fecunditatis basins and Tsiolkovsky crater through image-based nonlinear spectral mixture modeling of Clementine ultraviolet-visible (UV-VIS) light spectrometer multispectral data. The mare in these regions differ in ages, but they are characterized by having simple geological contacts. The symmetric distribution of mare and highland soil constituents across their geological contact indicates that lateral transport is more efficient than deep vertical transport during the formation of the observed mixing zones. Observations across the lunar limb with the Clementine UV-VIS filters show that there is a stray light component of scattered light across high-contrast albedo boundaries. However, the magnitude and spatial properties of scattered light do not significantly affect the nature of compositional boundaries determined here. Since repetitive meteorite bombardment governs lateral transport across the geological contacts and is a random process, a stochastic model is developed to describe this lateral transport. Analysis of the power decay law for crater ejecta thickness indicates that the high-velocity ejecta travels long distances and follows a -3 power decay law. This results in an infinite variance, which requires an anomalous diffusion model since a classical diffusion model would be invalid. Mathematical modeling supports this result where it is shown that classical diffusion produces a relatively poor fit to profiles of material abundance, while the anomalous diffusion model fits the profiles adequately. These results indicate that high-velocity ejecta dominates the formation of the observed compositional gradients, while the ejecta near the crater rim is relatively less important. On the basis of these ejecta distributions and the assumption of random impact cratering, we derive a relationship that can be used as an index for relative age dating of geological contacts as well as for investigating cratering rates.

show abstract

“…These zones correspond, in part, to small fresh craters for which spectral reflectance data from Earth-based telescopes show no mafic absorption [Hawke et al, 1991[Hawke et al, , 1993. Hawke and coworkers interpreted the spectra to indicate the presence of pure anorthosite deposits.…”

Section: Geologic Settingmentioning

confidence: 99%

Compositional studies of the Orientale, Humorum, Nectaris, and Crisium lunar basins

Bussey¹,

Spudis²

2000

J. Geophys. Res.

View full text Add to dashboard Cite

Abstract. We have used full-resolution (250 m/pixel) Clementine images to map the compositions of ejecta from four multiring basins on the Moon: Orientale, Humorurn, Nectaris, and Crisium. All basins have relatively feldspathic ejecta, with iron contents ranging from 2 to 6 wt % Fee. Some basins show remarkably homogeneous ejecta blankets (Orientale), while others display distinct compositional zoning within exterior sectors of the basin (Crisium); in some cases this zoning correlates with morphologically observed ejecta facies (Nectaris). The iron-poor composition of most basin ejecta indicates that the crust of the Moon at these locations is feldspathic down to depths of at least several tens of kilometers, the likely sampling depth of basin-forming impacts. The inner rings of all four basins display massifs and small crater floors of nearly pure anorthosite (Fee < 1 wt %), virtually the only such occurrences of this rock type on the Moon. Because basin rings are structurally emplaced topographic elements derived from depths of at least 10-20 km into the Moon, we postulate that basin inner rings are sampling a unique stratigraphic level in the Moon and at these depths, the primordial, pristine anorthositic crust of the Moon is largely preserved. Below this zone of anorthosite is the more mafic region of the lower crust, probably having "highland basalt" composition (Fee -10 wt %, A12e 3 -18-22 wt %). The petrologic nature of lower crustal levels remains uncertain but must at least in part include members of the mafic highland suite, such as norites and troctolites. IntroductionThe formation of impact basins has had a profound effect in shaping the Moon. These impacts excavated vast amounts of material and redistributed it across the lunar surface. We are using basins as probes to build up a three-dimensional picture of the crust. By studying the variations in composition of basin ejecta deposits, we have the opportunity to look "into" the crust of the Moon to learn about its makeup and origin. In this paper we discuss the results of a study of several nearside impact basins using the Clementine multispectral data set. The Clementine mission has given us complete coverage of the Moon, allowing all exposed basin ejecta to be characterized. Moreover, the newly developed techniques

show abstract

Remote sensing studies of the Orientale Region of the Moon: A pre‐Galileo view

Cited by 43 publications

References 9 publications

Remote sensing studies of the terrain northwest of Humorum Basin

Remote sensing studies of the terrain northwest of Humorum Basin

Compositional gradients across mare‐highland contacts: Importance and geological implication of lateral transport

Compositional studies of the Orientale, Humorum, Nectaris, and Crisium lunar basins

Contact Info

Product

Resources

About