Investigation of Sedimentary and Altered Deposits in and around Ladon Basin

Objectives: This proposal seeks to analyze and interpret sedimentary and hydrated deposits in and around Ladon basin, with implications for the aqueous history of Margaritifer Terra. Ladon basin and surroundings have some of the best-developed, preserved and exposed fluvial landforms and basin stratigraphy on Mars, making it an ideal site to test local and regional source-to-sink pathways of sedimentary rocks deposited by varying processes under changing environmental conditions dating from the Noachian through the Early Amazonian. The study area includes Ladon basin, northern Ladon Valles, and surrounding uplands. Where CRISM data is available, these deposits are characterized by clay signatures that could represent fluvial or lacustrine sediments, or hydrothermal alteration by volcanic or impact processes. The proposed tasks would make use of multiple complementary datasets and analyses (morphologic, mineralogic, and stratigraphic) to better establish the aqueous history of this important region of Mars as it relates to past climate and habitability. This study is especially time critical because two top priority Mars 2020 landing sites undergoing evaluation at nearby Eberswalde and Holden craters have likely been affected by the same aqueous processes that we intend to investigate as part of this proposal.

Methods: We have already identified deposits that are sedimentary (i.e., deposits that appear light-toned, sometimes layered, and associated with valleys and/or basins) and/or hydrated (as determined by hyperspectral data), and sufficiently covered by high resolution data sets to enable detailed analyses. In Task 1, we will utilize HiRISE and CTX images to evaluate the morphology, CRISM data to interpret the mineralogy, and these three data sets combined with Digital Terrain Models (DTMs) to determine the stratigraphy of sedimentary and hydrated deposits. Task 2 will synthesize the results of our analyses to evaluate the environmental conditions during emplacement of the deposits, including implications for regional versus localized aqueous activity that can be ascertained from their distribution, lithologies, and inferred origins. We intend to combine our new observations of what may be past habitable environments with results from previous, complementary studies elsewhere to place the origin of the deposits in a broader geologic framework, thereby helping to decipher the history of potentially habitable environments in the region relative to other geologic events.