Thursday, June 17, 2021

Evidence Of Agriculture In The Amazon Ca. 1500 BCE

Some of the least well understood prehistoric cultures of the Americas are the sedentary food producing cultures of the Amazon river basin in South America, much of which is marsh and jungle now, and some of which was transformed into a savanna landscape when European cattle ranchers cleared the forest for this purpose. 

This farming and fish farming culture existed from at least 1500 BCE to 300 CE in the region.

The University of Central Florida's press release regarding a new paper notes that:
[P]re-Columbian people of a culturally diverse but not well-documented area of the Amazon in South America significantly altered their landscape thousands of years earlier than previously thought. . . . [There is] evidence of people using fire and improving their landscape for farming and fishing more than 3,500 years ago. This counters the often-held notion of a pristine Amazon during pre-Columbian times before the arrival of Europeans in the late 1400s. The study . . . also provides mores clues to the past of the diverse, but not well-documented, cultures that live in the area known as the Llanos de Mojos in northeastern Bolivia.

"This region has one the highest diversity of languages in the world, which reflects distinct ways of life and cultural heritage," says study co-author John Walker, an associate professor in UCF's Department of Anthropology. "We know something about the last 3,000 to 4,000 years of, say Europe or the Mediterranean, but we don't have some of that same information for the people here. That makes this an incredible story waiting to be written.". . . 

The flat, wetland landscape of the Llanos de Mojos is used for cattle ranching today, but archaeologists have noted for years the evidence from remnants of pre-Columbian raised fields and fish weirs for aquaculture. These remnants indicated the land was once used instead for farming and fishing. The archaeologists just didn't know when or how far back in time these activities started -- until now.

Previous research pointed to a date of about 300 C.E., or about 1,700 years ago. However, the new study combined expertise from multiple disciplines, such as anthropology, paleoethnobotany and paleoecology, to indicate that intensive land management started much earlier, at about 1,500 B.C.E, or about 3,500 years ago.

"This finding is important because it provides evidence that the Amazon is not a pristine wilderness but has been shaped and designed by indigenous people thousands of years before the Spanish arrived," Walker says.

This is new information for both the history of the cultures of the Amazon, which have not been studied as much as other cases, like the Mayas or Incas, and for the area, which is often thought of as an untouched world before the arrival of the Spanish.

Neil Duncan, the study's lead author . . . extracted two, five-foot long cores of earth from two locations about 13 miles apart in the Llanos de Mojos. By examining these cores, Duncan found corn and squash phytoliths dating as early as 1380 B.C.E and 650 B.C.E, or about 3,000 years ago. Phytoliths are microscopic silica particles from plant tissue, and the findings suggest these were crops grown in the numerous raised fields that dot the area. . . .

Both cores showed similar trends of initial dry conditions in the oldest layers of earth, followed by increased wet conditions and increased use of wood burning, as evidenced by the presence of high diatom concentrations and charcoal concentrations, respectively. The researchers say wood burning could be for cooking, pottery, warmth and more. . . .

"The intensification of plant, fire and water management occurred at the same time, which emphasizes how farming or fishing were equally important to the people of the region," . . .

Also of note is that the shifts in the two cores to more intensive land management happened at different periods, the researchers say.

One core, known as the Mercedes core, showed the shift to wetter conditions and increased fire use starting at 1,500 B.C.E, or about 3,500 years ago. The other, extracted from a location about 13 miles farther south and known as the Quinato-Miraflores core, showed the shift occurring at about 70 B.C.E., or about 2,100 years ago.

Since broadscale climate changes would have affected both areas at the same time, the time difference between the two cores suggests humans were purposefully engineering the land, including draining water in some areas, retaining it in others, and using trees for fuel.

"So, what's happening in the landscape is that that it's becoming wetter, and we think that some of those trees are being flooded out and so they're not as well represented," Duncan says. "And if things are getting wetter then we shouldn't see more charcoal. So, the interpretation is that we would only see these high amounts of charcoal if it's humans doing some very intentional and intensive burning."

The paper and its abstracts are as follows:


The Chavín, Moche, Tiwanaku, and Inka are well-known pre-Columbian cultures, but during the same time, in the southwestern Amazon, people were transforming a 100,000-km2 landscape over thousands of years. The extent of earthworks in the Llanos de Mojos has become clear since the 1960s, but dating these features has been difficult. We show that pre-Columbian people used hydrological engineering and fire to maximize aquatic and terrestrial resources beginning at least 3,500 years ago. 
In the 17th century CE, cattle and new technologies brought by Jesuit missions altered the form and function of these landscapes. 
The scale and antiquity of these Amazonian earthworks demand comparison with domesticated landscapes and civilizations from around the world.


In landscapes that support economic and cultural activities, human communities actively manage environments and environmental change at a variety of spatial scales that complicate the effects of continental-scale climate. 
Here, we demonstrate how hydrological conditions were modified by humans against the backdrop of Holocene climate change in southwestern Amazonia. 
Paleoecological investigations (phytoliths, charcoal, pollen, diatoms) of two sediment cores extracted from within the same permanent wetland, ∼22 km apart, show a 1,500-y difference in when the intensification of land use and management occurred, including raised field agriculture, fire regime, and agroforestry. Although rising precipitation is well known during the mid to late Holocene, human actions manipulated climate-driven hydrological changes on the landscape, revealing differing histories of human landscape domestication. 
Environmental factors are unable to account for local differences without the mediation of human communities that transformed the region to its current savanna/forest/wetland mosaic beginning at least 3,500 y ago. Regional environmental variables did not drive the choices made by farmers and fishers, who shaped these local contexts to better manage resource extraction. 
The savannas we observe today were created in the post-European period, where their fire regime and structural diversity were shaped by cattle ranching.


neo said...

worth mention

The most accurate distance measurement yet of ultra-diffuse galaxy (UDG) NGC1052-DF2 (DF2) confirms beyond any shadow of a doubt that it is lacking in dark matter. The newly measured distance of 22.1 +/-1.2 megaparsecs was obtained by an international team of researchers led by Zili Shen and Pieter van Dokkum of Yale University and Shany Danieli, a NASA Hubble Fellow at the Institute for Advanced Study.

This research has generated a great deal of scholarly interest, as well as energetic debate among proponents of alternative theories to dark matter, such as modified newtonian dynamics (MOND). However, with the team's most recent findings—including the relative distances of the two UDGs to NGC1052—such alternative theories seem less likely. Additionally, there is now little uncertainty in the team's distance measurements given the use of the TRGB method. Based on fundamental physics, this method depends on the observation of red giant stars that emit a flash after burning through their helium supply that always happens at the same brightness.

maybe Mond problems are piling up

andrew said...

The paper:
[Submitted on 20 Aug 2019 (v1), last revised 7 Dec 2019 (this version, v2)]
Modified Gravity Theories in Light of the Anomalous Velocity Dispersion of NGC1052-DF2
Tousif Islam, Koushik Dutta
Recent observations of ultra-dwarf galaxy NGC1052-DF2 started an interesting discussion between dark matter hypothesis and modified gravity theories. Reported low velocity dispersion (< 10.5 km/s at 90% confidence level) derived from the kinematic data of 10 globular clusters in the galaxy points towards an extraordinarily low dynamical mass (∼ 3.4×108M⊙) which is of the same order of the luminous mass (∼ 2.0×108M⊙) in the galaxy. This has been interpreted as the first evidence of a galaxy `without Dark Matter'. It has been argued that dark matter is not necessarily coupled to the the baryonic mass on the galactic scale and poses a challenge to modified gravity theories. We explore the dynamics of NGC1052-DF2 within the context of four popular alternative theories of gravity [Modified Newtonian Dynamcies (MOND), Weyl Conformal gravity, Modified gravity (MOG)/Scalar-Tensor-Vector Gravity (STVG) and Verlinde's Emergent gravity] and present the analysis of detailed radial variation of the velocity dispersion. We demonstrate that the dispersion data of NGC1052-DF2 is fully consistent with modified gravity paradigm (as well as with general relativity without dark matter). We reach similar conclusion for the ultra-dwarf NGC1052-DF4 which has been claimed to be the second candidate for galaxies `without Dark Matter'.
[Submitted on 27 Mar 2019]
Does the galaxy NGC1052-DF2 falsify Milgromian dynamics?
Pavel Kroupa (Bonn, Prague), Hosein Haghi (Zanjan), Behnam Javanmardi (Tehran), Akram Hasani Zonoozi (Bonn, Zanjan), Oliver Mueller (Basel), Indranil Banik (St. Andrews), Xufen Wu (Hefei), Hongsheng Zhao (St.Andrews, Amsterdam), Joerg Dabringhausen (Prague)
A great challenge in present-day physics is to understand whether the observed internal dynamics of galaxies is due to dark matter matter or due to a modification of the law of gravity. Recently, van Dokkum et al. reported that the ultra-diffuse dwarf galaxy NGC1052-DF2 lacks dark matter, and they claimed that this would -- paradoxically -- be problematic for modified gravity theories like Milgromian dynamics (MOND). However, NGC1052-DF2 is not isolated, so that a valid prediction of its internal dynamics in MOND cannot be made without properly accounting for the external gravitational fields from neighbouring galaxies. Including this external field effect following Haghi et al. shows that NGC1052-DF2 is consistent with MOND.
Comments: 15 pages, including supplementary information (the external field formulae), published by Nature: this https URL
Subjects: Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc)
Cite as: arXiv:1903.11612 [astro-ph.GA]
(or arXiv:1903.11612v1 [astro-ph.GA] for this version)

andrew said...
[Submitted on 11 Apr 2018]
MOND and the dynamics of NGC1052-DF2
B. Famaey, S. McGaugh, M. Milgrom
The dwarf galaxy NGC1052-DF2 has recently been identified as potentially lacking dark matter. If correct, this could be a challenge for MOND, which predicts that low surface brightness galaxies should evince large mass discrepancies. However, the correct prediction of MOND depends on both the internal field of the dwarf and the external field caused by its proximity to the giant elliptical NGC1052. Taking both into consideration under plausible assumptions, we find σMOND=13.4+4.8−3.7kms−1. This is only marginally higher than the claimed 90\% upper limit on the velocity dispersion (σ<10.5kms−1), and compares well with the observed root mean square velocity dispersion (σ=14.3kms−1). We also discuss a few caveats on both the observational and theoretical side. On the theory side, the internal virialization time in this dwarf may be longer that the time scale of variation of the external field. On the observational side, the paucity of data and their large uncertainties call for further analysis of the velocity dispersion of NGC1052-DF2, to check whether it poses a challenge to MOND or is a success thereof.
Comments: 4 pages. Submitted to MNRAS
Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
DOI: 10.1093/mnras/sty1884
Cite as: arXiv:1804.04167 [astro-ph.GA]
(or arXiv:1804.04167v1 [astro-ph.GA] for this version)
[Submitted on 13 May 2018 (v1), last revised 15 May 2018 (this version, v2)]
Reply to the claim by van Dokkum et al. for a galaxy not containing dark matter
Riccardo Scarpa, Xavier Hernandez, Ricardo Adan Cortes Martin, Renato Falomo, Martin Lopez-Corredoira
The following is a short comment on the recent claim made by van Dokkum and collaborators about the existence of a low surface brightness galaxy, NGC1052-DF2, not containing dark matter. A discovery used by the authors to both reject proposals of a failure of Newtonian dynamics in the low acceleration regime (e.g., MOND), and prove the dark matter hypothesis is correct. It is shown here that the claim in untenable.
Comments: Three pages, no figures
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:1805.04817 [astro-ph.GA]
(or arXiv:1805.04817v2 [astro-ph.GA] for this version)

andrew said...
[Submitted on 7 Jun 2019]
A new formulation of the external field effect in MOND and numerical simulations of ultra-diffuse dwarf galaxies − application to NGC 1052-DF2 and NGC 1052-DF4
Hosein Haghi, Pavel Kroupa, Indranil Banik, Xufen Wu, Akram Hasani Zonoozi, Behnam Javanmardi, Amir Ghari, Oliver Müller, Jörg Dabringhausen, Hongsheng Zhao
The ultra-diffuse dwarf galaxy NGC 1052-DF2 (DF2) has ten (eleven) measured globular clusters (GCs) with a line-of-sight velocity dispersion of σ=7.8+5.2−2.2km/s (σ=10.6+3.9−2.3km/s). Our conventional statistical analysis of the original ten GCs gives σ=8.0+4.3−3.0km/s. The overall distribution of velocities agrees well with a Gaussian of this width. Due to the non-linear Poisson equation in MOND, a dwarf galaxy has weaker self-gravity when in close proximity to a massive host. This external field effect is investigated using a new analytic formulation and fully self-consistent live N-body models in MOND. Our formulation agrees well with that of Famaey and McGaugh (2012). These new simulations confirm our analytic results and suggest that DF2 may be in a deep-freeze state unique to MOND. The correctly calculated MOND velocity dispersion agrees with our inferred dispersion and that of van Dokkum et al. (2018b) if DF2 is within 150 kpc of NGC 1052 and both are 20 Mpc away. The GCs of DF2 are however significantly brighter and larger than normal GCs, a problem which disappears if DF2 is significantly closer to us. A distance of 10-13 Mpc makes DF2 a normal dwarf galaxy even more consistent with MOND and the 13 Mpc distance reported by Trujillo et. al. (2019). We discuss the similar dwarf DF4, finding good agreement with MOND. We also discuss possible massive galaxies near DF2 and DF4 along with their distances and peculiar velocities, noting that NGC 1052 may lie at a distance near 10 Mpc.
Comments: 14 pages, 9 figures, 2 Tables, accepted for publication in MNRAS
Subjects: Astrophysics of Galaxies (astro-ph.GA)
DOI: 10.1093/mnras/stz1465
Cite as: arXiv:1906.03268 [astro-ph.GA]
(or arXiv:1906.03268v1 [astro-ph.GA] for this version)

neo said...

we have a warzone here reminds me of strings vs lqg

DDeden said...

neo said...

The center of the Milky Way could be dark matter instead of a supermassive black hole, according to a new study.

The study is based on observations of the objects that orbit closest to the center.

andrew said...

The full paper in the tweet that DDeden called attention to:

Human-food feedback in tropical forests
Bernardo M. Flores, Carolina Levis

Science 11 Jun 2021:
Vol. 372, Issue 6547, pp. 1146-1147
DOI: 10.1126/science.abh1806

andrew said...

The image at the link is quite convincing:

The theoretical explanation offered, no so much, as I think I've discussed previously somewhere in a comment at this blog.

andrew said...

The main paper that the Yahoo story discusses is this open access one:

The motion of S-stars around the Galactic center implies that the central gravitational potential is dominated by a compact source, Sagittarius A* (Sgr A*), which has a mass of about 4 × 106 M⊙ and is traditionally assumed to be a massive black hole (BH). The explanation of the multiyear accurate astrometric data of the S2 star around Sgr A*, including the relativistic redshift that has recently been verified, is particularly important for this hypothesis and for any alternative model. Another relevant object is G2, whose most recent observational data challenge the scenario of a massive BH: its post-pericenter radial velocity is lower than expected from a Keplerian orbit around the putative massive BH. This scenario has traditionally been reconciled by introducing a drag force on G2 by an accretion flow. As an alternative to the central BH scenario, we here demonstrate that the observed motion of both S2 and G2 is explained in terms of the dense core – diluted halo fermionic dark matter (DM) profile, obtained from the fully relativistic Ruffini-Argüelles-Rueda (RAR) model. It has previously been shown that for fermion masses 48−345 keV, the RAR-DM profile accurately fits the rotation curves of the Milky Way halo. We here show that the solely gravitational potential of such a DM profile for a fermion mass of 56 keV explains (1) all the available time-dependent data of the position (orbit) and line-of-sight radial velocity (redshift function z) of S2, (2) the combination of the special and general relativistic redshift measured for S2, (3) the currently available data on the orbit and z of G2, and (4) its post-pericenter passage deceleration without introducing a drag force. For both objects, we find that the RAR model fits the data better than the BH scenario: the mean of reduced chi-squares of the time-dependent orbit and z data are ⟨χ̄2⟩S2,RAR ≈ 3.1 and ⟨χ̄2⟩S2,BH ≈ 3.3 for S2 and ⟨χ̄2⟩G2,RAR ≈ 20 and ⟨χ̄2⟩G2,BH ≈ 41 for G2. The fit of the corresponding z data shows that while for S2 we find comparable fits, that is, χ̄2z,RAR ≈ 1.28 and χ̄2z,BH ≈ 1.04, for G2 the RAR model alone can produce an excellent fit of the data, that is, χ̄2z,RAR ≈ 1.0 and χ̄2z,BH ≈ 26. In addition, the critical mass for gravitational collapse of a degenerate 56 keV-fermion DM core into a BH is ∼ 108 M⊙. This result may provide the initial seed for the formation of the observed central supermassive BH in active galaxies, such as M 87.

The basic issue is that letting one outlier point drive your entire analysis isn't solid.

ramones1986 said...

Here's what I've thought: Could these discoveries within the Amazon basin find a clue on the origins of the (spoken)languages spoken there like Tupian and Macro-Jê?

andrew said...

@ramones1986 Certainly. That is very plausible.

ramones1986 said...