DOI: 10.1016/j.epsl.2017.12.043
Scopus记录号: 2-s2.0-85044267310
论文题名: Direct thermal effects of the Hadean bombardment did not limit early subsurface habitability
作者: Grimm R.E. ; Marchi S.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 485 起始页码: 1
结束页码: 8
语种: 英语
英文关键词: habitability
; Hadean bombardment
; impact heating
; thermal evolution
Scopus关键词: Gallium
; Groundwater
; Projectiles
; Silicates
; Sterilization (cleaning)
; Detrital zircon
; Ground-water infiltration
; habitability
; Hadean bombardment
; Impact heating
; Subsurface biosphere
; Thermal evolution
; Thermal model
; Surface waters
英文摘要: Intense bombardment is considered characteristic of the Hadean and early Archean eons, yet some detrital zircons indicate that near-surface water was present and thus at least intervals of clement conditions may have existed. We investigate the habitability of the top few kilometers of the subsurface by updating a prior approach to thermal evolution of the crust due to impact heating, using a revised bombardment history, a more accurate thermal model, and treatment of melt sheets from large projectiles (>100 km diameter). We find that subsurface habitable volume grows nearly continuously throughout the Hadean and early Archean (4.5–3.5 Ga) because impact heat is dissipated rapidly compared to the total duration and waning strength of the bombardment. Global sterilization was only achieved using an order of magnitude more projectiles in 1/10 the time. Melt sheets from large projectiles can completely resurface the Earth several times prior to ∼4.2 Ga but at most once since then. Even in the Hadean, melt sheets have little effect on habitability because cooling times are short compared to resurfacing intervals, allowing subsurface biospheres to be locally re-established by groundwater infiltration between major impacts. Therefore the subsurface is always habitable somewhere, and production of global steam or silicate-vapor atmospheres are the only remaining avenues to early surface sterilization by bombardment. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110041
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
There are no files associated with this item.
作者单位: Planetary Science Directorate, Southwest Research Institute, 1050 Walnut St #300, Boulder, CO, United States
Recommended Citation:
Grimm R.E.,Marchi S.. Direct thermal effects of the Hadean bombardment did not limit early subsurface habitability[J]. Earth and Planetary Science Letters,2018-01-01,485