Lapurr Sandstone

{{Short description|Geological formation in Kenya}}

{{Infobox rockunit

| name = Lapurr Sandstone

| image =

| caption =

| type = Geological formation

| age = Campanian-Paleocene
~{{fossilrange|72|65}}

| period = Maastrichtian

| prilithology = Sandstone

| otherlithology =

| namedfor = Lake Turkana

| namedby =

| region = Rift Valley Province

| country = {{KEN}}

| coordinates = {{coord|4.3|N|35.8|E|display=inline,title}}

| paleocoordinates = {{coord|13.8|S|27.8|E|display=inline}}

| unitof =

| subunits =

| underlies = Oligocene basalt

| overlies = Precambrian metamorphic basement

| thickness = {{convert|400|-|610|m|ft|abbr=on}}

| extent = Turkana Basin, Great Rift Valley, Kenya

| area =

| map = {{Location map+ | Kenya

| relief = 1

| width = 250

| float = center

| places =

{{Location map~ | Kenya

| lat_deg = 4.3

| lon_deg = 35.8

| mark = Lightgreen pog.svg

| marksize = 12

}}

}}

| map_caption =

}}

The Lapurr Sandstone, also spelled Lapur Sandstone, previously considered part of the informal "Turkana Grits", is a geological formation in Kenya (Turkana County). It is the oldest unit in the Turkana Basin. The strata date back to the Late Cretaceous, likely Campanian to Maastrichtian, based on palynology and the presence of dyrosaurs and mosasaurs, the upper part of the unit likely extends into the Palaeogene, based on zircon dating.{{Cite journal|last1=Agyemang|first1=Prince C. Owusu|last2=Roberts|first2=Eric M.|last3=Downie|first3=Bob|last4=Sertich|first4=Joseph J. W.|date=August 2019|title=Sedimentary provenance and maximum depositional age analysis of the Cretaceous? Lapur and Muruanachok sandstones (Turkana Grits), Turkana Basin, Kenya|url=https://www.cambridge.org/core/product/identifier/S0016756818000663/type/journal_article|journal=Geological Magazine|language=en|volume=156|issue=8|pages=1334–1356|doi=10.1017/S0016756818000663|bibcode=2019GeoM..156.1334A|s2cid=134925592|issn=0016-7568}} It predominantly consists of fine-coarse arkosic sandstone, which has been interpreted as either been deposited in fluvial or shallow marine conditions.{{Cite journal|last1=Wescott|first1=W.A.|last2=Morley|first2=C.K.|last3=Karanja|first3=F.M.|date=May 1993|title=Geology of the "Turkana Grits" in the Lariu range and Mt. Porr areas, southern Lake Turkana, Northwestern Kenya|journal=Journal of African Earth Sciences (and the Middle East)|language=en|volume=16|issue=4|pages=425–435|doi=10.1016/0899-5362(93)90101-U|bibcode=1993JAfES..16..425W}} Dinosaur remains among other vertebrates have been recovered from it around Lokitaung Gorge, though these mostly consist of heavily abraded, isolated bones of robust morphology like sauropod limb bones and caudal vertebrae.Weishampel, et al. (2004). "Dinosaur distribution" Pp. 517-607. in Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. {{ISBN|0-520-24209-2}}. " Pp. 517-607.