Puddingstone, also known as either pudding stone or plum-pudding stone, is a popular name applied to a type of conglomerate that consists of distinctly rounded pebbles whose colours contrast sharply with the colour of the finer-grained, often sandy, matrix or cement surrounding them. The rounded pebbles and the sharp contrast in colour gives this type of conglomerate the appearance of a raisin or

Christmas pudding Christmas pudding is sweet, boiled or steamed pudding traditionally served as part of Christmas dinner in Great Britain, Britain and other countries to which the tradition has been exported. It has its origins in England in the Middle Ages, me ...

.Neuendorf, K.E.K., J.P. Mehl, Jr., and J.A. Jackson (2005) ''Glossary of Geology.'' Springer-Verlag, New York, 779 pp., The McGraw-Hill Companies (2003) ''McGraw-Hill dictionary of geology and mineralogy'', 2nd ed. The McGraw-Hill Companies, Inc, New York, 420 pp., There are different types of puddingstone, with different composition, origin, and geographical distribution. Examples of different types of puddingstones include the Hertfordshire, Schunemunk, Roxbury, and St. Joseph Island (Drummond Island) puddingstones.

Hertfordshire puddingstone

Hertfordshire puddingstone is a

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant f ...

-cemented conglomerate composed of rounded

flint Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone. Historically, flint was widely used to make stone tools and start ...

pebble A pebble is a clastic rocks, clast of rock (geology), rock with a grain size, particle size of based on the Particle size (grain size), Udden-Wentworth scale of sedimentology. Pebbles are generally considered larger than Granule (geology), gra ...

s and cobbles with matrix of fine

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural ...

and silica cement. The Hertfordshire Puddingstone is characterized by silica-cemented flint gravel that is brown to deep red in colour and often exhibits black exteriors and thin rinds on cut or polished surfaces. It typically occurs scattered across the land surface as isolated

concretion A concretion is a hard and compact mass formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. Concretions are often ovoid or spherical in shape, although irregular shapes a ...

-like masses in the areas of

Hertfordshire Hertfordshire ( or ; often abbreviated Herts) is a ceremonial county in the East of England and one of the home counties. It borders Bedfordshire to the north-west, Cambridgeshire to the north-east, Essex to the east, Greater London to the ...

and Plumstead Common,

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

. Large masses of Hertfordshire Puddingstone often occur within local

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

glacial

till image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...

s. More than a dozen large blocks of this puddingstone were recovered from

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

sediments during construction of the A10 bypass from Thundridge to Puckeridge in 2004. This indicates that the loose blocks of Hertfordshire Puddingstone were probably eroded out of these sediments. Although it is hypothesized that it is groundwater

silcrete Silcrete is an indurated (resists crumbling or powdering) soil duricrust formed when surface soil, sand, and gravel are cemented by dissolved silica. The formation of silcrete is similar to that of calcrete, formed by calcium carbonate, and ferri ...

, its origin remains unresolved.Lovell, B., and J. Tubb (2006
''Ancient Quarrying of Rare in situ Palaeogene Hertfordshire Puddingstone.''
Mercian Geologist. 16(3):185-189.Perkins, S. (2005
''Hertfordshire Puddingstone.''East Herts Rock Club
Ware, England.

Schunemunk puddingstone

The Schunemunk puddingstone is a conglomerate in

New York New York most commonly refers to: * New York (state), a state in the northeastern United States * New York City, the most populous city in the United States, located in the state of New York New York may also refer to: Places United Kingdom * ...

and

New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...

that is part of a thick

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

formally known as the Skunnemunk Conglomerate. It is exposed extensively on Bearfort Mountain, in Boonton and Rockaway Township in New Jersey and on Schunemunk Mountain in New York. This puddingstone is a distinctive, Late

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

, grayish-purple to grayish-red, thin to very thick-bedded, cross–bedded, conglomerate. Within the Skunnemunk Conglomerate, it is interbedded with grayish-purple to grayish-red

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

, thin-bedded, medium-gray sandstone, and greenish-gray and grayish-red

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

with

mudcrack Mudcracks (also known as mud cracks, desiccation cracks or cracked mud) are sedimentary structures formed as muddy sediment dries and contracts.Jackson, J.A., 1997, ''Glossary of Geology'' (4th ed.), American Geological Institute, Alexandria, VA ...

s. This conglomerate consists of pebbles and cobbles of white vein

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

, red and green

quartzite Quartzite is a hard, non- foliated metamorphic rock that was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tecton ...

, sandstone, red and gray

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...

, and red shale. The grayish-purple to grayish-red conglomerate and sandstone is cemented largely by

hematite Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...

and microcrystalline quartz. The cobbles that it contains range in size from to .Herman, G.C., and J.P. Mitchell (1991) ''Bedrock Geologic Map of the Green Pond Mountain Region from Dover to Greenwood Lake, New Jersey.'' Geological Map Series no. 91-2. New Jersey Geological and Water Survey, Trenton, New Jersey.Merguerian, C., and J.E. Sanders (1992) ''Guide 17: Delaware Water Gap and Vicinity, New Jersey and Pennsylvania, Trip 23: 20 June 1992.'' Duke Geological Laboratory, Westbury, New York. Pieces of Skunnemunk Conglomerate are easy to recognize and have been found in glacial deposits throughout the lower Hudson Valley region.Anonymous (2013a
''The Green Pond Outlier.''
Geology of National Parks, United States Geological Survey, Reston, Virginia.

Roxbury puddingstone

The Roxbury puddingstone is a massive,

Ediacaran The Ediacaran ( ) is a geological period of the Neoproterozoic geologic era, Era that spans 96 million years from the end of the Cryogenian Period at 635 Million years ago, Mya to the beginning of the Cambrian Period at 538.8 Mya. It is the last ...

, clast-supported pebble and cobble conglomerate that occurs within the Brookline Member of the Roxbury Conglomerate that is exposed around

Boston Boston is the capital and most populous city in the Commonwealth (U.S. state), Commonwealth of Massachusetts in the United States. The city serves as the cultural and Financial centre, financial center of New England, a region of the Northeas ...

Massachusetts Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode ...

region. This conglomerate is composed of a grey feldspathic sand matrix and well-rounded pebbles and cobbles of quartzite,

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

felsite Felsite is a very fine-grained volcanic rock that may or may not contain larger crystals. Felsite is a field term for a light-colored rock that typically requires petrographic examination or chemical analysis for more precise definition. Color ...

, and quartz monzonite. The beds of ‘puddingstone’ are complexly interbedded with layers of massive

diamictite Diamictite (; from Ancient Greek (): 'through' and (): 'mixed') is a type of lithified sedimentary rock that consists of nonsorted to poorly sorted terrigenous sediment containing particles that range in size from clay to boulders, suspended ...

and laminated and graded

argillite Argillite () is a fine-grained sedimentary rock composed predominantly of Friability, indurated clay particles. Argillaceous rocks are basically lithified muds and Pelagic sediment, oozes. They contain variable amounts of silt-sized particles. T ...

and sandstone. It likely accumulated as

turbidite A turbidite is the geologic Deposition (geology), deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean. Sequencing ...

s and submarine slumps within a submarine fan or outer slope environment within a deep rift basin submerged by marine waters.Carto, S.L., and N. Eyles (2011) ''Chapter 43 The Squantum Member of the Boston Basin, Massachusetts, USA'' In: E. Arnaud, G.P. Halverson, and G. Shields-Zhou, eds. pp. 475-480, The Geological Record of Neoproterozoic Glaciations. Memoirs no. 36. Geological Society, London, England.Passchier, S., and E. Erukanure (2010) ''Palaeoenvironments and weathering regime of the Neoproterozoic Squantum ‘Tillite’, Boston Basin: no evidence of a snowball Earth.'' Sedimentology. 57(6):1526–1544.

Jasper conglomerate

Jasper conglomerate, which is also denominated "pebble jasper conglomerate", "Saint Joseph Island puddingstone", "Drummond Island puddingstone", or "Michigan(ian) puddingstone", occurs in Saint Joseph Island and the vicinity of the Saint Mary's River, north and northwest of the Bruce Mines of

Northern Ontario Northern Ontario is a primary geographic and quasi-administrative region of the Provinces and territories of Canada, Canadian province of Ontario, the other primary region being Southern Ontario. Most of the core geographic region is located on p ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

, circa east of Sault Sainte Marie, Ontario. In these locales, it occurs as thick beds of

Paleoproterozoic The Paleoproterozoic Era (also spelled Palaeoproterozoic) is the first of the three sub-divisions ( eras) of the Proterozoic eon, and also the longest era of the Earth's geological history, spanning from (2.5–1.6 Ga). It is further sub ...

pebble conglomerate within the medial part of a

that is named the Lorrain Formation of the Cobalt Group. The jasper conglomerate consists of subrounded pebbles of red jasper, black chert, white quartzite, hematite, and semi-transparent quartz in a matrix of coarsely grained quartzite. It contains circa 30% to 90% of pebbles. Within the deposits of Lorrain Formation, the jasper conglomerates occur principally as the sedimentary fills of erosional troughs and channels of what are interpreted to be either

alluvial fan An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to Semi-arid climate, semiar ...

s or deposits of

braided river A braided river (also called braided channel or braided stream) consists of a network of river channel (geography), channels separated by small, often temporary, islands called ''braid bars'' or, in British English usage, ''aits'' or ''eyots''. ...

.Lowey, G.W. (1985) ''Stratigraphy and Sedimentology of the Lorrain Formation, Huronian Supergroup (Aphebian), Between Sault Ste. Marie and Elliot Lake, Ontario, and Implications For Stratiform Gold Mineralization.'' Open File Report no. 1154. Geological Survey of Canada, Ottawa, Canada.Baumann, S. D. J., T. Arrospide, and A. E. Wolosyzn (2011) ''Preliminary Redefinition of the Cobalt Group (Huronian Supergroup), in the Southern Geologic Province, Ontario, Canada.'' Midwest Institute of Geosciences and Engineering, Chicago, Illinois, USA. These deposits are inferred to be nonglacial in origin and immediately postdate the Paleoproterozoic Makganyene glaciation.Kopp R. E., J. L. Kirschvink, I. A. Hilburn, and C. Z. Nash. (2005) ''The Paleoproterozoic snowball Earth: a climate disaster triggered by the evolution of oxygenic photosynthesis.'' Proceedings of the National Academy of Sciences. 102(32): 11131–6. Elsewhere, e. g. in

Drummond Island Drummond may refer to: Places Antarctica * Drummond Peak, King Edward VII Land * Drummond Glacier, Graham Land Canada * Drummond (federal electoral district), a Quebec federal riding * Drummond (provincial electoral district), Quebec ...

Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, jasper conglomerate, there denominated "Drummond Island puddingstone", occurs as loose gravel within

glacial drift In geology, drift is a name for all sediment (clay, silt, sand, gravel, boulders) transported by a glacier and deposited directly by or from the ice, or by glacial meltwater. Drift is often subdivided into unstratified (unsorted) drift ( glac ...

. These fragments of jasper conglomerate are

glacial erratic A glacial erratic is a glacially deposited rock (geology), rock differing from the type of country rock (geology), rock native to the area in which it rests. Erratics, which take their name from the Latin word ' ("to wander"), are carried by gla ...

s that continental

ice sheet In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacier, glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are the Antarctic ice sheet and the Greenland ice sheet. Ice s ...

s from Northern Ontario eroded and then spread throughout Michigan, including in Drummond Island, and as far south as

Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...

and

Kentucky Kentucky (, ), officially the Commonwealth of Kentucky, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Illinois, Indiana, and Ohio to the north, West Virginia to the ...

during repeated glacial advances and retreats.Slawson, C. B. (1933) ''The Jasper Conglomerate, an Index of Drift Dispersion.'' The Journal of Geology. 41(5): 546–52.

Other examples

* Schirmeck, France * Fairburn, South Dakota * Farringdon, England * East Worldham, England * Bayfield, Colorado

References

{{reflist

External links

*Anonymous (nd
''Hertfordshire Puddingstone.''East Herts Rock Club
Ware, England. *Kelley, J.G., (2009
''Drummond Island Puddingstone.''
Drummond Island Tourism Association, Drummond Island, Michigan. *Share, J. (2011a

ttp://written-in-stone-seen-through-my-lens.blogspot.com/ Written In Stone...seen through my lens *Share, J. (2011a
''Architectural Geology of Boston: The Roxbury Conglomerate (Puddingstone) Part II - Quarries and Building Stone.''Written In Stone...seen through my lens
*Tubb, J. (2009
''Ancient Quarrying of Rare in situ Palaeogene Hertfordshire Puddingstone (Lovell and Tubb Mercian Geologist August 2006). An update.''East Herts Rock Club
Ware, England. Sedimentary rocks Conglomerates (geology)