Holocene Epoch

The Holocene epoch—formed from Greek words together meaning "entirely contempo"—is usually dated from virtually 12,000years ago and represents near 0.005% of the Quaternary menstruation.

From: Encyclopedia of the Anthropocene , 2018

Bail events and monsoon variability during Holocene—Bear witness from marine and continental athenaeum

Upasana S. Banerji , D. Padmalal , in Holocene Climatic change and Environment, 2022

12.1.one Holocene epoch

The Holocene epoch is the only geochronologic unit in the globe'southward geological history whose boundary has been divers based on climatostratigraphy. In contrast, biostratigraphy has been implemented to demarcate other Phanerozoic boundaries ( Ramesh et al., 2010). The term 'holocènes' was first coined past Paul Gervais (1867–1869, p. 32), which means "entirely recent," referring to the warm episode which commenced with the cease of the final glacial period (Walker et al., 2018). The first formal subdivisions of the Holocene were from Northern Europe and the substage boundaries were defined by radiocarbon dated chronozone and palynologically define biozones viz. Preboreal and Boreal (ten,000–8000 fourteenC yr BP), Atlantic and Sub-boreal (8000–2500 14C yr BP) and sub-Atlantic (post 2500 fourteenC year BP; Mangerud et al., 1974). However, such chronostratigraphic subdivisions based on biological evidence can provide local or regional scale climate and may lag in providing global scenario (Björck et al., 1998; Wanner et al., 2008). Recently, formal ratification of the Holocene epoch into three subdivisions has been proposed past Global Boundary Stratotype Sections and Points based on abrupt shifts in climate evident from water ice cadre of Greenland and speleothem of NE Bharat and thus named equally Greenlandian (11.seven–8.2 ka), Northgrippian (eight.two–4.2 ka), and Meghalayan (4.2 ka to 1950 Ad; Walker et al., 2019) stages. Basically, the Holocene subdivisions are made at ∼eleven.8 ka (onset of Holocene), ∼8.2 ka and ∼4.2 ka and these precipitous climatic events are generally encountered in most of the global records (Walker et al., 2018). The abrupt climatic event of 8.two ka and four.2 ka about in agreement with the two of the Bond events (BEs) evidenced from the North Atlantic Ocean (Bail et al., 2001). Bond and his team numbered the cold phases of the Holocene epoch from 0 to 8 wherein 0 corresponds to Trivial Ice Age (LIA: ∼0.v ka) and ane corresponds to Dark Age Cold Period (DACP: ∼i.four ka), while 2, 3, four, 5a, 5b, 6, vii, and 8 correspond to ∼ii.8, ∼iv.four, ∼5.five, ∼vii.5, ∼eight.1, ∼9.4, ∼x.3, and ∼11.1 ka (Fig. 12.2A), respectively (Bond et al., 2001; Wanner et al., 2011). Though, their drivers remain uncertain, some of the BEs demonstrate hemisphere calibration climatic teleconnections (Wanner et al., 2008; Fan et al., 2016). Further, the nine documented BEs and associated cooling phases have been linked with the reduced thermohaline circulation in the North Atlantic region (Zielhofer et al., 2019). The carbon-isotope composition of benthic foraminifera from the deep ocean sediment core of the subpolar north-eastern Atlantic suggested that deep-water production varied on a centennial−millennial timescale and the identified cold events (Oppo et al., 2003) and were mostly in understanding with the BEs (Bail et al., 2001). Based on BEs, a quasiperiodic "1500-twelvemonth" bicycle has been recognised in the IRD records of Holocene (Bond et al., 2001). This 1500-twelvemonth cycle plausibly represents a combination of 2 of the solar cycles viz. the Eddy cycle (chiliad yr) and the Hallstatt bicycle (2300 yr; Debret et al., 2009; Obrochta et al., 2012).

A close correlation between the millennial-calibration climate events of Northward Atlantic region and the Indian Summer Monsoon (ISM; Overpeck et al., 1996; Schulz et al., 1998) suggests a mechanistic link during the last ice age (Gupta et al., 2003). Unlike the ice age, a stable climate prevailed during the Holocene epoch wherein the aamplitude of North Atlantic climate variability was likewise little compared to the late Pleistocene D/O and H events. Thus, information technology is necessary to comprehend the link of ISM variability recorded in the continental and marine archives with the BEs, that was exclusively observed as a cold event of the North Atlantic Ocean during Holocene epoch.

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Holocene hydroclimatic shifts beyond the Indian subcontinent: A review based on interarchival coherences

Pavani Misra , ... Praveen One thousand. Mishra , in Holocene Climate change and Environment, 2022

15.6.1 Lake sediments

Oxygen isotopic tape for the Holocene epoch from the Himalaya is bachelor from two lakes, namely, Tso Moriri and Burfu ( Fig. 15.two). It is important to sympathise that multiple variables control the isotopic shifts in the Himalayan region. The δ18O (‰) records from this proglacial function of the land is complex to translate as fluctuations observed could be associated either with glacial melting or direct precipitation (Misra et al., 2019). Therefore, multiproxy analyses are required from this region to validate the isotopic signals. Instead of strengthened precipitation, the depleted δxviiiO (‰) values from these proglacial records at times may suggest increased inflow of glacial meltwater in the lacustrine system.

Fig 152

Effigy 15.2. Intra-archival comparison of oxygen isotopic records from the lacustrine deposits across the Indian subcontinent. The records include Tso Moriri (Mishra et al., 2015b), Burfu (Beukema et al., 2011), Karsandi (Dixit et al., 2018), Riwasa (Dixit et al., 2014a), Kotla Dahar (Dixit et al., 2014b), Banni (Pillai et al., 2017), and Lonar (Prasad et al., 2014). The black dashed line represents the Holocene–Pleistocene boundary, the two cerise dashed lines stand for the abrupt drying events globally recorded at eight.two and 4.2 kyr BP. The shaded regions represent the Younger Dryas (betwixt thirteen and 11.vii kyr BP) and the Holocene Climate Optimum (between 9 and 5 kyr BP).

Initially, around xvi kyr BP, reverse isotopic signals are observed at both lakes (Fig. fifteen.2). Tso Moriri shows enriched values while depleted values are observed at Burfu. Since Burfu is mainly a glacial-fed lake (Pant et al., 2006), the depletion observed in the δeighteenO (‰) values suggests an influx from glacial melting. Between 16 and ∼xiv kyr BP, the proportion of glacial meltwater input increases at Tso Moriri merely decreases at Burfu suggesting a drier climate at Tso Moriri simply increased atmospheric precipitation at Burfu (Fig. 15.two).

A short-wet phase is recorded at Tso Moriri between 13 and 11.7 kyr BP (Mishra et al., 2015a), whereas Burfu records a common cold catamenia betwixt 12.7 and 12.3 kyr BP which has been linked to the Younger Dryas event (Beukema et al., 2011). Even so, the Younger Dryas at Tso Moriri is recorded betwixt 11.7 and 11.2 kyr BP (Mishra et al., 2015a). Autonomously from the difference in the dominant climatic drivers observed by researchers at a fourth dimension at Tso Moriri and Burfu, the presence of millennial-scale lags and incoherence observed can too exist attributed to differences in the robustness of the chronological framework and their stratigraphic resolution. After xi.iii kyr BP, a synchronicity is observed in the isotopic signals with contribution from directly atmospheric precipitation at both the lakes suggesting a warmer climate with intensified monsoon (Fig. 15.2; Beukema et al., 2011; Mishra et al., 2015a). The δ18O (‰) paleolake records from Riwasa, Kotla Dahar, Karsandi, and Banni (Chachi) together requite insight into the Holocene climatic fluctuations from the eastern margin of Thar desert region (Fig. xv.2). The variations in the remainder of input to evaporative loss (P/E ratio) accept a pregnant effect on the lake's isotope rest in arid regions (Holmes et al., 2007; Liu et al., 2009). In hydrologically closed limnological systems, enriched (loftier) values mostly reflect preferential evaporative loss of the 16O (Pillai et al., 2017). The δ18Ocarb (‰) records of Riwasa and Karsandi propose initiation of lake filling started after eleven kyr BP and a elevation in wetness was recorded between 9.four and eight.3 kyr BP at Riwasa (Dixit et al., 2014a, 2018). A coherence in wetness is observed between Riwasa and Tso Moriri, as the latter also records a wet period betwixt 11 and viii.5 kyr BP (Dixit et al., 2014a; Mishra et al., 2015b). Between 11 and nine kyr BP, depleted δeighteenO (‰) values and lake deepening is also recorded at Lonar lake in Fundamental India (Prasad et al., 2014). Prevalence of dry weather condition is observed at Karsandi throughout betwixt 9 and 5.1 kyr BP, however an abrupt enrichment in δeighteenO (‰) values is recorded at Riwasa at ∼8.2 kyr BP (Dixit et al., 2014a, 2018). A point of ISM weakening is also recorded at Tso Moriri in the college Himalaya between 8.5 and 5.5 kyr BP, simply wet conditions continued to prevail at Lonar lake until ∼half dozen.2 kyr BP later on which ISM weakening was reported (Prasad et al., 2014). Nevertheless, unlike Riwasa, other lake records do not bear witness abrupt drying at 8.two kyr BP and instead record prolonged phases of drying and wetting effectually that fourth dimension. During the mid- to late-Holocene transition, the ISM weakened as enrichment in δ18O (‰) values is coherently recorded at Tso Moriri, Riwasa, Karsandi, and Lonar (Fig. xv.two). Approximately, between ∼vi and ∼4 kyr BP, Tso Moriri, Kotla Dahar, and Lonar lakes record gradual enrichment in δ18O (‰) with increased evaporation suggesting a long-term regional reduction in precipitation (Dixit et al., 2014b; Prasad et al., 2014; Mishra et al., 2015a, 2015b). Notwithstanding, at that place is a slightly contrasting signal observed at Karsandi which records wetter climate at ∼5.1 kyr BP (Dixit et al., 2018). Lonar lake in key Republic of india records a prolonged drought between 4.6 and 3.9 kyr BP, and Kotla Dahar near the desert boundary records abrupt enrichment in δeighteenO (‰) values at 4.i kyr BP suggesting a sudden aridification in the region (Fig. 15.2). Overall, there is a spatial coherence in aridity recorded during the mid to tardily Holocene transition. During the belatedly Holocene, all records testify a gradual increment in δ18O (‰) values indicating a weakened monsoon and a consistent increase in aridity across the land (Prasad et al., 2014; Mishra et al., 2015b; Pillai et al., 2017).

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Yellowish Sea

Sung Kwun Chough , in Geology and Sedimentology of the Korean Peninsula, 2013

14.5 Rising Sea Level

The sea-level curves of the Holocene epoch, derived from the Chinese coasts, mostly show a rapid rise from nearly −40  m (about ten   ka) to −ten   m (about seven   ka), followed by a gradual ascent (Feng and Wang, 1986; Pirazzoli, 1991; Yang and Xie, 1984). A refined curve of the Yangtze delta apparently, based on corrected data of long-term subsidence and tidal range, reveals that at that place was an early rapid rise up to about −4   m at near 7   ka and a wearisome rise since then (Chen and Stanley, 1998; Zong, 2004) (Figure 14.10). On the Korean coast, a sea-level curve (Flower and Park, 1985) shows a gradual rise of mean loftier-water level from −eight   g at about 8.5   ka to −2   m (nearly 5   ka) and a gradual ascent thereafter.

Figure fourteen.10. Holocene relative sea-level curves based on radiocarbon dates and estimated paleo-mean sea level in the Yangtze delta apparently (A) and the western declension of Korea (B).

 Source: (A) Zong, 2004 and (B) Chough et al. (2004) past permission of Geosciences Journal.

An integrated curve of the Korean coast shows a relatively rapid rise, up to −5   m about 7   ka, followed by a gradual rise to the present level without discernable fluctuations (Figure 14.10). The bend is based on boosted radiocarbon dates of found remains, peat, and shells of the Gomso Bay and other littoral areas. The paleo-mean bounding main level was determined nether the assumption that the tidal range (and frequency) and the bathymetric slopes were constant throughout the Holocene. The curve is similar to those given by Kim et al. (1999) and that of the Yangtze delta plain.

Based on radiocarbon dating on benthic foraminifera, Kim and Kennett (1998) have demonstrated that Holocene marine transgression started in the central Yellow Sea at about 11.3   ka and approached the present lower tidal apartment level most 7.5   ka. Based on shallow-marine, intertidal, and submerged terrestrial data of the East China Ocean, the Yellow Sea, and the Sunda shelf, Liu and Milliman (2004) take suggested a step-wise body of water-level curve for the western Pacific coast (Figure 14.eleven). It shows a series of rapid flooding events (as fast as 80   mm/yr) that were separated by long-term slow rises (2–10   mm/year).

Effigy 14.xi. A ocean-level curve showing the western Pacific mail service-glacial bounding main-level history suggested by Liu and Milliman (2004).

 Source: Chough et al. (2004) by permission of Geosciences Journal.

Recent measurements of sea level using tide gauges and satellites suggest that the curves over the past decades have been on the ascension, especially since the industrial revolution. With the explosive increase in human population and subsequent consumption of fossil fuels, greenhouse gases have begun to build up in the atmosphere, leading to global warming. Although the rate of body of water level ascent is dissimilar from place to identify, it is almost a few millimeters (3   mm on average) per year for the last decades around the globe (Pilkey and Immature, 2009). They suggest that some unstable parts of the globe can exist submerged at higher rate (1–2   m/100 years). Although the crust around the Korean Peninsula is tectonically stable, local erosion and deposition of sand and mud volition occur in the coastal area, specially along the artificial seawalls and dams, depending on the dominant coastal currents and storm waves. Besides, a large function of the coastlines effectually the peninsula will be submerged under water every bit deep as thirty   cm in 100 years. If this rate were constant in the next decades, property owners on the coastline and club in general would exist able to manage possible defect of the rising sea. The all-time way to cope with such gradual ecology change is, however, to prepare for retreat toward higher ground and pursue whatever merits the submerged lands may offer. The submerged ocean can be effectively used for fish and seaweed cultures and production of natural table salt also as for natural seashore parks.

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Teleconnections between the Indian summer monsoon and climate variability: a proxy perspective

S. Chakraborty , ... P.Chiliad. Mohan , in Indian Summer Monsoon Variability, 2021

7.4 Summary and recommendations

The Indian summertime monsoon has undergone pregnant variability in its intensity and pattern over the Holocene epoch. Several proxy records revealed a significant ascent in the monsoon atmospheric precipitation during the early on Holocene; simultaneously, it was characterized by substantial spatial heterogeneity. Subsequently, the ISM intensity weakened, believed to exist caused past a subtract in the solar insolation. However, proxy records likewise indicated a rise in La Niña events during this time, resulting in relatively enhanced rainfall than the late Holocene. An abrupt reduction in ISM intensity was observed at ∼8.2 ka, believed to be caused by a sharp cooling in the North Atlantic, indicating a strong connexion between ISM and North Atlantic climate. If global warming forces the Arctic ice sheets to melt at an accelerated pace, the resulting freshening of the N Atlantic may adversely affect the ISM intensity in the foreseeable time to come.

The mid-Holocene experienced ISM intensification, which is believed to have been modulated by the tropical Pacific SST variability. Afterwards, a progressive weakening of the ISM intensity was documented by various proxy records and climate model simulations. At the beginning of the last millennium, a moderate intensification of ISM activity was witnessed owing to increased solar activity. However, during the latter role of this millennium, proxy records indicated a pregnant reduction in ISM intensity attributable to increased ENSO episodes.

Though the proxy records take made a meaning contribution in enhancing our understanding of the ISM teleconnections to the global climate variables, they, nonetheless, suffer from some limitations. The proxies are non uniformly distributed, and the data are too sparse to capture the broad spectrum of the climate variability. An accurate chronology of the records is imperative to decipher the pb-lag characteristics of the climatic events. However, analytical uncertainties exert a limit in this endeavor. Although several proxy records have been generated with some success to reconstruct past shifts in the Indian summer monsoon; however, climate records established from individual proxy materials are inadequate and represent a smoothed indicate attributable to poor sample resolution and disability to decipher curt-term variations (Staubwasser, 2006). Individual proxies are unlikely to capture the various aspects of a natural event. Emile-Geay et al. (2021) opine that single sites provide only local-scale information; in order to capture the diverseness of ENSO'southward spatial footprint, multiple records must be analyzed to understand its total range of variability. Another issue is that any given site may not exist adequately teleconnected to a item event. In the Indian context, collection of speleothem samples are preferred from the monsoon core zone with a perception that this area would be near sensitive to external processes such as ENSO. But an objective analysis of the ISM and ENSO teleconnections (Mahendra et al., 2021) shows that the northern parts of cardinal India (approximately an area covering 74°N – 84°N, 26°E – 32°Eastward) is more than sensitive to ENSO processes. Hence, careful option of sample collection sites is a prerequisite to capture signals of the teleconnected processes. Similarly, they will assistance in identifying and quantifying the ascendant processes controlling ISM variability, which will guide future paleo-monsoon enquiry. High-resolution multiproxy records with well-constrained chronology integrated over the immense ocean and continental provinces coupled with global climate model simulations would likely provide a better agreement in this endeavor.

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The imprints of Holocene climate and environmental changes in the Due south Mahanadi Delta and the Chilika lagoon, Odisha, Republic of india—An overview

Siba Prasad Mishra , Kumar Chandra Sethi , in Holocene Climate change and Environment, 2022

19.4.two.two The shift of Indian summer monsoon

Three phases of moisture climate followed by three segments of dry conditions prevailed over India during Holocene epoch. The period from 11.7 to 9.i KYBP, 8.i to six.5 KYBP, and 6.35 to 5.00 KYBP were moisture periods, and the dry periods were noticed between 9.00 and 8.10 KYBP, half-dozen.650 and half-dozen.350 KYBP, and ∼5.00 and 4.00 KYBP. The residual of the periods were of normal years. During mid-Holocene, it was observed that there were migrations of monsoon activities from north Indian Ocean as there was shift in ITCZ from w to e. The civilizations those were built upwardly in west (Mohenjo-Daro, Harappa, etc.) and very big h2o bodies like Aral Sea accept become dried up and gradually desertification started in such areas.

Ali et al. (2018) reported about 5 positive and three negative shifts of ITCZ. The positive shifts were noticed since early Holocene. The first was observed toward finish of Younger Dryas (∼11.vii–11.4 KYBP), stable ISM betwixt ∼11 and 6 KYBP, and declining ISM betwixt 6 and 3 KYBP. During MWP and LIA periods, there was strong monsoon in Indian subcontinent. Still there were regional vicissitudes in ISM which were coupled with southward fluctuation in mean position of the ITCZ. During the LIA at that place was two depression solar irradiance period observed (90 years each). During the coldest years Spörer Minimum (1450–1540) and similarly the Maunder Minimum (1645–1715), the Chilika barrier spits were naturally constructed as there was sea level retrogression. The live glorious ports in coasts of the lagoon became dead or dormant.

The Holocene monsoon intensification transpired at 9.5 and nine.ane KYBP. Then monsoon debilitated gradually up to vii.0 KYBP in Bharat. Later the weak monsoon during post- and mid-Holocene periods was ∼8.0, 7.0, 5.5 and iii.v KYBP. There were significant periodicities of summertime monsoon during the latter part of Holocene (2.two, ane.half-dozen, i.35, 0.95, 0.75, 0.47, 0.32, 0.22, 0.156, 0.126, 0.113, 0.104, and 0.092 KYBP (Chauhan et al., 2010; Thamban et al., 2007).

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Neotectonism in the Indian Subcontinent

K.Southward. Valdiya , Jaishri Sanwal , in Developments in World Surface Processes, 2017

Active Faults: Cause and Manifestation

Faults that accept registered movement of any kind in the Quaternary Period, specially in the Late Pleistocene and Holocene epochs, abound in the very mobile Himalayan province. All major earthquakes that have rocked the province were related to these active faults. Indeed, the unabridged Himalaya province is tectonically the most resurgent function of the Indian subcontinent. Equally the Peninsular Bharat presses and pushes the Himalaya, the standing buildup of stress reactivates some of the older faults and thrusts. The transverse wrench faults non only serve every bit strain transfer zones but also every bit the loci of earthquakes. This is why the transverse tear faults (Figs iii.13 and 3.fifteen) are particularly more active, as borne out past the river response to tectonic movements. This is manifested by their intimate association with stream ponding in the past and the present, the dissonant deflection or fifty-fifty abandonment of their channels by rivers, and the development of very immature geomorphic features on fault planes (Valdiya, 1992, 1998b, 1999a,1999b, 2001b, 2005; Valdiya, Rana, Sharma, & Dey, 1992).

A few examples will suffice to bear witness that all the four latitudinal terranes of the Himalaya are neotectonically affected to various extents. In the post-obit pages, some well-described active faults are dealt with terrane-wise, beginning from the due north.

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Chief features of the Campos Bowl regional geology

Ricardo Defeo de Castro , João Paulo Picolini , in Geology and Geomorphology, 2016

3.3 Marine Sequence (Figure i)

The marine sequence corresponds to the Macaé and Campos groups (Ubatuba, Carapebus and Emborê formations) and contains sedimentary rocks from the Albian to Holocene epochs ( Winter et al., 2007). This sequence is the record of a thermal subsidence stage of the basin and open marine sedimentation, with restricted halokinesis during the Albian epoch. Starting from the Cenomanian stage, table salt movements get fundamental for the development of structural compartmentalization of the mail service-salt section, in addition to decisively influencing the sedimentation and the germination of petroleum structural traps (Dias et al., 1990).

The Macaé Group is positioned conformably on the Retiro Member evaporites and is divided into the Goitacás, Quissamã, Imbetiba and Outeiro formations. The Goitacás Formation represents the proximal environments characterized by the association of alluvial fans, fan deltas, lagoons and beaches. The northern surface area of the basin is dominated by alluvial fan deposits, which are made up of polymictic conglomerates and fine- and fibroid-grained sandstones, generally cemented by carbonate minerals. The southern bowl area is dominated by lagoonal deposits, which are characterized by calcilutites, fine-grained sandstones and pelites, in addition to embankment facies composed of fine- to medium-grained sandstones, typically stratified or laminated (Guardado et al., 1989).

The Quissamã Formation is the record of a carbonate system composed of low and high-energy facies. It presents an ecology zoning of the proximal surface area, characterized by rocks of mixed siliciclastic-carbonate limerick, to the distal expanse, where it developed a typical carbonate facies. The carbonate lithotypes include calcilutites with bioturbation, oolitic and oncolytic fine-to-coarse grained calcarenites, derived from carbonate bar and interbar systems, typically defining shallowing-upwardly cycles. Shales and marls characterize the most distal degradation of this carbonate sedimentation. The oolitic and oncolytic calcarenite deposited in shallow water banks are the primary hydrocarbon reservoirs of the Macaé Group.

The Outeiro Formation is stratigraphically positioned above the Quissamã Formation and occurs discordantly in the proximal area and concordantly in the distal area. The formation records siliciclastic-carbonate sedimentation consistent with a deeper sea. Its rocks nowadays a bottom-upwardly distribution composed of calcilutites that course into calcilutites intercalated with marl. Shales and marls boss the top of this formation. In that location are occurrences of microfossil ooze and moderate organic matter content, which are consistent with the progressive and sharp rise in the relative sea level and ameliorate water circulation with regards to the Quissamã Germination (Guardado et al., 1989).

There are sandstone bodies, originating from gravitational flows, interbedded with these fine-grained sediments. They are referred to every bit Namorado Sandstone and are of import hydrocarbon reservoirs. The occurrence of these turbidites shows an increase of the platform subsidence and consequent increase in the common salt movement that characterizes the evolution of the basin from the Cenomanian onwards (Dias et al., 1990; Saved et al., 1989).

The Campos Grouping, which is composed of rocks deposited in proximal environments (Emborê Formation), distal marine environments (Ubatuba Germination) and turbidite deposits (Carapebus Formation), is superimposed on the Macaé Grouping rocks. The occurrence of these turbidites is due to falls of relative sea level, mayhap associated with: a) tectonic reactivation of the basement, with crustal cake movements in the Serra do Mar area, b) thermal subsidence of the bowl, c) the creation of conduits and minibasins associated to the salt movements and d) global eustatic variations (Dias et al., 1990).

The passage from the Macaé Group to the Campos Group, 93   Grand.A. ago, is characterized by erosive unconformity distinctly marked throughout most of the basin, especially in the proximal areas (Dias et al., 1990; Guardado et al., 1989).

The Emborê Germination is characterized by polymictic conglomerates and fibroid sandstones typical of alluvial fan deposits, in addition to beach sandstones, generally fine- to medium-grained, with cross-bedding and lamination marked past heavy minerals. In the paleoshelf border positions, a carbonate platform called Membro Siri was developed and formed past banks of cerise algae with a predominance of bioclastic calcirudites.

The Ubatuba Germination is characterized past fine-grained deposits typical of hemipelagic sedimentation, including shales and marls, which are rich in foraminifera and calcareous nannofossils and highly used in the dating of the main intervals of the basin.

The Carapebus Formation corresponds to sandy submarine sediments deposited from gravitational sediment fluxes (Middleton and Hampton, 1976), mainly turbidites. The thickness of such deposits ranges from a few tens to hundreds of meters. The texture of the clastic sediments ranges from conglomerates to very fine-grained sandstones, commonly associated with muddy sediments (pelagic/hemipelagic and/or low density diluted turbulent currents), with subordinate landslide and debris flow deposits (Guardado et al., 1989). They develop submarine channels complexes formed past sets of amalgamated or spatially segregated channels (Moraes et al., 2006). The channel complexes are commonly confined in canyons and/or elongated troughs (tectonic, erosive, among others). In regions with a pregnant reduction in slope, such as in minibasins, or when sediments reach the ocean floor beyond the External Loftier, the development offspill complexes is common, confined or concluding, which are dominated by distributary channels or lobes (Oliveira et al., 2012). Bottom-electric current reworking complexes occur in subordinate ways, and generally tend to form interlaminated, often muddy and highly bioturbated intervals (Moraes et al., 2007). The fourth dimension interval that encompasses these sediments extends from the Late Cretaceous, when deep h2o weather were established, to the present. The Carapebus Formation encompasses the Campos Basin's main hydrocarbon reservoirs, including the giant fields of Roncador, Albacora, Albacora Leste, Barracuda and the Marlim complex, which includes the Marlim, Marlim Sul and Marlim Leste fields (Bruhn et al., 2003).

During the Late Miocene, a thick prograding wedge, consisting of deepwater marls and shales, adult in the central portion of the Campos Bowl, giving this region the convex profile that characterizes its current physiography. Souza Cruz (1995) attributed the development of this wedge to the deportment of lesser currents, conditioned by the climatic and paleoceanographic changes that accompanied the glaciation of Antartica.

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AMERICAS, North | California and the Sierra Nevada

Michael R. Walsh , in Encyclopedia of Archaeology, 2008

Early Holocene Diversification

At the close of the Pleistocene, warmer temperatures and decreased precipitation led to desiccation of ancient lakes and widespread extinction of megafauna. This begins the Early Holocene epoch, in which native Californians diversified their lifestyle in accordance with pocket-sized differences in local ecology weather condition. While archaeological assemblages suggest continued accent on hunting of large modern mammals, diet diversified to include increasing amounts of regionally distinctive plant foods, smaller mammals, and small-scale amounts of freshwater and marine shellfish. Increased numbers of sites, as well every bit discovery of express-employ sites, advise a highly mobile lifestyle, probably of minor family groups foraging far and broad over the grade of the twelvemonth, rarely returning to the same location twice.

Among the all-time known of these Early Holocene cultures are the San Diegito who plied the coastal regions, hills, valleys and deserts of southern California between near 7000–8000 and 10   000   BP. Large, coarse stone knives and projectile points advise continued emphasis on large mammals such every bit deer; but os assemblages from San Diegito sites suggest greatly increased hunting of small mammals, specially rabbits. Additional rough stone implements include drills and engraving tools, mayhap used to work bone or wood. Although bone tools are not feature of San Diegito sites until the afterwards stages of the era, wooden objects are non expected to preserve, and may take been nowadays throughout the time frame. The potential for wooden tools, too every bit a wide variety of heavy scraping and chopping tools, hints at increased levels of plant exploitation, or something more than than focused butchering of game. Past the cease of the San Diegito Period, grinding implements of stone (manos, metates) appeared, suggesting expansion of the nutrition to include hard seeds; bone awls indicate basket-making, a craft probably designed to assist in gathering plant foods; and the San Diegito expanded their diet to include small quantities of marine shellfish. In all, the San Diegito entered the time frame equally focused hunters of big game and exited as generalized hunter-gatherers. The expansion of habitat and dietary breadth was probably encouraged by, and in turn permissive of, steady population growth despite what was, from the Clovis perspective at least, a deteriorated environment.

Synonyms for the San Diegito fourth dimension frame include the statewide designations Early Holocene, Early Archaic, and the Western Pluvial Lakes Tradition; the Lake Mojave Tradition of the deserts; Buena Vista of the Key Valley; and the Borax Lake (Post) Pattern of northern California.

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BEETLE RECORDS | Postglacial Europe

P. Ponel , in Encyclopedia of Quaternary Science (Second Edition), 2013

Climatic Context

The Quaternary is marked by a climatic cyclicity of cold and warm periods (glacial–interglacial), and by the appearance and evolution of humans. The Postglacial or Holocene Epoch that started about xi  000 years ago is the concluding warm period of the Quaternary (the current interglacial) and can be considered an approximate replica of the penultimate interglacial, the Eemian (130   000–110   000 BP). The Holocene interglacial has been deeply affected by human being touch on natural ecosystems, peculiarly in its 2nd half. The glaciation that immediately preceded the Holocene is biologically important since glacial conditions that prevailed at that time (60   000–15   000 BP) eradicated most of temperate biota from Fundamental and Northern Europe, including insects, which were relegated to temperate refugia (probably located in Mediterranean peninsulas). The insect recolonization of Europe induced past the Holocene warming is the result of the northwards shift of biota from these southern 'reservoirs.' Far from beingness a steady process, the transition from the last glaciation to the current interglacial, approximately fifteen   000 and 10   000 BP, was marked by a complex series of sharp warm and common cold events. This period of climatic instability, commonly named the Late Glacial, includes a first climatic warming between xv   000 and thirteen   000 BP (the Oldest Dryas), a predominantly warm period betwixt xiii   000 and 10   700 BP, the Late Glacial interstadial, and a short but drastic climatic cooling between ten   700 and 10   300 BP (the Younger Dryas). The Late Glacial is particularly well documented from protrude records (Coope, 1994), and 1 of the major achievements of Quaternary Entomology is the demonstration of the amazing rapidity of the Late Glacial warming at 13   000 BP, since mean July temperatures in Britain rose by almost 1   °C per decade (for a total of most 7   °C), and corresponding winter temperatures rose past about twenty   °C (Atkinson et al., 1987). Following the second episode of rapid warming (by x   000 BP), temperate climate weather prevailed during about of the Holocene.

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PALEOCEANOGRAPHY, RECORDS | Postglacial Indian Body of water

P.D. Naidu , in Encyclopedia of Quaternary Science (2nd Edition), 2013

Solar activity

There is sound bear witness that the intensity of the summer monsoon has fluctuated dramatically in the by, varying with precessional changes in the distribution of solar radiations reaching the earth. The Holocene epoch has spanned one-half of precessional cycle. During this fourth dimension the Northern Hemisphere has changed from having maximum seasonality approximately 11  ka BP, when the summer solstice was aligned with perihelion, to a minimum today. The tropical seasonal monsoons are highly influenced past precessional variations in insolation, resulting in a wetter tropical climate equally monsoon intensity increases. Furthermore, variation of solar output has been suggested as the driver of both the North Atlantic cycles (Bond et al., 2001) and the variation of monsoon precipitation in Oman (Neff et al., 2001). Intensity of the Indian monsoon is found to have decreased during periods of solar minima during the last millennium suggesting solar control on the Indian monsoon on multidecadal time scale (Agnihotri et al., 2002).

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